Synthesis and spectroscopic and structural characterization of racemic ammonium dimeric (malato)dioxomolybdenum
- 化学化工－已发表论文 
The complex (NH4)(4)[MoLambdaO2(S,S-Hmal)(2)] . [MoDeltaO2(R,R-Hmal)(2)] was prepared from the reaction of ammonium molybdate and R, S-malic acid at pH = 2-3. It was characterized by elementary analysis. conductivity measurement, optical rotation, IR and X-ray diffraction. The complex crystallizes in monoclinic space group P2(1)/a with unit cell parameters: a = 0. 806 1(2) nm, b = 1. 328 6(2) nm, c = 1. 323 2(2) nm. beta = 91.82(2)degrees, V = 1. 416 4(9) nm(3), Z = 2, D-c = 2.008 g (.) cm(-3), F(000) = 864, mu = 9.700 cm(-1) for 1 902 reflections with I greater than or equal to3 sigma (I). The molybdenum atom is coordinated by two bidentate homochiral malic acid in distorted octahedron, while the beta -carboxyl groups remain uncomplexed. The crystal contains two isolated monomeric malatomolybdates(VI) anions in the configurations of A-S,S and Delta -R,R. The two enantiomeric anions result in the formation of racemic compound. There is no evidence for the other diastereoisomers like (NH4)(2)[MOLambdaO2 (R, S-Hmal)(2)]. (NH4)(2)[MoDeltaO2(R, S-Hmal)(2)], (NH4)(2)[MOLambdaO2(R,R-Hmal)(2)] and (NH4)(2)[MoDeltaO2(S,S-Hmal)(2)] in this experiment.