Nickel(II) complexes featuring dialkylcyanamide ligands: Synthetic and structural studies

The complexes [Ni(NCNAlk(2))(2)(H2O)(4)]X-2 ([1]X-2-[2]X-2; X = Cl, Br; Alk(2) = Me-2 [1](2+), C4H8O [2](2+)) were prepared by the reaction of NiX2 center dot nH(2)O (X = Cl, n = 0; Br, n = 3) with 2 equivs NCNAlk(2) (Alk(2) = Me-2, C4H8O) in methanol at 20-25 degrees C for 1 d. The complex [Ni(NCNMe2)(4)(H2O)(2)]I-2 ([3]I-2) was synthesized by treatment of NiI2 center dot 6H(2)O with 4 equivs NCNMe2 in MeOH at 20-25 degrees C for 1 d. All dialkylcyanamide complexes were characterized by elemental analysis (Ni), high resolution ESI+-MS, IR spectroscopy, and X-ray diffraction. Complexes [1]X-2-[2]X-2 bearing two coordinated dialkylcyanamides crystallize in the two isomeric forms, viz. trans- and cis-(N,N). The trans-(N,N)-isomers were characterized by X-ray crystallography for [1]Cl-2 center dot 2H(2)O, [1]Br-2 center dot 2H(2)O, [2]Cl-2 center dot 4H(2)O and the cis-(N,N)-isomers for [2]Cl-2 center dot 2H(2)O and [2]Br-2 center dot 2H(2)O. (C) 2014 Elsevier B.V. All rights reserved.