2H)PBu3 units which are bonded in a fac configuration to a central Co(II) atom through the arsinyl O and 2 adjacent dmg O atoms. The average Co(II)-O bond length (6 bonds) is 2.08Å. The 2 Co(III) atoms are axially bound to Bu3P and PhMeAs(O) units. The molecule has approximately (noncrystallographic) 2-fold symmetry and is dissymmetric. Solutions of Me2AsCo(dmgH)2PBu3 react with MeI to give Me3As and methylcobalt complexes. The Me group of MeCo(dmgH)2C5H5N is not transferred to As on reactions with AsH3. The relevance of these reactions to models for the biological methylation of As is discussed. ">

Pub No:
120
Title:
Preparation of Arsinocobaloximes and the Crystal Structure of [(CH3)(C6H5)As(O)CoIII(dmgH)(dmg)]2CoII
Authors:
Cullen, W.R., Dolphin D., Einstein, F.W.B., Mihichuk, L.M., and Willis, A.C.
Journal:
J. Am. Chem. Soc.
Year:
1979
Pages:
101, 6898-6904
Abstract:
The cobaloxime Bu3PCo(dmgH)2Br (dmgHg2 = dimethylglyoxime) reacts with Me2AsCl, Me2AsI, PhAsCl2, PhMeAsCl, and Ph2AsCl to give solutions of the air-sensitive species R'R''AsCo(dmgH)2PBu3. When R' = R'' = Me and R' = Ph, R'' = Cl, the ultimate product is {[Bu3P]2Co(dmgH)2}+X- (X = Cl,I). When R' = Ph and R'' = Ph, Me, a red solid can be isolated of formula [R'R''As(O)Co(dmg2H)PBu3]2Co which is hydrated (2H2O) in the case R' = Ph, R" = Me. The crystal structure of a hydrated complex (final R1 = 0.102) consists of 2 PhMeAsOCo(dmg2H)PBu3 units which are bonded in a fac configuration to a central Co(II) atom through the arsinyl O and 2 adjacent dmg O atoms. The average Co(II)-O bond length (6 bonds) is 2.08Å. The 2 Co(III) atoms are axially bound to Bu3P and PhMeAs(O) units. The molecule has approximately (noncrystallographic) 2-fold symmetry and is dissymmetric. Solutions of Me2AsCo(dmgH)2PBu3 react with MeI to give Me3As and methylcobalt complexes. The Me group of MeCo(dmgH)2C5H5N is not transferred to As on reactions with AsH3. The relevance of these reactions to models for the biological methylation of As is discussed.

View the full publication here