Soluble yttrium chalcogenides: syntheses,structures, and NMR properties of Y[eta 3-N(SPPh2)2]3 and Y[eta 2-N(SePPh2)2]2[eta 3-N(SePPh2)2

The compounds YN(QPPh2)2]3 (Q = S (1), Se (2)) have been synthesized in good yield from the protonolysis reactions between YN(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).