Unusual solvent influence of formamide on the structural variations of chiral and achiral Mn(II) complexes based on tetrachlorophthalate

Abstract

Using an achiral ligand 3,4,5,6-tetrachloro-1,2-benzenedicarboxylic acid (1,2-H2BDC-Cl4), a short series of chiral or achiral manganese(II) complexes with the formulae [Mn(1,2-BDC-Cl4)(MF)2(H2O)2]n (1), [Mn(1,2-BDC-Cl4)(DMF)(H2O)2]n (2) and [Mn2(1,2-BDC-Cl4)2(DEF)2(H2O)6]·2H2O (3) (MF=N-methylformamide; DMF=N,N-dimethylformamide and DEF=N,N-diethylformamide) have been spontaneously obtained through the alteration of formamide solvent media, and characterized by single-crystal X-ray diffraction, elemental analysis, IR, thermal gravimetric analyses (TGA) and powder X-ray diffractions (PXRD). Complex 1 crystallizes in the monoclinic P21/c space group and shows a one-dimensional fishbone chain structure, complex 2 crystallizes in the orthorhombic P212121 space group and has a chiral double-stranded helical chain consisting of two single-stranded helices of the same right-handness, and complex 3 crystallizes in the triclinic P1 space group and possesses a dinuclear [Mn(1,2-BDC-Cl4)]2 metallomacrocycle directing a two-dimensional hydrogen-bonded water layer based on both coordinated and lattice water molecules. This remarkable structural difference displays the significant influence of formamide solvents on the formation of such chiral and achiral Mn(II) complexes. The spectroscopic, thermal stability and luminescence properties of 1–3 have also been investigated briefly.