A three-dimensional manganese(II) coordination polymer with two functional properties: magnetism and photochemical detection.

Hydrothermal reaction of Mn with the ditopic ligand 2,5-bis(1H-1,2,4-triazol-1-yl)benzoic acid (Hdtba) resulted in the complex poly[aqua[μ-2,5-bis(1H-1,2,4-triazol-1-yl)benzoato-κN:N:O]chloridomanganese(II)] monohydrate], {[Mn(CHNO)Cl(HO)]·HO}, (I). Coordination polymer I has been characterized by X-ray diffraction, IR spectroscopy, elemental analysis, thermogravimetry and susceptibility measurements. The topology of I corresponds to a three-dimensional (3,6)-conn net linked by {MnCl(COO)} building blocks and dtba anions. Significant antiferromagnetic exchange is observed within the dinuclear {MnCl(COO)} subunits. A fit of the susceptibility data resulted in the magnetic parameters g = 1.93 and J = -1.52. Studies of the photoluminescence properties revealed that I represents a promising luminescence sensor for sensitively detecting dichromate ions in aqueous solution. The associated photochemical detection mechanism was studied in detail.