A comparative study of the structures and reactivity of cyclometallated platinum compounds of N-benzylidenebenzylamines and cycloplatination of a primary amine

作者：Capape Alejandro; Crespo Margarita^*; Granell Jaume; Font Bardia Merce; Solans Xavier

来源：Dalton Transactions, 2007, (20): 2030-2039.

DOI：10.1039/b618128g

The reaction of cis-[PtCl2(dmso)(2)] with ligands 4-ClC6H4CHNCH2C6H5 (1a) and 4-ClC6H4-CHNCH2(4-ClC6H4) (1b) in the presence of sodium acetate and using either methanol or toluene as solvent produced the corresponding five-membered endo-metallacycles [PtCl{(4-ClC6H3)CHNCH2-C6H5}{SOMe2}] (2a) and [PtCl{(4-ClC6H3)CHNCH2(4 '-ClC6H4}{SOMe2}] (2b). An analogous reaction for ligands 2,6-Cl2C6H3CHNCH2C6H5 (1c) and 2,6-Cl2C6H3CHNCH2(4-ClC6H4) (1d) produced five-membered exo-metallacycles [PtCl{(2,6-Cl2C6H3)CHNCH2C6H4}{SOMe2}](2c) and [PtCl{(2,6-Cl2C6H3)CHNCH2(4 '-ClC6H3)}{SOMe2}](2d) when the reaction was carried out in methanol and seven-membered endo-platinacycles [PtCl{(MeC6H3)ClC6H3CHNCH2C6H4}{SOMe2}] (3c) and [PtCl{(MeC6H3) ClC6H3CHNCH2(4 '-ClC6H3)}{SOMe2}](3d) when toluene was used as a solvent. The reaction of 2,4,6-(CH3)(3)C6H2CHNCH2(4-ClC6H4) (1e) produced in both solvents an exo-platinacycle [PtCl{(2,4,6-(CH3)(3)C6H2)CHNCH2(4 '-ClC6H3)}{SO(CH3)(2)}] (2e). Cyclometallation of 4-chlorobenzylamine was also achieved to produce compound [PtCl{(4-ClC6H3)CH2NH2}-{SOMe2}] (2g). The reactions of endo- and exo-metallacycles with phosphines evidenced the higher lability of the Pt-N bond in exo-metallacycles while a comparative analysis of the crystal structures points out a certain degree of aromaticity in the endo-metallacycle.

• 出版日期2007