Abstract
This paper reports the syntheses and spectral investigations of the new complexes [Pd(k(1)-S-ptt)(2)(k(2)-dppmS(2))] (1), [Pd(k(1)-S-ptt)(2)(k(2)-dppp)] (2a), [Pd(k(1)-N-ptt)(2)(k(2)-dppp)] (2b),[Pd(k(1)-S-ptt)(2)(k(2)-dpppS(2))] (3),[Pd(k(1)-S-ptt)(2)(k(2)-dppb)] (4), [Pd(k(1)-S-ptt)(2)(k(2)-dppf)] (5a) and [Pd(k(1)-N-ptt)(2)(k(2)-dppf)] (5b),derived from 1-phenyl-5-thiol-1H-tetrazole (Hptt) and diphosphine (dppmS(2), dppp, dpppS(2), dppb and dppf) as co-ligand. The Hptt ligand acts as monodentate through the thiolato sulfur atom in complexes1,3and4. While in complexes2and5, the Hptt ligand also acts as monodentate through the nitrogen of heterocyclic ring, or sulfur of thiol group after deprotonation, as two linkage isomers. Theoretical calculations on the all complexes were performed, isomers based on2a, 2band5a, 5breveal that each pair of isomers is isoenergetic. For the2aand2bcomplexes the energy difference was 19.92 kcal mol(-1), while for the5aand5bcomplexes the difference was 11.78 kcal mol(-1). These differences are relatively small and suggest that the linkage isomers may be in equilibrium in solution. The reasons for the adoption of these different coordination modes are not clear but steric factors are likely to be a major contributory factor. Further, in vitro anti-bacterial activity and molecular docking analysis has been carried out to study the activity of the compound.