engleski

Synthesis of novel molybdenum(V) complexes: Structural characterization of two thiosemicarbazonato complexes [MoOCl2{;C6H4(O)CH:NNHC:SNHC6H5};] and [MoOCl2{;C10H6(O)CH:NNHC:SNHC6H5};] · CH3CN, and two oxohalomolybdates NH4[MoOCl4(CH3CN)] and [C5H5NH]2[MoOCl5] · CH2Cl2

Mononuclear oxomolybdenum(V) complexes with thiosemicarbazonato ligands as condensation products of aldehydes (salicylaldehyde, 2-hydroxynaphthaldehyde) with thiosemicarbazides (H2NNHC:SNHR ; R = H, CH3, C6H5) were prepared. The [MoOCl2HL] complexes (HL = thiosemicarbazonato ligand) were characterized by chemical analysis, IR spectroscopy, thermogravimetry and two of them, [MoOCl2{;C6H4(O)CH:NNHC:SNHC6H5};] and [MoOCl2{;C10H6(O)CH:NNHC:SNHC6H5};] Æ CH3CN, by single-crystal X-ray structural analysis. In both complexes the MoO3+ core is coordinated by a monobasic tridentate ONS thiosemicarbazonato ligand and two chloro ligands. The coordination around the molybdenum atom is a distorted octahedron. NH4[MoOCl4(CH3CN)] and unstable (C5H5NH)2[MoOCl5] Æ CH2Cl2 were isolated from the acetonitrile solution of (NH4)2[MoOCl5] and from the acetonitrile and dichloromethane (1:1) solution of (C5H5NH)2[MoOCl5], respectively. Isolation and structural characterization of NH4[MoOCl4(CH3CN)] from the acetonitrile solution suggests the [MoOCl4(CH3CN)] anion to be the reaction intermediate in the synthesis of molybdenum(V) thiosemicarbazonato complexes. (C5H5NH)2[MoOCl5] Æ CH2Cl2 is a rare example of a structurally characterized simple oxohalomolybdate(V) with a six-coordinate octahedral [MoOCl5]2 anion.

Oxomolybdenum(V) complexes; Thiosemicarbazone; X-ray crystal structure

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