Luminescent cyclometalated platinum(II) complexes with amino acid ligands for protein binding

Pt(C^N)(phe)(1, C^N = 2-(2ʹ-thienyl)pyridine, phe = phenylalanine) shows a high binding affinity (ca. 10^6 dm^3 mol^-1) and selectivity towards human serum albumin (HSA) and such binding is accompanied by an enhancement of photoluminescence at 562 nm; both the protein binding affinity and cytotoxicities of [Pt(C^N)(phe)(1), Pt(C^N)(trp)(2, trp = tryptophan) and Pt(C^N)(gly)(3, gly = glycine)] are affected by the amino acid ligand with 1 having an IC50 of up to 1 (mu)M against a number of carcinoma cell lines.