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排序方式: 共有396条查询结果,搜索用时 15 毫秒
1.
Anthony W. Coleman C. Mitchell Means Simon G. Bott Jerry L. Atwood 《Journal of chemical crystallography》1990,20(2):199-201
[NBu4][Br3] interacts with C6H6 to form an air-stable liquid clathrate. The tribromide anion reacts with phenol to give para-bromophenol in>95% yield. The HBr which is generated in the reaction combines with the Br– anion to form [Br-H-Br]–. The latter forms the basis for a new liquid clathrate, [NBu4][Br-H-Br]·n C6H6. The parent salt, [NBu4][Br3], crystallizes in the monoclinic space group C2/c witha=12.983(5),b=10.380(7),c=16.222(6) Å,=93.93(3)°, andD
c
=1.47 g cm–3 forZ=4. The final R value is 0.068 based on 787 observed reflections. 相似文献
2.
3.
A novel two-dimensional coordination polymer containing infinite, coherently pitched single and triple helical motifs is formed by the self-assembly of Cd2+, succinate, water and a bipyridyl ligand. 相似文献
4.
The crystal structure of iododimethyl(trimethylamine)aluminium has been determined from single-crystal X-ray diffraction data collected by counter methods. I(CH3)2Al · N(CH3)3 crystallizes in the othorhombic space group Pnma with cell dimensions a=12.59(1), b=10.75(1), c=7.58(1)å, and pcalc=1.58 g·cm?3 for Z=4. Least-squares refinement gave a final weighted R Value of 0.071 for 574 independet observed reflections. Each monomeric molecule lies on a crystallographic mirror plane with the trimethylamine and iododimethylaliminium groups in a staggered configuration about the aluminum nitrogen bond. 相似文献
5.
6.
Simon G. Bott Matthew Clark Joseph S. Thrasher Jerry L. Atwood 《Journal of chemical crystallography》1987,17(2):187-196
The X-ray structure of S-methyl(pentafluorosulfanyl)thiocarbamate, SF5NHC(O)SCH3, has been determined from three-dimensional diffractometer data and refined by full-matrix least-squares techniques. The crystals are monoclinic:P21/m,a=5.008 (5),b=7.811 (2),c=9.348 (4) Å, =99.08 (7)°, andZ=2; finalR=0.046 for 517 observed reflections. The structure comprises hydrogen-bonded (NHO) chains with the component monomers in thecis, cis-conformation, i.e., the arrangement of the nonhydrogen and nonfluorine atoms is nearly planar, the SF5 group and the O are in acis position with respect to the C-NH bond, and the O and the CH3 group are in acis position with respect to the C(O)-S bond. Theoretical methods including MNDO and molecular modeling were used to study the relative stabilities of the four possible conformations of SF5NHC(O)SCH3. 相似文献
7.
Brandon D. ConleyBurl C. Yearwood Sean ParkinDavid A. Atwood 《Journal of fluorine chemistry》2002,115(2):155-160
The preparation and characterization of the ammonium hexafluorosilicate salts, 2[R]+ [SiF6]2− (where R=piperidinium (2), methylammonium (3), quinolinium (4), acridinium (5), 2,2,6,6-tetramethylpiperidinium (6), and propylammonium (7)) is described.The salts were prepared from the reaction of the corresponding alkylammonium fluoride with silica gel. The compounds were characterized by NMR, IR, mass spectrometry and in the case of 1 (piperidinium fluoride), 2-4 by X-ray crystallography. Compounds 1-3 crystallize in the orthorhombic crystal system (space groups Iba2, Fdd2, and Pnnm, respectively), with Z=8, 14, and 4, respectively. Compound 4 crystallizes in the triclinic space group P-1, with Z=2. Compounds 1-4 exhibit hydrogen bonding. 相似文献
8.
Simon G. Bott Ulrich Kynast Jerry L. Atwood 《Journal of inclusion phenomena and macrocyclic chemistry》1986,4(3):241-246
18-crown-6 reacts with TiCl3 in CH2Cl2 to form a complex in which the crown ether functions as a tridentate ligand. Addition of moist hexane affords a molecular complex in which the crown ether functions as a bidentate ligand. A water molecule is bonded directly to the titanium atom and is further hydrogen bonded to three of the oxygen atoms of the crown. The deep blue crystals of the CH2Cl2 adduct belong to the monoclinic space groupP21/n witha=13.481(8),b=8.021(5),c=21.425(9) Å, =97.32(5)°, and
calc = 1.51 g cm–3 forZ=4. Refinement led to a conventionalR value of 0.040 based on 873 observed reflections. The Ti–O bond distances for the crown oxygen atoms are 2.123(8) and 2.154(9) Å, while the oxygen atom of the water molecule is bonded at 2.072(8) Å. The octahedral coordination sphere of the titanium atom is completed by the three chlorine atoms at distances of 2.340(5), 2.352(4), and 2.373(4) Å.
Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82034 (10 pages). 相似文献
9.
Jerry L. Atwood Hosny Elgamal Gregory H. Robinson Simon G. Bott James A. Weeks William E. Hunter 《Journal of inclusion phenomena and macrocyclic chemistry》1984,2(1-2):367-376
In contrast to aluminum alkyls, alkyl aluminum halides such as EtAlCl2 react with crown ethers to form cation-anion pairs which exhibit the liquid clathrate effect. Specifically, [12-C-4·AlCl2][AlCl3Et] and [18-C-6·AlCl2][AlCl3Et] have been isolated and characterized by X-ray diffraction techniques. The cations show aluminum in an octahedral environment made up of four of the oxygen atoms from the crown and two chlorine atoms. The 12-C-4 derivative crystallizes in the monoclinic space group P21/c with cell constants of a=7.497(4), b=22.121(8), c=12.339(5) Å, =94.99(3)o, and Z=4 for =1.43 g cm–3. Least-squares refinement based on 1413 observed reflections led to a final conventional R value of 0.093. The 18-C-6 complex belongs to the triclinic space group P1 with a=8.414(4), b=12.193(6), c=12.394(6) Å, =73.14(4), =86.07(4), =81.52(4)o, and Z=2 for =1.45 g cm–3. Refinement based on 2605 observed reflections led to R=0.063. The complex aluminum-containing species are related to a class of compounds called aluminoxanes. 相似文献
10.
William E. Hunter Jerry L. Atwood G. Fachinetti C. Floriani 《Journal of organometallic chemistry》1981,204(1):67-74
The crystal and molecular structure of (η5-C5H5)2Zr[C4(C6H5)4] has been determined by single crystal X-ray diffraction methods. The compound is isostructural with its titanium and hafnium analogues, and crystallizes in the monoclinic space group P21/n with unit cell parameters a = 13.790(5), b = 11.136(5), c = 18.692(7) », β = 92.82(4)°, and ?calc = 1.34 g cm?3 for Z = 4. Full-matrix least-squares refinement converged with a conventional R value of 0.049 for 2986 observed reflections. The metallocyclic ring is planar to within 0.05 », and the π-electron density is largely localized. The two independent ZrC(σ) bond lengths are 2.250(5) and 2.265(6) ». The ZrC(η5) distances range from 2.482(6) to 2.546(7) », and average 2.521(20) ». A comparison of zirconium- and hafnium-carbon bonds based on the data available shows that for M = Hf the MC bonds are shorter for all cases: C(sp), C(sp2), C(sp3), C(η5). 相似文献