Cyclopropenyl and oxocyclobutenyl complexes of molybdenum. Crystal and molecular structures of (2,2′-bipyridine)bromodicarbonyl(1—3-η-1,2,3-triphenylcyclopropenyl)molybdenum(II) and (2,2′-bipyridine)bromodicarbonyl(2—4-η-1-oxo-2,3,4-triphenylcyclobutenyl)molybdenum(II)

Abstract

Reactions of triphenylcyclopropenyl bromide with [Mo(CO)₄L₂][L₂= 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen), or 2,2′-dipyridylamine (dpa)] yield the two series of products [MoBr(CO)₂(η³-C₃Ph₃)L₂] and [MoBr(CO)₂(η³-C₄Ph₃O)L₂]. The cyclopropenyl complexes were also prepared from [MoBr(CO)₂(η³-C₃Ph₃)(NCMe)₂] by reaction with L₂ in MeCN, which yielded crystalline solvates suitable for an X-ray structure determination. Crystals of [MoBr(CO)₂(η³-C₄Ph₃O)(bipy)]·thf, (1), are monoclinic, a= 9.87(1), b= 20.36(1), c= 16.23(1)Å, β= 92.2(1)°, Z= 4, space group P2₁/c. Crystals of [MoBr(CO)₂(η³-C₃Ph₃)(bipy)]·MeCN, (2), are triclinic, a= 10.552(8), b= 11.607(9), c= 13.801(11)Å, α= 67.1(1), β= 100.4(1), γ= 89.5(1)°, Z= 2, space group P. 2 832 and 1 804 above background reflections were collected on a diffractometer and refined by full-matrix least squares to R 0.072 and 0.082 for (1) and (2) respectively. In both structures the molybdenum atoms are in octahedral environments, with the mutually cis carbonyl groups and the bipy ligand occupying an equatorial plane. In trans positions are a bromine atom and in (1) a η³-oxocyclobutenyl group and in (2) a η³-cyclopropenyl group.