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The compounds Y[N(QPPh2)2]3 (Q = S (1), Se (2)) have been synthesized in good yield from the protonolysis reactions between Y[N(SiMe3)2]3 and HN(QPPh2)2 in methylene chloride (CH2Cl2). The compounds are not isostructural. In 1, the Y atom is surrounded by three similar [N(SPPh2)2]- ligands bound eta 3 through two S atoms and an N atom. The molecule possesses D3 symmetry, as determined in the solid state by X-ray crystallography and in solution by 89Y and 31P NMR spectroscopies. In 2, the Y atom is surrounded again by three [N(SePPh2)2]- ligands, but two are bound eta 2 through the two Se atoms and the other ligand is bound eta 3 through the two Se atoms and an N atom. Although a fluxional process is detected in the 31P and 77Se NMR spectra, a triplet is found in the 89Y NMR spectrum of 2 (delta = 436 ppm relative to YCl3 in D2O, 2JY-P = 5 Hz). This implies that on average the conformation of one eta 3- and two eta 2-bound ligands is retained in solution. Crystallographic data for 1: C72H60N3P6S6Y, rhombohedral, R3c, a = 14.927(5) A, c = 56.047(13) A, V = 10815(6) A3, T = 153 K, Z = 6, and R1(F) = 0.042 for the 1451 reflections with I > 2 sigma(I). Crystallographic data for 2: C72H60N3P6Se6Y.Ch2-Cl2, monoclinic, P2(1)n, a = 13.3511(17) A, b = 38.539(7) A, c = 14.108(2) A, beta = 94.085(13) degrees, V = 7241(2) A 3, T = 153 K, Z = 4, and R1(F) = 0.037 for the 8868 reflections with I > 2 sigma(I).

The compounds Cp(2)Y[eta(3)-N(QPPh(2))(2)] (Q = S (1), Se (2)) have been synthesized in good yield from the protonolysis reaction between Cp(3)Y and HN(QPPh(2))(2) in tetrahydrofuran. In both compounds, the [N(QPPh(2))(2)](-) ligand is bound eta(3) to the Y center which, in 1, represents the first example of that mode of binding for the sulfur-containing ligand. The Y atom is also coordinated to two (C(5)H(5))(-) ligands and so is formally 9-coordinate. Both 1 and 2 are stable in inert environments for prolonged periods of time. Each is soluble in THF and CH(2)Cl(2). (1)H, (31)P, (77)Se, and (89)Y NMR data were collected to lend insight into the solution properties of these molecules. Crystallographic data for 1 (-120 degrees C): C(34)H(30)NP(2)S(2)Y, triclinic, P&onemacr;, a = 9.685(5) Å, b = 12.176(6) Å, c = 13.978(7) Å, alpha = 87.382(9) degrees, beta = 87.358(9) degrees, gamma = 68.689(9) degrees, V = 1533(1) Å(3), Z = 2, and R(1)(F) = 0.047 for the 4023 reflections with I > 2sigma(I). Crystallographic data for 2 (-120 degrees C): C(34)H(30)NP(2)Se(2)Y, triclinic, P&onemacr;, a = 9.745(5) Å, b = 12.222(6) Å, c = 13.930(7) Å, alpha = 88.024(9) degrees, beta = 87.380(9) degrees, gamma = 69.137(9) degrees, V = 1548(1) Å(3), Z = 2, and R(1)(F) = 0.056 for the 4324 reflections with I > 2sigma(I).

The compounds Cp2Ln[N(QPPh2)2] (Ln = La (1), Gd (2), Er (3), or Yb (4) for Q = Se, Ln = Yb (5) for Q = S) have been synthesized from the corresponding rare-earth tris(cyclopentadienyl) compound and H[N(QPPh2)2]. The structures of compounds 1, 2, 3, and 5, as determined by X-ray crystallography, consist of a Cp2Ln fragment, coordinated eta 3 through two chalcogen atoms and an N atom of the imidodiphosphinochalcogenido ligand [N(QPPh2)2]-. In compound 4, the Cp2Yb moiety is coordinated eta 2 through the two Se atoms of the [N(SePPh2)2]-ligand. 31P and 77Se (for 1) NMR spectroscopies lend insight into the solution nature of these species. Crystal data: 1, C34H30LaNP2Se2, triclinic, P1, a = 9.7959(10) A, b = 12.4134(13) A, c = 13.9077(14) A, alpha = 88.106(2) degrees, beta = 88.327(2) degrees, gamma = 68.481(2) degrees, V = 1572.2(3) A3, T = 153 K, Z = 2, and R1(F) = 0.0257 for the 5947 reflections with I > .2 sigma(I); 2, C34H30GdNP2Se2, triclinic, P1, a = 9.7130(14) A, b = 12.2659(17) A, c = 13.953(2) A, alpha = 88.062(2) degrees, beta = 87.613(2) degrees, gamma = 69.041(2) degrees, V = 1550.7(4) A3, T = 153 K, Z = 2, and R1(F) = 0.0323 for the 5064 reflections with I > 2 sigma(I); 3, C34H30ErNP2Se2, triclinic, P1, a = 9.704(2) A, b = 12.222(3) A, c = 13.980(4) A, alpha = 88.230(4) degrees, beta = 87.487(4) degees, gamma = 69.107(4) degrees, V = 1547.4(7) A3, T = 153 K, Z = 2, and R1(F) = 0.0278 for the 6377 reflections with I > 2 sigma(I); 4, C34H30NP2Se2Yb.C4H8O, triclinic, P1, a = 12.087(4) A, b = 12.429(4) A, c = 23.990(7) A, alpha = 89.406(5) degrees, beta = 86.368(5) degrees, gamma = 81.664(5) degrees, V = 3558.8(18) A3, T = 153 K, Z = 4, and R1(F) = 0.0321 for the 11,883 reflections with I > 2 sigma(I); and 5, C34H30NP2S2Yb, monoclinic, P21/n, a = 13.8799(18) A, b = 12.6747(16) A, c = 17.180(2) A, beta = 91.102(3) degrees, V = 3021.8(7) A3, T = 153 K, Z = 4, and R1(F) = 0.0218 for the 6698 reflections with I > 2 sigma(I).

The octanuclear Eu cluster Eu8(DMF)13(μ4-O)(μ3-OH)12(Se3)(Se4)2(Se5)2 has been synthesized by the reaction of EuCl3 (dissolved in tetrahydrofuran) with a polyselenide solution in dimethylformamide (DMF). Its structure (shown without the DMF molecules) comprises a triangulated dodecahedral Eu8 core centered by a μ4-O and face capped by 12 hydroxo groups. Five bidentate polyselenide chains and 13 DMF molecules complete the coordination spheres of the Eu atoms.

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