LANTHANIDE-GROUP-12 METAL CHALCOGENOLATES - A VERSATILE CLASS OF COMPOUNDS

Heterometallic chalcogenolate compounds containing both lanthanide (Ln ) and group 12 metals (M) represent an extremely broad molecular class , having the general formula LnM(EPh)(x)(L)(y), where L is a neutral d onor ligand. In this paper we show how M, L, and the ratio Ln:M can be varied to give bi-, tetra-, penta-, and hexametallic chalcogenolates. The compounds [(py)(3)Eu(mu(2)-SePh)(2)(mu(3)-SePh)Hg(SePh)](2) (1), (THF)(4)Eu(mu(2)-SePh)(3)ZnSePh (2), [Sm(THF)(7)][Zn-4(mu(2)-SePh)(6)( SePh)(4)] (3), and [Yb(THF)(6)][Hg-5(mu(2)-SePh)(8)(SePh)(4)]. 2THF (4 ) have been prepared, and their structures have been established by lo w temperature single crystal X-ray diffraction. The synthesis and stru ctural characterization of the heterometallic chalcogenolate [(py)(2)S m(SePh)(mu-SePh)(3)Na(py)(2)](2) (5) is also described in order to com pare the relative effects of the alkali and group 12 metals on heterom etallic structure and electronic properties. From the crystal structur es it is clear that the group 12 ion polarizes Se electron density awa y from the Ln ion, weakening the Ln-Se bond, and increasing the Ln-Se bond length. UV-visible data support the structural interpretations, w ith Ln(II) metal-to-pyridine charge transfer and lanthanide(III) selen olate to metal charge transfer absorption energies, both indicating th at the group 12 metal withdraws electron density from the lanthanide i on. Unambiguous assignment of heterometallic solution structure is imp ossible, because the molecules are fluctional, and the solution struct ure is solvent dependent. However, from spectroscopic measurements, an d from the isolation of 1 in 90% yield, it is clear that the compounds do maintain some form of heterometallic structure in donor solvents a s basic as pyridine. Crystal data (1-3 and 5, Mo Ka; 4, Cu KCL; -80 to -100 degrees C): 1, space group P (1) over bar, a = 12.374(4) Angstro m, b = 13.381(3) Angstrom, c = 14.222(4) Angstrom, alpha = 62.36(3)deg rees, beta = 70.96(3)degrees, gamma = 70.14(2)degrees, V = 1921 Angstr om, Z = 2; 2, space group P-n, a 10.991(4) Angstrom, b = 20.051(3) Ang strom, c 19.522(4) Angstrom, beta = 99.75(3)degrees, V = 4240 Angstrom , Z = 4; 3, triclinic space group P (1) over bar, a = 14.268(6) Angstr om, b = 19.220(10) Angstrom, c = 19.539(4) Angstrom, alpha = 92.64(3), beta = 104.20(3)degrees; gamma = 109.32(4)degrees, V = 4854 Angstrom, Z = 2; 4, monoclinic space group P2(1)/c, a = 14.239(3) Angstrom, b = 48.846(6) Angstrom, c = 17.282(4) Angstrom, beta = 113.79(2)degrees, V = 10999 Angstrom, Z = 4; 5, monoclinic space group C2/c, a = 23.822( 5) Angstrom, b = 16.902(2) Angstrom, c = 21.388(3) Angstrom, beta = 93 .35(2)degrees, V = 8597 Angstrom, Z = 8.