X-ray crystal structure of a p-hydroxycalix[6]arene derivative

The first molecular structure of a p-hydroxycalix[6]arene 6 has been determined by a single crystal X-ray diffraction study. The calix[6]arene molecule assumes a 1,2,3-alternate conformation with all OH groups at the upper rim engaged in H-bonds with pyridine molecules. The stacking of molecules of p-hydroxycalix[6]arene 6 along the a and c axes gives rise to a solvent pseudo-cylindrical cavity at the centre of the cell.     

Electronic structure of the thiabenzene anion

Chemistry of Heterocyclic Compounds -     

Persulfuration of phosphinines: Synthesis and X-ray crystal structure analysis of a P2S3 derivative

The reaction of 4,5-dimethyl-2-phenylphosphinine with sulfur in boiling benzene in the presence of N-methylimidazole as a catalyst first yields a P-sulfide. This monosulfide further reacts with sulfur to give a diphosphinine trisulfide and a diphosphinine tetrasulfide. The X-ray crystal structure analysis of the trisulfide has been carried out. The two head-to-tail 1,6-dihydrophosphinine rings are connected by P S C and P C links, thus forming a central 1,2,4-thiadiphospholane heterocycle. The P C bridge is weak [1.881(3) Å] and sulfur can insert into it to give the symmetrical tetrasulfide with two P S C bridges.     

X-ray crystal structure of trimethylsilylmethyllithium

The solid state structure of trimethylsilylmethyllithium has been determined by single crystal X-ray diffraction techniques. The compound crystallizes in the monoclinic system, space group P2₁/n. Cell dimensions were determined as follows: a 10.931(3), b 18.397(6), c 21.490(8) Å, β 96.0(2)°, V 4298(2) ų, Z = 4, and a final R_f 5.1% based on 2203 data with σ(I) ≥ 2.5σ(I). The compound is formed by hexameric units, {LiCH₂Si(CH₃)₃}₆, with two distinct classes of LiLi distances of 2.46 and 3.18 Å. There are also two LiC distances av 2.20 and 2.27 Å. The LiH distances to the methylene H atoms have been determined and are short varying between 2.0 and 2.3 Å to the closest lithium atom. The structure, including possible LiH interactions, is discussed and compared with the other known hexameric aggregates.     

Absolute configuration of bourgeanic acid: X-ray crystal structure of a 4-bromophenacyl derivative of hemibourgeanic acid.

The absolute configuration of the asymmetric centers of bourgeanic acid has been determined from an X-ray crystallographic analysis of the 4-bromophenacyl ester of hemibourgeanic acid, which is thus 3S-hydroxy-2S,4R,6R-trimethyl-octanoic acid.     

X-ray crystal structure of a heterobimetallic Al-Zn-oxide complex

OH/R (R = H, Me, i-Bu) exchange was observed in reactions of [MesnacnacZn(μ-OH)](2) (1) with metal complexes L(n)MR, whereas DippnacnacAl(Me)OH reacts with MesnacnacZnH with elimination of H(2) and formation of the heterobimetallic Al-Zn-oxide complex MesnacnacZnOAl(Me)Dippnacnac 2.     

二茂铁衍生物的合成及单晶结构研究

近年来 ,二茂铁金属有机液晶材料因其特异的液晶性能和较高的应用价值 ,引起了人们广泛的研究兴趣 ,得到了迅速的发展 ,使该类液晶材料的种类不断增加[1～ 4] 。本文报道的二茂铁衍生物是一个含有苯基、酯基和Ｓｃｈｉｆｆｓ的金属有机化合物 ,是一种潜在的金属有机液晶材料 ,其合成路线如下 :1　实验1 1　仪器与试剂仪器 :显微熔点测定仪。核磁共振仪为ＲｒａＫｅｒＡＶＡＮＣＥ - 30 0Ｇ型 ,ＴＭＳ作为内标。红外光谱仪为Ｐｅｒｋｉｎ Ｅｌｍｅｒ1 730型 ,ＫＢｒ压片。单晶测定仪为ＳｉｅｍｅｎｓＰ4型衍射仪。试剂均为国产化学纯。1 2…     

Synthesis and crystal structure of a new methooytrichloro derivative of achillin

A new trichlorometoxy derivative of achillin was isolated from the mixture of chlorination products of achillin in MeOH. The structure of this product was established by X-ray diffraction analysis. This confirmed the previously proposed stereochemistry for the molecules of other two products of this reaction.     

Synthesis and crystal structure of a pyrazole derivative of artemisia ketone

The oxime of artemisia ketone is smoothly converted to the pyrazole derivative by sodium nitrite and acetic acid in CHCl₃. The structure of the pyrazole was found by x-ray structural analysis. The PMR and¹³C NMR spectra were interpreted using two-dimensional¹H–¹³C NMR (COSY, COLOC).Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 121–123, March–April, 2000.     

X-ray crystal structure of a lithium aldolate - a tetrameric aggregate

The aldol adduct formed from addition of pivalaldehyde to the lithium enolate of pinacolone crystallized directly from the reaction mixture and was subjected to x-ray diffraction analysis.     

Synthesis and X-ray single crystal structure of a bivalent glycocluster

The crystal structure of a bivalent glycocluster containing aromatic amides reveals that alkylation of secondary amides alters amide configuration and thus carbohydrate presentation. This also facilitates non covalent interactions (azide-azide, carbonyl-pyranose and aromatic-pyranose) and thus carbohydrate-carbohydrate stacking.     

Synthesis ofo-thiatelluraphenylenezirconocenes. X-ray crystal structure of

o-Thiatelluraphenylenezirconocene complexes were obtained in good yield by reaction of dilithiumo-benzenthiatelluride with zirconocene dichlorides. These compounds represent the first examples of heterodichalcogenaphenylene bent metallocences. They were characterized by spectroscopic methods and the effect on the n.m.r. results of stepwise substitution of one and two Te atoms for S is discussed. X-ray crystal structure analysis was performed for one representative complex. The structure is very similar to that previously reported for a diselenaphenylene complex, but the disorder observed for chalcogen atoms prevents an accurate comparison of the geometrical parameters with other related compounds.     

Preparation and X-ray crystal structure analysis of a stable trimethylsilyloxy epoxide

Reaction of trimethylsilyl enol ether6 with buffered m-chloroperbenzoic acid at 20°C leads efficiently to7, the first shelf-stable silyloxy epoxide. The structural dimensions of7 have been ascertained by means of X-ray crystallography.     

Chemical degradation and X-ray crystal structure of rosaramicin

The X-ray crystal structure of rosaramicin is reported.     

一例单缺位Dawson型多酸稀土衍生物的合成、结构及荧光性能研究

在常规水浴条件下成功合成了一例基于单缺位Dawson型二聚的多酸基稀土衍生物[TMA]_8[Tb(H_2O)_8]H_3[Tb(H_2O)_2P_2W_(17)O_(61)]_2·49H_2O (1),并对其进行了红外、X射线单晶衍射等结构表征以及荧光性能研究.X射线单晶衍射结构分析表明,该化合物属于三斜晶系,P-1空间群.其晶胞参数为a=1.313 76(3)nm,b=1.814 70(5) nm,c=1.990 26(6) nm,α=93.549 0°,β=97.273 0(10)°,γ=96.656 0(10)°,Z=1,Mr=10 461.62,V=4.660 9(2) nm~3,μ=22.528 mm~(-1),R_1=0.033 7,wR_2=0.067 0 [I>2σ(I)].此外,化合物1具有Tb~(3+)离子本征荧光发射峰.