Supramolecular assembly of a phosphole-based moiety into nanostructures dictated by alkynylplatinum(II) terpyridine complexes through non-covalent Pt⋯Pt and π-π Stacking interactions: Synthesis, characterization, photophysics and self-assembly behaviors

Abstract

A new class of platinum(ii) terpyridine complexes with a phosphole-derived bridging alkynyl ligand have been prepared. The X-ray crystal structure of complex 2 has been determined, and reveals a polymeric zig-zag chain structure with the existence of π-π stacking interactions. The photophysical properties have also been studied, with 3MLCT/3LLCT phosphorescence exhibited in degassed CH2Cl2; the energy of which is varied by the π-conjugation of the terpyridine ligands. The solvent-induced assembly of complex 1 has been studied. The incorporation of hydrophobic hydrocarbon chains has been shown to play an important role in assisting the formation of self-assembled nanostructures via Pt⋯Pt, π-π stacking and hydrophobic-hydrophobic interactions. It has been established that an isodesmic growth mechanism operates in polar media to give nanospheres, while fibrous networks originate from the self-assembly of the complexes in non-polar media, predominantly driven by π-π stacking interactions.