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Journal articles on the topic 'J-Aggregate'

Author: Grafiati

Published: 4 June 2021

Last updated: 29 May 2022

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1

MAITI, NAKUL C., SHYAMALAVA MAZUMDAR, and N. PERIASAMY. "J- and H-Aggregates of Porphyrins with Surfactants: Fluorescence, Stopped Flow and Electron Microscopy Studies." Journal of Porphyrins and Phthalocyanines 02, no. 05 (October 1998): 369–76. http://dx.doi.org/10.1002/(sici)1099-1409(199807/10)2:4/5<369::aid-jpp92>3.0.co;2-3.

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The interaction of cationic surfactants such as CTAB (cetyl trimethyl ammonium bromide) with tetrakis-(4-sulfonato phenyl) porphine ( H 4 TPPS 2−), a dianion, leads to the formation of two premicellar aggregates of porphyrin when [CTAB] is below CMC (critical micelle concentration) and a micellized monomer when [CTAB] is above CMC. The premicellar aggregates are labeled as J- and H-aggregates because of their characteristic spectroscopic properties. Simple inorganic cations such as K +, Ba 2+, Ca 2+ and Zr 4+ also induce the formation of the J-aggregate but not of the H-aggregate. The formation of the J-aggregate is preceded by kinetic intermediates, while no intermediate was observed prior to the formation of the H-aggregate. The rate of formation of the H-aggregate was faster than that of the J-aggregate. The fluorescence depolarization (anisotropy) properties of the monomer and the H- and J-aggregates were studied and compared. The size and structure of the J-aggregate were examined by transmission electron microscopy (TEM). The structure of the J-aggregate reveals a fiber-like (linear stacking) or domain-like (helical stacking) arrangement of the porphyrin molecules.

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2

Ma, Suqian, Yingjie Liu, Jibo Zhang, Bin Xu, and Wenjing Tian. "Polymorphism-Dependent Enhanced Emission in Molecular Aggregates: J-Aggregate versus X-Aggregate." Journal of Physical Chemistry Letters 11, no. 24 (December 7, 2020): 10504–10. http://dx.doi.org/10.1021/acs.jpclett.0c02917.

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3

Hu, Shu, Yang Liao, Yang Zhang, Xiaoliang Yan, Zhenlu Zhao, Weiqiang Chen, Xin Zhang, et al. "Effect of Thermal Annealing on Conformation of MEH-PPV Chains in Polymer Matrix: Coexistence of H- and J-Aggregates." Polymers 12, no. 8 (August 7, 2020): 1771. http://dx.doi.org/10.3390/polym12081771.

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In diluted solid solution using poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) and polymethyl methacrylate (PMMA) or polystyrene (PS), both aggregated and extended conformations could be formed according to the weight ratio. Aggregated conformation in as-cast MEH-PPV/PMMA film presented a J-aggregate-like photoluminescence (PL) emission. After annealing at 160 °C, its PL showed characteristics of both J- and H-aggregates at the same time; however, extended conformation showed an oligomer-like emission, which was not sensitive to either measurement temperature or annealing temperature. Thus, the conformation transition between aggregated and extended is unlikely to happen in MEH-PPV/PMMA blends during thermal annealing. On the contrary, in MEH-PPV/PS blends, extended conformation dominated in as-cast film with oligomer-like emissions; after annealing at 160 °C, both J- and H- aggregate-like PL emissions were observed, indicating the conformation transitioned from extended to aggregated. Therefore, our work may suggest a new method to manipulate photophysical properties of conjugated polymers by combining appropriate host matrix and thermal annealing processes.

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4

Belko, Nikita V., Michael P. Samtsov, and Anatoly P. Lugovski. "Controlling H*- and J-aggregation of an indotricarbocyanine dye in aqueous solutions of inorganic salts." Journal of the Belarusian State University. Physics, no. 2 (June 2, 2020): 19–27. http://dx.doi.org/10.33581/2520-2243-2020-2-19-27.

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Aggregation process of a symmetrical cationic indotricarbocyanine dye in aqueous medium was studied. It was shown that self-assembled H*-aggregates with an absorption peak at 514 nm as well as J-aggregates with an absorption peak at 777 nm can be obtained. Both of the aggregate types are non-fluorescent. High concentration of a desired aggregate type can be obtained and stabilized by changing ionic strength and pH of the solution. At ionic strength of 170 mmol/L and pH 7.4 J-aggregates are stable. Decreasing pH as well as ionic strength leads to demise of J-aggregates and concomitant formation of H*-aggregates. Increasing temperature leads to a faster H*-aggregate formation. The type of aggregates can be changed by heating and subsequent cooling of the solution. An organic compound forming both H*- and J-aggregates has never been observed before. The fact that the H*- and J-bands are narrow, the shift between them is significant, the J-band is located in the far-red spectral region, and the type of aggregates can be controlled makes these objects promising for future applications.

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5

Anantharaman, Surendra B., Daniel Messmer, Amin Sadeghpour, Stefan Salentinig, Frank Nüesch, and Jakob Heier. "Excitonic channels from bio-inspired templated supramolecular assembly of J-aggregate nanowires." Nanoscale 11, no. 14 (2019): 6929–38. http://dx.doi.org/10.1039/c8nr10357g.

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6

Kato, Noritaka, Keiji Yamamoto, and Yoshiaki Uesu. "Aqueous Dispersions of J-Aggregates and J-Aggregate-Doped Silica Bulk Gels." Japanese Journal of Applied Physics 46, no. 8A (August 6, 2007): 5318–20. http://dx.doi.org/10.1143/jjap.46.5318.

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7

Melnik, A. D., T. S. Zhebit, A. B. Krylov, S. G. Pukhovskaya, Yu B. Ivanova, and M. M. Kruk. "FORMATION OF J-AGGREGATES OF THE 21-THIA-5,10,15,20-TETRA-(4-SULFONATOPHENYL)-PORPHYRIN IN WATER SOLUTIONS." Journal of Applied Spectroscopy 89, no. 2 (March 18, 2022): 177–83. http://dx.doi.org/10.47612/0514-7506-2022-89-2-177-183.

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The formation of J-aggregates of 21-thia-5,10,15,20-tetra-(4-sulfonatophenyl)-porphyrin in acidified water solutions is herein revealed for the first time and their spectral-luminescent properties are measured. It is shown that the spectral-luminescent properties of J-aggregates are due to the excitonic interactions, and the number of coherent interacting monomeric porphyrin molecules in the aggregate is evaluated. It is found that J-aggregates of heteroporphyrin have fluorescence, and the fluorescence quantum yield Фfl is found to be as low as 1.8 . 10–4. The photolability of J-aggregates is found, namely, upon J-aggregate photoexcitation to the absorption band at 503 nm they collapse to the monomeric doubly protonated molecules. The process of photomonomerisation is reversible: upon keeping the solution in the dark, J-aggregates form again.

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8

Белько, Н. В., М. П. Самцов, and А. А. Луговский. "Спектральные свойства индотрикарбоцианинового красителя в процессе самоорганизации его H-=SUP=-*-=/SUP=-- и J-агрегатов." Журнал технической физики 128, no. 11 (2020): 1627. http://dx.doi.org/10.21883/os.2020.11.50165.84-20.

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Self-assembly of H*- and J-aggregates of an indotricarbocyanine dye in phosphate buffered saline was investigated. At pH value of 7.0 the dye studied was shown to form non-luminescent H*-aggregates with the absorption band peaked at 516 nm, its FWHM being 35 nm (1303 cm-1), whereas, J-aggregates are absent. At pH value of 7.4 the H*-aggregates are not formed, whereas, the J-aggregates are observed. The absorption band of the J-aggregates is peaked at 777 nm, its FWHM being 30 nm (497 cm-1). Photoluminescence quantum yield of the J-aggregates does not exceed 10-6. An increase in the solution temperature from 20 to 31oC results in a 25-fold decrease in the self-assembly time of the H*-aggregates. An increase in the solution temperature from 20 to 80oC is followed by a reversible decay of both the H*- and J-aggregates. The H*-aggregate (J-aggregate) absorption band is reduced two-fold at the solution temperature of 37oC (32oC). Thansitions of the dye aggregates to high-lying electronic excited states were evidenced in the steady-state absorption in the spectral range between 400 and 480 nm.

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9

Wojtyk, James, Andrew McKerrow, Peter Kazmaier, and Erwin Buncel. "Quantitative investigations of the aggregation behaviour of hydrophobic anilino squaraine dyes through UV/vis spectroscopy and dynamic light scattering." Canadian Journal of Chemistry 77, no. 5-6 (June 1, 1999): 903–12. http://dx.doi.org/10.1139/v99-073.

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In continuing studies of the aggregation behaviour of squaraine dyes in DMSO-water mixtures, we have examined a series of symmetrical anilino-based squaraines with increasing N-alkyl chain length (n-butyl, n-octyl, and n-dodecyl). The aggregation behaviour was assessed through UV/vis spectroscopic and Dynamic Light Scattering (DLS) studies with quantitative interpretation based on exciton theory. This class of N-alkyl squaraines forms two distinct solution aggregates, Type J and Type H, depending on the composition of the DMSO-water medium. DLS measurement of the aggregates in the Type J and Type H morphologies showed that (i) the particle diameter increased with increasing hydrophobicity; (ii) DMSO has a large effect on the aggregate size; (iii) Type J aggregates are of equal dimensions with Type H aggregates. Moreover, even though as the DMSO-water solvent composition is varied the UV/vis spectra of Type H and Type J aggregates remained unchanged, the number of molecules comprising each aggregate varies widely. It is proposed that the dynamic conversion (J →> H) results from intramolecular reorganization of individual molecules within the aggregate. Quantification of aggregation through DLS has further developed the "kinetic" versus "thermodynamic" control model of dye aggregation.Key words: squaraine, dynamic light scattering, DMSO-water mixtures, self-assembly, kinetic/thermodynamic control.

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10

Rhodes, Samuel, Wenlang Liang, Xiaochen Wang, Nitin Ramesh Reddy, and Jiyu Fang. "Transition from H-Aggregate Nanotubes to J-Aggregate Nanoribbons." Journal of Physical Chemistry C 124, no. 21 (May 1, 2020): 11722–29. http://dx.doi.org/10.1021/acs.jpcc.0c02908.

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11

Miller, J. J., E. Bremer, B. W. Beasley, C. F. Drury, B. J. Zebarth, and F. J. Larney. "Long-term effect of fresh and composted cattle manure on the size and nutrient composition of dry-sieved soil aggregates." Canadian Journal of Soil Science 92, no. 4 (May 2012): 673–83. http://dx.doi.org/10.4141/cjss2011-056.

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Miller, J. J., Bremer, E., Beasley, B. W., Drury, C. F., Zebarth, B. J. and Larney, F. J. 2012. Long-term effect of fresh and composted cattle manure on the size and nutrient composition of dry-sieved soil aggregates. Can. J. Soil Sci. 92: 673–683. Application of feedlot manure to cropland may impact the size distribution and nutrient content of soil aggregates. The objective of this study was to determine the effects of fresh or composted feedlot manure containing straw or wood-chip bedding on dry-sieved aggregate size distribution and nutrient contents. Surface (0–15 cm) soil samples were obtained from a long-term field experiment where treatments were fresh (FM) or composted manure (CM) containing straw or wood-chips applied annually at 0 (control) or 77 Mg ha−1yr−1for 11 yr. Air-dried soil samples were separated using a rotary sieve into six aggregate size fractions ranging from <0.47 mm to >12.7 mm. Total C, total N, C:N ratio, soil mineralizable N (41-d incubation), total P, soil test P, and P saturation index were determined on the six aggregate fractions. The amendments significantly (P≤0.05) increased the proportion of smaller (<0.47 mm) aggregates and decreased the proportion of the larger (>12.7 mm) aggregates relative to the unamended control. The geometric mean diameter (GMD) was also lower and wind erodible fraction (WEF) was greater for the amended treatments than unamended control. We attributed this manure effect to increased organic matter content in the soil making the aggregates more friable and susceptible to breakdown by tillage. Carbon, N, and P concentrations were not shifted to smaller aggregate sizes where root growth and nutrient uptake are generally greater. The exception was mineralizable N, which tended to be greater in the finer<0.47 mm fraction. Mineralizable soil N in all aggregate sizes ≥0.47 mm was reduced for wood-chip compared with straw bedding, and resulted in net N immobilization in aggregate sizes ≥1.2 mm. Phosphorus sorption was lower in soil amended with wood-chips compared with straw bedding for aggregates ≥0.47 mm. Long-term manure application may shift soil aggregates from larger to finer fractions because of greater friability and suggests that these soils should be managed to avoid the greater risk of wind erosion.

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12

Whitten, David G., Komandoor E. Achyuthan, Gabriel P. Lopez, and Oh-Kil Kim. "Cooperative self-assembly of cyanines on carboxymethylamylose and other anionic scaffolds as tools for fluorescence-based biochemical sensing." Pure and Applied Chemistry 78, no. 12 (January 1, 2006): 2313–23. http://dx.doi.org/10.1351/pac200678122313.

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We recently found that certain cyanines form tight complexes with carboxymethylamylose (CMA) in aqueous solutions and that in these complexes the cyanine exists as a strongly fluorescent and stable J-aggregate. Cyanine dyes are characterized by their ability to form J-aggregates showing very narrow absorption and fluorescence spectra relative to the monomer. Although they have found uses in sensing applications, the practicability has been limited in many cases due to the low quantum efficiencies for J-aggregate fluorescence. The CMA-cyanine complex is formed by a cooperative self-assembly in which both components undergo conformational changes during the association. The CMA exists as a random coil in solution prior to complex formation; helix formation is prevented due to repulsion of the charges on the carboxymethylated glucose units. The cyanine exists as a nonfluorescent monomer in the same solutions. A helical atomic force microscopy image and large induced circular dichroism (CD) spectra of the cyanine J-aggregate indicate that the self-assembly is a superhelix scaffold of CMA decorated with J-aggregates of the cyanine. Similar behavior was also observed with carboxymethylated cellulose (CMC). Enzymatic disruption of the helical structures (e.g., by the use of amylase to disrupt the structure of CMA helix) leads to the disappearance of the J-aggregate-associated fluorescence. The photophysical behavior and applications of this complex for sensing are discussed.

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13

Yakar, Ozan, Osman Balci, Burkay Uzlu, Nahit Polat, Ozan Ari, Ilknur Tunc, Coskun Kocabas, and Sinan Balci. "Hybrid J-Aggregate–Graphene Phototransistor." ACS Applied Nano Materials 3, no. 1 (December 11, 2019): 409–17. http://dx.doi.org/10.1021/acsanm.9b02039.

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14

Michetti, P., and G. C. La Rocca. "Photophysics of J-aggregate microcavities." physica status solidi (b) 245, no. 6 (June 2008): 1055–58. http://dx.doi.org/10.1002/pssb.200777607.

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15

Hämisch, Benjamin, and Klaus Huber. "Mechanism and equilibrium thermodynamics of H- and J-aggregate formation from pseudo isocyanine chloride in water." Soft Matter 17, no. 35 (2021): 8140–52. http://dx.doi.org/10.1039/d1sm00979f.

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Pseudo isocyanine chloride monomers equilibrate with H-oligomers and, separated by a threshold, with H-oligomers and fiber-like J-aggregates. The mechanism and thermodynamics of J-aggregate formation is interpreted with the concept of chain growth.

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16

Ma, Hongmin, Shuting Sun, Xin Chen, Dan Wu, Peihua Zhu, Bin Du, and Qin Wei. "Spectroscopic studies of aggregation behavior of meso-tetra(4-hydroxyphenyl)porphyrin in aqueous AOT solution." Journal of Porphyrins and Phthalocyanines 12, no. 02 (February 2008): 101–8. http://dx.doi.org/10.1142/s1088424608000133.

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The interactions of two amphiphilic porphyrins with anionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in aqueous solutions were studied by UV-vis absorption spectroscopy, fluorescence spectroscopy, resonance light scattering technique, fluorescence anisotropy and surface tension measurements. The two porphyrins, meso-tetra(4-hydroxyphenyl)porphyrin (THPP) and meso-tetra(3,5-dibromo-4-hydroxylphenyl)porphyrin (T(DBHP)P), exist as irregular aggregates in aqueous solutions with a broad and low absorption peak near the maximum of monomer peak. The interaction of THPP with AOT leads to the formation of a fluorescent aggregate of porphyrin which was assigned as J-type aggregate according to exciton theory. A long red-shifted Soret band together with a new strong Q-band, a broad emission peak and a sharply peaked resonance light scattering signal are observed for this J-aggregate. The formation of J-aggregate is independent of the initial THPP concentration and can be influenced greatly by ionic strength. The aggregation kinetics has been investigated by UV-vis absorption spectroscopy and fluorescence anisotropy. Conversion of the porphyrin monomers to J-aggregate is observed. The addition of THPP increases the surface tension of solution and changes the critical micelle concentration of AOT. J-aggregate was not observed for T(DBHP)P in AOT solutions which only shows solubilization. The mechanism of aggregation was discussed.

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17

Malyukin, Yu V., A. V. Sorokin, S. L. Yefimova, and A. N. Lebedenko. "Photo-induced reorganization of molecular packing of amphi-PIC J-aggregates (single J-aggregate spectroscopy)." Journal of Luminescence 112, no. 1-4 (April 2005): 429–33. http://dx.doi.org/10.1016/j.jlumin.2004.09.082.

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18

Wang, Enheng, Richard M. Cruse, Xiangwei Chen, and Aaron Daigh. "Effects of moisture condition and freeze/thaw cycles on surface soil aggregate size distribution and stability." Canadian Journal of Soil Science 92, no. 3 (March 2012): 529–36. http://dx.doi.org/10.4141/cjss2010-044.

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Wang, E., Cruse, R. M., Chen, X. and Daigh, A. 2012. Effects of moisture condition and freeze/thaw cycles on surface soil aggregate size distribution and stability. Can. J. Soil Sci. 92: 529–536. Freeze/thaw cycles can affect soil aggregate stability, which in turn impacts wind and water erosion. The objectives of this laboratory study were: (1) to determine the effect of variable freeze/thaw cycles and soil water conditions on aggregate size distribution and stability; and (2) to evaluate differences in aggregate size distribution and stability between disturbed soil and undisturbed soil cores as affected by freeze/thaw cycles and soil water conditions. Surface soil was collected before freezing in late fall of 2009. Aggregates isolated from disturbed soil or intact soil cores were subjected to a factorial combination of 3 gravimetric water content treatments: 0.15 m3 m−3, 0.23 m3 m−3 or 0.30 m3 m−3, and 3 freeze/thaw treatments: 0, 3, or 9 cycles. A freeze/thaw cycle involved soil freezing at –10∘C for 24 h, followed by thawing at 5∘C for 24 h. Most aggregate size classes were affected significantly (P<0.05) by freeze/thaw cycles except for wet-sieved aggregates >5 mm. Dry-sieved aggregates were relatively more sensitive to the freeze/thaw treatment than wet-sieved aggregates. The mean weight diameter (MWD) of dry-sieved aggregates was significantly (P<0.05) greater at 0.30 m3 m−3 than 0.15 m3 m−3 water content, but the opposite trend was observed for MWD of wet aggregates and aggregate stability. There was a significant (P<0.05) response of the MWD in dry-sieved aggregates to the interactive freeze/thaw×water content effect that differed for aggregates obtained from disturbed soil and those in the undisturbed soil core, but not for the MWD of wet-sieved aggregates and aggregate stability.

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19

Schomakers, Jasmin, Franz Zehetner, Axel Mentler, Franz Ottner, and Herwig Mayer. "Study of soil aggregate breakdown dynamics under low dispersive ultrasonic energies with sedimentation and X-ray attenuation." International Agrophysics 29, no. 4 (October 1, 2015): 501–8. http://dx.doi.org/10.1515/intag-2015-0057.

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Abstract It has been increasingly recognized that soil organic matter stabilization is strongly controlled by physical binding within soil aggregates. It is therefore essential to measure soil aggregate stability reliably over a wide range of disruptive energies and different aggregate sizes. To this end, we tested highaccuracy ultrasonic dispersion in combination with subsequent sedimentation and X-ray attenuation. Three arable topsoils (notillage) from Central Europe were subjected to ultrasound at four different specific energy levels: 0.5, 6.7, 100 and 500 J cm-3, and the resulting suspensions were analyzed for aggregate size distribution by wet sieving (2 000-63 μm) and sedimentation/X-ray attenuation (63-2 μm). The combination of wet sieving and sedimentation technique allowed for a continuous analysis, at high resolution, of soil aggregate breakdown dynamics after defined energy inputs. Our results show that aggregate size distribution strongly varied with sonication energy input and soil type. The strongest effects were observed in the range of low specific energies (< 10 J cm-3), which previous studies have largely neglected. This shows that low ultrasonic energies are required to capture the full range of aggregate stability and release of soil organic matter upon aggregate breakdown.

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20

Feller, K. H., R. Gadonas, V. Krasauskas, V. Fidler, and S. Vajda. "Time-Resolved Spectroscopy of Polymethine J-Aggregates." Laser Chemistry 11, no. 1 (January 1, 1991): 1–12. http://dx.doi.org/10.1155/lc.11.1.

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The deactivation process of J-aggregates of DDEOCI (3,3'-diethyl-5,5'-diphenyl-9-ethyl-oxacarbocyanine iodide) was investigated by means of steady-state and time-resolved absorption and fluorescence spectroscopy. The decay kinetics as well as the transient absorption spectra have been analyzed including different aggregate structures and exciton-exciton annihilation.

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21

Knoester, Jasper. "Modeling the optical properties of excitons in linear and tubular J-aggregates." International Journal of Photoenergy 2006 (2006): 1–10. http://dx.doi.org/10.1155/ijp/2006/61364.

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The theory of the optical properties of linear and tubular molecular J-aggregates is reviewed. The primary optical excitations in these systems are Frenkel excitons, which may be delocalized over many molecules. The collective nature of these excitations gives rise to special optical properties and dynamics, which are of interest for purely scientific reasons, but also enable the application of J-aggregates as photographic sensitizers and artificial light-harvesting systems. The focus of this paper is on the effect of aggregate geometry, disorder, and temperature on the absorption and fluorescence spectra. Also transport of excitations between J-aggregates is discussed. Connection is made to experiments on aggregates of cyanine dyes and natural light-harvesting systems.

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22

Shapiro, B. I. "Nanoarchitecture of Aggregates of Polymethine Dyes." Fine Chemical Technologies 14, no. 2 (May 20, 2019): 5–14. http://dx.doi.org/10.32362/2410-6593-2019-14-2-5-14.

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In recent years, the class of polymethine (cyanine) dyes has attracted increasing attention of researchers in the field of nanotechnology due to the structural features of their chromophore system and their tendency to form polymolecular states – dye aggregates. The processes of the formation of aggregates with new optical and electronic properties in aqueous solutions were studied as exemplified by anionic thyatrimethinecyanine dyes. It was shown that the aggregates are formed by a “block” mechanism from dimers. The nanoarchitecture of the aggregates is determined by the type of the alkyl substituent in the meso position of the polymethine chain of the dye. The C2H5 group promotes the formation of long-wavelength J-aggregates with the “brickwork” packing of molecules. The CH3 group promotes the formation of short-wave H-units with the “stepladder” packing of molecules. The formation of spatial isomers – J- and H-aggregates from cis and trans conformations of dye molecules – was established. Inorganic and organic cations, which stabilize highly organized aggregate structures, have a significant effect on the formation of aggregated forms of anionic dyes. Thus, the work presents the author's ideas about a new scientific direction – the nanoarchitecture of aggregates of polymethine dyes.

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23

Mal’tsev, Eugene I., Dmitry A. Lypenko, Boris I. Shapiro, Maria A. Brusentseva, George H. W. Milburn, Jeffrey Wright, Andre Hendriksen, Vladimir I. Berendyaev, Boris V. Kotov, and Anatoly V. Vannikov. "Electroluminescence of polymer/J-aggregate composites." Applied Physics Letters 75, no. 13 (September 27, 1999): 1896–98. http://dx.doi.org/10.1063/1.124864.

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24

Shen, Chia-An, and Frank Würthner. "NIR-emitting squaraine J-aggregate nanosheets." Chemical Communications 56, no. 68 (2020): 9878–81. http://dx.doi.org/10.1039/d0cc03686b.

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25

Thilagam, A. "Entanglement dynamics of J-aggregate systems." Journal of Physics A: Mathematical and Theoretical 44, no. 13 (March 1, 2011): 135306. http://dx.doi.org/10.1088/1751-8113/44/13/135306.

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26

Sorokin, A. V. "Influence of pseudoisocyanine J-aggregate agglomeration on the optical properties." Functional materials 25, no. 1 (March 28, 2018): 088–92. http://dx.doi.org/10.15407/fm25.01.088.

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27

Uemori, Yoshio, Hiroki Munakata, Sakiko Kitazawa, Astuko Osada, and Hiroyasu Imai. "Optically active J-aggregate formed from water-soluble porphyrin with phenylalanine." Journal of Porphyrins and Phthalocyanines 16, no. 12 (December 2012): 1285–92. http://dx.doi.org/10.1142/s1088424612501441.

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A water-soluble porphyrin bearing multi-dentate ligands was prepared, and its aggregation behavior in solution under various conditions (temperature, pH, metal ion, chiral compound) was investigated using UV-vis absorption spectroscopy, fluorescence spectroscopy, circular dichroism (CD) spectroscopy. Upon the addition of Ca2+, Ba2+ , or Sr2+ to a solution of porphyrin, the porphyrin first forms an H-aggregate and is then transformed to a J-aggregate at 25 °C in buffered aqueous solution (pH 7.4). On the other hand, the porphyrin forms a self-aggregate (H-aggregate) at 25 °C in buffered aqueous solution (pH 6.0), and the H-aggregate does not form the J-aggregate upon the addition of the group II metal ions. The measurement of CD spectra revealed that the H-aggregate that forms right after the addition of Ba2+ to the porphyrin solution in the presence of D- or L-phenylalanine does not show an induced CD signal, while the J-aggregate formed from the H-aggregate shows induced CD signals in the Soret region.

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28

Yulnafatmaawita, Ita. "CHARACTERISTICS OF MECHANICALLY FRACTIONATED AGGREGATES OF TWO CONTRASTING SOILS." Jurnal Solum 9, no. 1 (March 23, 2014): 1. http://dx.doi.org/10.25077/js.1.1.1-8.2004.

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Tillage often decreases physical condition of agricultural land, especially aggregate degradation which causes land and environmental quality decreased. As aggregates disperse into single particles, chemical properties of the soil could change. The objective of this research was to study whether or not mechanical fractionation causes soil dispersion indicating by different chemical properties. Aggregates of two soils, Vertisol and Oxisol, were degraded by using puddler at 3 different energy rates (40, 60, and 150 J kg-1 soil minute-1) and then were separated into 3 different sizes (2000-20, 20-2, <2 um). Therefore, each soil sample would have 15 soil separates at different energy and aggregate size. The result showed that aggregate fractionation especially the fraction size, in general, affected EC, ESP, and CEC but not pH of both soils. The pattern of EC and CEC values seemed to be equal, the highest values were found at the smallest aggregate size (< 2 um). The CEC values of Oxisols did not affected by fractionation, while CEC values of Vertisols increased by decreasing aggregate size, and decreased by increasing energy applied. This indicated that Vertisol is easier to disperse than Oxisol.

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29

Dagesse, Daryl F. "Freezing cycle effects on water stability of soil aggregates." Canadian Journal of Soil Science 93, no. 4 (September 2013): 473–83. http://dx.doi.org/10.4141/cjss2012-046.

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Dagesse, D. F. 2013. Freezing cycle effects on water stability of soil aggregates. Can. J. Soil Sci. 93: 473–483. The freezing process is commonly implicated as a key factor in defining the state of soil structural stability following the winter months. Controversy exists, however, regarding the efficacy, and even the net effect, of this process. The objective of the study was to establish the separate effects of the freezing, freeze–thaw and freeze-drying processes in defining soil structural stability following the over-winter period. Aggregates from soils of varying clay content (0.11, 0.33, 0.44 kg kg−1) and initial water content (0.10, 0.20 or 0.30 kg kg−1) were subjected to freeze-only (F), freeze–thaw (FT) and freeze-dry (FD) treatments. Post-treatment aggregate stability determination was via wet aggregate stability (WAS) and dispersible clay (DC). Freezing alone and freeze-dry treatments generally resulted in greater aggregate stability, while the freeze–thaw generally resulted in lower aggregate stability as compared with a control, not frozen treatment (T). These data suggest the freezing-induced desiccation process improves aggregate stability, while the addition of a thaw component following freezing, with the attendant liquid water, is responsible for degradation of aggregate stability. Clay content and initial water content are important factors governing the magnitude of this process.

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Cacciola, Adriano, Claudia Triolo, Omar Di Stefano, Armando Genco, Marco Mazzeo, Rosalba Saija, Salvatore Patanè, and Salvatore Savasta. "Subdiffraction Light Concentration by J-Aggregate Nanostructures." ACS Photonics 2, no. 7 (June 25, 2015): 971–79. http://dx.doi.org/10.1021/acsphotonics.5b00197.

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Gallos, L. K., A. V. Pimenov, I. G. Scheblykin, M. Van der Auweraer, G. Hungerford, O. P. Varnavsky, A. G. Vitukhnovsky, and P. Argyrakis. "A Kinetic Model for J-Aggregate Dynamics†." Journal of Physical Chemistry B 104, no. 16 (April 2000): 3918–23. http://dx.doi.org/10.1021/jp993655z.

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Kato, Noritaka, Toshinori Serata, Kentaro Saito, and Yoshiaki Uesu. "Novel Thermochromism of Merocyanine J-Aggregate Monolayers." Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals 349, no. 1 (September 2000): 199–202. http://dx.doi.org/10.1080/10587250008024899.

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Koti, A. S. R., Jharna Taneja, and N. Periasamy. "Control of coherence length and aggregate size in the J-aggregate of porphyrin." Chemical Physics Letters 375, no. 1-2 (June 2003): 171–76. http://dx.doi.org/10.1016/s0009-2614(03)00866-2.

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KE, JIAN-HONG, ZHEN-QUAN LIN, and YOU-YI ZHUANG. "SCALING THEORY FOR INTERMEDIARY-ACTIVATED MIGRATION PROCESSES." International Journal of Modern Physics B 18, no. 17n19 (July 30, 2004): 2628–32. http://dx.doi.org/10.1142/s0217979204025816.

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We study kinetic behavior of the growth of A aggregates through reversible migrations between the B intermediaries and the A aggregates. In a model with the migration rate kernels K(k;j)=K'(k;j)∝kujv (u,v≥0) at which monomers migrate from the aggregates Ak of size k to the B intermediaries of size j, we find that for all cases with 0≤u<2 and v>0, the size distribution of A aggregates always obeys the conventional scaling form. When v=0, A aggregates may scale according to a logarithm-correction form. Moreover, the typical aggregate size of A aggregates grows as tv/(2-u) in the v>0 case and as ( ln t)1/(2-u) in the v=0 case.

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35

Ávila-Rovelo, Nelson Ricardo, and Amparo Ruiz-Carretero. "Recent Progress in Hydrogen-Bonded π-Conjugated Systems Displaying J-Type Aggregates." Organic Materials 02, no. 01 (January 2020): 047–63. http://dx.doi.org/10.1055/s-0040-1708502.

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Supramolecular approaches are of great interest in the design of functional materials. The types of aggregates arising from different noncovalent interactions endow materials with intriguing properties. In this sense, J-type aggregates are very attractive due to their unique optical properties and capacity to transport excitons. These features make them great candidates in the design of materials for organic electronic devices. Furthermore, the incorporation of additional hydrogen-bonding functionalities provides J-aggregates with superior directionality and connection among the different π-conjugated cores. The control over the formation of H-bonds to achieve functional aggregates is therefore a promising strategy towards controlled structures with specific functions.This review outlines the most relevant and recent works of π-conjugated systems exhibiting J-type aggregates resulting from hydrogen-bonding interactions. Different types of hydrogen-bonding functionalities will be discussed together with their roles in the aggregate properties, their impact in the optoelectronic properties, the self-assembly mechanisms, and their applications in organic electronics.

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Cavael, Ulrike, Philipp Tost, Katharina Diehl, Frederick Büks, and Peter Lentzsch. "Correlations of Soil Fungi, Soil Structure and Tree Vigour on an Apple Orchard with Replant Soil." Soil Systems 4, no. 4 (December 3, 2020): 70. http://dx.doi.org/10.3390/soilsystems4040070.

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The soil-borne apple replant disease (ARD) is caused by biotic agents and affected by abiotic properties. There is evidence for the interrelation of the soil fungal population and soil aggregate structure. The aim of this study conducted between March and October 2020 on an orchard in north-east Germany was to detect the correlations of soil fungal density, soil structure and tree vigour under replant conditions in a series of time intervals. By using the replant system as the subject matter of investigation, we found that replanting had an impact on the increase of soil fungal DNA, which correlated with a mass decrease of large macro-aggregates and an increase of small macro- and large micro-aggregates in the late summer. Increased proportions of water-stable aggregates (WS) with binding forces ≤ 50 J mL−1, decreased proportions of WS > 100 J mL−1 and a decrease of the mean weight diameter of aggregates (MWD) emphasised a reduction of aggregate stability in replant soils. Correlation analyses highlighted interactions between replant-sensitive soil fungi (Alternaria-group), the loss of soil structure and suppressed tree vigour, which become obvious only at specific time intervals.

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Kitahama, Yasutaka, Tomoaki Yago, Akihiro Furube, and Ryuzi Katoh. "Formation process of micrometer-sized pseudoisocyanine J-aggregates studied by single-aggregate fluorescence spectroscopy." Chemical Physics Letters 457, no. 4-6 (May 2008): 427–33. http://dx.doi.org/10.1016/j.cplett.2008.04.021.

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Micali, Norberto, Valentina Villari, Maria Angela Castriciano, Andrea Romeo, and Luigi Monsù Scolaro. "From Fractal to Nanorod Porphyrin J-Aggregates. Concentration-Induced Tuning of the Aggregate Size." Journal of Physical Chemistry B 110, no. 16 (April 2006): 8289–95. http://dx.doi.org/10.1021/jp060730e.

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KACHANOSKI, R. G., R. P. VORONEY, and E. G. GREGORICH. "ULTRASONIC DISPERSION OF AGGREGATES: DISTRIBUTION OF ORGANIC MATTER IN SIZE FRACTIONS." Canadian Journal of Soil Science 68, no. 2 (May 1, 1988): 395–403. http://dx.doi.org/10.4141/cjss88-036.

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Aggregates (1–2 mm) from a soil under continuous corn management were subjected to a mild shaking treatment and ultrasonic energy levels ranging from 100 to 1500 J mL−1 water to determine the degree of aggregate disruption and dispersion. More clay- and fewer sand-size particles were recovered with greater amounts of applied energy indicating greater aggregate disruption and dispersion with higher energy levels. Most of the breakdown of sand-size aggregates occurred between energy levels of 300 and 500 J mL−1. Ultrasonic energy levels of 500 J mL−1 or greater were more effective than using 20% hydrogen peroxide plus 16 h of shaking in dispersing sand-size microaggregates. Surface area measurements of the clay indicated no severe fragmentation or alteration of primary particles had occurred. With increased applied ultrasonic energy and more complete dispersion, the amount of organic C recovered increased in the clay- and decreased in the sand-size fractions. At complete dispersion, there was no evidence of redistribution of organic matter by ultrasonification and the sand-, silt- and clay-size fractions contained 5, 30 and 60% of the soil organic C. Results of this study suggest that ultrasonic dispersion techniques can be used as a physical method to separate microaggregates from soil and thereby study the nature of organic matter within them. Key words: Ultrasonic dispersion methodology, aggregates, organic matter distribution, particle size fractions

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Harada, Takunori, Hiroshi Moriyama, Hiromi Takahashi, Kazuo Umemura, Haruo Yokota, Ryo Kawakami, and Kenji Mishima. "Spectroscopic Characterization of Supramolecular Chiral Porphyrin Homoassociates at the Air–Water Interface." Applied Spectroscopy 68, no. 11 (November 2014): 1235–40. http://dx.doi.org/10.1366/13-07432.

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The water-soluble 4-sulfonatophenyl meso-substituted porphyrin (TPPS) dye exhibits a transformation to a chiral self-aggregate from the non-aggregated species (diprotonated H4TPPS2–) at low concentration (no more than 1 × 10−5 M). Immobilization of supramolecular chiral porphyrin homoassociates was mediated by the electrostatic interaction between the anionic TPPS molecule and cationic surfactant monolayer at the air–water interface. With the immobilization, a reversible transformation from monomeric TPPS to J-aggregate ( M→J) could be changed into an irreversible ( M→J), which is desirable for stabilization of aggregation structure for a long period. The novel finding was achieved using a fine-tuned specialized solid-state circular dichroism (CD) spectrophotometer and derived analytical procedure to obtain artifact-free CD signals. To our knowledge, this is the first report achieving the chiral control of a homoassociate induced by a chiral surfactant at the air–water interface, indicating that the handedness of the formed homoassociate could be determined.

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Kirstein, Stefan, Hans von Berlepsch, and Christoph Böttcher. "Photo-induced reduction of Noble metal ions to metal nanoparticles on tubular J-aggregates." International Journal of Photoenergy 2006 (2006): 1–7. http://dx.doi.org/10.1155/ijp/2006/47917.

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Palladium and silver nanoparticles are formed on the surface of tubular J-aggregates of an amphiphilic tetrachlorobenzimidacarbocyanine dye by reduction of the respective metal cations in aqueous solution. Upon addition of the palladium complex Na2PdCl4to the aggregate solution, the absorption spectrum shows significant changes which is explained by partial destruction of the aggregates. Cryogenic transmission electron microscopy (cryo-TEM) images show that the tubular J-aggregates are randomly covered by well-separated Pd nanoparticles of approximately 1–3 nm size. Larger particles and higher particle density along the aggregates are obtained when an auxiliary reducing agent is added to the solution. The presence of the metallic particles leads to efficient fluorescence quenching giving clear evidence for super quenching. In similar experiments using AgNO3, silver nanoparticles are grown which are larger in size but less dense distributed along the aggregates. At least in the case of the silver particles, the spontaneous formation of metal nanoparticles is assumed to be initiated by a photo-induced electron transfer process (PET).

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Kawasaki, Mitsuo, Satoshi Aoyama, and Eishi Kozawa. "Enhanced Intra-Aggregate Charge Separation from Binary Excitons in Mixed J-Aggregates of Cyanine Dyes." Journal of Physical Chemistry B 110, no. 48 (December 2006): 24480–85. http://dx.doi.org/10.1021/jp065598x.

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NAKAZAWA, Takahiro, Hideki SAKAI, Masahiko ABE, Hirobumi SHIBATA, and Mutsuyoshi MATSUMOTO. "Patterning of Langmuir-Blodgett Films with J-aggregate." Journal of the Japan Society of Colour Material 80, no. 10 (2007): 409–13. http://dx.doi.org/10.4011/shikizai1937.80.409.

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Dimitriev, O. P., Yu P. Piryatinski, and Yu L. Slominskii. "Abnormal Emission in the Heterogeneous J-Aggregate System." Journal of Physical Chemistry C 123, no. 47 (November 4, 2019): 28611–19. http://dx.doi.org/10.1021/acs.jpcc.9b08248.

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Occhiuto, Ilaria, Giovanna De Luca, Mariachiara Trapani, Luigi Monsù Scolaro, and Robert F. Pasternack. "Peripheral Stepwise Degradation of a Porphyrin J-Aggregate." Inorganic Chemistry 51, no. 19 (September 13, 2012): 10074–76. http://dx.doi.org/10.1021/ic301570p.

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Wang, Hao, Yanlin Ke, Ningsheng Xu, Runze Zhan, Zebo Zheng, Jinxiu Wen, Jiahao Yan, et al. "Resonance Coupling in Silicon Nanosphere–J-Aggregate Heterostructures." Nano Letters 16, no. 11 (October 6, 2016): 6886–95. http://dx.doi.org/10.1021/acs.nanolett.6b02759.

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Moshino, Hiroko, Soukaku Hasegawa, Syuji Mouri, Yasuhiro F. Miura, and Michio Sugi. "Kinetics of Hydrothermally Induced Reorganization of J-Aggregate." Japanese Journal of Applied Physics 47, no. 2 (February 15, 2008): 1034–41. http://dx.doi.org/10.1143/jjap.47.1034.

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Grande, Vincenzo, Bartolome Soberats, Stefanie Herbst, Vladimir Stepanenko, and Frank Würthner. "Hydrogen-bonded perylene bisimide J-aggregate aqua material." Chemical Science 9, no. 34 (2018): 6904–11. http://dx.doi.org/10.1039/c8sc02409j.

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Spano, Frank C., and Carlos Silva. "H- and J-Aggregate Behavior in Polymeric Semiconductors." Annual Review of Physical Chemistry 65, no. 1 (April 2014): 477–500. http://dx.doi.org/10.1146/annurev-physchem-040513-103639.

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Patil, Avinash J., Young-Chul Lee, Ji-Won Yang, and Stephen Mann. "Mesoscale Integration in Titania/J-Aggregate Hybrid Nanofibers." Angewandte Chemie 124, no. 3 (December 7, 2011): 757–61. http://dx.doi.org/10.1002/ange.201101383.

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