排序方式: 共有77条查询结果,搜索用时 31 毫秒
1.
The structures of the inclusion compounds formed by the host 9,9’-(ethyne-1,2-diyl)bis(fluoren-9-01) with pyridine and picolines are similar and display tubular topology. The host discriminates poorly between
these guests. The kinetics of desorption of the pyridine compound is governed by the Avrami-Erofe’ev equation A2, with an
activation energy of 111(7) kJ mol−1. 相似文献
2.
Luigi R. Nassimbeni Sevi Papanicolaou Madeleine H. Moore 《Journal of inclusion phenomena and macrocyclic chemistry》1986,4(1):31-42
The structures of Ni(NCS)2(4-PhPy)4·4DMSO and Ni(NCS)2(3-MePy)4·CHCl3 have been elucidated. Movement of guest molecules through channels in the host structure was simulated by potential energy calculations. Ni(NCS)2(3,5-diMePy)4 does not form inclusion compounds. An intra-molecular potential energy study shows that theortho-hydrogens on the 3,5-dimethylpyridine ligands control the conformation of the molecule. The same result is obtained with the 4-methylpyridine ligand, which suggests that the extent of rotation of substituted pyridines about the Ni–N bounds is not a factor governing clathrate formation.
Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82030 (43 pages). 相似文献
3.
M. R. Caira A. Coetzee L. R. Nassimbeni E. Weber A. Wierig 《Supramolecular chemistry》2013,25(4):235-241
Abstract This study dealt mainly with the structure-reactivity relationship of selected organic inclusion compounds. The crystal structures of the inclusion compounds of three related hosts, 2,2′–bis(2,7–di-tert-butyl-9–hydroxy-9–fluorenyl)biphenyl, 2,2′–bis (2,7–dichloro-9–hydroxy-9–fluoienyl)biphenyl and 2, 2′–bis(2,7-dibromo-9–hydroxy-9–fluorenyl)biphenyl with 1,4–dioxane (Compound 1), 1,3–dioxane (Compound 2) and 1,3–dioxolane (Compound 3) respectively were elucidated, using single crystal X-ray crystallography. It was found that the guests were either located in channels or constricted channels (cavities), formed by the host framework. The kinetics of desolvation of these compounds were studied and their activation energies were compared. 相似文献
4.
Nassimbeni Luigi R. Niven Margaret L. Stuart Debra A. Zemke Klaus J. 《Journal of chemical crystallography》1986,16(4):557-567
The crystal structure of the 21 channel complex of desoxycholic acid and ethyl acetate has been investigated at 298 and 163 K. The space group isP212121(No. 19) with four molecules of desoxycholic acid in the unit cell. The ethyl acetate molecules are enclathrated along the 21 axes parallel toc and exhibit differing degrees of disorder in the low- and room-temperature structures. Differences in the disorder imply that it is both statistical and dynamic in nature. Our best model for each structure yieldsR=0.064 [R
w
=0.058,w=(
2
F)–1] andR=0.068 [R
w
=0.064,w=(
2
F)
–1
] for the ambient- and low-temperature studies respectively.IUPAC Nomenclature: 3, 12-dihydroxy-5-cholan-24-oic acid. 相似文献
5.
6.
7.
8.
Luigi R. Nassimbeni Margaret L. Niven Johannes J. Cruywagen J. Bernard B. Heyns 《Journal of chemical crystallography》1987,17(1):99-107
The crystal structure of the product of the reaction between [(–)Co(en)3]I3 and a mixture of Na2MoO4 and NaHC2O4 in aqueous solution is reported: [(–)Co(en)3][MoO3(C2O4)OH2]I·2H2O, space groupP212121,a=8.131(2),b=14.590(4),c=17.509(4) Å;Z=4. FinalR=0.048,R
w=0.050,w=(
2
F)–1 for 1899 reflections. The configuration of the Mo(VI) oxalate complex differs notably from that proposed previously on the basis of chemical analysis and equilibrium studies. 相似文献
9.
Ayesha Jacobs Luigi R. Nassimbeni Amina Sayed Edwin Weber 《Journal of chemical crystallography》2011,41(6):854-857
Abstract
Racemic 1,1′-binaphthyl-2,2′-dicarboxylic acid (BNDA) was resolved using quinine as the resolving agent. The structure of the resultant quininium (S)-1,1′-binaphthyl-2,2′-dicarboxylate dihydrate salt (1) was elucidated. The asymmetric unit contained one 1,1′-binaphthyl-2,2′-dicarboxylate anion, two quininium cations and two water molecules. The structure was solved successfully in the orthorhombic space group P212121 with unit cell dimensions: a = 11.100(2) ?, b = 16.572(3) ?, c = 28.726(6) ?. 相似文献10.