Synthesis, structure, redox and spectra of green iridium complexes of tridentate azo-aromatic ligands

Journal of Chemical Sciences

Manashi Panda¹  Sreebrata Goswami1¹  Chayan Das¹  Chen-Hsiung Hung² 

[1] Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032$$;Institute of Chemistry, Academia Sinica, Nankong, Taipei 115, Taiwan$$

关键词: Iridium complexes;    azo-aromatic ligands;    synthesis;    X-ray structure;    redox and spectral properties.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

Reactions of IrCl3$cdot$ 𝑥 H2O with the ligands, 2-[(phenylamino)phenylazo]pyridine (HL1a) and 2-[(𝑝-tolylamino)phenylazo]pyridine (HL1b) produce [Ir(L1)2]Cl (L1 = L1a, [1]Cl and L1 = L1b, [2]Cl) along with many unidentified products. The iridium complexes have been characterized by various techniques such as X-ray crystallography, mass spectrometry, 1H and 13C NMR, cyclic voltammetry and absorption studies. The complex [1]ClO4 crystallises in triclinic space group. The crystallographic data have been determined. Notably, the Ir-N (azo) lengths are short (av. 1.9875(4) Å) as compared to the remaining four Ir-N lengths (av. 2.052(5) Å). There is significant degree of ligand backbone conjugation in the coordinated ligands, which result in shortening of the C-N lengths on the other side of the middle phenyl ring and also in lengthening of the diazo (N=N) lengths. The complexes display multiple low energy transitions ranging between 1010 and 450 nm. These are electro active and show three reversible redox responses in the potential range, +1.5 V to -1.5 V. The cathodic potential responses are ascribed as ligand reductions, while the redox process at the anodic potential occurs at a mixed metal-ligand (HOMO) orbital.

【 授权许可】

Unknown