Fluoropolymers exhibit many interesting properties such as high chemical, UV and thermal resistance, low flammability and surface energy. However, macromolecular engineering is challenging because fluorinated olefins can only be (co)polymerized radically and are associated to very reactive radicals. In addition, unsymmetrical monomers such as vinylidene fluoride (VDF), H2C=CF2, suffer from inverted (head-to-head and tail-to-tail) monomer addition defects, leading to dormant species that are even more difficult to reactivate than the regular ones obtained after head-to-tail addition. This is noted in both iodine-transfer polymerization (ITP) and reversible addition−fragmentation chain-transfer polymerization. In VDF polymerization, successful reactivation of all chains could be achieved in ITP through the use of reactive Mn(CO)5 radicals generated from Mn2(CO)10 under visible light irradiation. Mn(CO)5 radical abstracts the iodine atom from all PVDF-I chain ends to yield I-Mn(CO)5, but the possible direct radical chain trapping to yield PVDF-Mn(CO)5 was not addressed. This would correspond to the dormant species of a putative organometallic mediated radical polymerization (OMRP) process. This contribution presents the synthesis and full characterization of several new R-Mn(CO)5 complexes (R = alkyl, fluoroalkyl) and the analysis of their Mn-R bond strengths. The possible use of these complexes as initiators in controlled radical polymerization of monomers will also be shown.

Alkyl and fluoroalkyl manganese pentacarbonyl complexes as models of OMRP dormant species

254th National Meeting (2017)

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