Structural design of coordination polymers based on manganese and chromium ions bridged by oxalate ligands

Abstract

Coordination polymers based on oxalate-bridged {[MnIICrIII-(oxalate)3]-}∞ complexes of (DAT-2H2+)(DCH[18]crown-6)2[MnII(CH3OH)CrIII(oxalate)3]-2(CH3OH)3 and (DABCO-H+)2(DABCO-2H2+)[MnII(CH3OH)(Cl-)CrIII(oxalate)3]2-2- (CH3OH), where DAT, DABCO, and DCH[18]crown-6 denote 2,5-diaminotoluene, 1,4-diazabicyclo[2.2.2]octane, and cis-syncis-dicyclohexano[18]crown-6, respectively, were synthesized. The crystal structure of the former complex was composed of [MnII(Δ)(CH3OH)CrIII(Δ)(oxalate)3]- units, whereas that of the latter crystal was composed of [MnII(Δ)(CH3OH)(Cl-)-CrIII(Δ)(oxalate)3]2- units. The large flexible supramolecular cation in the former provided the two-dimensional structure of [MnII(Δ)(CH3OH)CrIII(Δ)(oxalate)3]-, although the two-dimensional honeycomb structure of the {[MnII(Δ)CrIII(Δ)-(oxalate)3]-}∞ and {[MnII(Δ)CrIII(Δ)(oxalate)3]-}∞ networks are often observed for the oxalate complexes. The round-shaped DABCO molecule in the latter induced a one-dimensional chain structure of [MnII(Δ)(CH3OH)CrIII(Δ)(oxalate)3]-. The former crystal showed a magnetic field dependence of magnetization typical for a spin-canting system.