Cis鈥揟rans Ring Substituent Isomerism in Cyano-Substituted Metallathietane-3,3-dioxide Complexes of Platinum(II) and Palladium(II)
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- 作者：Sacha A. M. Dowling-Mitchell ; William Henderson ; Edward R. T. Tiekink ; J. Petrakopoulou ; Michael P. Sigalas
- 刊名：Organometallics
- 出版年：2012
- 出版时间：July 9, 2012
- 年：2012
- 卷：31
- 期：13
- 页码：4662-4669
- 全文大小：428K
- 年卷期：v.31,no.13(July 9, 2012)
- ISSN：1520-6041
文摘
Reactions of the platinum complexes cis-[PtCl2(PPh3)2], [PtCl2(dppf)], or [PtCl2(dppe)], and the palladium complexes, [PdCl2(PPh3)2] or [PdCl2(dppe)], with bis(cyanomethyl)sulfone NCCH2SO2CH2CN in methanol with added trimethylamine base gave the new cyano-substituted metallathietane-3,3-dioxide complexes [M{CH(CN)SO2CH(CN)}L2] (M = Pd, Pt) in good yields and purities. 1H and 31P{1H} NMR spectroscopy indicates that (in the majority of cases) the products are formed as a mixture of cis and trans isomers, with regard to the disposition of the cyano groups across the four-membered ring. An X-ray structure determination on a crystal of [Pd{CH(CN)SO2CH(CN)}(PPh3)2] showed it to be of the cis isomer, the first structurally characterized cis isomer of this type of complex. The four-membered palladacyclic ring is highly planar, in contrast to other metallathietane-3,3-dioxide complexes that have puckered rings. Factors influencing the relative abundances of the two isomers of [Pd{CH(CN)SO2CH(CN)}(PR3)2] have been investigated by means of NMR spectroscopy and DFT calculations.