A Novel Coordination Mode for Pentalene in Trinuclear Chromium Complexes

The first chromium pentalene complexes have been characterized;
in these the ligand displays a hitherto-unknown bonding mode
whereby a dimeric [Cr(Cp*)]2(μ-OR) unit is bound (μ:η2:η2)- to
one face, and Cp*Cr is bound η5- to the other. The magnetic
properties of these compounds can be understood as the
superposition of those of a chromocene and an antiferromagnetically coupled Cr−Cr bonded unit.