Journal articles: '13C NMR spectrum'

1

Buchanan, G. W., A. B. Driega, A. Moghimi, C. Bensimon, and K. Bourque. "cis-Cyclohexano-9-crown-3 ether. Solid state and low-temperature solution stereochemistry as determined by X-ray crystallography and nuclear magnetic resonance spectroscopy." Canadian Journal of Chemistry 71, no. 7 (1993): 951–59. http://dx.doi.org/10.1139/v93-127.

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The X-ray crystal structure of the title material has been determined at −130 °C. Low-temperature 1H1H COSY, 13C1H HETCOR, and DEPT 13C NMR spectra have been recorded, which permit unambiguous assignments of all carbon resonances when ring inversion is slow on the NMR timescale. The limiting low-temperature solution phase 13C spectrum has many common features with the solid phase 13C CPMAS spectrum recorded at 300 K. Spectra for the 7,10-tetra-deuterio derivative have also been obtained and substituent influences on 13C shieldings are discussed in detail.

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Saito, Takayuki, Seiichi Kawahara, and Yoshito Ohtake. "ASSIGNMENT OF NMR SIGNALS FOR CHLOROPRENE RUBBER BY TWO-DIMENSIONAL NMR SPECTROSCOPY." Rubber Chemistry and Technology 86, no. 2 (2013): 250–60. http://dx.doi.org/10.5254/rct.13.87981.

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ABSTRACT Various pulse techniques of NMR spectroscopy were applied to CR to assign some small signals in 13C and 1H NMR spectra for the rubber. First, the rubber was subjected to distortionless enhancement by polarization transfer and attached proton test. The small signals in the 13C NMR spectrum were assigned to secondary, tertiary, and quaternary carbons. Second, correlations between 13C and 1H were investigated by heteronuclear multiple quantum correlation, heteronuclear two bond correlation, and heteronuclear multiple bond correlation measurements to assign the small signals in the 13C NMR spectrum in detail. By using the resulting correlations between 13C and 1H, the small unassigned signals in 1H NMR spectrum were assigned to methylene and methine protons of the rubber.

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JURS, P. C., J. W. BALL, L. S. ANKER, and T. L. FRIEDMAN. "ChemInform Abstract: 13C NMR Spectrum Simulation." ChemInform 23, no. 47 (2010): no. http://dx.doi.org/10.1002/chin.199247272.

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Elguero, José, Alain Fruchier, María Luisa Jimeno, and Pedro Molina. "An Experimental Study of the 4hJ(31P–31P) Coupling Constant and the 12C/13C Isotope Effect on 31P in an Iminophosphorane-Substituted Proton Sponge." Journal of Chemical Research 2002, no. 1 (2002): 34–36. http://dx.doi.org/10.1177/1747519802200200103.

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The 13C NMR spectra of the bromide of the protonated iminophosphorane -substituted sponge 7 were recorded at different fields. Together with the use of 13C satellites of the 31P NMR spectrum, these experiments allow determination of a reasonable set of chemical shifts and coupling constants. The most interesting are a 4h JPP = 1.6 Hz, determined directly from the 31P NMR spectrum, which probably involves the hydrogen bond, and a 2Δ31P(13C) isotope shift of 9 ppb.

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ARSHAD, M. A., J. A. RIPMEESTER, and M. SCHNITZER. "ATTEMPTS TO IMPROVE SOLID STATE 13C NMR SPECTRA OF WHOLE MINERAL SOILS." Canadian Journal of Soil Science 68, no. 3 (1988): 593–602. http://dx.doi.org/10.4141/cjss88-057.

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This study describes a number of different preparation techniques for recording solid state 13C NMR spectra of whole mineral soils. Removal of paramagnetic Fe3+ improves the quality of 13C NMR spectra of whole soils and of particle size fractions. The C:Fe ratio appears to be an important indicator for obtaining satisfactory 13C NMR spectra of whole soils and fractions separated from them. If the C:Fe ratio is >> 1, the quality of the spectrum will be good; if the ratio is > 1, a reasonable spectrum will be obtained, but if the ratio is < 1, the spectrum will be poor. Organic-matter-rich soil and particle size fractions separated by a flotation technique produce well-defined 13C NMR spectra, typical of humic materials. Reduction of C-enriched fractions with sodium dithionite and stannous chloride improves the spectral resolution. The data presented herein show that satisfactory solid state 13C NMR spectra can be run on untreated soil particle size fractions, non-magnetic portions of whole soils, and fractions enriched in soil organic matter by flotation, especially after chemical reduction. Key words: 13C NMR spectroscopy, paramagnetic mineral separation

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Aoki, Dan, Kenta Nomura, Masashi Hashiura, et al. "Evaluation of ring-5 structures of guaiacyl lignin in Ginkgo biloba L. using solid- and liquid-state 13C NMR difference spectroscopy." Holzforschung 73, no. 12 (2019): 1083–92. http://dx.doi.org/10.1515/hf-2019-0011.

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Abstract To discuss the macromolecular structure and properties of lignin, the complementary use of solid- and liquid-state nuclear magnetic resonance (NMR) combined with a specific 13C-enrichment technique may provide useful information. The 13C-enriched lignin was prepared by administering [guaiacyl ring-5(G5)-13C]-coniferin to a growing Ginkgo biloba L. shoot. The 13C-enriched cellulolytic enzyme lignin (EL) and its acetate prepared from the ginkgo shoot were examined by solid- and liquid-state 13C NMR spectroscopy. The 13C NMR spectrum derived only from the G5 carbon was obtained as a difference spectrum based on the spectra of the G5-13C enriched and un-enriched (UE) samples. The condensed structures, including the enriched G5-carbon, were evaluated using difference spectra. The chemical shifts of the enriched G5 carbon in both the solid- and liquid-state 13C NMR spectra agreed with each other in principle. The quantitative ratio of the condensed and uncondensed structures at G5 was found to be larger by solid-state cross polarization/magic angle spinning (CP/MAS) NMR than by liquid-state NMR.

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Robinson, Alastair, Peter Richardson, and Meghan Halse. "Hyperpolarised 1H–13C Benchtop NMR Spectroscopy." Applied Sciences 9, no. 6 (2019): 1173. http://dx.doi.org/10.3390/app9061173.

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Benchtop NMR spectrometers with sub-ppm spectral resolution have opened up new opportunities for performing NMR outside of the standard laboratory environment. However, the relatively weak magnetic fields of these devices (1–2 T) results in low sensitivity and significant peak overlap in 1H NMR spectra. Here, we use hyperpolarised 13C{1H} NMR to overcome these challenges. Specifically, we demonstrate the use of the signal amplification by reversible exchange (SABRE) parahydrogen-based hyperpolarisation technique to enhance the sensitivity of natural abundance 1D and 2D 13C{1H} benchtop NMR spectra. We compare two detection methods for SABRE-enhanced 13C NMR and observe an optimal 13C{1H} signal-to-noise ratio (SNR) for a refocused INEPT approach, where hyperpolarisation is transferred from 1H to 13C. In addition, we exemplify SABRE-enhanced 2D 13C benchtop NMR through the acquisition of a 2D HETCOR spectrum of 260 mM of 4-methylpyridine at natural isotopic abundance in a total experiment time of 69 min. In theory, signal averaging for over 300 days would be required to achieve a comparable SNR for a thermally polarised benchtop NMR spectrum acquired of a sample of the same concentration at natural abundance.

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Orendt, Anita M., Julio C. Facelli, Juliusz G. Radziszewski, W. James Horton, David M. Grant, and Josef Michl. "13C Dipolar NMR Spectrum of Matrix-Isolatedo-Benzyne-1,2-13C2." Journal of the American Chemical Society 118, no. 4 (1996): 846–52. http://dx.doi.org/10.1021/ja953417r.

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9

Uhrín, Duan, A. V. Krishna Prasad, Jean-Robert Brisson, and David R. Bundle. "Carbohydrate-antibody interactions by NMR for a 13C-labelled disaccharide ligand." Canadian Journal of Chemistry 80, no. 8 (2002): 904–7. http://dx.doi.org/10.1139/v02-063.

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Incorporation of a 13C label into a carbohydrate ligand, methyl 3-O-(3,6-dideoxy-α-D-xylohexopyranosyl)-2-O-methyl-α-D-mannopyranoside permitted by NMR spectroscopy the study of its binding to the Fab from a monoclonal antibody, Se 155-4. The signals of the free and bound form were observed in the 13C spectrum of the carbohydrate-protein complex. The dissociation rate constants were consequently determined by full lineshape analysis of the 13C spectrum. Comparison with simplified analyses relying only on the linewidth of the 1H and 13C signals of the free ligand were made and the justifications of underlying assumptions used in these analyses were discussed. For 1H NMR, the protein resonances were purged with a 13C filter to observe only the ligand resonances and NOEs between the ligand and the protein.Key words: carbohydrate, binding, NMR, C-13 label, chemical exchange.

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10

Takeuchi, Yoshito, Yoko Imafuku, and Miki Nishikawa. "Reassignment of the 13C NMR spectrum of minomycin." Arkivoc 2003, no. 15 (2003): 39–46. http://dx.doi.org/10.3998/ark.5550190.0004.f06.

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11

Buchanan, G. W., M. F. Rastegar, G. PA Yap, A. Moghimi, and M. Ghandi. "Oxidative coupling of naphtho-9-crown-3 ether: X-ray crystal structure and solution and solid-state NMR analysis of the dimer." Canadian Journal of Chemistry 79, no. 10 (2001): 1505–10. http://dx.doi.org/10.1139/v01-166.

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Treatment of naphtho-9-crown-3 ether with FeCl3 and aqueous H2SO4 generates bis-naphtho-9-crown-3 ether in ca. 30% yield. This compound crystallizes in the monoclinic P21/n space group; a = 9.2004(9), b = 18.0868(17), and c = 13.2078(13) Å, β = 97.799(2)° and Z = 4. 1H and 13C NMR data have been obtained in solution, and the solid-state 13C NMR spectrum is included for comparison. A chemical shift range of ca. 12 ppm has been found for the oxygenated aliphatic carbons in the solid state, in contrast to the 3 ppm range in the solution 13C NMR spectrum. These results are discussed in terms of the torsional environments of the carbon sites in the crystal structure.Key words: crown ether, stereochemistry, oxidative dimerization.

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12

van der Velden, G. P. M., and J. Kelm. "Quantitative Analysis of Vulcanized SBR/EPDM Diblends. Magic Angle Spinning 13C-NMR Experiments at 80°C." Rubber Chemistry and Technology 63, no. 2 (1990): 215–22. http://dx.doi.org/10.5254/1.3538252.

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Abstract A new quantitative expression has been derived in order to estimate the styrene-butadiene ratio from the 13C-NMR olefinic resonances. With the help of this expression, the cis-1,4, trans-1,4, vinyl-1,2, butadiene and styrene ratios could be determined. From the aliphatic region, subsequently, the ethylene and propylene contents could be determined and finally the SBR/EPDM blend ratio. From the 13C-solid-state-NMR spectrum, no evidence could be obtained for homo- or co-vulcanization. The 13C-NMR spectra of the blends are simply a co-addition of the 13C-NMR solution spectra of SBR and EPDM rubbers. No evidence has been found for cis-1,4/trans-1,4 ratio changes for SBR (in comparison to the starting material).

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13

Jeffries, Rex E., Shawn M. Gomez, Jeffrey M. Macdonald, and Michael P. Gamcsik. "Direct Detection of Glutathione Biosynthesis, Conjugation, Depletion and Recovery in Intact Hepatoma Cells." International Journal of Molecular Sciences 23, no. 9 (2022): 4733. http://dx.doi.org/10.3390/ijms23094733.

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Nuclear magnetic resonance (NMR) spectroscopy was used to monitor glutathione metabolism in alginate-encapsulated JM-1 hepatoma cells perfused with growth media containing [3,3′-13C2]-cystine. After 20 h of perfusion with labeled medium, the 13C NMR spectrum is dominated by the signal from the 13C-labeled glutathione. Once 13C-labeled, the high intensity of the glutathione resonance allows the acquisition of subsequent spectra in 1.2 min intervals. At this temporal resolution, the detailed kinetics of glutathione metabolism can be monitored as the thiol alkylating agent monobromobimane (mBBr) is added to the perfusate. The addition of a bolus dose of mBBr results in rapid diminution of the resonance for 13C-labeled glutathione due to a loss of this metabolite through alkylation by mBBr. As the glutathione resonance decreases, a new resonance due to the production of intracellular glutathione-bimane conjugate is detectable. After clearance of the mBBr dose from the cells, intracellular glutathione repletion is then observed by a restoration of the 13C-glutathione signal along with wash-out of the conjugate. These data demonstrate that standard NMR techniques can directly monitor intracellular processes such as glutathione depletion with a time resolution of approximately < 2 min.

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Jeffries, Rex E., Shawn M. Gomez, Jeffrey M. Macdonald, and Michael P. Gamcsik. "Direct Detection of Glutathione Biosynthesis, Conjugation, Depletion and Recovery in Intact Hepatoma Cells." International Journal of Molecular Sciences 23, no. 9 (2022): 4733. http://dx.doi.org/10.3390/ijms23094733.

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Nuclear magnetic resonance (NMR) spectroscopy was used to monitor glutathione metabolism in alginate-encapsulated JM-1 hepatoma cells perfused with growth media containing [3,3′-13C2]-cystine. After 20 h of perfusion with labeled medium, the 13C NMR spectrum is dominated by the signal from the 13C-labeled glutathione. Once 13C-labeled, the high intensity of the glutathione resonance allows the acquisition of subsequent spectra in 1.2 min intervals. At this temporal resolution, the detailed kinetics of glutathione metabolism can be monitored as the thiol alkylating agent monobromobimane (mBBr) is added to the perfusate. The addition of a bolus dose of mBBr results in rapid diminution of the resonance for 13C-labeled glutathione due to a loss of this metabolite through alkylation by mBBr. As the glutathione resonance decreases, a new resonance due to the production of intracellular glutathione-bimane conjugate is detectable. After clearance of the mBBr dose from the cells, intracellular glutathione repletion is then observed by a restoration of the 13C-glutathione signal along with wash-out of the conjugate. These data demonstrate that standard NMR techniques can directly monitor intracellular processes such as glutathione depletion with a time resolution of approximately < 2 min.

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Aitken, R. Alan, Dheirya K. Sonecha, and Alexandra M. Z. Slawin. "Homopiperazine (Hexahydro-1,4-diazepine)." Molbank 2021, no. 2 (2021): M1200. http://dx.doi.org/10.3390/m1200.

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16

Eshimbetov, Alisher, Shahobiddin Adizov, Inderpreet Kaur, and Akhmed Reymov. "Is it possible to differentiate between 2-phenylaminodihydro-1,3-thiazine from 2-phenyliminotetrahydro-1,3-thiazine by spectral methods? New glance to the old problem." European Journal of Chemistry 12, no. 1 (2021): 77–80. http://dx.doi.org/10.5155/eurjchem.12.1.77-80.2068.

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Several studies have reported the presence of amine and imine tautomeric forms for hydrogenated 1,3-thiazine derivatives. However, identification of their tautomeric forms by UV, FTIR and mass-spectral methods does not yield expected results. Here, we report the synthesis of 2-phenylaminodihydro-1,3-thiazine and 2-phenyliminotetrahydro-1,3-thiazine and the analysis of their UV, FTIR and NMR (1H and 13C) spectral data. An identical picture of UV spectra was recorded for both compounds. However, distinctive characteristics were found in the FTIR, 1H and 13C NMR spectra. The C=N band of amine form was observed in higher frequency region relative to imine form. The signal of C2 carbon of amine form in 13C NMR spectrum was occurred in more downfield (δ 165.3 ppm) relative to C2 signal of imine form (δ 152.1 ppm). In addition, the difference between C2 and C8 carbon signals of amine form was very high (Δδ = 30.6 ppm) relative to imine form (δ 5.4 ppm). The position of C2 and C8 signals and the difference between them in 13C NMR spectrum was found to be more promising in identification of tautomeric forms in case of hydrogenated 1,3-thiazine derivatives.

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17

Marinova, Petya, Dimitar Stoitsov, Nikola Burdzhiev, et al. "Investigation of the Complexation Activity of 2,4-Dithiouracil with Au(III) and Cu(II) and Biological Activity of the Newly Formed Complexes." Applied Sciences 14, no. 15 (2024): 6601. http://dx.doi.org/10.3390/app14156601.

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The goal of this study is to synthesize, determine the structure, and examine the antimicrobial properties of novel Cu(II) and Au(III) complexes of 2,4-dithiouracil and its derivatives. These complexes were obtained by mixing aqueous solutions of the corresponding metal salts with the ligand dissolved in DMSO and aqueous NaOH, using a metal-to-ligand ratio of 1:4:2. The structures of the new compounds were analyzed by melting point determination, microwave plasma atomic emission spectrometry (MP-AES) for Cu and Au, inductively coupled plasma optical emission spectrometry (ICP-OES) for S, attenuated total reflection (ATR), solution and solid-state NMR, and Raman spectroscopy. The data for 2,4-dithiouracil obtained from the 1H NMR, 13C NMR, distortionless enhancement by polarization transfer spectrum (DEPT-135), proton–proton homonuclear correlation spectrum (1H-1H COSY), long-range 1H-13C heteronuclear multiple bond correlation experiment (HMBC), and heteronuclear single quantum coherence spectra (HSQC) aided the interpretation of the NMR data for the gold and copper complexes. Furthermore, the antimicrobial effect of the free ligands and their complexes was assessed against Gram-positive and Gram-negative bacteria, as well as yeasts.

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Silverberg, Lee, Carlos Pacheco, Anthony Lagalante, et al. "Synthesis and Spectroscopic Properties of 2,3-Diphenyl-1,3-thiaza-4-one Heterocycles." International Journal of Chemistry 7, no. 2 (2015): 150. http://dx.doi.org/10.5539/ijc.v7n2p150.

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Synthetic and spectroscopic data (1H NMR, 13C NMR, IR, UV/Vis) for a series of six 2,3-diphenyl-1,3-thiaza-4-one heterocycles which differ in ring size and substitution is reported. The results show that there are significant differences in spectroscopic signals common to all six compounds. Distinctions can be made among the compounds using the IR absorbance of the C4 carbonyl and the 1H NMR signal at C2, and to a lesser extent the 13C NMR signal at C4 and the UV/Vis spectrum.{The equation can be found in the PDF file}.

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19

Bernstein, Michael A., and Laurance D. Hall. "An evaluation of high resolution nuclear magnetic resonance experiments and protocols in the structure elucidation of organic molecules. I. A relatively simple system, brucine." Canadian Journal of Chemistry 63, no. 2 (1985): 483–90. http://dx.doi.org/10.1139/v85-078.

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Using a combination of one-dimensional (1D) and two-dimensional (2D) high resolution nmr methods, the 1H nmr spectrum of brucine was fully assigned. The 2D J-resolved and homonuclear chemical shift correlated (COSY) experiments provided assignments without full structural information; this was obtained from nuclear Overhauser effect (nOe) enhancement experiments (1D and 2D). With the proton spectrum fully assigned, proton-bearing carbons in the 13C nmr spectrum were easily assigned using the 2D heteronuclear chemical shift correlation map (CSCM) experiment.

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Pearce, Clive M., and Dudley H. Williams. "Complete assignment of the 13C NMR spectrum of vancomycin." Journal of the Chemical Society, Perkin Transactions 2, no. 1 (1995): 153. http://dx.doi.org/10.1039/p29950000153.

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21

Miana, Ghulam A., and Hassan M. G. Al-Hazimi. "Assignment of the 13C NMR spectrum of quinovic acid." Phytochemistry 26, no. 1 (1986): 225–27. http://dx.doi.org/10.1016/s0031-9422(00)81517-4.

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Siegel, Renée, Julien Trébosc, Jean-Paul Amoureux, and Zhehong Gan. "3D 1H–13C–14N correlation solid-state NMR spectrum." Journal of Magnetic Resonance 193, no. 2 (2008): 321–25. http://dx.doi.org/10.1016/j.jmr.2008.05.013.

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23

Coxon, Bruce. "Two-dimensional DEPT JCH)-resolved 13C NMR spectrum editing." Journal of Magnetic Resonance (1969) 66, no. 2 (1986): 230–39. http://dx.doi.org/10.1016/0022-2364(86)90026-0.

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24

Buchanan, G. W., A. B. Driega, A. Moghimi, and C. Bensimon. "Electronic effects on crown ether conformation. X-ray crystal structure and 13C NMR study in solution and the solid phase of 4-nitrobenzo-9-crown-3 ether." Canadian Journal of Chemistry 72, no. 8 (1994): 1764–68. http://dx.doi.org/10.1139/v94-223.

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The X-ray crystal structure of the title material has been determined and the results are compared to previous findings for benzo-9-crown-3 itself. The 13C NMR spectrum in solution has been unambiguously assigned using COSY and HETCOR methods. The solid phase 13C spectrum has been obtained and the 7, 10-d4 derivative has been examined to aid in spectral assignments.

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Ayer, William A., and Peter A. Craw. "Biosynthesis and biogenetic interrelationships of metabolites of the fungus Arthropsistruncata." Canadian Journal of Chemistry 70, no. 5 (1992): 1348–55. http://dx.doi.org/10.1139/v92-173.

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The incorporation of sodium [1-13C]acetate and sodium [1,2-13C2]acetate into a number of polyketide metabolites produced by the fungus Arthropsistruncata has been examined. The location of sodium [1-13C]acetate incorporation into arthropsadiol A (1), cycloarthropsone (2), and arthropsatriol C (3) has been determined by 13C nuclear magnetic resonance spectra of the corresponding diacetate derivatives, and a biosynthetic pathway is proposed to account for the formation of 1–3. Multiple incorporation of sodium [1,2-13C2]acetate into arthropsadiol A (1) leads to a complicated pattern of satellite multiplets in the 13C nmr spectrum of the corresponding diacetate 6 that are interpreted with the aid of 2D-INADEQUATE spectra. A biosynthesis of arthropsolide A (5) is proposed and the absence of 5 and related metabolites in cultures of the Arthropsistruncata fed with 13C-labelled sodium acetate is discussed.

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Mamantov, Andrew. "1-Norbornyl cation may be in equilibrium with 2-norbornyl cation." Progress in Reaction Kinetics and Mechanism 45 (August 22, 2019): 146867831986131. http://dx.doi.org/10.1177/1468678319861319.

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New 1H and 13C NMR 400 MHZ spectra of the 2-Nb cation under stable ion conditions, for example, in SbF5/SO2F2/SO2ClF, −80 oC, show besides the usual 1H NMR resonances at δ 4.93, 2.82, 1.85, the never before seen singlet, δ 9.63, and doublet, δ 2.97 (J2,6 = 16.6 Hz), ratio 1.00 : 1.07, proposed to be due to resonance-stabilized bridgehead 1-Nb cationic enantiomers in equilibrium with 2-Nb cation. The corresponding 13C proton-coupled NMR spectrum, −80 oC, has a C3,5,7 triplet, δ 30.45, J(CH) = 139.14 Hz, and C4 doublet, δ 37.7, J(CH) = 154.54 Hz. The C1,2,6 absorption, δ 91.04 is relatively broad, whereas previously, at −70 oC, it was a pentuplet. The 13C proton-decoupled spectrum at −80 oC shows the C4 doublet and C3,5,7 triplet collapsed to a singlet, but the C1,2,6 resonance is still broad. Analyses support the slowing exchange between resonance stabilized enantiomeric 2-cations at ≤ –159 oC. Some future studies are proposed.

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Buchanan, G. W., A. B. Driega, A. Moghimi, C. Bensimon, R. A. Kirby, and T. D. Bouman. "Benzo-9-crown-3 ether: X-ray crystal structure, NMR studies in solution and the solid phase, and ab initio calculations of isotropic 13C chemical shifts using LORG with a D95V basis set." Canadian Journal of Chemistry 71, no. 12 (1993): 1983–89. http://dx.doi.org/10.1139/v93-247.

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Using the X-ray crystal geometry as input, the 13C NMR chemical shifts of benzo-9-crown-3 ether have been calculated via ab initio methods using a localized orbital local origin (LORG) approach. Reasonable agreement is found between the calculated values for an isolated molecule in the gas phase and those obtained in the 13C CPMAS NMR spectrum. Solid phase 13C spectra of the C7,10-d4 derivative confirm the existence of a 7.9 ppm shift difference between these sites in the solid, whereas in solution they are conformationally averaged to one resonance. The effects of C—H bond length variation on calculated 13C shifts have been explored.

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Anugrahati, Nuri Arum, Yudi Pranoto, Yustinus Marsono, and Djagal Wiseso Marseno. "Structural Changes in Cooked Rice Treated with Cooling-Reheating Process and Coconut Milk Addition as Observed With FT-IR and 13C NMR." Agritech 37, no. 1 (2017): 78. http://dx.doi.org/10.22146/agritech.10669.

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The molecular structural changes of food could be observed by the technique of FT-IR and 13C NMR spectroscopy. This research was aimed to study the structural changes in cooked rice treated with cooling-reheating process and coconut milk addition using FT-IR and 13C NMR. It was found that the cooling-reheating process and addition of coconut milk cause several structural changes of cooked rice. The IR analysis showed the bands at 3,400, 2,900, 1,018 and 856 cm-1 changed due to the retrogradation during cooling process. The spectrum of 13C NMR showed the change of peaks at 100.28 and 100.10 ppm. These changes may be related to the addition of coconut milk during rice cooking.

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Friedrich, Jan O., and Roderick E. Wasylishen. "A 1H and 13C nuclear magnetic resonance study of carnosine." Canadian Journal of Chemistry 64, no. 11 (1986): 2132–38. http://dx.doi.org/10.1139/v86-351.

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The proton and carbon-13 resonance signals of carnosine (β-alanyl-L-histidine) were unambiguously assigned using a variety of nmr techniques including proton–carbon chemical shift correlations, titrations of nmr chemical shifts, coupling constants, and isotope shifts. From the 13C nmr titration, carnosine's three pKa values were estimated to be 2.7, 7.1, and 10.6, and it was found that the imidazole ring existed predominantly as the 3-H tautomer in basic solution. Conformational information about the Cα—Cβ bond and about the N—Cα bond was deduced from observed 3J(C,H) and 3J(H,H) values. The 13C nmr spectrum of carnosine in solution is also compared with that obtained for a solid sample.

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Bal, Dominika, Anna Kraska-Dziadecka, Wanda Gradowska, and Adam Gryff-Keller. "Investigation of a wide spectrum of inherited metabolic disorders by 13C NMR spectroscopy." Acta Biochimica Polonica 55, no. 1 (2008): 107–18. http://dx.doi.org/10.18388/abp.2008_3103.

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High-resolution (1)H NMR spectroscopy of body fluids has proved to be very useful in diagnostics of inherited metabolic diseases, whereas (13)C NMR remains almost unexploited. In this paper the application of (13)C NMR spectroscopy of fivefold concentrated urine samples for diagnosis of selected metabolic diseases is reported. Various marker metabolites were identified in test urine samples from 33 patients suffering from 10 different diseases, providing information which could be crucial for their diagnoses. Spectra were accumulated for 2 h or overnight when using spectrometers operating at 9.4 or 4.7 T magnetic fields, respectively. Interpretation of the measurement results was based on a comparison of the peak positions in the measured spectrum with reference data. The paper contains a table with (13)C NMR chemical shifts of 73 standard compounds. The method can be applied individually or as an auxiliary technique to (1)H NMR or any other analytical method.

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Buchert, Karen L., Jack L. Koenig, Shi-Qing Wang, and John L. West. "Molecular Motion Analysis of 5CB in PDLCs Using Solid-State 13C NMR Relaxation Spectroscopy." Applied Spectroscopy 47, no. 7 (1993): 933–41. http://dx.doi.org/10.1366/0003702934415174.

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In samples of polymer-dispersed liquid crystals (PDLCs), submicron droplets of liquid crystal reside within a polymer matrix. By the use of the cross polarization technique for solid-state 13C NMR spectroscopy, the NMR spectrum of the liquid crystal can be obtained without interference from the polymer spectrum, even though the two materials have some similar chemical structures. Both 13C T1 and 13C T1 ρ relaxation experiments were performed on a PDLC system of 5CB in epoxy as a function of 5CB domain size. The 13C T1 relaxation constants and the localized motions they measure showed no significant change over the liquid crystal domain size studied. However, the 13C T1 ρ relaxation constants and the segmental motions of molecules they measure revealed a significant change over the liquid crystal domain size studied. Therefore, the 13C T1 ρ values can be used to determine the change in mobility of the molecular segments of the SCB molecules resulting from increased interaction between the liquid crystal and the polymer matrix and to further understand the importance of the molecular motions of the liquid crystal in the switching phenomenon for PDLC materials.

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32

Buchanan, G. W., C. Morat, R. A. Kirby, and J. S. Tse. "The hydroxonium perchlorate complex of cis-syn-cis-dicyclohexano 18-crown-6 ether: conformational analysis in the solid state and in solution at low temperature as studied via 13C NMR methods." Canadian Journal of Chemistry 69, no. 12 (1991): 1964–69. http://dx.doi.org/10.1139/v91-282.

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From 100.6-MHz 13C NMR coalescence temperature measurements, the title complex is shown to undergo a single degenerate ring inversion process with a free energy barrier of [Formula: see text]. This is ca. 5 kJ/mol higher than the barrier in the free crown. The solid state 13C CPMAS spectrum is indicative of a totally unsymmetrical conformation and the shift trends in the solid are analyzed in terms of local torsional angle variations. Comparisons of experimental vs. calculated (GIAO) 13C chemical shift ranges for the CH2O carbons in the solid are made and satisfactory agreement with respect to the overall range and magnitude of the 13C shielding differences is obtained. Key words: crown ethers, stereochemistry, NMR.

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33

Ahlers, Friedhelm, Jörg Lambert, and Rolf Wiermann. "Acetylation and Silylation of Piperidine Solubilized Sporopollenin from Pollen of Typha angustifolia L." Zeitschrift für Naturforschung C 58, no. 11-12 (2003): 807–11. http://dx.doi.org/10.1515/znc-2003-11-1210.

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Abstract Silyl and acetyl derivatives of sporopollenin from the pollen of Typha angustifolia L. were prepared. The derivatized products were readily soluble in piperidine-d11 and could be investigated employing one- and two-dimensional proton and carbon NMR (nuclear magnetic resonance) spectroscopy (1H,1H-COSY and 13C,1H-HETCOR techniques). For the first time, a two dimensional 13C,1H-HETCOR NMR spectrum of a sporopollenin could be obtained. The results underline the importance of derivatization techniques for obtaining two dimensional 13C-NMR spectra of sporopollenins. Moreover, piperidine turns out to be a more suitable solvent for sporopollenins than 2-aminoethanol, as it allows for higher solubilities, being important for 2D-NMR investigations. From the HETCOR and COSY spectra of the silylated and the acetylated Typha samples the occurrence of aliphatic polyhydroxy compounds as well as phenolic OH groups became evident.

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34

Becalska, Anna, Roland K. Pomeroy, and William A. G. Graham. "Reassignment of the structure of M3(CO)12(Cl)(SnCl3) (M = Ru, Os)." Canadian Journal of Chemistry 67, no. 7 (1989): 1236–38. http://dx.doi.org/10.1139/v89-187.

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Reaction of M3(CO)12 (M=Ru, Os) with SnCl4 in benzene at room temperature affords M3(CO)12(Cl)(SnCl3) in essentially quantitative yield. The 13C nmr spectra of these complexes indicate they have a ClM3(SnCl3) arrangement of atoms with the Cl ligand cis and the SnCl3 group trans to a linear Os3 chain. This is contrary to previously proposed structures for these compounds. The 13C nmr spectrum of Os3(CO)12(I)2 which has the iodo ligands cis to the Os3 chain is also reported for comparison. Keywords: ruthenium–tin, osmium–tin, osmium–iodine, l3C nmr spectroscopy.

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35

Khandelwal, Deepika, Vikrant Kumar, Neeti Misra, et al. "NMR spectroscopy based configurational and compositional analysis of isobornyl methacrylate—Acrylonitrile copolymers." Applied Chemical Engineering 6, no. 1 (2023): 82. http://dx.doi.org/10.24294/ace.v6i1.1999.

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The authors conducted free radical polymerization using an initiator to synthesize a copolymer of isobornyl methacrylate—Acrylonitrile (I/A). The reactivity ratios of I (r1) and A (r2) monomers were determined as r1 = 1.63 ± 0.14, r2 = 0.61 ± 0.06 for linear KT (Kelen–Tudos) method and r1 = 1.58, r2 = 0.60 for the EVM (Error-in-Variable Method). We interpreted 1H and 13C{1H} NMR spectra of the I/A copolymers using DEPT-135 and 2D HSQC spectra. The α-CH3 carbon in the I-unit was identified and confirmed using a 2D HSQC NMR spectrum, up to the level of triad of compositional and configurational sequences. The CH (C14) and β-CH2 carbon peaks were also identified up to the triad level and higher, respectively. A 2D TOCSY spectrum revealed geminal and vicinal interactions within various CH and β-CH2 protons. A 2D HMBC NMR spectrum provided a complete assignment of the coupling between nitrile, carbonyl, and quaternary carbons with CH3 and CH2 protons.

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36

Tidwell, Cynthia P., Prakash Bharara, Kenneth A. Belmore, et al. "Synthesis and spectral evaluation of 5,10,15,20-tetrakis(3,4-dibenzyloxyphenyl)porphyrin." Heterocyclic Communications 23, no. 2 (2017): 79–83. http://dx.doi.org/10.1515/hc-2016-0188.

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AbstractPorphyrins are of interest in many applications that involve electron transfer and absorption of light, such as solar energy and photodynamic cancer therapy. The newly synthesized 5,10,15,20-tetrakis(3,4-dibenzyloxyphenyl)porphyrin, TDBOPP, was characterized using 1H NMR, 13C NMR, UV-vis and fluorescence spectroscopy and MALDI-TOF/TOF high resolution mass spectrometry. Standard 1H NMR and 13C NMR experiments coupled with nuclear Overhauser effect (NOE) experiments confirmed the structure of the compound. The expected M+ and [M+H]+ ions are observed in the MALDI-TOF/TOF mass spectrum. The UV-vis absorption spectrum of TDBOPP shows a Soret band at 424 nm and three Q bands at 519 nm, 556 nm, and 650 nm with molar absorptivity 3.6×105 cm−1m−1, 1.6×104 cm−1m−1, 1.0×104 cm−1m−1 and 5.3×103 cm−1m−1, respectively. Excitation at 424 nm gives emission at 650 nm. The quantum yield of the porphyrin is 0.11.

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37

Coxon, Bruce. "Two-dimensional POMMIE carbon–proton chemical shift correlated 13C NMR spectrum editing." Canadian Journal of Chemistry 68, no. 7 (1990): 1145–50. http://dx.doi.org/10.1139/v90-177.

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Two pulse sequences are described for acquisition of two-dimensional, carbon–proton chemical shift correlated 13C NMR spectra by the "phase oscillations to maximize editing technique". One of these sequences provides two-dimensional, carbon–proton chemical shift correlated spectra in which the 1H–1H coupling constants are present in the 1H chemical shift dimension, whereas the other sequence includes a bilinear rotation decoupling unit that removes the vicinal 1H–1H couplings in this dimension. Extensions of these techniques to generation of two-dimensional, carbon–proton chemical shift correlated CH, CH2, and CH313C NMR subspectra from linear combinations of three two-dimensional data sets are described. Decreased residual signals in the edited 2D subspectra have been achieved by Pascal programs that include six floating point coefficients, and a method for their calibration is discussed. Results are reported for troleandomycin (1). Keywords: 13C nuclear magnetic resonance, carbon–proton chemical shift correlation, DEPT, Pascal programs, POMMIE, two-dimensional NMR spectrum editing, troleandomycin.

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38

Ke, Wei Chang, Yi Kun Chen, Guo Xi Xiong, Xiang Hong Peng, Chao Zhu, and Xiao Qiu Yang. "Synthesis and Characterization of the Water-Soluble Oleoyl Acetyl Chitosan." Advanced Materials Research 284-286 (July 2011): 1782–85. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.1782.

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Oleoyl chloride was synthesized by oleic acid and thionyl dichloride (SOCl2), and then reacted with chitosan in dichloromethane to obtain the oleoyl chitosan. Novel water-soluble oleoyl acetyl chitosan (OACh) was synthesized using oleoyl chloride reacted with acetic anhydride in pyridine. The chemical structure of the OACh was characterized by FT-IR, 1H and 13C NMR. There existed the peaks at 1743.9 cm-1 (C=O) and 1658.1 cm-1(C=C) in FT-IR spectrum, and the peaks at 170.8, 171.6 and 172.5 ppm which were assigned to the C=O of the oleoyl and acetyl groups in 13C NMR spectrum. The results indicated that OACh had oleoyl as hydrophobic moieties and acetyl as hydrophilic moieties.

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39

Niu, Hujun, Xudong Chen, Yunbo Zhao, Junyi Zhou, and Yimin Xie. "Exploration of the Linkages between Lignin and Carbohydrates in Kraft Pulp from Wheat Straw Using a 13C/2H Isotopic Tracer." Molecules 28, no. 22 (2023): 7493. http://dx.doi.org/10.3390/molecules28227493.

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To further our understanding of the change in association between lignin and carbohydrates after kraft pulping, isotope-labeled kraft pulp (KP) was prepared using 13C and D double-isotope-labeled wheat straw, and it was subjected to enzymatic hydrolysis and ionic liquid treatment to explore the linkages between lignin and carbohydrate complexes in wheat straw. Isotope abundance determination showed that 13C and D abundances in the experimental groups were substantially higher than those in the control group, indicating that the injected exogenous coniferin-[α-13C], coniferin-[γ-13C], and d-glucose-[6-D2] were effectively absorbed and metabolized during wheat internode growth. Solid-state CP/MAS 13C-NMR spectroscopy showed that lignin was mainly linked to polysaccharides via acetal, benzyl ether, and benzyl ester bonds. Kraft pulp (KP) from the labeled wheat straw was degraded by cellulase. The obtained residue was fractionated using the ionic liquid DMSO/TBAH to separate the cellulose–lignin complex (KP-CLC) and xylan–lignin complex (KP-XLC). X-ray diffractometer determination showed that the KP-CLC regenerated cellulose type II from type I after the ionic liquid conversion. The 13C-NMR spectrum of Ac-En-KP-CLC showed that the cellulose–lignin complex structure was chemically bonded between the lignin and cellulose through acetal and benzyl ether bonds. The 13C-NMR spectrum of En-KP-XLC showed a lignin–hemicellulose complex structure, wherein lignin and xylan were chemically bonded by benzyl ether and acetal bonds. These results indicate that the cross-linking between lignin and carbohydrates exists in lignocellulosic fibers even after kraft pulping.

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40

Lankhorst, Peter, Jozef van Rijn, and Alexander Duchateau. "One-Dimensional 13C NMR Is a Simple and Highly Quantitative Method for Enantiodiscrimination." Molecules 23, no. 7 (2018): 1785. http://dx.doi.org/10.3390/molecules23071785.

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The discrimination of enantiomers of mandelonitrile by means of 1D 13C NMR and with the aid of the chiral solvating agent (S)-(+)-1-(9-anthryl)-2,2,2-trifluoroethanol (TFAE) is presented. 1H NMR fails for this specific compound because proton signals either overlap with the signals of the chiral solvating agent or do not show separation between the (S)-enantiomer and the (R)-enantiomer. The 13C NMR method is validated by preparing artificial mixtures of the (R)-enantiomer and the racemate, and it is shown that with only 4 mg of mandelonitrile a detection limit of the minor enantiomer of 0.5% is obtained, corresponding to an enantiomeric excess value of 99%. Furthermore, the method shows high linearity, and has a small relative standard deviation of only 0.3% for the minor enantiomer when the relative abundance of this enantiomer is 20%. Therefore, the 13C NMR method is highly suitable for quantitative enantiodiscrimination. It is discussed that 13C NMR is preferred over 1H NMR in many situations, not only in molecules with more than one chiral center, resulting in complex mixtures of many stereoisomers, but also in the case of molecules with overlapping multiplets in the 1H NMR spectrum, and in the case of molecules with many quaternary carbon atoms, and therefore less abundant protons.

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41

Drew, Jacinta, Jean-Robert Brisson, Peter Morand, and Arthur G. Szabo. "1H and 13C nuclear magnetic resonance assignment of fluorescent olefinic sterol derivatives for use as membrane probes." Canadian Journal of Chemistry 65, no. 8 (1987): 1784–94. http://dx.doi.org/10.1139/v87-300.

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A number of fluorescent steroids with unsaturated sidechains have been analyzed by high resolution 1H and 13C nmr spectroscopy. The geometry of the olefinic systems was assigned on the basis of 1H–1H shift-correlated spectra (COSY) and selected nOe difference experiments. For one of these compounds, a 13C–1H shift-correlated spectrum, a COSY spectrum, a 1H J-resolved spectrum as well as nOe experiments on the angular methyl groups permitted complete ring proton assignment and coupling constant analysis. The high degree of similarity of the ring carbon 13C chemical shifts of these steroids and cholesterol would indicate that the former have the potential for use as fluorescent probes of cholesterol domains in membranes.

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42

SMALL, G. W. "ChemInform Abstract: Database Retrieval Techniques for 13C NMR Spectrum Simulation." ChemInform 23, no. 47 (2010): no. http://dx.doi.org/10.1002/chin.199247273.

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43

Muharni, Muharni, Fitrya Fitrya, Widia Purwaningrum, and Ahmad Yogi Nugraha. "Secondary Metabolite from Endophytic Fungi Aspergillus Sp. The Leave Of Kunyit Putih (Curcuma zedoaria (Berg) Roscoe)." Molekul 11, no. 1 (2016): 125. http://dx.doi.org/10.20884/1.jm.2016.11.1.201.

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The compound from endophytic fungi of Aspergillus sp. from leaves of kunyit putih (Curcuma zedoaria (Berg.) Roscoe) has been isolated. Isolation begins with cultivation ofAspergillus sp. in 18 L PDB’s media (Potato Dextrose Broth) for 28 days. The liquid cultivation medium was extracted by partitioning method using ethylacetate and then evaporated. The extract was separated and purified by chromatography techniques. Elucidation stucture of the isolated compound was analysis by spectroscopic method NMR 1D and 2D. Antibacterial activity of isolated compound was tested using the disc diffusion method at concentrations 2500, 1000, 500, and 125 ppm. The isolated compounds obtained in the form of a yellow oil (24.30 mg). The 13C NMR spectrum indicated 24 signals of carbon and base on analysis spectrum DEPT 135 showed 5 signal methynes carbon, 1 signals methylene, 9 signals of methyl and 9 signals quarternary carbon. These signals from 1H and 13C-NMR suggested that this compound contained aromatic group and four carbonyl. The isolated compound show antibacterial activity at concentration 2500 ppm which inhibition zone for E. coli, S. dysenteriae, S. aureus, B. subtilis were 10.3 ; 8.3; 8.4; and 7.8 mm, respectively. Based on the analysis result of NMR 1D and 2D, the compound was methyl 6-(5'-(2"-acetoxy-2”-methylpropanoyl)-3"- methyl-2'-(3"'-methylbutanoyl)phenyl)-3-methylbutanoate and has weak antibacterial activity.

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44

Conejo-Dávila, Alain Salvador, Marco Armando Moya-Quevedo, David Chávez-Flores, Alejandro Vega-Rios, and Erasto Armando Zaragoza-Contreras. "Role of the Anilinium Ion on the Selective Polymerization of Anilinium 2-Acrylamide-2-methyl-1-propanesulfonate." Polymers 13, no. 14 (2021): 2349. http://dx.doi.org/10.3390/polym13142349.

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The development of anilinium 2-acrylamide-2-methyl-1-propanesulfonate (Ani-AMPS) monomer, confirmed by 1H NMR, 13C NMR, and FTIR, is systematically studied. Ani-AMPS contains two polymerizable functional groups, so it was submitted to selective polymerization either by free-radical or oxidative polymerization. Therefore, poly(anilinium 2-acrylamide-2-methyl-1-propanesulfonic) [Poly(Ani-AMPS)] and polyaniline doped with 2-acrylamide-2-methyl-1-propanesulfonic acid [PAni-AMPS] can be obtained. First, the acrylamide polymer, poly(Ani-AMPS), favored the π-stacking of the anilinium group produced by the inter- and intra-molecular interactions and was studied utilizing 1H NMR, 13C NMR, FTIR, and UV-Vis-NIR. Furthermore, poly(Ani-AMPS) fluorescence shows quenching in the presence of Fe2+ and Fe3+ in the emission spectrum at 347 nm. In contrast, the typical behavior of polyaniline is observed in the cyclic voltammetry analysis for PAni-AMPS. The optical properties also show a significant change at pH 4.4. The PAni-AMPS structure was corroborated through FTIR, while the thermal properties and morphology were analyzed utilizing TGA, DSC (except PAni-AMPS), and FESEM.

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45

Chimichi, Stefano, Barbara Cosimelli, Fabrizio Bruni, and Silvia Selleri. "1H and 13C NMR study of the pyrazolo[1,5-a]pyrimidine system." Canadian Journal of Chemistry 70, no. 4 (1992): 1093–97. http://dx.doi.org/10.1139/v92-144.

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The 13C and 1H NMR spectra of some pyrazolo[1,5-a]pyrimidine derivatives are discussed. All 13C resonances were unambiguously assigned by means of both 2D experiments and gated decoupled spectra from which one-bond and long-range 13C–1H coupling constants were determined. The literature assignments for H-5 and H-7 in the parent system have been revised and a simple method for distinguishing between 5-methyl and 7-methyl compounds is suggested, based on the carbon chemical shift of the methyl group or on its fine structure in the 1H NMR spectrum. Regioselective syntheses for all the reported methyl derivatives are also described.

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46

Cantini, Francesca, Emanuele Andreano, Ida Paciello, et al. "2D NMR Analysis as a Sensitive Tool for Evaluating the Higher-Order Structural Integrity of Monoclonal Antibody against COVID-19." Pharmaceutics 14, no. 10 (2022): 1981. http://dx.doi.org/10.3390/pharmaceutics14101981.

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The higher-order structure (HOS) of protein therapeutics has been confirmed as a critical quality parameter. In this study, we compared 2D 1H-13C ALSOFAST-HMQC NMR spectra with immunochemical ELISA-based analysis to evaluate their sensitivity in assessing the HOS of a potent human monoclonal antibody (mAb) for the treatment of coronavirus disease 2019 (COVID-19). The study confirmed that the methyl region of the 2D 1H-13C NMR spectrum is sensitive to changes in the secondary and tertiary structure of the mAb, more than ELISA immunoassay. Because of its highly detailed level of characterization (i.e., many 1H-13C cross-peaks are used for statistical comparability), the NMR technique also provided a more informative outcome for the product characterization of biopharmaceuticals. This NMR approach represents a powerful tool in assessing the overall higher-order structural integrity of mAb as an alternative to conventional immunoassays.

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Гермов, А. Ю., К. Н. Михалёв, Р. В. Скорюнов та ін. "Применение политетрафторэтилена для дозиметрического контроля по данным ЯМР 19F". Дефектоскопия 7 (липень 2021): 52–56. http://dx.doi.org/10.31857/s013030822107006x.

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The 13C, 19F NMR spectra of the initial and irradiated polytetrafluoroethylene samples were studied in the range of gamma radiation doses up to 50 kGy. In this range, the 19F NMR spectrum width increases linearly with an increase in the absorbed dose. It is concluded that it is possible to control technological doses by the NMR method using polytetrafluoroethylene as a detector.

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48

Gyöngyösi, Tamás, Tamás Milán Nagy, Katalin E. Kövér, and Ole W. Sørensen. "Distinguishing between two- and three-bond correlations for all 13C multiplicities in heteronuclear NMR spectroscopy." Chemical Communications 54, no. 70 (2018): 9781–84. http://dx.doi.org/10.1039/c8cc05156a.

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Fritz, Monika, Johann Hiermeier, and Frank H. Köhler. "Fusing Nickelocene and Cyclopentadiene by Two Silyl Bridges. Synthesis and 1H, 13C, and 29Si NMR Investigation of a Paramagnetic Building Block for High-Nuclear Metallocenes." Zeitschrift für Naturforschung B 49, no. 6 (1994): 763–69. http://dx.doi.org/10.1515/znb-1994-0608.

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Two isomers of tetrahydro-4,4,8,8-tetramethyl-4,8-disila-s-indacene (LH2) were monodeprotonated and treated with cyclopentadienyl anion and NiBr2(THF)1,5 to give a 72% yield of the mixed nickelocene CpNi(LH) where a cyclopentadiene is fused to a nickelocene. The analysis of the paramagnetic 1H, 13C, and 29Si NMR spectra demonstrated that the syn and anti isomer of CpNi(LH) formed in a ratio of 5/1. Both isomers could be deprotonated to yield the anion CpNi(L-). According to its 13C NMR spectrum the bridging ligand L is not planar

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Birin, Kirill P., Yulia G. Gorbunova, and Aslan Yu Tsivadze. "The approach to the direct interpretation of 13C NMR of heteroleptic triple-decker (porphyrinato)(phthalocyaninato) lanthanum(III) without carbon labeling." Journal of Porphyrins and Phthalocyanines 15, no. 07n08 (2011): 667–73. http://dx.doi.org/10.1142/s1088424611003598.

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A complete assignment of 13C NMR resonance peaks in the spectrum of heteroleptic triple-decker (porphyrinato)(phthalocyaninato) lanthanum of type [Br4TPP]La[(15C5)4Pc]La[Br4TPP] ( Br4TPP = 5,10,15,20-tetrakis-(4-bromophenyl)-porphyrinato-ligand, (15C5)4Pc = tetrakis-(15-crown-5)-phthalocyaninato-ligand) is performed. Application of set of gradient-enhanced homonuclear 1H-1H-correlation techniques (COSY and NOESY) allowed the unambiguous interpretation of proton spectrum of the complex. Application of INEPT polarization transfer technique allowed to separate quaternary carbon resonances from proton-bound carbon ones. Gradient-enhanced proton-detected HMQC and HMBC techniques allowed to correlate all the resonances in 13C-spectrum.

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Journal articles on the topic '13C NMR spectrum'

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