Structural and Mechanistic Look at the Orthoplatination of Aryl Oximes by Dichlorobis(sulfoxide or sulfide)platinum(II) Complexes
详细信息 查看全文
- 作者：Alexander D. Ryabov ; Stefanus Otto ; Pavel V. Samuleev ; Vladimir A. Polyakov ; Larissa Alexandrova ; Grigory M. Kazankov ; Sergiu Shova ; Mikhail Revenco ; Janusz Lipkowski ; and Maria H. Johansson
- 刊名：Inorganic Chemistry
- 出版年：2002
- 出版时间：August 12, 2002
- 年：2002
- 卷：41
- 期：16
- 页码：4286 - 4294
- 全文大小：172K
- 年卷期：v.41,no.16(August 12, 2002)
- ISSN：1520-510X
文摘
Structural and mechanistic aspects of orthoplatination of acetophenone and benzaldehyde oximes by the platinum(II) sulfoxide and sulfide complexes [PtCl2L2] (2, L = SOMe2 (a), rac-SOMePh (b), R-SOMe(C6H4Me-4) (c), andSMe2 (d)) to afford the corresponding platinacycles cis-(C,S)-[PtII(C6H3-2-CR'=NOH-5-R)Cl(L)] (3, R, R' = H, Me)have been investigated. The reaction of acetophenone oxime with sulfoxide complex 2a in methanol solvent occursnoticeably faster than with sulfide complex 2d due to the fact that the sulfoxide is a much better platinum(II)leaving ligand than the sulfide. Evidence is presented that the orthoplatination is a multistep process. The formationof unreactive dichlorobis(N-oxime)platinum(II) cations accounts for the rate retardation by excess acetophenoneoxime and suggests the importance of pseudocoordinatively unsaturated species for the C-H bond activation byPtII. A comparative X-ray structural study of dimethyl sulfoxide platinacycle 3b (R = R' = Me) and its sulfideanalogue 3e (R = H, R' = Me), as well as of SOMePh complex 3c (R = H, R' = Me), indicated that they arestructurally similar and a sulfur ligand is coordinated in the cis position with respect to the 
-bound phenyl carbon.The differences concern the Pt-S bond distance, which is notably longer in the sulfide complex 3e (2.2677(11) Å)as compared to that in sulfoxide complexes 3b (2.201(2)-2.215(2) Å) and 3c (2.2196(12) Å). Whereas the metalplane is practically a plane of symmetry in 3b due to the H-bonding between the sulfoxide oxygen and the protonat carbon ortho to the Pt-C bond, an S-bonded methyl of SOMePh and SMe2 is basically in the platinum(II) planein complexes 3c and 3e, respectively. There are intra- and intermolecular hydrogen bond networks in complex 3b.An interesting structural feature of complex 3c is that the two independent molecules in the asymmetric unit of thecrystal reveal an extremely short Pt-Pt contact of 3.337 Å.
-bound phenyl carbon.The differences concern the Pt-S bond distance, which is notably longer in the sulfide complex 3e (2.2677(11) Å)as compared to that in sulfoxide complexes 3b (2.201(2)-2.215(2) Å) and 3c (2.2196(12) Å). Whereas the metalplane is practically a plane of symmetry in 3b due to the H-bonding between the sulfoxide oxygen and the protonat carbon ortho to the Pt-C bond, an S-bonded methyl of SOMePh and SMe2 is basically in the platinum(II) planein complexes 3c and 3e, respectively. There are intra- and intermolecular hydrogen bond networks in complex 3b.An interesting structural feature of complex 3c is that the two independent molecules in the asymmetric unit of thecrystal reveal an extremely short Pt-Pt contact of 3.337 Å.