Rare-earth substituted polyoxoanions:: [{La(CH3COO)(H2O)2(α2-P2W17O61)}2]16- and [{Nd(H2O)3(α2-P2W17O61)}2]14-

The lanthanum-substituted polyoxometalate [{La(CH3COO)(H2O)(2)(alpha(2)-P2W17O61)}(2)](16-) (1) and the neodymium-substituted species [{Nd(H2O)(3)(alpha(2)-P2W17O61)}(2)](14-) ( 2) have been synthesized and characterized by IR spectroscopy and elemental analysis. Single-crystal X-ray analysis was carried out on K-16[{La(CH3COO) (H2O)(2)(alpha(2)-P2W17O61)}(2)].36H(2)O, which crystallizes in the triclinic system, space group P(1) over bar, with a = 12.3863(6) Angstrom, b = 12.8934(6) Angstrom, c = 31.7285(14) Angstrom, alpha = 84.2000(10)degrees, beta = 81.2300(10)degrees, gamma = 61.6500(10)degrees, and Z = 1; K6.5Nd2.5[{Nd(H2O)(3) (alpha(2)-P2W17O61)}(2)].55H(2)O, which crystallizes in the monoclinic system, space group P2(1)/n, with a = 17.5030(9) Angstrom, b = 23.7842(12) Angstrom, c = 19.1869(10) Angstrom, beta = 100.6610(10)degrees, and Z = 1. The head-on, trans-oid dimer 1 consists of two (alpha(2)-P2W17O61)(10-) fragments connected by a lanthanum-acetate dimer, (La-2(CH3COO)(2)(H2O)(4))(4+). Each La3+ ion is nine-coordinated in a monocapped, square-antiprismatic fashion. The neodymium-derivative 2 is also a trans-oid dimer, but the mode of binding is different from 1 and is best described as side-on. Each Nd3+ ion is eight-coordinated in a square-antiprismatic fashion with three terminal water molecules.