Coordination compounds of a didentate pyrazole-containing ligand. Spectroscopic analyses and crystal structures of bis-[chloro-μ-chloro-{ N, N′-(2-(3,5-dimethyl-1-pyrozolyl)ethyl)ethylamine}nickel(II)] [trichloro-{ N-(2-(3,5-dimethyl-1-pyrozolyl)ethyl)hydrolammonium}copper(II)

Abstract

The ligand (2-(3,5-dimethyl-1-pyrazolyl)ethyl)ethylamine (dae) coordinates to divalent metal ions through the pyrazole and the amine nitrogen atoms in the compounds [Co(dae)Cl 2], [Co(dae)(NCS) 2]·2H 2O, [Ni(dae)Cl 2] 2, [Cu(dae)(NO 3) 2]·H 2O, [Cu(dae)F](BF 4)·H 2O, [Zn(dae)Cl 2] and [Zn(dae)(NCS) 2]·2H 2O. In [Cu(daeH)Cl 3] the ligand dae is protonated 1 1 The recommended IUPAC term for added H + in the natural isotropic mixture is hydronated. on the amine nitrogen and monodentate coordinated to the copper(II) ion through the pyrazole nitrogen. The anions participate in the coordination of the metal ion in all compounds as shown by spectroscopic analysis. The metal ions are four-, five- or six-coordinated, depending on the particular cation-anion combination. The compound [Ni(dae)Cl 2] 2 crystallizes in the orthorhombic space group Pbcn with a = 13.3466(5), b = 10.7977(5), c = 18.1993(15) A ̊ and Z = 8. The R value is 0.046 ( R w = 0.046) for 2230 significant reflections. This dinuclear compound is centrosymmetric, with the two nickel(II) ions separated by 3.6059(9) Å. Each Ni(II) ion is in a distorted trigonal bipyramidal N 2Cl 3 environment of two bridging chloride ions at 2.458(1) and 2.351(1) Å, an amine and a pyrazole nitrogen of dae at 2.022(3) and 2.036(3) Å, and a third chloride ion at 2.339(1) Å. The compound [Cu(daeH)Cl 3] crystallizes in the monoclinic space group P2 1/ n with a = 10.340(2), b = 15.078(2), c = 10.389(2) A ̊ , β = 118.41(2)° and Z = 4. The R value is 0.035 ( R w = 0.045) for 2819 significant reflections. The Cu(II) ion is in a distorted tetrahedral environment of one pyrazole nitrogen of the ligand dae and three chloride ions at 1.992(2), 2.228(1), 2.2451(8) and 2.2650(9) Å, respectively. The protonated 1 amine nitrogen of the ligand dae is hydrogen bridged to a chloride atom which is coordinated to a copper(II) ion of another asymmetric unit, thereby linking the molecules in a chain.