Methyl transfer reactivity of five-coordinate CH3CoIIIPc.
CH3CoIIIPc (Pc = dianion of phthalocyanine) has been characterized by equilibrium studies of its trans axial ligation and cyclic voltammetry as a relatively "electron poor" model of methylcobalamin, which in noncoordinating solvents persists as a five-coordinate complex. Axial base (N-donors, PBu3, SCN-, weakly binding O-donors) inhibition of methyl transfer from CH3CoIIIPc shows that the reaction proceeds via the reactive five-coordinate species, even in coordinating solvents. The virtual inactivity of six-coordinate CH3CoIIIPc(L) complexes provides a reference point for important biological processes.
Galezowski
Wlodzimierz
W
Department of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland. wlodgal@amu.edu.pl
D007211:Indoles / Q000737:chemistry*; D007700:Kinetics; D008745:Methylation; D008956:Models, Chemical; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000737:chemistry*
D007211:Indoles; D009942:Organometallic Compounds; C500487:methylcobalt phthalocyanine; C019476:mecobalamin; D014805:Vitamin B 12