Two different one-dimensional supramolecular chains formed from the reaction of 2-[1-(pyridin-4-ylmethyl)-1H-benzimidazol-2-yl]quinoline with two different precursors, Co(NO₃)₂ and CoCl₂

Abstract

Two different one-dimensional supramolecular chains with Co(II) cations have been synthesized based on the semi-rigid ligand 2-[1-(pyridin-4-ylmethyl)-1H-benzimidazol-2-yl]quinoline (L), obtained by condensation of 2-(1H-benzimidazol-2-yl)quinoline and 4-(chloromethyl)pyridine hydrochloride. Starting from different Co(II) salts, two new compounds have been obtained, viz. catena-poly[[[dinitratocobalt(II)]-μ-2-[1-(pyridin-4-ylmethyl)-1H-benzimidazol-2-yl]quinoline] dichloromethane monosolvate acetonitrile monosolvate], {[Co(NO3)2(C22H16N4)]·CH2Cl2·CH3CN}n, (I) and catena-poly[[[dichloridocobalt(II)]-μ-2-[1-(pyridin-4-ylmethyl)-1H-benzimidazol-2-yl]quinoline] methanol disolvate], {[CoCl2(C22H16N4)]·2CH3OH}n, (II). In (I), the Co(II) centres lie in a distorted octahedral [CoN3O3] coordination environment. {Co(NO3)2L}n units form one-dimensional helical chains, where the L ligand has different directions of twist. The helical chains stack together via interchain π-π interactions to form a two-dimensional sheet, and another type of π-π interaction further connects neighbouring sheets into a three-dimensional framework with hexagonal channels, in which the acetonitrile molecules and disordered dichloromethane molecules are located. In (II), the Co(II) centres lie in a distorted trigonal-bipyramidal [CoCl2N3] coordination environment. {CoCl2L}n units form one-dimensional chains. The chains interact via C-H···π and C-H···Cl interactions. The result is that two-dimensional sheets are generated, which are further linked into a three-dimensional framework via interlayer C-H···Cl interactions. When viewed down the crystallographic b axis, the methanol solvent molecules are located in an orderly manner in wave-like channels.