Structural diversity and magnetic properties of six ferrocenyl monocarboxylate Mn(ii), Ni(ii) and Co(ii) complexes with 1D aqua, carboxyl or dinuclear hydroxyl bridges

Abstract

Using asymmetric 2-chloro-4-ferrocenylbenzoic acid, six new complexes formulated as {[Mn(OOCClH₃C₆Fc)₂(H₂O)₃]·(CH₃OH)}_n (1), {[Ni(OOCClH₃C₆Fc)₂(H₂O)₃](CH₃OH)}_n (2), [Co(OOCClH₃C₆Fc)₂(H₂O)₃]_n (3), [Co(η₂-OOCClH₃C₆Fc)(fcz)]₂·CH₃OH (4) [Hfcz = a-(2,4-difluorophenyl)-a-(1H-1,2,4,-triazol-1-ylmethyl)-1H-1,2,4-triazole-1-ethanol], [Ni(η₂-OOCClH₃C₆Fc)(fcz)]₂·2CH₃OH (5), and [Mn(OOCClH₃C₆Fc)₂(phen)(H₂O)] (6) [phen = 1,10-phenanthroline monohydrate] have been synthesized and structurally characterized. 1–3 are isostructural and display 1D aqua-bridged chain structures, in which 1–3 reveal antiferromagnetic coupling with J = −2.35 cm⁻¹ for 1, J = −25.92 cm⁻¹ for 2 and J = −3.98 cm⁻¹ for 3. Notably, 2 and 3 with 1D μ₂-aqua bridges haven't been reported before. Complexes 4 and 5 show dinuclear hydroxyl-bridged structures, in which 4 also exhibits antiferromagnetic coupling with J = −2.46 cm⁻¹. For 6 with a 1D carboxyl-bridged chain structure, it also exhibits antiferromagnetic behaviour with J = −1.11 cm⁻¹.