Two new carboxylate–oxygen bridged trinuclear M(II) (MMn and Co) compounds with zwitterionic dicarboxylate ligands: crystal structures and magnetism

• First trinuclear Mn(II) magnetic system with mixed (μ-COO)2(μ2-Ocarboxylate) bridges from a new zwitterionic ligand L1.
• First trinuclear Co(II) magnetic system with mixed (μ-COO)2 (μ-H2O) bridges from a new zwitterionic ligand L2.
• The (μ-COO)2(μ2-Ocarboxylate) and (μ-COO)2(μ-H2O) bridges transmit AF exchange within the Mn3 and Co3 units respectively.

Two new Mn(II) and Co(II) coordination polymers with azide and zwitterionic dicarboxylate ligands L1 and L2 (L1 = [4-((1-carboxylatobenzyl)pyridimium-3-yl) benzoic acid] chloride, L2 = [1,1′-bis(4-carboxylatobenzyl)-4,4′-bipyridinium] dichloride) were synthesized and structurally and magnetically characterized. They are formulated as [Mn3(L1)4(N3)(CH3CH2OH)(H2O)]ClO4·4H2O (1) and [Co3(L2)4(N3)2(H2O)2]·4NO3 (2). Compound 1 contains two different linear trinuclear [Mn3(COO)8(CH3CH2OH)2]2 − and [Mn3(COO)6(H2O)2(N3)2]2 − units built from the mixed bridges of (μ-COO)2(μ2-Ocarboxylate). The trinuclear units are alternately linked into 1D chains by L1. Compound 2 contains linear trinuclear [Co3(N3)2(COO)4(H2O)2] units built from the mixed bridges (μ-COO)2(μ-H2O). Magnetic studies demonstrated that the mixed triple bridges are antiferromagnetic in compounds 1 and 2.

Two new linear Mn(II)3 and Co(II)3 magnetic systems with mixed carboxylate–oxygen bridges derived from two zwitterionic ligands were obtained. The mixed carboxylate–oxygen bridges transmit antiferromagnetic interactions between M(II) ions.Figure optionsDownload as PowerPoint slide