Fluorescent bis-chelated-1,10-phenanthroline-azido-copper(II) complex for selective sensing of aniline

A pentacoordinated Cu(II) complex, [Cu(phen)(2)N-3](NO3)center dot(H2O) (1) [phen = 1,10-phenanthroline], was synthesized and characterized by elemental analysis, IR, single crystal X-ray crystallography, thermal analysis and OFT calculations. The single crystal structural determination reveals that complex 1 is a discrete complex cation [Cu(phen)(2)N-3](+) with the metal in a distorted trigonal bipyramidal coordination geometry, a nitrate anion and a lattice water molecule. The complex cations are connected by pi-pi interactions among the phen aromatic rings giving rise to a 1D chain. The complex exhibits intense fluorescence (lambda(ex) = 271 nm, lambda(em)= 350, 366 and 382 nm) in water-MeOH (1:1) solution at room temperature with a fluorescence quantum yield Phi(s) = 5.2. Complex 1 was tested with several aromatic compounds such as m-toluidine, aniline and nitrobenzene in water-methanol (1:1) solution, and results show it behaves as a fluorescence sensor for aniline. Results from DFT calculation show a good agreement with X-ray structural data. (C) 2012 Elsevier Ltd. All rights reserved.