Fluorinated Poly(substituted methylene)s Prepared by Pd-Initiated Polymerization of Fluorine-Containing Alkyl and Phenyl Diazoacetates: Their Unique Solubility and Postpolymerization Modification

Abstract

Pd-initiated polymerization of fluorine (F)-containing alkyl and phenyl diazoacetates is described. Polymerization of 2,2,2-trifluoroethyl diazoacetate [Et­(CF3)­DA] with π-allylPdCl afforded a C–C main chain polymer bearing a 2,2,2-trifluoro­ethoxycarbonyl group on each main chain carbon atom. The polymer showed upper critical solution temperature (UCST)-type phase separation in multiple common organic solvents with differing polarities. Although homopolymerization of 3,3,4,4,5,5,6,6,6-nonafluorohexyl diazoacetate [Hex­(C4F9)­DA] with a higher fluorine content yielded an insoluble product, copolymerization of Hex­(C4F9)­DA with non-fluorinated ethyl diazoacetate (EDA) proceeded homogeneously to give a soluble F-containing copolymer. Polymerization of a series of F-containing phenyl diazoacetates was also conducted with the same initiator, giving poly­[(F-containing aryloxy­carbonyl)­methylene]­s, which showed significant solubility differences depending on the substitution pattern of F atoms on the phenyl ring. Efficient postpolymerization modification of poly­[(F-containing aryloxycarbonyl)­methylene]­s was achieved with a primary amine, affording a polymer with both a five-membered cyclic imide structure and an N-alkylcarbamoyl group in its side chains.

A Dinuclear Mechanism Implicated in Controlled Carbene Polymerization

“…Comparison of 1 and ( π -allyl)palladium acetate dimer 27–29 (2), as well as ( π -allyl)palladium methacrylate dimer (3) in the polymerization of EDA and 2,2,2-trifluoroethyl diazoacetate (TFEDA) 30 under equivalent conditions revealed that, as anticipated, in the presence of 2 and 3, both monomers were polymerized in nearly quantitative yield, while 1 afforded low yields of corresponding polycarbenes and mostly produced maleate and fumarate esters (Figure 2A). Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) confirmed that the polymer chains were virtually uniformly carboxylate-initiated and hydrogen-terminated, the latter presumably generated through protodepalladation upon exposure to air (Figure 2B, Supporting Information (SI), Figures S1 and S2).…”

Surface Modification of Parylene C Film via Buchwald–Hartwig Amination for Organic Solvent‐Compatible and Flexible Microfluidic Channel Bonding

“…[ 26,27 ] Nonetheless, although well established in the organic chemistry toolbox, such reactions have not been applied for functionalization of polymer surfaces, and rarely for the homogeneous post‐functionalization of synthetic polymers. [ 28,29 ] In the latter case, this may be due to the high molecular weight nature of the polymer reactant, which can pose significant synthetic challenges, including highly diluted reaction condition, limited conversion, and problems in the purification and characterization processes. [ 30 ] We anticipate that such difficulties may be avoided in the surface modification because the reaction occurs in the heterogeneous phase between a solid substrate and the reactants in the solution.…”

Synthesis and Solid-State Properties of PolyC3 (Co)polymers Containing (CH2–CH2–C(COOR)2) Repeat Units with Densely Packed Fluorocarbon Lateral Chains

“…One exception to the above rule might be the substituted polymethylene (PolyC 1 ) discussed in the Introduction although its solubility in fluorinated solvents has not been reported yet. 5 A possible partial explanation for this observation might be related to the fact that 4 has two lateral fluorinated chains on a small repeat unit, thus generating a highly fluorine-rich polymers (e.g., the added thiol chains makes 82 wt-% of the total mass in 4 while the original 3a backbone contributes only to the remaining 18 wt-%). In addition, the location of the ester groups on the polymer chain, with two lateral chains protruding from the backbone on every third carbon alongside the backbone (see Scheme 1c), generates a very high density of fluorinated grafts, which might "hide" the central chain and reinforce the polytetrafluoroethylene-like character of the polymer, including its low solubility.…”

“…A very recent contribution by the Ihara group looked at carbon-chain polymers substituted on every single carbon by ester bearing fluorinated side chains, providing evidences not only that these extremely crowded polymers were accessible but also that they exhibit solubility behavior in sharp contrast to polymers exhibiting the same fluorinated side-chain but on every second carbon. 5 In this contribution, we wish to explore another substitution pattern in which two fluorinated side chains are attached on every third carbon on an all carbon-chain backbone (see Scheme 1a).…”