Syntheses and characterization of organoimido complexes of niobium(V); Potential CVD precursors

Abstract

New niobium imido complexes (RN)Nb(NEt2)(3) (R = Pr-n, Pr-i and Bu-t), potential precursors to grow niobium containing thin films by chemical vapor deposition (CVD), were prepared by reacting the corresponding (RN)NbCl(3)py(2) complexes (R = Pr-n, Pr-i and Bu-t; py = pyridine) with LiNEt2 in hydrocarbon solvents. The structures of (RN)NbCl(3)py(2) (R = Pr-i and Bu-t), determined by X-ray crystallography, are mononuclear with distorted octahedral geometries. For each complex, three chloride ligands are cia to the imido ligand and occupy meridional positions. One of two py ligands is cia to and the other is trans to the imido ligand. For ((PrN)-N-i)NbCl(3)py(2), the Nb = NPri bond distance (Angstrom) is 1.733(3) and the angle Nb=N-Pr-i angle (degrees) is 178.0(3). Crystal data: monoclinic, space group P2(1)/n, a = 8.805(2), b = 14.930(4), c = 13.407(3) Angstrom, beta = 93.37(2)degrees, V = 1759.5(7) Angstrom(3), Z = 4, D-c 1.565 g cm(-3). For ((BuN)-N-t)NbCl(3)py(2), the Nb=NBut bond distance (Angstrom) is 1.734(4) and the angle Nb=N-Bu-t angle (degrees) is 174.8(4). Crystal data: monoclinic, space group P2(1)/c, a = 9.609(1), b = 13.591(6), c = 14.615(2) Angstrom, beta = 90.05(1)degrees, V = 1908.5(9) Angstrom(3), Z = 4, D-c = 1.492 g cm(-3).