Experimental and computational study of the interplay between C-H/pi and anion-pi interactions

The synthesis of octahedral copper and zinc coordination complexes containing ligands of the type 6R,2,4-bis(3,5-dimethylpyrazol-1-yl)triazine is described. They exhibit the simultaneous presence of C-H/pi and anion-pi interactions on both sides of the same triazine ring. When the pyrazolyl groups are not methylated, lone pair-pi and anion-pi interactions coexist on the same triazine ring. In addition, the interplay between C-H/pi and anion-pi interactions is studied by means of high level correlation ab initio calculations. They demonstrate that synergistic effects are present when both interactions coexist. These synergistic effects have been evaluated using the genuine non-additivity energies and symmetry adapted perturbation theory (SAPT).