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The determination of the subduction coefficients for states of the unitary group U(n) under the restrictions U(n) ↓ U(n1) ? U(n2) have been considered for the spin free states of many electron systems. Using the transformation properties of the tensor basis spanning the irreducible representation 〈2N/2–S, 12S〉 of U(n) under the permutations of electron coordinates, a simple programmable procedure has been developed for the determination of these coefficients. The procedure has been illustrated using a simple example. 相似文献
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Nucleosides and Nucleotides. Part 16. The Behaviour of 1-(2′-Deoxy-β-D -ribofuranosyl)-2(1H)-pyrimidinone-5′-triphosphate, 1-(2′-Deoxy-β-D -ribofuranosyl-2(1H))-pyridinone-5′-triphosphate and 4-Amino-1-(2′-desoxy-β-D -ribofuranosyl)-2(1H)-pyridinone-5′-triphosphate towards DNA Polymerase The behaviour of nucleotide base analogs in the DNA synthesis in vitro was studied. The investigated nucleoside-5′-triphosphates 1-(2′-deoxy-β-D -ribofuranosyl)-2(1 H)-pyrimidinone-5′-triphosphate (pppMd), 1-(2′-deoxy-β-D -ribofuranosyl)-2(1 H)-pyridinone-5′-triphosphate (pppIId) and 4-amino-1-(2′-deoxy-β-D -ribofuranosyl)-2(1 H)-pyridinone-5′-triphosphate (pppZd) can be considered to be analogs of 2′-deoxy-cytidine-5′-triphosphate. However, their ability to undergo base pairing to the complementary guanine is decreased. When pppMd, pppIId or pppZd are substituted for pppCd in the enzymatic synthesis of DNA by DNA polymerase no incorporation of these analogs is observed. They exhibit only a weak inhibition of the DNA synthesis. The mode of the inhibition is uncompetitive which shows that these nucleotide analogs cannot serve as substrates for the DNA polymerase. 相似文献
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Ferdinand Krner Markus Schürmann Hans Preut Wolfgang Kreiser 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):76-77
Esterification of a single diastereomer of 2‐(4‐methylenecyclohex‐2‐enyl)propanol, (II), with (1R,4S)‐(+)‐camphanic acid [(1R,4S)‐4,7,7‐trimethyl‐3‐oxo‐2‐oxabicyclo[2.2.1]heptane‐1‐carboxylic acid] leads to the crystalline title compound, C20H28O4. The relative configuration of the camphanate was determined by X‐ray diffraction analysis. The outcome clarifies the relative and absolute stereochemistry of the naturally occurring bisabolane sesquiterpenes β‐turmerone and β‐sesquiphellandrene, since we have converted (II) into both natural products via a stereospecific route. 相似文献
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Luis E. Seijas Gerzon E. Delgado Asilo J. Mora Ali Bahsas Alexander Briceo 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(5):o303-o305
In the title compound, also known as N‐carbamoyl‐l ‐proline, C6H10N2O3, the pyrrolidine ring adopts a half‐chair conformation, whereas the carboxyl group and the mean plane of the ureide group form an angle of 80.1 (2)°. Molecules are joined by N—H...O and O—H...O hydrogen bonds into cyclic structures with graph‐set R22(8), forming chains in the b‐axis direction that are further connected via N—H...O hydrogen bonds into a three‐dimensional network. 相似文献
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Mateusz F. Serafin Kraig A. Wheeler 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(11):o620-o621
The title bimolecular compound, C4H5N3·C21H18O2, constructed from 2‐aminopyrimidine and 3,3,3‐triphenylpropanoic acid, forms a tetramolecular hydrogen‐bonded motif via O—H...N, N—H...O and N—H...N contacts. This aggregate organizes to give crystal‐packing motifs with hydrophilic and hydrophobic regions. 相似文献
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《Acta Crystallographica. Section C, Structural Chemistry》2017,73(9):688-691
Metalloporphyrin complexes containing an additional imidazole ligand can provide information about the effect of deprotonation or hydrogen bonding on the axial histidine unit in heme proteins. The title high‐spin five‐coordinate imidazolate‐ligated iron(II) porphyrinate, [K(C18H36N2O6)][Fe(C4H5N2)(C44H28N4)]·C4H6N2·2C4H8O, has been synthesized and investigated. The solvated salt crystallizes with one 2‐methylimidazole molecule, two tetrahydrofuran solvent molecules and a potassium cation chelated inside a cryptand‐222 (4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane) molecule. The imidazolate ligand is ordered. The average Fe—Np (Np is a porphyrin N atom) bond length is 2.113 (11) Å and the axial Fe—NIm (NIm is an imidazolate N atom) is 2.0739 (13) Å. The out‐of‐plane displacement of the FeII atom from the 24‐atom mean plane is 0.6098 (5) Å, indicating an apparent doming of the porphyrin core. 相似文献
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Shar S. Al‐Shihry Anthony Linden 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):m40-m42
The title compound, [Fe(C5H5)(C21H21O3)], was obtained from successive Stobbe condensations between ketones and dimethyl succinate. The succinic anhydride five‐membered ring is distorted significantly from planarity, with the butadiene moiety being twisted by 49.3 (2)° from planarity and the C atoms at the succinic anhydride end of the alkene bonds showing significant pyramidalization. The cyclopentadiene rings of the ferrocenyl moiety adopt an almost eclipsed conformation. 相似文献
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Wen Zhenyi 《International journal of quantum chemistry》1986,29(6):1779-1787
By use of the graphical method of spin algebra, simple, and closed expressions for SN1+N2 ? SN1 ? SN2 and U(n1 + n2) ? U(n1) ? U(n2), subduction coefficients are derived. 相似文献
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Yang‐Yi Yang Lap Szeto Gang‐Feng Ouyang Zhong‐Qi Huang Wing‐Tak Wong Seik Weng Ng 《应用有机金属化学》2005,19(3):352-353
There are two types of Cd in the title compound, the six‐coordinated Cd atom in the cation is in a distorted octahedral geometry while the four‐coordinated Cd in the anion shows a distorted tetrahedral geometry. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Eric P. Kelson Norman S. Dean Edgar Algarín 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(3):m108-m110
The title compound, [Ru(C6H6NO2)2(C15H11N3)(H2O)]·CH3CN·H2O, is a transfer hydrogenation catalyst supported by nitrogen‐donor ligands. This octahedral RuII complex features rare monodentate coordination of 3‐methoxy‐2‐pyridonate ligands and interligand S(6)S(6) hydrogen bonding. Comparison of the title complex with a structural analog with unsubstituted 2‐pyridonate ligands reveals subtle differences in the orientation of the ligand planes. 相似文献
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Co(CH3)(PMe3)4 forms 100 % regioselectively with (2‐(2‐diphenylphosphanyl)phenyl)‐1,3‐dioxalane and 2‐diphenylphosphanyl‐pyridine, by elimination of methane, the four‐membered metallacycles Co{(C3O2HC6H3)P(C6H5)2}(PMe3)3 ( 1 ) and Co{(CNC4H3)P(C6H5)2}(PMe3)3 ( 4 ). The regioselectivity is independent of the steric requirement of the ortho substituent in the 2‐diphenylphosphanylaryl‐ligands. Oxidative addition with iodomethane transforms 1 and 4 into octahedral, diamagnetic low‐spin d6 complexes Co(CH3)I‐{(C3O2HC6H3)P(C6H5)2}(PMe3)2 ( 2 ) and Co(CH3)I‐{(CNC4H3)P(C6H5)2}(PMe3)2 ( 5 ). Under an atmosphere of carbon monoxide, insertion into the Co‐C bond results in ring expansion by forming the new assembled phosphanylbenzoyl complexes Co{(C4O3HC6H3)‐P(C6H5)2}CO(PMe3)2 ( 3 ) and Co{(OCNC4H3)P(C6H5)2}CO(PMe3)2 ( 6 ). The three different types of cobaltacycles are supported by X‐ray diffraction of 1 , 3 , 5 and 6 . 相似文献
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Michael A. Shestopalov Olga A. Efremova Anton I. Smolentsev Yuri V. Mironov Vladimir E. Fedorov Yong‐Won Song 《Helvetica chimica acta》2011,94(10):1786-1791
A new germanium complex, cis‐[Ge(pyca)2(OH)2]?2 H2O ( 1 ; pyca=pyridine‐2‐carboxylato), was synthesized by the reaction of [Ge(acac)2Cl2] (acac=acetylacetonato=pentane‐2,4‐dionato) with potassium pyridine‐2‐carboxylate (Kpyca) in H2O/THF. According to the single‐crystal X‐ray diffraction analysis, each Ge‐atom of 1 is coordinated by two pyca ligands and two OH? groups (Fig. 1). These molecules are bonded to each other via a system of H‐bonds resulting in a sheet‐like structure (Fig. 2). The complex is decomposed during heating with stepwise mass loss and formation of GeO2 as final product (Fig. 3). 相似文献