Synthesis, structure and optically limiting NLO properties of a distorted cubane-like cluster (µ-Cl)(µ3-WSe4)(CuPPh3)3.

Treatment of [Et₄N]₂[WSe₄] with three equivalents of CuCl and PPh₃ (Ph = phenyl) in a mixed solvent of 25 mL of CH₂Cl₂ and 5 mL of DMF afforded a distorted cubane-like cluster [(µ-Cl)(µ₃-WSe₄)(CuPPh₃)₃] (1), which has been structurally characterized by single-crystal X-ray diffraction. The coordination geometry of the tungsten center and two copper atoms is tetrahedral, whereas that of the other copper atom is triangular. Regarding the NLO properties, a large optical limiting effect with a threshold of 0.91 J cm⁻² was observed with laser pulses of 7 ns at 532 nm. [ABSTRACT FROM AUTHOR]