Three-Coordinate, Cyclic Bent Allene Iron Complexes

2013-05-13T00:00:00Z (GMT) by Conor Pranckevicius Douglas W. Stephan
Novel three-coordinate Fe complexes featuring 1,2-diphenyl-3,5-bis­(2,6-dimethylphenoxy)­pyrazolin-4-ylidine or “cyclic bent allene” (CBA) have been synthesized. Reaction with FeCl<sub>2</sub>(PPh<sub>3</sub>)<sub>2</sub> results in the loss of both phosphines to yield monomeric Fe­(CBA)­Cl<sub>2</sub>. Treatment with 2 equiv of benzyl Grignard affords the three-coordinate alkylated product Fe­(CBA)­(Bn)<sub>2</sub>. Exposure of the alkylated species to an atmosphere of CO results in reductive elimination of 1,3-diphenylpropanone and formation of trigonal-bipyramidal Fe­(CBA)­(CO)<sub>4</sub>.