Mono- and dinuclear triphos-metal(II)-complexes with nitriles as co-ligands

The triphos ligand CH3C(CH2PPh2)(3) reacts with Co(BF4)(2) (aq) or Fe(BF4)( 2) (aq) in the presence of nitriles RCN to produce the pentacoordinate [tri phosCo(NCR)(2)](BF4)(2) (1) or the hexacoordinate [triphosFe(NCR)(3)](BF4)( 2) (2). With alpha,omega-dinitriles NC-X-CN dinuclear compounds [triphosFe( NC-X CN)(3)Fetriphos](BF4)(4) (X = (CH2)(3) (3a) X = O-C6H4 (3b) are formed . The compound [triphosFe((CH3)(2)C=C(CN)(2))(3)Fetriphos] (3c) is obtained from FeCl2 by addition of the triphos ligand, the dinitrile and NaPF6. All compounds are characterised by the usual analytical techniques includin g X-ray analyses. It is observed that the quadruply positively charged comp ounds 3 tend to associate the respective anions in pockets formed by the th ree segments of the Fe(NC-X-CN)(3)Fe bridging units.