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

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 pi-pi stacking interactions. The photophysical properties have also been studied, with (MLCT)-M-3/(LLCT)-L-3 phosphorescence exhibited in degassed CH2Cl2; the energy of which is varied by the pi-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 center dot center dot center dot Pt, pi-pi 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 selfassembly of the complexes in non-polar media, predominantly driven by pi-pi stacking interactions.