Organometallic Mo–O–Bi complexes

The reaction between Ph3BiBr2 and wet [NBu4]2[MoO4] leads to a white solid that according to Klemperer and Liu analyses as [NBu4]2[BiPh3(MoO4)2] · 3H2O (1aq). Working under strictly anhydrous conditions allowed us the isolation of the solvate-free complex [NBu4]2[BiPh3(MoO4)2] (1), which in contrast to 1aq could also be characterised by means of single crystal X-ray diffraction. The results reveal a structure with a BiV ion being surrounded by three phenyl substituents and two molybdate units. Remarkably the resulting two MoVI–O–BiV linkages are linear and according to a DFT investigation this is due to a predominantly ionic interaction between the O and Bi atoms. Moreover a novel MoVI–O–BiIII complex, NBu4[{Cp∗Mo(O)2-μ-O-}2(Bi(o-tolyl)2)] (2), has been prepared via reaction of the coordination polymer [(Cp∗Mo(O)2)-μ-O-(Bi(o-tolyl)2)]n with [NBu4][Cp∗MoO3] and the crystal structure of 2 has been investigated. According to DFT results the character of the bonds within the bent Mo–O–Bi unit is described most appropriately as covalent. The structure of 2 is discussed also with respect to corresponding Mo–O–Bi moieties occurring in bismuthmolybdate catalysts, for which it could represent a molecular structural model.

Covalent Mo–O–Bi moities are found in the novel organometallic complex depicted, while structural analysis in combination with DFT calculations proved the interactions between molybdate anions and a bimuth(V) centre in a published compound to be of an electrostatic nature. Such complexes are interesting as molecular models for bismuthmolybdate catalysts.Figure optionsDownload as PowerPoint slide