Preparation and photoluminescent properties of gold(I)-alkanethiolate complexes having highly ordered supramolecular structures

Au(I)-alkanethiolates (Au(I)-SRs, R = -(CH2)(n)H, n = 2-10, 12, 14, 16, and 18) are synthesized by mixing gold salt, HAuCl4, and n-alkanethiols in tetrahydrofuran. Au(I)-SRs show a highly ordered layer structure, and the ordering increases as the length of the alkyl chain increases. Au(I)-SRs with n >= 4 emit a bright orange-red light (lambda(cm) similar to 610 nm) visible to the naked eye upon irradiation with UV light, and the emission intensity increases with increasing length of the alkyl chain. We also found that noticeable aurophilic interactions between Au(I)-Au(I) exist for the Au(I)-SRs with longer alkyl groups having highly ordered layer Structures.