Three chiral cyanide-bridged Cr–Cu complexes: Synthesis, crystal structures and magnetic properties

Abstract

Two trans-dicyanidochromium(III)-containing building blocks and one chiral copper(II) compound have been employed to assemble cyanide-bridged heterometallic complexes, resulting in three chiral cyanide-bridged Cr(III)–Cu(II) complexes, {[Cu(L1)2Cr(L3)(CN)2]ClO4}2·CH3OH·H2O (1a, L1 = (S,S)-1,2-diaminocyclohexane, L3 = 1,2-bis(pyridine-2-carboxamido)benzenate), {[Cu(L2)2Cr(L2)(CN)2]ClO4}2·CH3OH·H2O (1b, L2 = (R,R)-1,2-diaminocyclohexane) {[Cu(L3)2Cr(L4)(CN)2][Cr(L4)(CN)2]}·CH3OH·2H2O (2), (L4 = 1,2-bis(pyridine-2-carboxamido)-4-chlorobenzenate). All the three complexes have been characterized by elemental analysis, IR spectroscopy and X-ray structure determination. Single-crystal X-ray diffraction analysis shows that the two enantiomeric complexes 1a, 1b and the complex 2 belong to cyanide-bridged cationic binuclear structure type with ClO4– or the anionic cyanide building block as balance anion for complexes 1a, 1b or 2, respectively. Investigation of the magnetic properties of the complexes 1a and 2 reveals the weak ferromagnetic coupling between the neighboring Cr(III) and Cu(II) ions through the bridging cyanide group.

Keywords

• Chiral
• Cyanide-bridged
• Heterobimetallic
• Crystal structure
• Magnetic property