Relationship between Metallophilic Interactions and Luminescent Properties in Pt(II) Complexes: TD-DFT Guide for the Molecular Design of Light-Responsive Materials

DFT/TD-DFT investigation has been performed on pyridyl triazolatoplatinum(II) complexes with a systematic variation of the donor/acceptor properties of the ligand in order to illuminate its effect on the metallophilic intermolecular interaction in ground and excited states. The X electronic properties of the pyridyl triazolate ligand were modified by the pyridine substituent: N(CH3)(2), H, CHO, or CHC(CN)(2). The simulations reveal that the donor/ acceptor strength of the substituent has a strong impact on the metallophilic interaction in the excited state and affects the emission properties at the supramolecular level. The theoretically derived structure property relationships are corroborated by experimental data. Finally, it is proposed that the modification of the pi-electronic character of the substituent (ligand field) can be applied in the molecular design of smart luminescent materials with light -driven metallophilic interactions.