The flexibly-bridged hexadentate tetraanionic ligands, LH4 [LH4 = Schiff’s bases obtained by the condensation of methylene- or dithio-bis(salicylaldehyde) with S-methyldithiocarbazate and S-benzyldithiocarbazate], react with [MoO2(acac)2] in a 1 : 2 molar ratio in refluxing methanol to give complexes of the type [(MoO2)2L]. These complexes show an intense ν(Mo=O) band at 924—948 cm−1 and a broad but strong band at ca. 850 cm−1 due to weakened ν → Mo interactions. An oligomeric structure, in which each Mo(VI) ion achieves a pseudo-octahedral structure via M2)2L] reacts with monodentate ligands (D) like pyridine, 4-methylpyridine, and dimethylsulfoxide and forms six-coordinated complexes of the type [(MoO2)2L(D)2] which are monomers. Cyclic voltammetry measurements indicate that these MoVIO2 complexes are resistant to MoIVO reduction. → Mo interactions. An oligomeric structure, in which each Mo(VI) ion achieves a pseudo-octahedral structure via MoO → Mo bridging, has been suggested for these complexes. [(MoO → Mo bridging, has been suggested for these complexes. [(MoO
柔性桥接的六价四阴离子
配体 LH4 [LH4 = 亚甲基或二
硫代双(
水杨醛)与 S-甲基二
硫代卡巴
肼和 S-苄基二
硫代卡巴
肼缩合得到的希夫碱],在回流
甲醇中以 1 : 2 的摩尔比与 [ (acac)2]反应,得到 [(
MoO2)2L]类型的络合物。这些络合物在 924-948 cm-1 处显示出强烈的 ν(Mo=O)带,在约 850 cm-1 处显示出宽而强的带,这是由于ν(Mo=O)带被削弱所致。850 cm-1 处有一个宽而强的波段,这是由于ν → Mo 的相互作用减弱所致。低聚物结构中,每个 Mo(VI) 离子通过 M2)2L 实现了假八面体结构]与单齿
配体(D)(如
吡啶、4-
甲基吡啶和
二甲基亚砜)反应,形成了六配位的单体[( )2L(D)2]型配合物。循环伏安法测量结果表明,这些 MoVIO2 复合物具有抗 MoIVO 还原能力。→ Mo 的相互作用。有人认为这些络合物具有低聚物结构,其中每个 Mo(VI) 离子通过 MoO → Mo 桥接实现了假八面体结构。有人认为这些配合物具有[(MoO → Mo 桥接]结构。[(MoO