Crystal and molecular structure of tetrakis(N,N?-diallylthiourea)nickel(II) iodide

Tris(allylthiourea-κS)chlorozinc(II) chloride

“…The S C and average CÐN distances [1.713 (3) and 1.326 (4) A Ê , respectively] agree well with the values found in other metal± allylthiourea complexes (e.g. Chiesi et al, 1971;Ferrari et al, 1972;Filinchuk et al, 1996), which appear to be, respectively, longer and shorter than the values reported in free allylthiourea of 1.656 (10) and 1.366 (12) A Ê , respectively (Dragonette & Karle, 1965), the large uncertainties notwithstanding. These variations re¯ect the coordination of the S atom to the central element.…”

Structural Characterization of Thermochromic and Spin Equilibria in Solid-State Ni(detu)4Cl2 (detu = N,N′-Diethylthiourea)

“…An early review by Barefield et al highlighted five other examples of nickel­(II) complexes that exhibit “anomalous magnetism”, particularly temperature-dependent solid-state susceptibilities attributed to thermal spin equilibria. − None of the relevant spin isomers were structurally characterized, although X-ray structures of derivative complexes were consistent with tetragonal distortion as a basis for spin equilibria (Scheme ). − Our particular attention was drawn to a family of N , N ′-dialkylthiourea halide complexes Ni­(R 2 tu) 4 X 2 that display spin equilibria over a range of temperatures depending on the ligand substituents (R = n Bu < Et < Me) and the halide (X = Cl < Br < I). − The lead complex of this type, Ni­(detu) 4 Cl 2 was reported by Holt, Bouchard, and Carlin as the prototypical example of solid-state spin crossover for nickel­(II), with T 1/2 = 383 K (Figure ). Spin crossover in response to applied pressure was also reported for Ni­(detu) 4 X 2 in 1990 by Bray and Drickamer .…”

Hexakis(N,N′-dimethylthiourea-κS)nickel(II) nitrate

“…For background to nickel(II) complexes of thiourea and its derivatives, see: Ambujam et al (2006); Basso et al (1969); Bentley & Waters (1974); Chiesi et al (1971); Crane & Herod (2004); Eaton & Zaw (1975); El-Bahy et al (2003); Figgis & Reynolds (1986); Monim-ul-Mehboob et al (2010); Sonar et al (1979);Weininger et al (1969);Weininger & Amma (1976). For the crystal structures of similar nickel(II) complexes, see: Bentley & Waters (1974);El-Bahy et al (2003);Monim-ul-Mehboob et al (2010);Weininger et al (1969).…”

“…These studies showed that nickel(II) can adopt a variety of coordination geometries (octahedral, tetragonal, square-planar and tetrahedral) both in the solid state and in solution, which were prepared by varying the ligands or the anions (Ambujam et al, 2006;Bentley et al, 1974;Chiesi et al, 1971;Eaton & Zaw, 1975;El-Bahy et al, 2003;Figgis & Reynolds, 1986;Monim-ul-Mehboob et al, 2010;Sonar et al, 1979;Weininger et al 1969, Weininger & Amma, 1976. When the anion is chloride, bromide or iodide, the predominant coordination about the nickel(II) atom in the crystalline solid state is tetragonal with the halide anions in the apical positions, leading to [NiL 4 ]X 2 complexes (Ambujam et al, 2006;Chiesi et al, 1971;Crane et al, 2004;Figgis & Reynolds, 1986;Weininger & Amma, 1976), although [NiL 6 ]X 2 complexes are also formed (El-Bahy et al, 2003;Weininger et al, 1969). The formation (in the solid state) of the octahedral species NiL 6 2+ is ascribed to crystal packing forces and extensive hydrogen bonding (Ambujam et al, 2006;El-Bahy et al, 2003;Monim-ul-Mehboob et al, 2010;Weininger et al, 1969).…”