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

Hydrothermal reaction of Mn2+ with the ditopic ligand 2,5-bis(1H-1,2,4-triazol1-yl)benzoic acid (Hdtba) resulted in the complex poly[aqua[ 3-2,5-bis(1H1,2,4-triazol-1 -yl)benzo ato-K3N4:N4': 0] chloridomanganese (II)] monohydrate], {[Mn(CiiH7N602)C1(H20)1-H201, (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 {Mn2C12(COO)2} building blocks and dtba- anions. Significant antiferromagnetic exchange is observed within the dinuclear {Mn2C12(COO)2} 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.