Heteroleptic lanthanide compounds with chalcogenolate ligands: Reduction of PhNNPh/PhEEPh (E = Se or Te) mixtures with Ln (Ln = Ho, Er, Tm, Yb). Thermolysis can give LnN or LnE

Lanthanide metals reduce mixtures of azobenzene and PhEEPh (E = Se or Te) i n pyridine to give the bimetallic compounds [(py)(2)Ln(EPh)(PhNNPh)](2) (E = Se, Ln = Ho (1), Er (2), Tm (3), Yb (4); E = Te, Ln = Ho (5), Er (6), Tm (7), Yb (8)). The structures of [(py)(2)Er(mu-eta (2)-eta (2)-PhNNPh)(SePh) ](2). 2py (2) and [(py)(2)Ho(mu-eta (2)-eta (2)-PhNNPh)(TePh)](2) 2py (5) h ave been determined by low-temperature single-crystal X-ray diffraction, an d the nearly identical unit cell volumes of the remaining compounds indicat e they are most likely isomorphous to 2 or 5. In all compounds, the Ln(III) ions are bridged by a pair of mu-eta (2)-eta (2)-PhNNPh ligands that, from the N-N bond length, have clearly been reduced to dianions. Charge is bala nced by the single terminal EPh ligand on each Ln, and the coordination sph ere is saturated by two pyridine donors to give seven coordinate metal cent ers. Thermal decomposition of 5 gives HoTe, 8 gives a mixture of YbN and Yb Te, and 1 does not give a crystalline solid-state product. Crystal data (Mo K alpha, 153(2) K) are as follows: 2, monoclinic group P2(1/n), a = 11.864 (3)Angstrom, b = 14.188(2) Angstrom c = 17.624(2) Angstrom, beta = 91.62(2) degrees, V = 2965(1) Angstrom (3), Z = 4; 5, triclinic space group P (1) ov er bar, a = 10.349(2) Angstrom, b = 17.662(4) Angstrom, c 17.730(8) Angstro m, alpha = 75.82(3)degrees, beta = 74.11(3)", gamma = 89.45(2)degrees, V= 3 016(2) Angstrom (3), Z = 2.