Harry B. Davis

A qualitative study of the reactions of 3,5-dimethylpyrazolyldiphenylphosphine with tetracarbonyl complexes of molybdenum(0) and tungsten(0)

The reactions of diphenyl(3,5-dimethylpyrazolyl)- phosphine (LL) with [(nbd)M(CO)4] (nbd = norbornadiene, M = Mo, W) and with [(CH3CN)2W(CO)4] under mild conditions proceed in a stepwise fashion to yield a mixture of products in equilibrium. The four-membered metallocyclic species (LL)M(CO)4 and the phosphorus-coordinated complex cis-[LL)2 M(CO)4] are formed in competition, being favoured by 1:1 and >2:1 reaction stoichiometries respectively.

Reactions of five-coordinate molybdenum(0) and Tungsten(0) complexes [PhP(Me2pz)2M(CO)3]with small molecules

Abstract The coordinatively unsaturated species [PhP(Me 2 pz) 2 M(CO) 3 ] (Me 2 pz = 3,5-dimethylpyrazolyl; M = Mo, I; M = W, II) react reversibly with CO, and irreversibly with H 2 , C 2 H 4 , P(OMe) 3 and PF 3 , but not with N 2 and Ph 3 P. The tricarbonyl/tetracarbonyl interconversion (I, II) + CO ⇄ [PhP(Me 2 pz) 2 - M(CO) 4 ] (III, M = Mo; IV; M = W) involves a novel structural interchange between the pseudo C 3v , phosphorus-free, six-membered [P(NN) 2 M] boat metallocyclic form of I and II, and the pseudo C 2v , phosphorus-coordinated, four-membered [ PNNM ] metallocyclic structures of III and IV. The reaction of 1 with PF 3 gives [PhP(Me 2 pz) 2 Mo(PF 3 ) 2 ] (V), in which the pyrazolylphosphine ligand again defines a four-membered [ PNNM o] chelate structure. A trans -dicarbonyl, cis-( bis -trifluorophosphine) arrangement is indicated.

A variable energy valence level photoelectron study of Os(CO)4PMe3: the Os 5d assignment using np → nd resonances

Abstract The high resolution valence level photoelectron spectra of Os(CO) 4 PMe 3 using He I and He II laboratory sources and synchrotron radiation, are reported. The binding energies of the osmium 5p core orbitals have also been determined. The metal 5p → 5d resonances were observed using variable synchrotron radiation, and have been successfully used to assign the osmium 5d valence orbitals.

A trinuclear cluster of osmium and molybdenum. Crystal structure of the co-crystallized molecules MoOs2(CO)11[P(OMe)3]2 and [(MeO)3P](OC)4OsMo(CO)5

Abstract The crystal structure of MoOs 2 (CO) 11 [P(OMe) 3 ] 2 ·[(MeO) 3 P](OC) 4 OsMo(CO) 5 is comprised of a slightly disordered, triangular cluster with a Mo(CO) 5 and two Os(CO) 3 [P(OMe) 3 ] moieties (OsMo bond lengths are 3.041(2) and 3.079(2) A) together with a [(MeO) 3 P](OC) 4 OsMo(CO) 5 molecule having a donor-acceptor OsMo bond of length 3.075(2) A.