DFT study of nucleophilicity of organometallic (2,2′-bipyridine) platinum(II) complexes

The structures of [Pt(bpy)R-2] complexes (bpy = 2,2'-bipyridine, R = Me, Ph, 4-MeC6H4, 4-MeOC6H4, 3-MeOC6H4, 4-NMe2C6H4, 4-FC6H4, 3-FC6H4, 4-ClC6H4, CCH, CCPh, CF3, CN) were optimized. Energy of neutral, cationic and anionic forms of these complexes were calculated at the B3LYP/6-311G(d,p) level of theory. Nucleophilicity indexes and electron-donating powers were calculated for these complexes. A relatively good correlation for nucleophilicity index and a very good correlation for electron-donating power were found between these descriptors and logk(2) (when available) (k(2) is the second order rate constants for oxidative addition of methyl iodide on these complexes). Also a good correlation was found between the energy of platinum d(Z)2 orbital and logk(2). The condensed-to-atom Fukui functions for nucleophilic and electrophilic attacks on these complexes show that in all of these complexes, Pt center is the especially preferable site for electrophilic attack. These observations support the mechanism of S(N)2 type for oxidative addition of polar organic reagents on organoplatinum(II) complexes. (C) 2014 Elsevier B.V. All rights reserved.