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This paper presents a postulate for a new approach in the measurement of households’ satisfaction from durable consumer goods, based on a modified inflation expectation measurement method used in survey research. The authors examine the application of a three-step qualitative evaluation, followed by the quantification of responses using a modified Carlson and Parkin method adopted in the context of the free tangent law. 相似文献
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Relation between the substituent effect and aromaticity 总被引:1,自引:0,他引:1
Krygowski TM Ejsmont K Stepień BT Cyrański MK Poater J Solà M 《The Journal of organic chemistry》2004,69(20):6634-6640
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Roman Gajda Maciej Makowski Krzysztof Ejsmont 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(2):o80-o83
tert‐Butoxycarbonylglycyl‐dehydroalanyl‐glycine methyl ester (systematic name: methyl {2‐[(tert‐butoxycarbonylamino)acetamido]prop‐2‐enamido}acetate) (Boc0‐Gly1‐ΔAla2‐Gly3‐OMe), C13H21N3O6, has been structurally characterized by single‐crystal X‐ray diffraction and by density functional theory (DFT) calculations at the B3LYP/6–311+G** level. The peptide chain in both the solid‐state and calculated structures adopts neither β nor γ turns. All amino acid residues in the tripeptide sequence are linked trans to each other. The bond lengths and valence angles of the amino acid units in the crystal structure and gas phase are comparable. However, the conformation of the third glycyl residue (Gly3) is different in the crystalline state and in the gas phase. It is stabilized in the calculated structure by an additional intramolecular short contact between Gly3 NH and methyl ester COMe groups. 相似文献
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William H. Watson Krzysztof Ejsmont Jie Liu Michael G. Richmond 《Journal of chemical crystallography》2006,36(8):509-515
The tricobalt cluster MeC(O)CCo3(CO)9 reacts with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-l,3-dione (bpcd) in the presence of added Me3NO to furnish the disubstituted cluster MeC(O)CCo3(CO)7(bpcd) in good yield. MeC(O)CCo3(CO)7(bpcd) has been characterized in solution by IR and NMR (1H and 31P) spectroscopies, and the solid-state structure determined by X-ray crystallography. MeC(O)CCo3(CO)7(bpcd) crystallizes in the monoclinic space group P21/c, a=14.8421(8), b=16.6162(9), c=14.9363(8) ?, β=99.705(1)°, V=3630.9(3) ?3, Z=4, D
cacl=1.632 Mg/m3; R=0.0288, R
w=0.0683 for 8618 observed reflections with I > 2σ(I). The bridging of adjacent cobalt atoms by the bpcd ligand in MeC(O)CCo3(CO)7(bpcd) is crystallographically established, and the facile isomerization of the bridging bpcd to the chelating isomer at low temperature is confirmed by VT 31P NMR measurements. 相似文献
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Krzysztof Ejsmont Jacek Zaleski Isaac H. Joe Victor S. Jayakumar 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(10):o553-o555
The structure of the title compound, 2C4H9N2O3+·C2O42−, which has been determined by X‐ray diffraction, contains discrete glycylglycine (HGly–Gly)+ cations in general positions and oxalate anions which lie across centres of inversion. Although the geometry of the (HGly–Gly)+ cation is not significantly different compared with other structures containing this residue, a few changes in conformation are observed which indicate the presence of molecular interactions. The molecular network in the crystal consists of one nearly linear O—H⋯O, five N—H⋯O and two weak C—H⋯O hydrogen bonds. 相似文献
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Andrzej Domaski Krzysztof Ejsmont Janusz B. Kyzio Jacek Zaleski 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):467-470
Two isomeric trans‐4‐aminoazoxybenzenes, trans‐1‐(4‐aminophenyl)‐2‐phenyldiazene 2‐oxide (α, C12H11N3O) and trans‐2‐(4‐aminophenyl)‐1‐phenyldiazene 2‐oxide (β, C12H11N3O), have been characterized by X‐ray diffraction. The α isomer is almost planar, having torsion angles along the Caryl—N bonds of only 4.9 (2) and 8.0 (2)°. The relatively short Caryl—N bond to the non‐oxidized site of the azoxy group [1.401 (2) Å], together with the significant quinoid deformation of the respective phenyl ring, is evidence of conjugation between the aromatic sextet and the π‐electron system of the azoxy group. The geometry of the β isomer is different. The non‐substituted phenyl ring is twisted with respect to the NNO plane by ca 50°, whereas the substituted ring is almost coplanar with the NNO plane. The non‐oxidized N atom in the β isomer has increased sp3 character, which leads to a decrease in the N—N—C bond angle to 116.8 (2)°, in contrast with 120.9 (1)° for the α isomer. The deformation of the C—C—C angles (1–2°) in the phenyl rings at the substitution positions is evidence of the different character of the oxidized and non‐oxidized N atoms of the azoxy group. In the crystal structures, molecules of both isomers are arranged in chains connected by weak N—H?O (α and β) and N—H?N (β) hydrogen bonds. 相似文献
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Tuning the Electronic Properties of the Dative N−B Bond with Associated O−B Interaction: Electron Localizability Indicator from X‐Ray Wavefunction Refinement 下载免费PDF全文
Dr. Lilianna Chęcińska Dr. Stefan Mebs Dr. Borys Ośmiałowski Dr. Anna Zakrzewska Dr. Krzysztof Ejsmont Dr. M. Kohout 《Chemphyschem》2016,17(15):2395-2406
Despite the immense growth in interest in difluoroborate dyes, the nature of the interactions of the boron atom within the N‐BF2‐O kernel is not yet fully understood. Herein, a set of real‐space bonding indicators is used to quantify the electronic characteristics of the dative N?B bond in difluoroborate derivatives. The atoms‐in‐molecules (AIM) partitioning scheme is complemented by the electron localizability indicator (ELI‐D) approach, and both were applied to experimental and theoretical electron‐density distributions (X‐ray constrained wavefunction fitting vs. DFT calculations). Additionally, Fermi orbital analysis was introduced for small DFT models to support and extend the findings for structures that contain BF2. 相似文献