Novel 1,10-phenanthroline - di-2-picolylamine scaffold as a selective chemosensor for copper and cyanide ions

• A novel 1,10-phenanthroline - di-picolylamine based chemosensor.
• Greater bulk around phenanthroline nitrogen atoms to achieve Cu2 + selectivity.
• Red shifted and increased absorbance of chemosensor with Cu2 + ions.
• Recognition of CN− ions by displacing Cu2 + from 1-Cu2 + complex.
• Photophysical results have been well supported by DFT calculations.

A new phenanthroline - di-2-picolylamine (DPA) conjugate 1 has been designed and synthesised with an aim to create greater bulk around phenanthroline N′s, hence excluding them from metal ion binding. Chemosensor 1 showed red shifted and increased absorbance with Cu2 + ions only upon examination for its recognition ability towards various cations. The selectivity displayed by the synthesised model compound 2 towards Cu2 + ions ascertained the participation of pyridine N′s of DPA as the major binding sites. The photophysical results have been well supported by the DFT calculations. Moreover, the addition of CN− ions to the 1-Cu2 + complex displaced Cu2 + from the complex, enabling estimation of CN− from the solution. Chemosensor 1 also exhibited moderate antibacterial activity towards Staphylococcus aureus and Streptococcus pneunomoniae.

A new phenanthroline-DPA based chemosensor 1 has been designed and synthesised for selective recognition of Cu2 + and CN− ions. The stearic bulk created by two 2-di-picolyl units attached at the 2,9-position of phenanthroline in 1 made phenanthroline N′s of 1 silent to cation binding.Figure optionsDownload as PowerPoint slide