Fabrication and performances of an optical sensor system constructed by a novel Cu(I) complex embedded on silica matrix

In this paper, a novel diamine ligand of 2-(pyridin-2-yl)-5-p-tolyl-1,3,4-oxadiazole (PTO) and its corresponding Cu(I) complex of [Cu(PTO)(PPh3)(2)]BF4 with triphenylphosphine (PPh3) as the auxiliary ligand are synthesized. Single crystal analysis confirms its identity. Its photophysical properties, including UV-vis absorption, emission spectrum, and luminescence decay dynamics, are measured and studied. The room temperature luminescence is a yellow one with long excited state lifetime of 64.4 mu s under pure nitrogen atmosphere. Combined with density functional calculation on the cation of the Cu(I) complex, the yellow emission is assigned as a phosphorescent character of metal-to-ligand-charge-transfer, whose excited state is expected to be sensitive towards molecular oxygen. [Cu(PTO)(PPh3)(2)]BF4 is then doped into a silica supporting matrix of MCM-41 to construct an oxygen-sensitive probe of [Cu(PTO)(PPh3)]BF4/MCM-41, which shows a maximum sensitivity (luminescence intensity in O-2 medium/intensity in N-2 medium) of 5.95 towards oxygen with short response time of 10 s. This sensing system shows a good photodurability upon continuous excitation radiation. (C) 2011 Elsevier B.V. All rights reserved.