Visible‐Light Hypervalent Iodide Carboxylate Photo(trifluoro)methylations and Controlled Radical Polymerization of Fluorinated Alkenes

Abstract

IFAB-ulous trifluoromethylation: (CX3COO)2I(III) h (X=F, H) and (CH3COO)3I(V)(C6H4COO) are introduced as CX3·/CX3I precursors for metal-free, visible-light, radical (trifluoro)(iodo)methylations of alkenes, illustrated by their use as photoinitiators for the controlled radical polymerization of vinylidene fluoride with external (I(CF2)6I) and in situ generated (CF3I) iodine chain transfer agents, and for block copolymer synthesis.

Photochemically Enabled Iodine Degenerative Transfer Controlled Radical Homo- and Block Copolymerization of Vinylidene Fluoride at Ambient Temperatures with Mn2(CO)10and Visible Light

“…Remarkably, unlike other radical abstractors, Mn(CO) 5 • reacts faster with primary rather than secondary or tertiary halides, due to the sterics of the CO ligands (84). Moreover, prior to our work (50)(51)(52)(53), there were no examples of Mn 2 (CO) 10 mediated activation of perfluoroalkyl or sulfonyl halides, or trifluoromethylations with CF 3 -I or CF 3 -SO 2 -I.…”

“…Likewise, we have also confirmed (50,(79)(80)(81)(82) that VDF free radical polymerization (FRP) occurs readily under UV irradiation at rt in the presence of TBPO. However, before our work (50)(51)(52)(53), there were no reports on the VDF polymerization using regular visible light. Thus, while aiming to maintain an ambient reaction temperature and a relatively low pressure in the glass tubes, and also considering the very poor stability of most organometallic complexes under UV irradiation, we decided to investigate photopolymerizations mediated by commercially available transition metal complexes, using low wattage (< 30 W), white light fluorescent bulbs.…”

“…Indeed, the capability to carry out such reactions under mild conditions would be of great synthetic use not only in polymer fluoro-functionalization, or the initiation and CRP of FMs and synthesis of their complex architectures, but also in perfluoroalkylations and trifluoromethylations that are in increasing demand in organic/medicinal chemistry (49). Yet, prior to our recent work (50)(51)(52)(53), there were no disclosures on metal-mediated FM or VDF polymerizations, let alone VDF-CRP.…”

Synthesis of Chlorotrifluoroethylene-Based Block Copolymers by Iodine Transfer Polymerization

“…15 Moreover, ITP of VDF induces the formation of -CH 2 CF 2 -I and -CF 2 CH 2 -I chain-ends, which exhibit widely different reactivities. 15,18,19 Scheme …”

“…h Determined by TGA at 10°C/min, under air. i Determined by 19 F NMR using the following equations: %CH 2 CF 2 -I = (∫ −39 )/(∫ −39 + ∫ −108 ) and %CF 2 CH 2 -I = (∫ −108 )/(∫ −39 + ∫ −108 ). These equations do not take into account the integral of the signal at −115 ppm that corresponds to -CF 2 -H dead-ends.…”