Photoconductive Properties And Electronic Structure In 3,5-Disubstituted 2-(2 '-Pyridyl)Pyrroles Coordinated To A Pd(Ii) Salicylideneiminate Synthon

The synthesis and the electrochemical, photophysical, structural, and photoconductive properties of three new heteroleptic Pd(II) complexes with various 3',5'-disubstituted-2-(2'-pyridil) pyrroles H(N<^>N) as coordinated ligands are reported. The coordination of the metal center was completed by a functionalized Schiff base H(O<^>N) used as an ancillary ligand. The [(N<^>N)Pd(O<^>N)] complexes showed highly interesting photoconductive properties which have been correlated to their electronic and molecular structures. Theoretical density functional theory (DFT) and time-dependent DFT calculations were performed, and the results were confronted with the organization in crystalline phase, allowing to point out that the photoconductive properties are mainly a consequence of an efficient intramolecular ligand-to-metal charge transfer, combined to the proximity between the central metal and the donor moieties in the solid-state molecular stacks. The reported results confirm that these new Pd(II) complexes form a novel class of organometallic photoconductors with intrinsic characteristics suitable for molecular semiconductors applications.