Synthesis, crystal structure and second-order nonlinear optical properties of the trinuclear palladium orthometalated complex [(μ3-S)(μ3-OH)Pd3(C^N)3] (HC^N = p-image–C6H4–CHdouble bond; length as m-dashN–C6H4–NO2-p)

A smooth reaction of [(μ2-OH)2Pd2(C^N)2] (3) with CS2·(HC^N = p -View the MathML source(Bu2nN)–C6H4–CHdouble bond; length as m-dashN–C6H4–NO2-p) provides [(μ3-S)(μ3-OH)Pd3(C^N)3] (4). The X-ray structures of 4 shows that the complex contains a (μ3-S)(μ3-OH)Pd3 core which forces an all-cis arrangement of the three orthometalated ligands. The variation of the β(0) value per imine moiety, on going from the free imine to the trinuclear complex (4) is negative: −17%. In contrast, for the dinuclear complexes [(μ2-SBu)(μ2-OAc)Pd2(C^N)2] (5) or [(μ2-SBu)(μ2-Cl)Pd2(C^N)2] (6), having also a cis-arrangement of the orthometallated imines, this variation is positive: +14% and +30%, respectively. The β(0) variation seems to be concordant with the trend of the molar extinction coefficients values.