Mononuclear anionic AO2X3 compounds with non-VSEPR structure

Abstract

The molybdenyl compound [NBu4][MoO2(C 6F5)3] (1) has been obtained by low-temperature treatment of MoO2Cl2 with LiC6F5 in Et2O followed by addition of [NBu4]Br. This compound of the (AO2X3)- type shows an unusual five-coordinate structure not lying in the Berry-pseudorotation path: it can be described rather as an edge-capped tetrahedron (TE-5). The same kind of structure has been found by DFT calculations to be the most energetically favored for the mononuclear (MoO2X3)- model species, where X = H, Cl or CN. Compound 1 exhibits marked stereochemical stability, as it shows no sign of exchange between chemically inequivalent C6F5 groups even at 150 °C in dmf solution ( 19F NMR spectroscopy). This journal is © the Partner Organisations 2014.