Two cluster-based metal-organic frameworks with selective detection of Hg2+ ion and magnetic properties

Two cluster-based metal-organic frameworks {[Cd5L4Br10]center dot 2(CH3)(2)NH}(n) (1) and {[(Mn3OL)-O-III(TA)(3)]F center dot sol}(n) (2) (L = 1,3,5-tris(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene, TA = terephthalate anion) containing a semi-rigid tribenzimidazol-based ligand were synthesized and characterized. Single crystal X-ray analyses show that the structure of 1 contains pentanuclear cadmium clusters with an interesting four-fan shape, in which each mu(2)-Br interlinks two crystallographically unique Cd atoms, while 2 contains a trimanganese cluster with three Mn3+ ions present in an equilateral triangle distribution. Furthermore, 1 exhibits highly selective fluorescent detection of trace Hg2+, with the detection limit of 5.26 x 10(-7) M-1. 2 shows antiferromagnetic interactions between Mn3+ ions.