Dimolybdenum(III) Complexes of −OSi(OtBu)3, −O2P(OtBu)2, and −OB[OSi(OtBu)3]2 as Single-Source Molecular Precursors to Molybdenum-Containing, Multi-Component Oxide Materials

The following dimolybdenum complexes containing −OSi(OtBu)3, −O2P(OtBu)2, and −OB[OSi(OtBu)3]2 ligands have been synthesized and structurally characterized:  Mo2(NMe2)4[OSi(OtBu)3]2 (1), Mo2(OtBu)4[OSi(OtBu)3]2 (2), Mo2(NMe)4{OB[OSi(OtBu)3]2}2 (3), Mo2(NMe2)2[μ-O2P(OtBu)2]2[O2P(OtBu)2]2 (4), Mo2(NMe2)2[OSi(OtBu)3]2[μ-O2P(OtBu)2]2 (5), and Mo2(NMe2)2[μ-O2P(OtBu)2]2{OB[OSi(OtBu)3]2}2 (6). The isolation and structural characterization of trans-
and cis-isomers of complexes 4 and 5 (4a and 4b, 5a and 5b, respectively) are also reported.
Studies of the thermal decompositions of the complexes (by thermogravimetric analysis and
solution 1H NMR spectroscopy) were performed. Xerogels with approximate compositions of
2MoO1.5·2P2O5 and 2MoO1.5·2P2O5·2SiO2 were derived from 4a and 5a or 5b, respectively,
via solution thermolyses (toluene). The as-synthesized (and dried) xerogels contain one equiv
of HNMe2 per molybdenum center (by combustion analysis, IR spectroscopy, and thermogravimetric analysis), and these materials have high surface areas (up to 270 m2 g-1). Upon
calcination at 300 °C, the coordinated amines are lost and the surface areas are significantly
reduced (to 40 m2 g-1 and

以下含有−OSi(OtBu)3、−O2P(OtBu)2和−OB[OSi(OtBu)3]2配体的钼配合物已合成并进行了结构表征：Mo2(NMe2)4[OSi(OtBu)3]2 (1), Mo2(OtBu)4[OSi(OtBu)3]2 (2), Mo2(NMe)4{OB[OSi(OtBu)3]2}2 (3), Mo2(NMe2)2[μ-O2P(OtBu)2]2[O2P(OtBu)2]2 (4), Mo2(NMe2)2[OSi(OtBu)3]2[μ-O2P(OtBu)2]2 (5), 以及Mo2(NMe2)2[μ-O2P(OtBu)2]2{OB[OSi(OtBu)3]2}2 (6)。复合物4和5（分别为4a和4b，5a和5b）的顺式和反式异构体的分离和结构表征亦已报道。对复合物的热分解进行了研究（通过热重分析和溶液1H NMR光谱学）。从4a和5a或5b分别通过溶液热解（甲苯）得到了具有约2MoO1.5·2P2O5和2MoO1.5·2P2O5·2SiO2组成的凝胶。所合成的（并干燥）凝胶每摩尔钼中心含有等当量的HNMe2（通过燃烧分析、红外光谱和热重分析确定），这些材料具有极高的比表面积（高达270 m2 g-1）。在300°C煅烧后，配位的胺基丧失，比表面积显著减小（降至40 m2 g-1）