Synthesis, structural characterization and catalysis of ruthenium(ii) complexes based on 2,5-bis(2'-pyridyl)pyrrole ligand

Yi-Qing Zhong; Hui-Qiong Xiao; Xiao-Yi Yi

doi:10.1039/c6dt03464k

Synthesis, structural characterization and catalysis of ruthenium(ii) complexes based on 2,5-bis(2'-pyridyl)pyrrole ligand

Dalton Trans. 2016 Nov 15;45(45):18113-18119. doi: 10.1039/c6dt03464k.

Authors

Yi-Qing Zhong¹, Hui-Qiong Xiao¹, Xiao-Yi Yi¹

Affiliation

¹ College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, P. R. China. xyyi@csu.edu.cn.

PMID: 27783071
DOI: 10.1039/c6dt03464k

Abstract

Treatment of the 2,5-bis(2'-pyridyl)pyrrolato (PDP^-) anion with {Ru(COD)Cl₂}_n in THF readily yielded [Ru(PDP)(COD)Cl] (1) in almost quantitative yield. Anion metathesis of 1 in organic solvent by NO₃^- and OTf^- (OTf^- = triflato) gave [Ru(PDP)(COD)(NO₃)] (2) and [Ru(PDP)(COD)(OTf)] (3), and in aqueous solution by BF₄^- and PF₆^- afforded aqueous complexes [Ru(PDP)(COD)(H₂O)](BF₄) (4+·BF₄^-) and [Ru(PDP)(COD)(H₂O)](PF₆) (4+·PF₆^-), respectively. Treatment of 1 with PhICl₂ in CH₂Cl₂ afforded 5 with halogenated pyrrole. These complexes exhibit similar structure, including one Ru(ii) atom, one 2,5-bis(2'-pyridyl)pyrrole and one monodentate anion or aqua ligand. Each Ru(ii) tightly binds to three adjacent coplanar sites of PDP^- ligand to form a meridional configuration. Complex 1 with NaIO₄ as the oxidant in EtOAc-CH₃CN-H₂O (ratio = 3 : 1 : 2) proved to be highly effective in the catalytic oxidation of olefins to carbonyl products.