Oxomolybdenum coordination compounds with alkyl-substituted pyridines. Solvothermal syntheses and structural characterization of [Mo 10O 26(3,5-Lut) 8]·2(3,5-Lut), [Mo 10O 26(3-MePy) 8]·(3-MePy), [Mo 10O 26(3-MePy) 8] and [Mo 12O 28(OCH 3) 2Cl 2(3-MePy) 8

Abstract

Reactions of (PyH) 2[MoOCl 5] with methanol and 3,5-lutidine or 3-methylpyridine carried out under conditions of solvothermal synthesis at 130°C have resulted in two Mo(V, VI) clusters containing the same molybdenum oxide framework, [Mo 10O 26(3,5-Lut) 8]·2(3,5-Lut) (3,5-Lut=3,5-lutidine (C 7H 9N)) ( i) and [Mo 10O 26(3-MePy) 8]·(3-MePy) (3-MePy=3-methylpyridine (C 6H 7N)) ( ii), and in a novel [Mo 12O 28(OCH 3) 2Cl 2(3-MePy) 8] ( iv). [Mo 10O 26(3-MePy) 8] ( iii) was also obtained by oxidizing (NH 4) 2[MoCl 5(H 2O)] in a mixture of methanol, 3-methylpyridine and nitromethane. X-ray structural analyses revealed Mo 2O 4 2+ unit as a common structural motif in both cluster types. In i– iii ten molybdenum atoms are grouped into four Mo 2 V pairs with MoMo bonds and two Mo(VI) sites. The oxomolybdenum core of iv is composed of six Mo 2 V pairs connected through oxo and methoxo bridges.