Chemistry of azopyrimidines. Part IV. Aromatic hydroxylation in palladium(II)-arylazopyrimidines

Journal of Chemical Sciences

Ramkrishna Roy¹  Chittaranjan Sinha1¹  Prasanta Kumar Santra¹ 

[1] Department of Chemistry, University of Burdwan, Burdwan 713 104, India$$

关键词: Arylazopyrimidines;    palladium(II);    aromatic hydroxylation;    oxygen insertion;    spectral characterization;    electrochemistry.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

2-(Arylazo)pyrimidines (aapm) are N,N -chelating ligands and synthesise orange-red complexes of composition [Pd(aapm)Cl2], 1, with Pd(MeCN)2Cl2 in MeCN. The complex has cis-PdCl2 configuration [(Pd−Cl): 340, 360 cm-1]. The treatment of Tollen’s reagent (`AgOH’) leads to chelatative hydroxylation in the pendant aryl ring, affording a green phenolato complex, Pd(aapmO)Cl, 5 (aapmO is deprotonated 2-((8-hydroxo)arylazo)pyrimidine). The reaction is also carried out by controlled addition of dilute sodium hydroxide in air or by the addition of PhIO/𝑚-chloroperbenzoic acid to a MeCN suspension of the complex. A single Pd-Cl stretch at 360 cm-1 supports the composition of phenolato complex. Unlike Pd(aapm)Cl2 the hydroxylated product, Pd(aapmO)Cl, has a structured intense absorption in the visible region near 670 nm. The Pd-Cl bond in Pd(aapmO)Cl is highly sensitive to nucleophilic substitution and slowly hydrolyses in aqueous medium.

【 授权许可】

Unknown