Dimeric versus monomeric nickel(II) complexes with tetraorganodichalcogenoimidodiphosphinato ligands: Crystal structures of Ni-2[(OPPh2)(2)N](4) center dot CH2Cl2, Ni[(OPPh2)(2)N](2)(DMF)(2) center dot 2H(2)O and [KNi[(SPPh2){OP(OEt)(2)}N](3)](2)


POLYHEDRON, vol.27, pp.2143-2150, 2008 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 27
  • Publication Date: 2008
  • Doi Number: 10.1016/j.poly.2008.04.006
  • Title of Journal : POLYHEDRON
  • Page Numbers: pp.2143-2150


Nickel(II) complexes of the type Ni[(XPR2)(YPR'(2))N](2) [X = S (1) or O (2), Y = O, R = Ph, R' = OEt] and Ni-2[(OPPh2)(2)N](4) (3) were prepared by reacting either anhydrous NiCl2 or NiCl2 center dot 6H(2)O with the potassium salt of the appropriate tetraorganodichalcogenoimidodiphosphinic acid, in 1:2 molar ratio. Recrystallization of 3 from dimethylformamide resulted in Ni[(OPPh2)(2)N](2)(DMF) (4). Reaction between NiCl2 and K[(SPPh2){OP(OEt)(2)}N] in an 1:3 molar ratio resulted in the ionic species KNi[(SPPh2)-(OP(OEt)(2)}N](3) (5). Compounds 1-5 were characterized by IR, electronic spectroscopy and mass spectrometry. The molecular structures of 3 center dot CH2Cl2, 4 center dot 2H(2)O and 5 were determined by single-crystal X-ray diffraction. A dimeric structure was found in case of complex 3 center dot CH2O2, with both monometallic biconnective and homobimetallic triconnective [(OPPh2)(2)N](-) units, while an octahedral environment around nickel was established in the monomeric complex 4 center dot 2H(2)O by monometallic biconnective [(OPPh2)(2)N](-) and DMF ligands, respectively. The crystal of the ionic species 5 contains discrete tetranuclear units in which the phosphorus ligands act heterobimetallic, either (O,O,S)-triconnective or (S,O,O,O-Et)-tetraconnective, and (N,O,O,S)-heterotrimetallic tetraconnective, resulting in an octahedral environment around nickel and a square-pyramidal one around potassium, respectively. Powder X-ray diffraction studies on 5 are in agreement with the single-crystal investigation. (C) 2008 Elsevier Ltd. All rights reserved.