The reaction of heterocyclic amine with pendant naphthyl group in Pd(α/β-NaiR)Cl2 (α/β-NaiR = 1-alkyl-2-(naphthyl-α./β-azo)imidazoles) and the product characterisation

Department of Chemistry, Inorganic Chemistry Section, Jadavpur University, Kolkata-700 032, India

E-mail : c_r_sinha@yahoo.com

Department of Chemistry, University of St-Andrews, St-Andrews, KY16 9ST, UK

Manuscript received 06 February 2012, accepted 10 February 2011

The reaction of Pd(α/β-NaiR)Cl₂ (1-alkyl-2-(naphthyl-α/β-azo)imidazoles, α-NaiR (1) and β-NaiR (2)) with m-aminopyridine (m-NH₂-Py) and o-aminopyrimidine (o-NH₂-Pym) in acetonitrile solution has synthesized a C-N coupled product, chloro[1-alkyl-2-{ (7-imidophenyl)pyridyl-α/β-azo }imidazole-N ,N' ,N"]palladium(II), Pd(α/β-NaiR-N-Py-m)Cl (3, 4) and Pd(α/β-NaiR-N₂-Py-o)Cl (5, 6). The structural confirmation has been carried out by X-ray diffraction study. The solution electronic spectra of C-N fused products, 3-6, show transitions within 600-900 nm those are absent in Pd(α/β-NaiR)Cl₂. Cyclic voltammogram shows four successive redox couples, one of them (positive to SCE) is oxidative in nature and others (negative to SCE) are ligand reductions. Emission is observed from ligand centred orbitals and has been ascribed to 𝝅-𝝅* excitation process. The excited state decays following radiative and nonradiative biexponential routes. Absorption and fluorescence spectra of pyridylamine fusion product show H⁺ and metal ion (Zn²⁺, Cd²⁺) sensitivity.