Insight into the Properties of Heteroleptic Metal Dithiolenes: Multistimuli Responsive Luminescence, Chromism, and Nonlinear Optics.

A comprehensive investigation of the functional properties of heteroleptic donor-M-acceptor dithiolene complexes BuN[M(L1)(L2)] is presented (M = Pd, Pt). The acceptor L1 consists of the chiral ()-(+)α-methylbenzyldithiooxamidate (()-α-MBAdto), the donor L2 is 2-thioxo-1,3-dithiole-4,5-dithiolato (dmit) in (Pd) and (Pt), 1,2-dicarbomethoxyethylenedithiolate (ddmet) in (Pd) and (Pt), or [4',5':5,6][1,4]dithiino[2,3-]quinoxaline-1',3'-dithiolato (quinoxdt) in (Pd) and (Pt). L1 is capable of undergoing proton exchange and promoting crystal formation in noncentrosymmetric space groups. L2 has different molecular structures while it maintains similar electron-donating capabilities. Thanks to the synergy of the ligands, - behave as H and Ag switchable linear chromophores. Moreover, the compounds exhibit a H-switchable second-order NLO response in solution, which is maintained in the bulk for , , and when they are embedded into a PMMA poled matrix. and show unique anti-Kasha H and Ag tunable colored emission originating from the quinoxdt ligand. A correlation between the electronic structure and properties is shown through density functional theory (DFT) and time-dependent DFT calculations.