八核钼过氧化合物的合成、表征和转化

Synthesis,characterization and transformation of peroxo octamolybdate complex

以乳酸为模板剂,在强酸性钼过氧水溶液中分离到新的八核钼过氧化合物K_4[Mo_8O_(24)(O_2)2(H_2O)_2]·4H_2O(1)。1在弱酸性条件下转化为七核钼过氧化合物K_6[Mo_7O_(22)(O_2)_2]·9H_2O(2),转化后钼过氧合物的核数发生变化,但过氧基团的数目不变。1的阴离子为γ-Mo_8O_(26)构型,与强酸性钼酸盐溶液中的[Mo_8O_(26)]^(4-)离子结构相似。1的结构中具有罕见的超短过氧基团[1.308(6)],其对应的红外振动吸收峰为953 cm^(-1)。1的紫外可见光谱最大吸收波长为302 cm^(-1),可能是由过氧基团到钼原子的荷移跃迁引起的。

A novel peroxo octamolybdate complex K4[Mo8O（24）（ O2）2（ H2O）2]·4H2O（ 1） was synthesized by S-lactic acid as a template in strong acidic peroxo molybdenum solution.1 transforms to K6[Mo7O（22）（ O2）2]·9H2O（ 2） in weak acidic solution. After the transformation,the nuclear number of the peroxo molybdenum complex changes,but the number of peroxo groups remains unchanged.The anion of 1 contains γ-Mo8O（26） unit,which is similar with the structure of the anion[Mo8O（26）]^（4-）. The bond distance of peroxo group is unexpectedly short[1. 308（ 6） ]and the corresponding IR vibration frequency is 953 cm^（-1）. The maximun absortion wavelength of UV specrum of 1 is 302 cm^（-1）. It may be caused by the charge tranfer from peroxo group to molybdenum atom.