Substitutions of organopalladium(II) species with benzimidazole derivatives

The [Pd(cod)(cotl)]ClO4 complex (cod = cycloocta-1,5-diene; cotl = cyclooctenyl, C18H13 -) undergoes substitutions with new Schiff base ligands containing benzimidazole L [L = 2-(2′-N-n-propylidenephenyl)benzimidazole (L1); 2(2′-N-i-propylidenephenyl)benzimidazole (L2); 2-(2′-N-n-butylidenephenyl)benzimidazole (L3); 2-(2′-N-i-butylidenephenyl)benzimidazole (L4)]. Facile displacement of cod by L occurs to produce complexes of the type [Pd(cotl)L]ClO4·nMe2CO (n = 0; L = L1, L2 or L3; n = 2, L = L4). Dihalobridge complexes of the type [Pd(cotl)X]2 (X = Cl or Br) undergo halogen-bridge cleavage with L1-L4 to give mononuclear complexes of the type Pd(cotl)LX·nH2O (n = 2, X = Cl, L = L1; n = 0, X = Br, L = L1; n = 0, X = Cl, L = L 2; n = 0, X = Cl or Br, L = L3; n = 0, X = Cl, L = L 4; n = 2, X = Br, L = L4) and a binuclear complex [Pd(cotl)Br]2L2. The complexes were characterised by physical properties, i.r., 1H- and 13C-n.m.r. spectral techniques and by mass spectra. Probable structures have been proposed