Large third-order optical nonlinearity of two cubane-like clusters containing oxotrithiometalate anions and silver:: synthesis, characterization, reactivity, and NLO properties-structure correlation

Using low heating temperature solid-state reactions and self-assembly reactions, two new candidates [Et4N](3)[MOS3(mu(3)-I)(AgI)(3)] (M = Mo, 1; W, 2) for nonlinear optical (NLO) materials have been synthesized and characterized crystallographically as tetranuclear cubane-like heterothiometallic clusters. Their optical nonlinearities were measured by the Z-scan technique with an 8 ns pulsed laser at 532 nm. These two isomorphous clusters both exhibit strong NLO absorptive abilities [alpha(2) = 1.0 x 10(-9) m W-1 (1), 1.2 x 10(-9) m W-1 (2)] and effective self-focusing performance [n(2) = 8.8 x 10(-17) m(2) W-1 (1), 4.5 x 10(-1)7 m(2) W-1 (2)]. The optical limiting (OL) investigation demonstrates that these two clusters show large OL effects. The NLO properties of tetranuclear Ag-containing cubane-like clusters with oxotrithiometalate anions are reported here for the first time and the third-order NLO properties and OL effects suggest that clusters 1 and 2 are promising candidates for NLO applications. A comparison of the NLO effect among clusters with the same C-3v symmetry has been made in order to further understand and explore the function-structure relationships of these heterothiometallic clusters.