Monodentately coordinated o-phenylenediacetonitrile seven-coordinate complexes of molybdenum(II) and tungsten(II): X-ray crystal structure of [WI2(CO)(3){1,2-C6H4(CH2CN)(2)-N}(2)]

Treatment of [MI2(CO)(3)(NCMe)(2)] (M = Mo orW) with 2 equiv. of o-phenylen ediacetonitrile ( 1,2-C6H4(CH2CN)(2)) gives the complexes [MI2(CO)(3){1,2-C 6H4(CH2CN)(2)-N}(2)] (1 and 2) via displacement of the acetonitrile ligands . The tungsten complex [WI2(CO)(3){1,2-C6H4( CH2CN)(2)-N}(2)] (2) has been characterised crystallographically. The geometry surrounding the coordinati on sphere is capped octahedral with a carbonyl group in the unique capping position, an iodide and two carbonyls in the capped face and an iodide and two nitrogen atoms from nitrile groups in the uncapped face. Reactions of 1 and 2 with equimolar amounts of L (L = PPh3, AsPh3, SbPh3, P(OPh)(3)) affo rds [MI2(CO)(3)(NCMe)L], which followed by an in situ reaction with 1 equiv . of 1,2-C6H4(CH2CN)(2) gives the new mixed ligand complexes [MI2(CO)(3){1, 2-C6H4(CH2CN)(2)-N}L] (3-10) in high yield. Reaction of [MI2(CO)(3)(NCMe)(2 )] and [MI2(CO)(3)(NCMe) (PPh3)] with 22 and 1 equiv. of L-1 (L-1 = [WI2(CO )(3){1,2-C6H2(CH2CN)(2)-N}(2)] (2)) gives the first trimetallic [MI2(CO)(3) L-2(l) (11 and 12) and bimetallic [MI2(CO)(3)L-I(PPh3)] (13 and 14) o-pheny lene diacetonitrile bridged complexes in high yield. (C) 2000 Elsevier Scie nce Ltd All rights reserved.