Metal complexes of fluorophosphines: XIV. Structures of five zerovalent metal complexes of methylaminobis(difluorophosphine)

Abstract

Details are presented of single crystal X-ray diffraction determinations of the structures of the five zerovalent metal complexes Cr[PF 2N(CH 3) 2] 4[(PF 2) 2NCH 3], Fe[(PF 2) 2NCH 3] 4, and [CH 3N(PF 2) 2] 3Co 2L 2 (L = CO, CH 3NHPF 2, and (CH 3) 2NPF 2). The chromium atom in Cr[PF 2N(CH 3) 2] 4[(PF 2) 2NCH 3] has a distorted octahedral coordination with four monodentate (CH 3) 2NPF 2 ligands and one bidentate CH 3N(PF 2) 2 ligand; the small bite of the latter ligand distorts one of the idealized 90° angles of the CrP 6 octahedron to 67°. The iron atom in Fe[(PF 2) 2NCH 3] 4 has a distorted trigonal bipyramidal coordination with three monodentate CH 3N(PF 2) 2 ligands and one bidentate CH 3N(PF 2) 2 ligand. The bidentate CH 3N(PF 2) 2 ligand in Fe[(PF 2) 2NCH 3] 4 is coordinated to an axial and an equatorial position of the FeP 5 trigonal bipyramid and because of its small bite squeezes the relevant P ax-Fe-P eq angle from the ideal value of 90° down to 69°. The structures of the binuclear cobalt complexes [CH 3N(PF 2) 2] 3Co 2L 2 (L = CO, (CH 3) 2NPF 2, and CH 3NHPF 2) may be regarded as consisting of two CoCoLP 3 trigonal bipyramids linked through a cobalt-cobalt bond. Further linking of the two trigonal bipyramids occurs through the three biligate bimetallic CH 3N(PF 2) 2 ligands, each of which bridges an equatorial position of one trigonal bipyramid with an equatorial position of the other trigonal bipyramid thereby leading to a [3.3.3]propellane structure in which the edge shared by the three five-membered chelate rings is the cobalt-cobalt bond. Significant deviations from three-fold symmetry occur in these trigonal bipyramids and in a given binuclear cobalt complex the two trigonal bipyramids are twisted by about 30° relative to each other.