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91.
The 13C chemical shift assignments of title compounds were made on the basis of their coupled and decoupled spectra. The size of the ipso and allylic 13CH coupling constants establish unequivocally the identity of symmetry related carbon pairs and show that several assignments reported previously are incorrect. 相似文献
92.
Misa V. Jovanovic Edward R. Biehl Patrice De Meester Shirley S. C. Chu 《Journal of heterocyclic chemistry》1984,21(6):1793-1800
The crystal structure of 4′-nitro-10-phenylphenothiazine, 1 , has been determined by the single crystal x-ray diffraction studies and consists of two independent molecules in the asymmetric cell unit with a pseudo-center of symmetry. The crystal belongs to the monoclinic System with the space group P21/c. The central ring of the phenothiazine ring system is in a boat conformation and the 4′-nitro substituent is in a boat-axial conformation with respect to the central ring of phenothiazine. Compound 1 is the first reported 10-aryl phenothiazine in which the 10-phenyl ring is perpendicular to the plane bisecting the dihedral angle of the phenothiazine nucleus. This geometry allows for resonance interaction between the lone pair of electrons on N10 and the 4′-nitro-10-phenyl ring which influences both the spectral properties and structure of the phenothiazine tricyclic ring. The correlation between the x-ray structure and 13C nmr spectral properties of 1 is discussed. The uv/vis and esr studies of the radical cation of 1 indicate that the 10-aryl ring is twisted with respect to the phenothiazine ring. 相似文献
93.
Dr. Tatsuya Morofuji Yu Matsui Misa Ohno Gun Ikarashi Prof. Naokazu Kano 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(22):6713-6718
Herein, a photocatalytic Giese-type reaction with alkylsilicates bearing C,O-bidentate ligands as stable alkyl radical precursors has been reported. The alkylsilicates were prepared in one step from organometallic reagents. Not only primary, secondary, and tertiary alkyl radicals, but also elusive methyl radicals, could be generated by using the present reaction system. The generated radicals were trapped by electron-deficient olefins bearing various functional groups to give the desired alkyl adducts. The silicon byproduct can be recovered after the photoreaction. The radical generation process was investigated by theoretical calculations, which provided an insight into the facile generation of methyl radicals from methylsilicate bearing C,O-bidentate ligands. 相似文献
94.
Akihide Hanaki 《Archiv der Mathematik》2018,111(1):43-46
Let p be a prime number. It is known that the standard module of a p-association scheme over a field of characteristic p is indecomposable. By examples, the converse of the above fact is not true. We will prove that, for a schurian association scheme, the standard module is indecomposable if and only if the association scheme is a p-scheme. 相似文献
95.
Using a backtracking algorithm along with an essential change to the rows of representatives of known 13 710 027 equivalence classes of Hadamard matrices of order 32, we make an exhaustive computer search feasible and show that there are exactly 6662 inequivalent skew‐Hadamard matrices of order 32. Two skew‐Hadamard matrices are considered SH ‐equivalent if they are similar by a signed permutation matrix. We determine that there are precisely 7227 skew‐Hadamard matrices of order 32 up to SH ‐equivalence. This partly settles a problem posed by Kim and Solé. As a consequence, we provide the classification of association schemes of order 31. 相似文献
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98.
We investigate the indecomposable decomposition of the modular standard modules of two families of association schemes of finite order. First, we show that, for each prime number p, the standard module over a field F of characteristic p of a residually thin scheme S of p-power order is an indecomposable FS-module. Second, we describe the indecomposable decomposition of the standard module over a field of positive characteristic of a wreath product of finitely many association schemes of rank 2. 相似文献
99.
100.