Surprisingly high quantum yield of emission in a fluorescent coordination polymer with paramagnetic Mn(ii) ions.

A two-dimensional coordination polymer, [Mn3(HEBTC)2(DMSO)6] (1), has been achieved by a solvothermal reaction of Mn2+ with 1,1'-ethynebenzene-3,3',5,5'-tetracarboxylic acid (H4EBTC). The layer of a coordination polymer is composed of trinuclear Mn2+ clusters linked by HEBTC3- ligands to form a (3,6)-connected topological net. CP 1 with paramagnetic Mn2+ ions shows dual emissions centered at 397 and 468 nm in the solid state under ambient conditions with respectable quantum yields of 15.3% (397 nm) and 12.3% (468 nm). The dual emissions arise from n ← π* transition in HEBTC3- and MLCT between HEBTC3- and Mn2+ centers.