Ruthenium N‐Confused Porphyrins: Selective Reactivity for Ambident 2‐Heteroatom‐Substituted Pyridines Serving as Axial Ligands. Issue 6 (14th February 2019)

• Record Type: Journal Article
• Authors: Miyazaki, Takaaki; Fukuyama, Kazuki; Mashita, Shunichi; Deguchi, Yuya; Yamamoto, Takaaki; Ishida, Masatoshi; Mori, Shigeki; Furuta, Hiroyuki
• Is Part Of: ChemPlusChem. Volume 84:Issue 6(2019)
• Page Start: 603
• Page End: 607
• Publication Date: 2019-02-14
• Subjects: N-confused porphyrins -- oxidation reactions -- pentadentate ligands -- ruthenium -- tautomerism; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.201800630
• Languages: English
• ISSNs: 2192-6506

Abstract

Abstract: Three types of ruthenium(II) N‐confused porphyrin (NCP) complexes bearing an axial 2‐thiopyridine, 2‐pyridone, and 2‐iminopyridine moiety at the inner carbon atom, respectively, were synthesized. The unique reactivity of the 2‐substituted pyridine derivatives (2‐X‐pyridine; X=SH, OH, NH2 ) toward the inner carbon atom of the NCP allows the formation of two types of coordinated products (i. e., pyridine donor versus 2‐heteroatom donors), as inferred from single‐crystal X‐ray structures. The selective reactivity was investigated by using density functional theory (DFT) calculations. Finally, the catalytic activity of these ruthenium complexes was demonstrated through the styrene oxidation reactions. As a result, the ruthenium(II) NCP complex bearing a 2‐thiopyridine moiety, together with aqueous H2 O2 as an oxidant showed the highest selectivity for benzaldehyde (benzaldehyde/styrene oxide=20 : 1). Abstract : Sorting out confusion : The unique reactivity of the inner carbon atom of ruthenium(II) N‐confused porphyrins (NCPs) allows the synthesis of three complexes bearing an axial 2‐thiopyridine, 2‐pyridone, and 2‐iminopyridine moiety, respectively. The axial‐ligand‐dependent catalytic activity of these complexes was demonstrated through the styrene oxidation reactions.