Nickel(II) complexes of Schiff-base ligands derived from the condensation of 2,6-diacetylpyridine with ethanolamine (L1) or propanolamine (L2); X-ray crystal structures of [NiL12][ClO4]2·H2O, [{NiL1(NCS)2}2], [NiL22][ClO4]2, and [{NiL2(NCS)2}x]{L1= 2,6-bis[1-(2-hydroxyethylimino)ethyl]pyridine and L2= 2,6-bis[1-(3-hydroxypropylimino)ethyl]pyridine}

Abstract

Four structurally diverse nickel(II) complexes have been synthesised by Schiff-base condensation of 2,6-diacetylpyridine and ethanolamine {L¹= 2,6-bis[1-(2-hydroxyethylimino)ethyl]pyridine} or propanolamine {L²= 2,6-bis[1-(3-hydroxypropylimino)ethyl]pyridine} in the presence of Ni²⁺. These complexes have been characterised by combinations of analytical, spectroscopic, magnetic, conductance, and single-crystal X-ray diffraction methods: [NiL¹₂][ClO₄]₂·H₂O (1), monomeric, tetragonal, a= 10.109(1), c= 16.540(2)Å; [{NiL¹(NCS)₂}₂](2), dimeric, monoclinic, a= 12.623(4), b= 10.799(3), c= 14.174(5)Å, β= 106.61 (3)°; [NiL²₂][ClO₄]₂(3), monomeric, monoclinic, a= 19.482(4), b= 10.438(2), c= 21.324(5)Å, β= 123.48(2)°; [{NiL²(NCS)₂}_x](4), polymeric, monoclinic, a= 14.922(7), b= 9.305(4), c= 16.140(7)Å, and β= 114.50(3)°. Reasons for the structural diversity are discussed and comparisons are drawn with related complexes.