C-ON bond homolysis of alkoxyamines triggered by paramagnetic copper(II) salts

Gérard Audran (1) , Elena Bagryanskaya (2) , Irina Bagryanskaya (2) , Paul Brémond (1) , Mariya Edeleva (2) , Sylvain R.A. Marque (1, 2) , Dmitriy Parkhomenko (2) , Evgeny Tretyakov (2) , Svetlana Zhivetyeva (2)

1 ICR - Institut de Chimie Radicalaire
2 RAS, SB, NN - Vorozhtsov Novosibirsk Institute of Organic Chemistry

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.

Mots clés: adducts; cancer; crystal; family; fragment; Nitroxide-mediated polymerization; polymers; theranostic agents

Domaines: Chimie de coordination; Cristallographie; Polymères

Gérard Audran, Elena Bagryanskaya, Irina Bagryanskaya, Paul Brémond, Mariya Edeleva, et al.. C-ON bond homolysis of alkoxyamines triggered by paramagnetic copper(II) salts. Inorganic Chemistry Frontiers, 2016, 3 (11), pp.1464-1472. ⟨10.1039/c6qi00277c⟩. ⟨hal-01460663⟩