Oxidation of Half-Lantern Pt2(II,II) Compounds by Halocarbons. Evidence of Dioxygen Insertion into a Pt(III)鈥揅H3 Bond

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• 作者：V. Sicilia ; M. Baya ; P. Borja ; A. Mart铆n
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：August 3, 2015
• 年：2015
• 卷：54
• 期：15
• 页码：7316-7324
• 全文大小：490K
• ISSN：1520-510X

文摘

The half-lantern compound [{Pt(bzq)(渭-N^S)}₂] (1) [bzq = benzo[h]quinoline, HN^S = 2-mercaptopyrimidine (C₄H₃N₂HS)] reacts with CH₃I and haloforms CHX₃ (X = Cl, Br, I) to give the corresponding oxidized diplatinum(III) derivatives [{Pt(bzq)(渭-N^S)X}₂] (X = Cl 2a, Br 2b, I 2c). These compounds exhibit half-lantern structures with short intermetallic distances (鈭?.6 脜) due to Pt鈥揚t bond formation. The halogen abstraction mechanisms from the halocarbon molecules by the Pt₂(II,II) compound 1 were investigated. NMR spectroscopic evidence using labeled reagents support that in the case of ¹³CH₃I the reaction initiates with an oxidative addition through an S_N2 mechanism giving rise to the intermediate species [I(bzq)Pt(渭-N^S)₂Pt(bzq)(¹³CH₃)}]. However, with haloforms the reactions proceed through a radical-like mechanism, thermally (CHBr₃, CHI₃) or photochemically (CHCl₃) activated, giving rise to mixtures of species [X(bzq)Pt(渭-N^S)₂Pt(bzq)R] (3a鈥?b>c) and [X(bzq)Pt(渭-N^S)₂Pt(bzq)X] (2a鈥?b>c). In these cases the presence of O₂ favors the formation of species 2 over 3. Transformation of 3 into 2 was possible upon irradiation with UV light. In the case of [I(bzq)Pt(渭-N^S)₂Pt(bzq)(¹³CH₃)}] (3d), in the presence of O₂ the formation of the unusual methylperoxo derivative [I(bzq)Pt(渭-N^S)₂Pt(bzq)(O鈥揙¹³CH₃)}] (4d) was detected, which in the presence of ¹³CH₃I rendered the final product [{Pt(bzq)(渭-N^S)I}₂] (2c) and ¹³CH₃OH.