Synthesis, Structure, and Reactivity of Molybdenum- and Tungsten-Indane Complexes with Tris(pyrazolyl)borate Ligand

The reaction of molybdenum complexes with a tris(pyrazolyl)borate ligand (Et4N[TpMo(CO)3] and Et4N[Tp*Mo(CO)3] (Tp = hydridotris(pyrazolyl)borate, Tp* = hydridotris(3,5-dimethylpyrazolyl)borate)) and InBr3 at a 1:1 molar ratio afforded molybdenum-indane complexes (Et4N[TpMo(CO)3(InBr3)] 1 and Et4N[Tp*Mo(CO)3(InBr3)] 2). In addition, tungsten-indane complexes, Et4N[TpW(CO)3(InBr3)] 3 and Et4N[Tp*W(CO)3(InBr3)] 4, were obtained by the reaction of corresponding tungsten complexes. Complex 4 reacted with H2O to form the hydrido complex Tp*W(CO)3H, in which the W-In bond was cleaved. On the other hand, 4 reacted with three equiv. of AgNO3 to form Et4N[Tp*W(CO)3{In(ONO2)}] 5, in which three substituents on the In were exchanged while retaining the W-In dative bond. Complexes 1-5 were fully characterized using NMR measurements and elemental analyses, and the structures of 1-5 and Et4N[Tp*W(CO)3] were determined via X-ray crystallography. These are the first examples of mononuclear molybdenum- and tungsten-indane complexes with Mo-In and W-In dative bonds.