Reaction of Hafnium Tetrafluoride Monohydrate with Imidotetraphenyldiphosphinic Acid in dmso: The Crystal Structure of HfF_2[Ph_2P(O)NP(O)Ph_2]_2 centre dot dmso

摘要

~(19)F and ~(31)P NMR spectra are used to demonstrate that the reaction between HfP_4 centre dot H_2O and Ph_2P(O)-N=PPh_2OH (HL) in a mixture of equal volumes of dmso and CH_2C1_2 results in the octahedral complexes cis-HfF_2L_2, cw-HfF_2(dmso)~+_2, fac-HfF_3L(dmso), and cw-HfF_4L~- with chelating ligand L~- and HfFg . The existence of isomers of dimeric complexes (mu-F_2)(HfF_3Q)_2, where Q = dmso or H_2O, with CN = 7 is suggested on the basis of the ~(19)F NMR spectra obtained at temperatures below 203 K. With a twofold excess of HL, HfF_2L_2(dmso) single crystals are isolated. The crystals are characterized by IR spectroscopy and X-ray crystallography. The monoclinic unit cell parameters are as follows: space group P21/c, a = 11.560(3) A, b = 23.444(4) A, c = 18.198(4) A, (3 = 101.06(2)°, V= 4840(4) A3, Z = 4, mu(MoK_alpha) = 0.44 mm~(-1). In HfF_2L_2(dmso), the central ion has a distorted octahedral surrounding (which is atypical of fluorine compounds of hafnium) with two cis fluorine atoms and two cis-chelating ligands L~-. One of the chelate rings has a half-boat conformation; the other is a flattened chair. When HfF_2L_2(dmso) reacts with SbF_3, fluoride ions displace the coordinated L~- from the inner sphere of the complex.