The binding of a diiminoplatinum(II) complex of 4‐ethynylbenzo‐15‐crown‐5 to divalent metal ions such as Mg2+ or Zn2+ is accompanied by substantial enhancement of emission intensity (1035‐ and 870‐fold increase, respectively, with 40 equivalents of metal salt) at λmax ≈︁ 555 nm; H+, Cd2+ and alkali‐metal ions cause minor enhancement of the photoluminescence (⩽ 10‐fold) under similar conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Pt(C/N)(phe)(1, C/N = 2-(2'-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 having an IC(50) of up to 1 microM against a number of carcinoma cell lines.