Luminescent high nuclearity Cu(I)-alkynyl clusters, [Cu-16(hfac)(8)(3,3-dimethyl-1-butynyl)(8)] and [Cu-20(hfac)(8)(3-phenyl-1-propynyl)(12)]

Two novel high nuclearity copper(I) alkynyl complexes, [Cu-16(hfac)(8)(C=CBu')(8)] (1) and [Cu-20(hfac)(8)(C=CCH2Ph)(12)] (2), that consist of complicated alkynyl bridged Cu(I) cores 'capped' by peripheral hfac ligands have been synthesised and characterised by X-ray structure determination. The photoluminescent properties of 1 and 2 together with the clusters, [Cu-18(hfac)(10)(C=CBun)(8)] (4) and [Cu-26(hfac)(11)(C=CPrn)(15)] (5) and the monomeric species, [Cu(hfac)(HC=CCH2OMe)] (3), [Cu(hfac)(Me3SiC=CSiMe3)] (6) and [Cu(hfac)(COD)] (7) are reported. A comparison of the photoluminescent spectra of the high nuclearity species with the related monomeric complexes have shown that the cluster luminescence is derived from transitions within the delocalised Cu-hfac chelate ring.