Boron as a Bridging Ligand

Getting boron into line: The reaction of the dichloroboryl complex 1, with Na[Fe(CO)4]2− yields [{(η5-C5Me5)Fe(CO)2}(μ2-B){Fe(CO)4}] (2; see scheme green B). Na2[Cr(CO)5] reacts analogously with 1 to give [{(η5-C5Me5)Fe(CO)2}(μ2-B){Cr(CO)5}] (3). Both compounds 2 and 3 contain an unprecedented linearly bridging “naked” boron atom.