Iridium mediated phenolic O-H activation and cyclometalation of 2-(naphthyl-1'-azo)-4-methylphenol - Formation of organoiridium complexes

Journal of Chemical Sciences

Shie-Ming Peng¹  Rama Acharyya²  Samaresh Bhattacharya²  Gene-Hsiang Lee¹ 

[1] Department of Chemistry, National Taiwan University, Taipei, Taiwan, Republic of China$$;Department of Chemistry, Inorganic Chemistry Section, Jadavpur University, Kolkata 700 032$$

关键词: 2-(Naphthyl-1'-azo)-4-methylphenol;    iridium;    C-H activation;    structure;    electrochemical properties.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

Reaction of 2-(naphthyl-1'-azo)-4-methylphenol with [Ir(PPh3)3Cl] in refluxing ethanol in the presence of a base (NEt3) affords an organoiridium complex of type [Ir(PPh3)2(L)(H)], where L represents the coordinated 2-(naphthyl-1'-azo)-4-methylphenolate ligand. A similar reaction carried out in toluene affords the [Ir(PPh3)2(L)(H)] complex along with a similar complex of type [Ir(PPh3)2(L)Cl]. Structures of both the [Ir(PPh3)2(L)(H)] and [Ir(PPh3)2(L)Cl] complexes have been determined by X-ray crystallography. In both the complexes, 2-(naphthyl-1'-azo)-4-methylphenol is coordinated to iridium, via C-H activation at the 2' position of the naphthyl ring, as a dianionic tridentate C, N, O-donor and the two triphenylphosphines are trans. The organoiridium complexes show intense MLCT transitions in the visible region. Cyclic voltammetry on the [Ir(PPh3)2(L)(H)] and [Ir(PPh3)2(L)Cl] complexes shows a reversible Ir(III)-Ir(IV) oxidation respectively at 0.55 and 0.73 V vs SCE. An irreversible oxidation of the coordinated 2-(naphthyl-1'-azo)-4-methylphenolate ligand is observed above 1.0 V vs SCE and an irreversible reduction of the same is observed near -1.0 V vs SCE.

【 授权许可】

Unknown