Some nickel(II) and copper(II) compounds with β-amino-imine ligands; the structures of {4,5-dimethyl- (and 4,6-diethyl-6-methyl-) -3,7-diazanon-3-ene-1,9-diamine}nickel(II) tetrachlorozincate

Reactions of tris(ethane-1,2-diamine)nickel(II) or bis(ethane-1,2-diamine)copper(II) tetrachlorozincates with methanol/butanone form (4,6-diethyl-6-methyl-3,7-diazanon-3-ene-1,9-diamine)-nickel(II) or -copper(II) tetrachlorozincate, [M(enmek)][ZnCl4]. In the presence of paraformaldehyde more rapid reactions yield (4,5-dimethyl-3,7-diazanon-3-ene-1,9-diamine)nickel(II), as [Ni(enmekf)][ZnCl4], or the copper(II) analogue, isolated as [Cu(enmekf)][ZnCl4] · H2O. Both [Ni(enmek)][ZnCl4] and [Ni(enmekf)][ZnCl4] have singlet ground state nickel(II) in square-planar coordination, with the cations linked into chains by tetrachlorozincate ions, bound by weak axial Ni⋯Cl interactions and N–H⋯Cl hydrogen bonds. Structural parameters for [Ni(enmek)][ZnCl4], [Ni(enmekf)][ZnCl4] are: Ni–N1: 1.904(2), 1.916(2); Ni–N3 (imine): 1.907(2), 1.898(2); Ni–N7: 1.912(2), 1.920(2); Ni–N9: 1.925(2), 1.922(2); displacements of N atoms from the N4 planes: ±0.014(1), ±0.006(1), with the Ni displaced from the plane by 0.018(1), 0.004(1) Å. The C6 methyl substituent for [Ni(enmek)][ZnCl4] and the C5 methyl substituent for [Ni(enmekf)][ZnCl4] are axially oriented, with 6SR,7RS and 5SR,7RS configurations, respectively.

Reaction of tris(ethane-1,2-diamine)nickel(II) or bis(ethane-1,2-diamine)copper(II) tetrachlorozincate with butanone yields (4,6-diethyl-6-methyl-3,7-diazanon-3-ene-1,9-diamine)-nickel or -copper(II) tetrachlorozincate while the reaction in the presence of paraformaldehyde yields (4,5-dimethyl-3,7-diazanon-3-ene-1,9-diamine)-nickel or -copper(II) tetrachlorozincate. The structures of the nickel(II) compounds are reported.Figure optionsDownload as PowerPoint slide