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Similar Molecular Structure (similar + molecular_structure)
Selected AbstractsIn situ detection of flavonoids in weld-dyed wool and silk textiles by surface-enhanced Raman scatteringJOURNAL OF RAMAN SPECTROSCOPY, Issue 10 2008Z. Jurasekova Abstract Luteolin and apigenin flavonoid have been detected in silk and wool fibres dyed with weld (Reseda luteola L.) through surface-enhanced Raman scattering (SERS) measurements carried out ,on the fibre'. For such purpose, Ag nanoparticles were produced and immobilised in situ via the laser photoreduction of a silver nitrate water solution in contact with the fibre. Control SERS spectra of pure luteolin and apigenin, as well as of mixtures of them, on analogous Ag nanoparticles were also obtained. In this work flavonoids with a similar molecular structure were identified on dyed fibres for the first time without previously hydrolysing the mordant,dye complex. Copyright © 2008 John Wiley & Sons, Ltd. [source] The Effect of Heavy Atoms on Photoinduced Electron Injection from Nonthermalized and Thermalized Donor States of MII,Polypyridyl (M=Ru/Os) Complexes to Nanoparticulate TiO2 Surfaces: An Ultrafast Time-Resolved Absorption StudyCHEMISTRY - A EUROPEAN JOURNAL, Issue 2 2010Sandeep Verma Abstract We have synthesized ruthenium(II), and osmium(II),polypyridyl complexes ([M(bpy)2L]2+, in which M=OsII or RuII, bpy=2,2,-bipyridyl, and L=4-(2,2,-bipyridinyl-4-yl)benzene-1,2-diol) and studied the interfacial electron-transfer process on a TiO2 nanoparticle surface using femtosecond transient-absorption spectroscopy. Ruthenium(II)- and osmium(II)-based dyes have a similar molecular structure; nevertheless, we have observed quite different interfacial electron-transfer dynamics (both forward and backward). In the case of the RuII/TiO2 system, single-exponential electron injection takes place from photoexcited nonthermalized metal-to-ligand charge transfer (MLCT) states. However, in the case of the OsII/TiO2 system, electron injection takes place biexponentially from both nonthermalized and thermalized MLCT states (mainly 3MLCT states). Larger spin,orbit coupling for the heavier transition-metal osmium, relative to that of ruthenium, accounts for the more efficient population of the 3MLCT states in the OsII -based dye during the electron-injection process that yields biexponential dynamics. Our results tend to suggest that appropriately designed OsII,polypyridyl dye can be a better sensitizer molecule relative to its RuII analogue not only due to much broader absorption in the visible region of the solar-emission spectrum, but also on account of slower charge recombination. [source] Different Photophysical Properties of Aryl-bipyridine Linked Pyrene and AnthraceneCHINESE JOURNAL OF CHEMISTRY, Issue 7 2005Xiong Fei Abstract 6-Phenyl-2,2,-bipyridine linked pyrene and anthracene were synthesized and their photophysical properties were measured in different solvents with different polarity. 4-Pyren-1,-yl-6-phenyl-2,2,-bipyridine (Ppbpy) showed significant solvent-dependent properities while 4-anthracen-yl-9,-yl-6-phenyl-2,2,-bipyridine (Apbpy) displayed solvent-independence, although they had similar molecular structure. Because of different twist angle between the arene and aryl-bipyridine, Ppbpy displayed intermixing behaviors of local excited state (1La and 1Lb) and intramolecular charge transfer (ICT), but Apbpy only showed the properties of local excited state 1La. [source] Rho1-GEFs Rgf1 and Rgf2 are involved in formation of cell wall and septum, while Rgf3 is involved in cytokinesis in fission yeastGENES TO CELLS, Issue 12 2005Tadashi Mutoh The Rho GTPase acts as a binary molecular switch by converting between a GDP-bound inactive and a GTP-bound active conformational state. The guanine nucleotide exchange factors (GEFs) are critical activators of Rho. Rho1 has been shown to regulate actin cytoskeleton and cell wall synthesis in the fission yeast Schizosaccharomyces pombe. Here we studied function of fission yeast RhoGEFs, Rgf1, Rgf2, and Rgf3. It was shown that these proteins have similar molecular structures, and function as GEFs for Rho1. Disruption of either rgf1 or rgf2 did not show a serious effect on the cell. On the other hand, disruption of rgf3 caused severe defects in contractile ring formation, F-actin patch localization, and septation during cytokinesis. Rgf1 and Rgf2 were localized to the cell ends during interphase and the septum. Rgf3 formed a ring at the division site, which was located outside the contractile ring and inside the septum where Rho1 was accumulated. In summary, Rgf1 and Rgf2 show functional redundancy, and roles of these RhoGEFs are likely to be different from that of Rgf3. Rho1 is likely to be activated by Rgf3 at the division site, and involved in contractile ring formation and/or maintenance and septation. [source] Four 7-aryl-substituted pyrido[2,3- d]pyrimidine-2,4(1H,3H)-diones: similar molecular structures but different crystal structuresACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009Jorge Trilleras Molecules of 1,3-dimethyl-7-(4-methylphenyl)pyrido[2,3- d]pyrimidine-2,4(1H,3H)-dione, C16H15N3O2, (I), are linked by paired C,H...O hydrogen bonds to form centrosymmetric R22(10) dimers, which are linked into chains by a single ,,, stacking interaction. A single C,H...O hydrogen bond links the molecules of 7-(biphenyl-4-yl)-1,3-dimethylpyrido[2,3- d]pyrimidine-2,4(1H,3H)-dione, C21H17N3O2, (II), into C(10) chains, which are weakly linked into sheets by a ,,, stacking interaction. In 7-(4-fluorophenyl)-3-methylpyrido[2,3- d]pyrimidine-2,4(1H,3H)-dione, C14H10FN3O2, (III), an N,H...O hydrogen bond links the molecules into C(6) chains, which are linked into sheets by a ,,, stacking interaction. The molecules of 7-(4-methoxyphenyl)-3-methylpyrido[2,3- d]pyrimidine-2,4(1H,3H)-dione, C15H13N3O3, (IV), are also linked into C(6) chains by an N,H...O hydrogen bond, but here the chains are linked into sheets by a combination of two independent C,H...,(arene) hydrogen bonds. [source] Four 2-amino-6-aryl-4-methoxy-11H -pyrimido[4,5- b][1,4]benzodiazepines: similar molecular structures but different crystal structuresACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2008Ricaurte Rodríguez 2-Amino-4-methoxy-6-phenyl-11H -pyrimido[4,5- b][1,4]benzodiazepine, C18H15N5O, (I), and its 6-(2-fluorophenyl)-, 6-(3-nitrophenyl)- and 6-(4-methoxyphenyl)- analogues, viz. C18H14FN5O, (II), C18H14N6O3, (III), and C19H17N5O2, (IV), respectively, all adopt molecular conformations which are almost identical, containing boat-shaped seven-membered rings. In each structure, paired N,H...N hydrogen bonds link the molecules into centrosymmetric dimers. In each of (I),(III), the dimers are further linked, forming a different three-dimensional framework in each case, while in compound (IV) the dimers are linked into sheets. The significance of this study lies in the observation of different crystal structures in four compounds whose molecular structures are very similar. 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