苹果酸钼外消旋体的合成、光谱性质和结构表征

Abstract

[中文文摘]钼酸铵和外消旋苹果酸溶液反应得到外消旋苹果酸钼(VI)配合物,(NH4)4[Mo∧O2(S,S-Hmal)2]·[MoΔO2(R,R-Hmal)2],对该配合物进行了元素分析、电导测定、旋光和红外光谱表征 ,并测定了晶体结构 .该化合物晶体属单斜晶系,P21/a空间群,晶胞参数:a=0.8061(2)nm,b=1.3286(2)nm,c=1.3232(2)nm,β=91.80(2)°,V=1 .4164(9)nm3,Z=2,Dc=2.008g·cm-3,F(0 00)=864,μ=9.70cm-1,一致性因子 R=0.051,Rw=0.0 58.在该单核配合物阴离子中,钼上的两个苹果酸配体具有相同手性,它以α-烷氧基和α-羧基双齿配位形成畸变的八面体构型,而另一个β-羧酸则保持自由状态。[英文文摘]The complex (NH4)4 [Mo∧O2(S,S-Hmal)2]·[MoΔO2(R,R-Hmal)2] was prepared from the reaction of ammonium molybdate and R,S-malic acid at pH= 2—3. It w as characterized by elementary analysis, conductivity measurement,optical rotation, IR and X-ray diffraction. The complex cry stallizes in monoclinic space group P21/a with unit cell parameters:a=0. 8061(2)nm,b=1.3286(2)nm,c=1.3232(2)nm, β= 91.82(2)°,V=1.4164(9)nm3,Z= 2, Dc= 2.008g ·cm-3,F(000)=864,μ=9.700cm-1 for 1902 reflections with I≥3%(I).The molybdenum atom is coordinated by two bidentate homochiral malic acid in distorted octahedron,w hile the β-carboxy l groups remain uncomplexed.The crystal contains two isolated monomeric malatomoly bdates(Ⅵ)anions in the configurat ions of ∧-S,S and Δ-R,R.The two enantiomeric anions result in the formation of racemic compound. There is no evidence for the other diastereoisomers like (NH4)2[Mo∧O2(R,S-Hmal)2],(NH4)2[MoΔ O2 (R,S-Hmal)2],(NH4)2[Mo∧O2(R,R-Hmal)2]and ( NH4 )2[MoΔO2(S,S-Hmal)2] in this experiment.