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

A pentacoordinated Cu(II) complex, [Cu(phen)2N3](NO3)·(H2O) (1) [phen = 1,10-phenanthroline], was synthesized and characterized by elemental analysis, IR, single crystal X-ray crystallography, thermal analysis and DFT calculations. The single crystal structural determination reveals that complex 1 is a discrete complex cation [Cu(phen)2N3]+ with the metal in a distorted trigonal bipyramidal coordination geometry, a nitrate anion and a lattice water molecule. The complex cations are connected by π–π interactions among the phen aromatic rings giving rise to a 1D chain. The complex exhibits intense fluorescence (λex = 271 nm, λem = 350, 366 and 382 nm) in water–MeOH (1:1) solution at room temperature with a fluorescence quantum yield Фs = 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.

A reaction of Cu(NO3)·3H2O and 1,10-phenanthroline monohydrate with sodium azide in water–methanol (1:1) solvent leads to a pentacoordinated Cu(II) complex which behaves as a fluorescence sensor for aniline. Results from DFT calculation show good agreement with X-ray experimental data.Figure optionsDownload as PowerPoint slide