Synthesis and Structure of a Dichromatetraborane Derivative [{(OC)₄Cr}₂(η⁴-<i>H</i>,<i>H</i>‘,<i>H</i>‘‘,<i>H</i>‘‘‘-BH₂BH₂·PMe₂CH₂PMe₂)]

Abstract

Photolysis of [Cr(CO)6] in the presence of BH3·PMe2CH2PMe2·BH3 (2) afforded a dichromatetraborane derivative [{(OC)4Cr}2(η4-H,H‘,H‘‘,H‘‘‘-BH2BH2·PMe2CH2PMe2)] (3) via an intramolecular dehydrogenative coupling of BH3 units on the metal. The complex 3 can be depicted as a dichromatetraborane derivative, with the wing-tip BH2+ groups in tetraborane(10) replaced by Cr(CO)4 fragments, which are isolobal with BH2+, and the terminal hydrides attaching to the basal boron atoms replaced by isoelectronic phosphine ligands.