HETEROMETALLIC LANTHANIDE - GROUP-14 METAL CHALCOGENOLATES

Heterometallic chalcogenolate compounds containing both lanthanide (Ln ) and group 14 metals (M; M = Sn, Pb) form a variety of structures tha t can be understood in the context of relative metal-chalcogen bond st rengths. The compounds (THF)(2)Eu(mu(2)-SePh)(6)Pb-2 (1), [Yb(THF)(6)] [Sn(SePh)(3)](2) (2), and [(py)(2)Eu(2-S-NC5H4)(2)Sn(2-S-NC5H4)(2)](n) (3) have been prepared, and their structures have been established by low-temperature single-crystal X-ray diffraction. Ln-S bonds are foun d to be relatively insensitive to the presence of a group 14 metal thi olate, whereas Ln-Se bonds are readily distorted upon coordination to Pb(SePh)(2), and cleaved by the addition of the stronger Lewis acid Sn (SePh)(2). The stereochemically active lone pair of electrons on the g roup 14 metal influences structure, as does the identity of the chalco genolate. All three compounds show no interaction between the Ln ion a nd the group 14 metal lone pair. Crystal data (1-3 Mo K alpha; -80 to -100 degrees C): 1, triclinic space group P (1) over bar, a = 10.582(3 ) Angstrom, b = 12.114(2) Angstrom, c = 18.946(6) Angstrom, alpha = 89 .57(2)degrees, beta = 86.11(4)degrees, gamma = 75.87(2)degrees V = 235 0(1) Angstrom(3), Z = 2; 2, monoclinic space group P2(1)/c, a = 12.961 (2) Angstrom, b = 22.768(4) Angstrom, c = 22.560(4) Angstrom, beta = 9 5.04(2)degrees, V = 6632(2) Angstrom(3), Z = 4; 3, monoclinic space gr oup Cc, a = 20.737(6) Angstrom, b = 9.801(3) Angstrom, c = 18.849(5) A ngstrom, beta = 125.34(2)degrees, V = 3125(2) Angstrom(3), Z = 4.