Tuning of the sensing properties of luminescent Eu3+ complexes towards the nitrate anionElectronic supplementary information (ESI) available. CCDC 1436955. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5dt04665c

• Main Authors: Piccinelli, Fabio, Leonzio, Marco, Bettinelli, Marco, Monari, Magda, Grazioli, Cristian, Melchior, Andrea, Tolazzi, Marilena
• Format: Journal Article
• Published: 16.02.2016
• DOI: 10.1039/c5dt04665c
• ISSN: 1477-9226

A new family of imine-based ligands containing pyridine or furan as an aromatic donating ring [ N , N ′-bis(2-pyridylmethylidene)-1,2-( R , R + S , S )-cyclohexanediamine, L1 ; N , N ′-bis(2-furanylmethylidene)-1,2-( R , R + S , S )-cyclohexanediamine, L2 and N , N ′-bis(2-thienylmethylidene)-1,2-( R , S )-cyclohexanediamine, L3 ] has been prepared in high yield by means of an easy synthetic protocol. Their trifluoromethansulphonate (CF 3 SO 3 − , OTf − ) Eu( iii ) complexes have been employed for luminescence sensing of the NO 3 − anion in an anhydrous acetonitrile solution. Spectrophotometric titrations have been carried out to define the speciation in the solution and study the formation of ternary species occurring with the addition of NO 3 − anions. The sensing response towards this anion is strongly dependent on the nature of the ligand, the stoichiometry of the complexes and their concentration. The dependence of the luminescence sensing towards nitrate on the ligand donor ability, ligand stereochemistry, complex stoichiometry and concentration is shown.