C–ON bond homolysis of alkoxyamines triggered by paramagnetic copper(ii) salts. Issue 11 (30th September 2016)

• Record Type: Journal Article
• Authors: Audran, Gérard; Bagryanskaya, Elena; Bagryanskaya, Irina; Brémond, Paul; Edeleva, Mariya; Marque, Sylvain R. A.; Parkhomenko, Dmitriy; Tretyakov, Evgeny; Zhivetyeva, Svetlana
• Is Part Of: Inorganic chemistry frontiers. Volume 3:Issue 11(2016)
• Page Start: 1464
• Page End: 1472
• Publication Date: 2016-09-30
• Subjects: Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6qi00277c
• Languages: English
• ISSNs: 2052-1553

Abstract

Abstract : Pyridine-based alkoxyamines were used as ligands for Cu(hfac)2 to prepare the first metallic complexes of alkoxyamines. Structures of complexes were determined by X-ray analysis and a 21-fold increase in the C–ON bond homolysis was observed. Abstract : The metal complexation reactions of bis(hexafluoroacetylacetonato)copper(ii ) (Cu(hfac)2 ) with alkoxyamines (diethyl(2, 2-dimethyl-1-( tert -butyl-(1-(pyridine-4-yl)ethoxy)amino)propyl)phosphonate and diethyl (2, 2-dimethyl-1-( tert -butyl-(1-(pyridine-2-yl)ethoxy)amino)propyl)phosphonate) were studied. According to X-ray analysis, the molecular and crystal structures of 1 : 1 complexes depend on the configuration of the free alkoxyamines, that is dimeric ( RSSR ) and chain-polymeric ( RR / SS ) structures for para -pyridyl-substituted alkoxyamines, and cyclic unimeric ( RS / SR ) structure for ortho -pyridyl derivative. The complex (2 : 1 ratio Cu(hfac)2 /alkoxyamine) for ortho -pyridyl-substituted alkoxyamine is not resolved. Upon warming, ortho complexes decomposed into free alkoxyamines and only a weak activation was observed. Upon warming, para complexes decomposed into their corresponding unimers, and then, a 21-fold increase in the rate constant of the C–ON bond homolysis was observed compared to the corresponding free alkoxyamines. Tuning of the homolysis rate constant of the C–ON bond via addition of pyridine is also reported.