title: Synthesis and cation-binding studies of gold(I) complexes bearing oligoether isocyanide ligands with ester and amide as linkers.
abstract: A series of dinuclear gold(I) isocyanide complexes of bis(alkynyl)calix[4]arene was designed and synthesized, and their photophysical and cation recognition properties were studied. Complex 1, [{calix[4]arene-(OCH2CONH-C6H4C≡C)2}{Au(CN-C6H4O(CH2CH2O)2CH3)}2], was found to show a high selectivity towards Al(3+) in CH2Cl2-MeCN (1 : 1 v/v). Upon addition of Al(3+), drastic changes in the electronic absorption, emission and (1)H NMR spectra were observed. These changes have been attributed to the formation of Au(I)Au(i) interactions induced by the high binding affinity of the amide site for the Al(3+) ion, instead of the high binding affinity expected of the oligoether site for alkali and alkaline earth metal ions. Further studies with the control complex, [{calix[4]arene-(OOC-C6H4C≡C)2}{Au(CN-C6H4O(CH2CH2O)2CH3)}2] (4), indicated that the amide carbonyl oxygen in the flexible pendants is crucial for the binding of Al(3+).
authors.affiliation: Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee, Hong Kong) and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China. wwyam@hku.hk.
authors.forename: Franky Ka-Wah
authors.initials: FK
authors.lastname: Hau
authors.affiliation: Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee, Hong Kong) and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China. wwyam@hku.hk.
authors.forename: Vivian Wing-Wah
authors.initials: VW
authors.lastname: Yam