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141.
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143.
Synthesis of carboxylated chlorophyll derivatives and their activities in dye-sensitized solar cells
Hitoshi Tamiaki Norihisa Hagio Shinsaku Tsuzuki Yuxiao Cui Taisuke Zouta Xiao-Feng Wang Yusuke Kinoshita 《Tetrahedron》2018,74(30):4078-4085
Chlorophyll-a derivatives possessing a carboxy group in the substituent at the 3-position were prepared by chemical modification of methyl pyropheophorbide-d bearing the 3-formyl group via a Wittig, Barbier-type, or Knoevenagel reaction. The synthetic carboxylated chlorophyll pigments were employed as dye sensitizers for solar cells and their performances were compared in a conventional device based on a mesoporous titanium dioxide electrode and a liquid electrolyte. The solar power conversion efficiency was suppressed with an increase in the length of the oligomethylene moiety between the chlorin π-system and the carboxy group, while a corresponding π-linked ethenylene spacer enhanced the efficiency. 相似文献
144.
Gold-silver alloy colloids were produced in epoxy resin by thermal decomposition of gold and silver complexes, and their optical absorption spectra were measured. A linear law was found for the maximal absorption wavelengths: the maximal absorption wavelength for gold-silver alloy colloids of arbitrary composition was determined from the wavelengths for pure gold and pure silver colloids and the initial concentration ratio of gold and silver complexes. The change of absorbance and absorption wavelengths with heating periods is presented. Copyright 2001 Academic Press. 相似文献
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146.
Takashi Nishikaze Junko Amano 《Rapid communications in mass spectrometry : RCM》2009,23(23):3787-3794
A sample preparation method that is suitable for sensitive detection of underivatized oligosaccharides by matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) has been investigated. As compared with the conventional dried‐droplet or ethanol (EtOH) recrystallization method, superior mass spectra in terms of ion yield and signal‐to‐noise (s/n) ratio were obtained when methanol (MeOH) was used as a solvent for the mixture of matrix and oligosaccharides. Based on these results, a new sample preparation method, named the ‘reverse thin layer method’, was developed. This method comprises two steps: first, complete drying of the oligosaccharide solution on the MALDI target plate; and second, deposition of the matrix dissolved in a small amount of MeOH. Using this method, a relatively homogeneous matrix crystal was generated and higher yields of both positive and negative ions were obtained from oligosaccharides compared with conventional methods. Notably, the method can be applied to various matrices including both solid and liquid matrices. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
147.
Shinsaku Fujita 《Journal of mathematical chemistry》2001,30(3):249-270
Among the four methods of the unit-subduced-cycle-index (USCI) approach, the subduced-cycle-index (SCI) method and the partial-cycle-index (PCI) method have been discussed by using adamantane of T
d
-symmetry as a probe for enumeration problems, where USCIs are derived on the basis of permutaion representations, coset representations (CRs) and marks. After the examination of the SCIs and PCIs, Pólya's theorem that is a standard method of chemical combinatorics has been derived from the USCI approach. As another approach, a new method called the characteristic-monomial (CM) method has been developed by virtue of charactereistic monomials (CMs). The CMs have been derived from Q-conjugacy representations and Q-conjugacy characters, which have been related to irreducible representations and irreducible characters of the standard repertoire of chemical group theory. The two approaches have been compared to discuss group-theoretical tools for chemical combinatorics on a common basis. 相似文献
148.
The submillimeter-wave rotational transitions of TiCl in the ground state were observed using a double-modulation technique. TiCl was generated in a DC-discharge of a mixture of TiCl4 vapor (less than 1 mTorr) and Ar buffer gas (80 mTorr) at a current of 200 mA. The 4Φ3/2, 4Φ5/2, 4Φ7/2, and 4Φ9/2 spin components of Ti35Cl (v=0, 1, 2) and Ti37Cl (v=0) were detected. The data were analyzed using effective rotational constants for each spin component as well as with the usual N2 reduced Hamiltonian. Recent Fourier transform and laser data were included in our fits and we confirm that the ground state of TiCl is a 4Φr electronic state. 相似文献
149.
Kazuaki Kudo Takuya Yoshizawa Takashi Hamada Jun Li Seiji Sakamoto Shinsaku Shiraishi 《Macromolecular rapid communications》2006,27(17):1430-1436
Summary: Four constitutionally isomeric copoly(amide acid)s (coPAAs), two alternating and two random, have been successfully obtained from the same combination of one non‐symmetrical alicyclic tetracarboxylic dianhydride (1.0 molar equivalents) and two symmetric aromatic diamines (0.5 molar equivalents each) by only slightly changing the reaction procedures. When the reaction mixture is subjected to chemical imidization conditions without isolation of coPAAs, the corresponding copolyimides (coPIs) are obtained in one pot. All of the coPIs are slightly yellow amorphous powders and the solubility of them is similar to each other. The glass transition temperatures of the alternating coPIs are lower in comparison to those of the random coPIs.
150.
The electroreduction of N-methyl, N-p-anisyl, and N-unsubstituted phthalimides with aldehydes in the presence of chlorotrimethylsilane and triethylamine gave intermolecularly coupled products, 3-hydroxy-3-(1-hydroxyalkyl)isoindolin-1-ones. The coupling products were reduced with Et3SiH/BF3·Et2O to 3-(1-hydroxyalkyl)isoindolin-1-ones, which were dehydrated to alkylideneisoindolin-1-ones. From N-unsubstituted phthalimides, Z-isomers of alkylideneisoindolin-1-ones were obtained stereospecifically. 相似文献