Synthesis and characterization of two manganese tert-butylphosphonate complexes

Two manganese(II) phosphonate complexes, Mn2(t-BuPO3H)4(bipy)2 1 (bipy = 2,2′-bipyridine) and [Mn(H2O)6][t-BuPO3H]2·6H2O 2 have been synthesized with identical procedure from similar system containing tert-butylphosphonic acid and bipy ligands in different ratio at different temperature. The complexes have been characterized by single crystal X-ray diffraction, IR spectroscopy, X-ray powder diffraction, magnetic measurement and thermal analysis. Compound 1 crystallizes in the triclinic space group P-1 with C2v symmetry, and exhibits infinite double-chains linked by hydrogen bonds and the double-chains are further packed into two-dimensional network via the π–π stacking interactions, whereas compound 2 crystallizes in a monoclinic space group P2(1)/c, and the mononuclear molecules in 2 are linked by hydrogen bonds to form sandwich-like two-dimensional formation. The magnetic measurement reveals weak antiferromagnetic exchange interactions between the manganese(II) ions in compound 1.