Uranyl‐Nickel(II) Cation‐Cation Interaction in a Triperiodic Framework with cis‐1,2‐Cyclohexanedicarboxylate and Isonicotinate Ligands

Abstract

Uranyl and nickel(II) nitrates have been reacted with cis‐1,2‐cyclohexanedicarboxylic (H2chdc) and isonicotinic (Hint) acids under solvo‐hydrothermal conditions, giving the heterometallic, mixed‐ligand complex [(UO2)2Ni(chdc)2(int)2]⋅CH3CN (1). The uranyl cation is bound to carboxylate groups of both ligands while NiII is attached to two carboxylate and two nitrogen donors, with two strong additional interactions with uranyl oxo groups giving a nearly regular octahedral environment. The short Ni–O(oxo) bond length of 2.114(3) Å amounts to 67% of the sum of van der Waals radii. The trimetallic (UO2)2Ni6+ clusters thus formed are assembled by chdc2– ligands into linear chains which are further bridged by int– links to give a triperiodic framework with the dia topology, in which small channels encompass two rows of acetonitrile solvent molecules. Complex 1 does not display uranyl luminescence under excitation in the solid state.