Synthesis and Structure of the First Terminal Borylene Complexes.

A nearly linear arrangement is observed for the three atoms in the central W-B-N unit of the tungsten complex [(CO)5 WBN(SiMe3 )2 ] (1) in the crystal (W-B-N 177.9°; see picture). This compound along with its Cr analogue represent the first examples of terminal borylene complexes with a two-coordinate metal-bound boron atom. The geometries of the axial and equatorial CO groups in 1 are similar, and thus indicate that there is no trans effect of the borylene ligand. © 1998 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.