Associative and dissociative mechanisms in the formation of phthalazine bridged organodiplatinum(II) complexes.
The reaction of phthalazine with the binuclear organoplatinum complexes [Me(2)Pt(μ-SMe(2))(μ-dppm)PtR(2)], R = Me, Ph, 4-tolyl or R(2) = (CH(2))(4), dppm = bis(diphenylphosphino)methane, gives the corresponding complexes [Me(2)Pt(μ-phthalazine)(μ-dppm)PtR(2)] by displacement of the bridging dimethylsulfide ligand. The structures of [Me(2)Pt(μ-SMe(2))(μ-dppm)PtMe(2)] and [Me(2)Pt(μ-phthalazine)(μ-dppm)PtMe(2)] have been determined. Kinetic studies show that the reactions occur mostly by a second order reaction when R = Me or R(2) = (CH(2))(4) but entirely by a first order reaction when R = Ph or 4-tolyl. Evidence is presented that the reactions when R = Me or R(2) = (CH(2))(4) can occur by either associative or dissociative mechanisms but that the reactions when R = Ph or 4-tolyl occur only by an unusual dissociative mechanism involving formation of an intermediate with a donor-acceptor Pt-Pt bond.
Rashidi
Mehdi
M
Department of Chemistry, Faculty of Sciences, Shiraz University, Shiraz 71454 Iran.
Nabavizadeh
S Masoud
SM
Zare
Ahad
A
Jamali
Sirous
S
Puddephatt
Richard J
RJ
D019281:Dimerization; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D009944:Organoplatinum Compounds / Q000737:chemistry*; D010793:Phthalazines / Q000737:chemistry*
D008024:Ligands; D009944:Organoplatinum Compounds; D010793:Phthalazines; C043388:phthalazine