Synthesis and characterisation of nickel(II) complexes with tripodal ligand tris[4-(3-(5-methylpyrazolyl)-3-aza-3-butenyl] amine (MPz(3)tren): X-ray crystal structure of [Ni(MPz(3)tren)](BF4)(2)center dot 0.5H(2)O

Nickel(II) complexes of the tripodal ligand (MPz(3)tren) of the general for mula [Ni(MPz(3)tren)]X-2.n H2O (X = Cl, Br, NO3, ClO4 and BF4; n = 0 for Cl and Br; n = 0.5 for NO3, ClO4 and BF4) have been prepared by template meth odology and characterised by elemental analyses. magnetic susceptibility an d conductivity measurements at RT, IR and electronic spectra. The molar con ductivities measured in MeOH for all the complexes show them to be 1:2 elec trolytes. The hexadentate character of the ligand in all the complexes is i nferred from IR spectral studies. The electronic spectra in solid state and in MeOH solution suggest octahedral geometry for all the complexes. The st ructure of [Ni(MPz(3)tren)](BF4)(2).0.5H(2)O has been determined by single- crystal X-ray diffraction studies (monoclinic, c2/c). Nickel(II) is in a tr igonal antiprismatic N-6 donor environment and the crystal structure is sta bilised by a network of strong H-bonding. (C) 2000 Elsevier Science B.V. Al l rights reserved.