Crystal structures of (RS)-Di-μ-chloro-tetrakis(ethane-1,2-diamine)nickel(II) dichloride and diperchlorate

Abstract

The crystal structures of [(en)₂NiCl₂Ni(en)₂] Cl₂ (1) and [(en)₂NiCl₂Ni(en)₂] (ClO₄)₂ (2) have been redetermined from single- crystal X-ray diffraction data at 295(1) K and refined by least squares to residuals of 0.073 and 0.052 respectively for 1345 and 1605 'observed' reflections respectively. Crystals of (1) are monoclinic, P2₁/n, a 14.053(4), b 11.309(3), c 6.326(1) Ǻ, β 94.22(2)°, Z 2. Crystals of (2) are monoclinic, P2₁/n, a 8.885(12), 6 19.707(20), c 7.120(8) Ǻ, β 108.99(4)°, Z 2. In both (1) and (2), a dimeric complex cation is observed, a pair of cis coordination sites about the nickel in each case being occupied by the bridging chlorines; the latter are asymmetric (Ni-Cl, 2.461(3), 2.551(3)(1); 2.461(3), 2.512(3) Ǻ (2)).