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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/164837

A combined kinetico-mechanistic and computational study on the competitive formation of seven- versus five-membered platinacycles; the relevance of spectator halide ligands

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The metalation reactions between [Pt2(4-MeC6H4)4(μ-SEt2)2] and 2-X,6-FC6H3CHvNCH2CH2NMe2 (X = Br, Cl) have been studied. In all cases, seven-membered platinacycles are formed in a process that involves an initial reductive elimination from cyclometallated PtIV intermediate compounds, [PtX(4-CH3C6H4)2(ArCHvNCH2CH2NMe2)] (X = Br, Cl), followed by isomerization of the resulting PtII complexes and a final cyclometallation step. For the process with X = Br, the final seven-membered platinacycle and two intermediates, isolated under the conditions implemented from parallel kinetic studies, have been characterized by XRD. Contrary to previous results for the parent non-fluorinated imine 2-BrC6H4CHvNCH2CH2NMe2 the presence of a fluoro substituent prevents the formation of the more stable five-membered platinacycle. Temperature and pressure dependent kinetico-mechanistic and DFT studies indicate that the final cyclometallation step is strongly influenced by the nature of the spectator halido ligand, the overall reaction being much faster for X = Cl. The same DFT study conducted on the previously studied systems with imine 2-BrC6H4CHvNCH2CH2NMe2 indicates that, when possible, fivemembered platinacycles are kinetically preferred for X = Br, while the presence of Cl as a spectator halido ligand leads to a preferential faster formation of seven-membered analogues.

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AULLÓN LÓPEZ, Gabriel, et al. A combined kinetico-mechanistic and computational study on the competitive formation of seven- versus five-membered platinacycles; the relevance of spectator halide ligands. Dalton Transactions. 2015. Vol. 44, num. 41, pags. 17968-17979. ISSN 1477-9226. [consulted: 18 of June of 2026]. Available at: https://hdl.handle.net/2445/164837

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