Complexes of copper(II), nickel(II), and cobalt(II) itaconates with chelating N-heterocycles: synthesis, structure, thermal properties, sorption activity, and their use in composites science

Abstract

The reactions between copper(II), nickel(II) or cobalt(II) itaconates and N-heterocycles (2,2′-bipyridine, 1,10-phenanthroline, 4′-phenyl-2,2′:6′,2′′-terpyridine) lead to new metal-containing monomers. The complex of cobalt(II) itaconate with 4′-phenyl-2,2′:6′,2′′-terpyridine crystallizes in the triclinic form with the formula unit C52H44CoN6O10 and a molar mass of 969.85 g/mol. Unit cell parameters: a 9.02 (4) Å, b 12.52 (5) Å, c 20.68 (10) Å, α 99.64°, β 99.06°, γ 100.22 (4)°, V 2224.64 Å3, Z = 2, Z′ = 0, T = 100 K, dcalc = 1.44 g/cm3, packing factor 0.71, crystal size 0.30 × 0.32 × 0.18 mm. Each cobalt ion is coordinated by six nitrogen atoms from two 4′-phenyl-2,2′:6′,2′′-terpyridine molecules lying in mutually perpendicular planes with the formation of the CoN6 coordination site. Medium-strength hydrogen bonds including terpyridine ligands, itaconate ions, and water molecules lead to infinite one-dimensional chains. Thermolysis of the metal-containing monomers proceeds through three successive stages (dehydration, solid-state polymerization, and destruction) and makes it possible to obtain the M@C nanomaterials with the core-shell structure. The tribological characteristics of the obtained nanomaterials have been studied.