Nickel(II) Coordination Polymers – 4,4′‐Bipyridine‐Connected Six‐ and Four‐Fold Metal–Succinate Helices and Their Corresponding Chiral and Achiral Networks

Abstract

The reaction of equimolar amounts of Ni(NO3)2·6H2O, Na2(suc)·6H2O (suc = succinate) and 4,4′‐bipyridine (bipy) under different conditions yield the coordination polymers [Ni(suc)(bipy)(H2O)2]n·2nH2O (1) and [Ni(suc)(bipy)(H2O)2]n·nH2O (2). The complexes were characterized by elemental analysis, spectroscopic, thermogravimetric, and magnetic susceptibility measurements. Crystal structures reveal that the metal centers in both complexes are in a distorted octahedral N2O4 coordination sphere assembled by mutually trans pairs of 4,4′‐bipyridine, succinate, and water molecules. The helical metal–succinate chains have a right‐handed sixfold configuration in 1, with guest water molecules inside the helix, and both right‐ and left‐handed fourfold configurations in 2, with guest water molecules outside the helix. The parallel helical substructures are connected by 4,4′‐bipyridine and provide 3D chiral 75.9 and achiral 65.8 networks in 1 and 2, respectively.

Tuning the formation of dicarboxylate linker-assisted supramolecular 1D chains and squares of Ni(ii) using coordination and hydrogen bonds

“…The succinate linker can have three rotamers-eclipsed, anti and gauche. 16,17 The gauche form is chiral and can form a chiral compound from achiral components. 18,19 In 4, its single crystal structure shows a helical arrangement of the 1D chains in the supramolecular assembly formed through the hydrogen bonding interactions.…”