Radical Polymerization of 5-(4-Vinylphenyl)-10,15,20-triphenyl Porphyrin

Abstract

ABSTRACT:Radical polymerizations of vinyl monomer in which vinyl group directly bind to a tetraphenyl porphyrin (TPP) moiety, 5-(4-vinylphenyl)-10,15,20-triphenylporphyrin (VTPP), were investigated. Homopolymerization occurred and high-molecular weight polymers (Mw > 100000) were obtained. Copolymerizations of VTPP (M 1 ) and styrene (M 2 ) were performed with 2,2' -azobis(isobutyronitrile) (AIBN) at 60°C. Monomer reactivity ratios were r 1 = 0.65 ± 0.15 and r 2 = 0.51 ± 0.15, Q and e for VTPP being 0.85 and 0.24, respectively. These values suggest a slightly distorted structure of propagating radicals. Rate constant of the addition of diphenyl phosphinoyl radicals (PhiJ''=O), generated by the photolysis of 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TMDPO), to VTPP was directly determined by time-resolved electron spin resonance (ESR) spectroscopy. The rate constant, -1.4 x 10 6 s-1 M-1 , was one order of magnitude smaller than that of styrene (-I.Ix 10 7 s-1 M-1 ), due to decrease of resonance stabilization caused from a steric hindrance of TPP moiety.KEY WORDS Tetraphenylporphyrin / Radical Polymerization / Copolymerization / Q, e Values / Monomer Reactivity Ratio / Time-Resolved ESR / Initiation Rate Constant / Polymers containing paramagnetic species in their side chains are potentially new magnetic materials, because a magnetic ordering of the paramagnetic species through an exchange interaction of unpaired electrons is possible in the polymers. 1 -3 To our knowledge, the radical homopolymerization of vinyl monomers containing a porphyrin moiety in the side chain has not been reported except in our previous papers. 4 -6 The homopolymerizations of such monomers have been considered difficult due to steric repulsion. We synthesized poly-acrylate, -methacrylate, -acrylamide, and -methacrylamide of tetraphenyl- , MAATPP, 7 respectively) and investigated physicochemical properties of their metal complexes. 8 -11 We measured the magnetic susceptibility of polymers containing paramagnetic metalloporphyrin moieties in their side chains. Although the silver(II) complex of polyAOTPP showed strong antiferromagnetic interaction, the silver(II) complex of monomer (AOTPP) showed a typical paramagnetic property. 2 Polymer effect on the magnetic ordering was found in the system, but the origin of the exchange interactions among these paramagnetic side chains still remains unknown. The strong antiferromagnetic interaction of polyAOTPP-Ag 11 is likely due to a superexchange interactions through oxygen atoms of carbonyl group suggested from an IR t To whom correspondence should be addressed. 215

Radical Polymerization of 5-(4′-Acrylamidophenyl)-10,15,20-triphenylporphine and 5-(4′-Methacrylamidophenyl)-10,15,20-triphenylporphine

“…The same was noted for VTPP and styrene. 9 These results are consistent with the small Q values for TPP monomers obtained from the copolymerization of TPP monomers with styrene.…”

Synthesis of Polymerizable Superoxide Dismutase Mimetics to Reduce Reactive Oxygen Species Damage in Transplanted Biomedical Devices

“…[23][24][25][26] SOD mimetic metalloporphyrins have also been conjugated onto linear polymers to increase circulation half-lives and bioavailability of their compounds, but retained only minimal levels of activity (i.e., $0.1%) compared to the activity of native SOD enzyme. [27,28] The work herein describes the creation of a polymerizable SOD mimetic that has the potential to be incorporated into any polymer system capable of formation by free radical polymerization, with retention of high levels of SOD mimetic activity.…”

Polymer Effects on Reversible Formation of Dioxygen Adduct with Silver(II) Tetraphenylporphyrin Moieties

“…The spectral shapes were different between the monomer and the polymer because of the spin exchange interaction in the polymer side chain as previously reported for other Ag porphyrin polymers. [12][13][14][15][16][17][18][19][20][21] As a result, the anisotropy observed in AgAATPP disappeared in its polymer form. In case of the polymer, the signal intensity decreased with a decrease in temperature.…”

“…[12][13][14][15][16][17][18][19][20][21] Their features revealed by ESR and UVvisible spectroscopies and magnetic susceptibility measurements have suggested that the metalloporphyrin moieties bonded to a polymer interact with each other magnetically and electronically. [13][14][15][16][17][18][19][20][21] In addition, unusual oxygen absorption has been found in the measurements of ESR spectra and magnetic susceptibility of polyacrylates containing (tetraphenylporphytinato)-cobalt(II) in their side chains. Very recently, when we measured the temperature dependence of the ESR spectra of silver(II) complexes of the tetraphenylporphyrin (AgTPP) polymers under oxygen atmosphere, it was found that the signal intensity decreased with a decrease in temperature.…”