First optical non-linearity study on Group 6-Group 10 sulfido mixed-metal complexes, synthesis and crystal structure of [NEt₄][PdWS₄(S₂CNC₄H₈)] and [NEt₄]₂[PdW₂S₈]

Two Group 6-Group 10 sulfido mixed-metal complexes, [NEt4][PdWS4(S2CNC4H8)] 1 and [NEt4]2[PdW2S8] 2, have been synthesized via reactions of [Pd(S2CNC4H8)2] with [NH4]2[WS4] and NEt4Cl in different molar ratios in dichloromethane. X-Ray crystallographic structure determinations revealed that palladium in 1 is co-ordinated by a pyrrolidinecarbodithioate and a tetrathiotungstate, while in 2 it is co-ordinated by two tetrathiotungstates symmetrically. Both dithiocarbamate and tetrathiotungstate act as bidentate ligands through two sulfur atoms chelating palladium. The Pd-W distances are 2.8669(7) and 2.9008(5) Å in 1 and 2, respectively. Non-linear optical properties of the compounds were studied with a 7 ns pulsed laser at 532 nm. Compound 1 exhibits mainly optical self-defocusing (n2= -6.8 × 10-18m2W-1as measured with a 1.0 × 10-3mol dm-3acetonitrile solution) with negligible non-linear absorption. Compound 2 exhibits both optical self-defocusing (n2= -7.5 × 10-18m2W-1, as measured with a 1.6 × 10-3mol dm-3acetonitrile solution) and optical non-linear absorption (α2= 3.5 × 10-11m W-1).