Two‐Photon Initiating Efficiency of a Ditopic Alkoxynitrostilbene Reacting through a Self‐Regenerative Mechanism. Issue 20 (22nd September 2020)

• Record Type: Journal Article
• Authors: Hobeika, Nelly; Chaumeil, Helene; Mhanna, Rana; Jin, Ming; Wu, Xingyu; Spangenberg, Arnaud; Versace, Davy‐Louis; Morlet‐Savary, Fabrice; Malval, Jean‐Pierre
• Is Part Of: Chemphyschem. Volume 21:Issue 20(2020)
• Page Start: 2301
• Page End: 2310
• Publication Date: 2020-09-22
• Subjects: nitrostilbenes -- photophysics -- reaction mechanism -- two-photon absorption -- two-photon polymerization; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.202000437
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: The photophysical properties and the photoinitiating reactivity of a ditopic alkoxynitrostilbene were compared to those of its single branch chromophore used as a reference. Whereas a trivial additive effect is observed when considering the one‐ and two‐photon absorption properties, a clear and very significant amplification has been highlighted for the photoreactivity of this free radical photoinitiator which was used as a hydrogen abstractor in presence of an aliphatic amine co‐reactant. We indeed demonstrate that the proximity of two nitroaromatics moieties within the same molecular architecture gives rise to an original cycling mechanism based on a stepwise photo triggering of each photoredox center followed by a subsequent regenerative process. The combination of a high two‐photon absorption cross‐section (δ780nm ≈330 GM) with a strong enhancement in photoreactivity makes this nitrostilbene bichromophore a very suitable candidate for two‐photon polymerization applications. Abstract : A two‐photon activable ditopic alkoxynitrostilbene was developed to promote free radical photoinitiation reactions. Taking benefit of a synergy between high two‐photon absorption cross‐sections (δ780 nm ∼330 GM) and a regenerative photoinitiation process, the bichromophore clearly exhibits an amplified two‐photon induced reactivity and constitutes a promising candidate for two‐photon polymerization applications.