Photosensitized initiation of vinyl polymerization by a system of ferrocene and carbon tetrachloride

Photoinduced loss of one or both ligands from bis(arene) metal complexes provides an attractive route to cationic Lewis acids that can function as initiators for polymerization and crosslinking reactions. In this article, we examine the spectroscopy, photochemistry and photoinitiation activity of two such complexes: Fe(mes)22+ (mes is mesitylene) and Cr(tol)2+ (tol is toluene). Acetonitrile solutions of Fe(mes)22+ undergo photochemical loss of both mesitylene rings to yield solvated Fe2+. The quantum efficiency of deligation ranges from 0.6 to 1.0 depending upon excitation wavelength, but is independent of complex concentration, solvent, oxygen concentration and excess counter‐ion. Reaction appears to occur from both ligand field and ligand‐to‐metal charge transfer excited states. Low thermal stability, however, limits the use of Fe(mes)22+ as a practical photoinitiator. Deligation of both arene rings also occurs upon 366 nm irradiation of Cr(tol)2+ in acetonitrile. The quantum efficiency for this process is 0.04 and is independent of oxygen concentration. Photoinitiated crosslinking and insolubilization occur in a thin film of COP (copolymer of glycidyl methacrylate and ethyl acrylate) containing Cr(tol)2+.

show abstract

“…This type of chemistry has been exploited as a source of radicals for the photoinitiated polymerization of vinyl monomers [14].…”

Section: Photochemistry Of Metal-sandwich Complexesmentioning

confidence: 99%

Photochemical generation of cationic lewis acids via deligation of metal‐sandwich complexes

Gamble

Kutal

1994

Polymers for Advanced Techs

View full text Add to dashboard Cite

show abstract

“…Ferrocenyl compounds as the initiation activity together with some suitable reagents were reported to be effective initiators for vinyl polymerization. 2 Otsu et al [3][4][5] found that some vinyl monomers could be polymerized in the presence of Fc together with organic halides. Imoto et al6-9 also reported initiation activity of Fc in the polymerization of vinyl monomers with carbon tetrachloride.…”

Section: Introductionmentioning

confidence: 99%

Ferrocene as an effective initiator for copolymerization of styrene with maleic anhydride

Kuramoto

Ogino

Kido

et al. 1995

J. Polym. Sci. A Polym. Chem.

View full text Add to dashboard Cite

SYNOPSIS Ferrocene (Fc) was found to be an effective initiator for copolymerization of styrene (ST) with maleic anhydride (MAH). Copolymerization could be initiated by charge transfer complex formed between MAH as an electron acceptor and Fc as an electron donor. A good relationship between the formation of charge transfer complex and initiation activitywas observed in the copolymerization of ST with MAH in various solvents. Overall energy of activation determined from an Arrhenius plot in dioxane was found to be 21.8 kJ/mol.

show abstract

“…Titanocenes and ferrocenes are numbered among the successfully implemented organometallic photoinitiators. [11][12][13][14][15][16][17][18][19][20][21][22][23] In a review article authored by Yang and Kutal,20 the mechanism of titanocene and ferrocene photoinitiation is delineated; however, in this research, the ferrocene photoinitiators, specifically involving free-radical initiation, will be explored in detail.…”

mentioning

confidence: 99%

Photoinitiation of multifunctional acrylates via ferrocene-alkyl chloride charge transfer complexes

et al. 2007

View full text Add to dashboard Cite

The propensity for ferrocene-alkyl chloride charge transfer complexes (CTCs) to photoinitiate free-radical polymerization of multifunctional acrylates was determined using photodifferential scanning calorimetry. Also, the effects of varying ferrocene (ferrocene, methoxyferrocene, and cyanoferrocene) and alkyl chloride (dichloromethane and benzyl chloride) derivatives were evaluated with regard to the overall polymerization rate and conversion. Furthermore, relative polymerization rates of traditional freeradical Type I and Type II photoinitiators were compared to those of the ferrocene-alkyl chloride CTCs. Semi-empirical quantum mechanical analysis of the complexation reaction was performed using PM3, indicating a thermodynamic preference of complexations involving benzyl chloride, and corroborated the reported complexation mechanism. In order to explain the varying polymerization rates, the association constants for each complex were determined, whereupon complexation of each ferrocene derivative with dichloromethane was found to be more facile than similar complexation with benzyl chloride due to steric considerations. Substituent effects were more pronounced for the benzyl chloride complexes relative to those involving dichloromethane where steric constraints caused deviation from the expected effect. Thus, the cyanoferrocene-benzyl chloride CTC was determined to be the most effective photoinitiator examined with regard to semi-empirical analysis, complexation kinetics, and polymerization rate.

show abstract

Photosensitized initiation of vinyl polymerization by a system of ferrocene and carbon tetrachloride

Cited by 17 publications

References 10 publications

Photochemical generation of cationic lewis acids via deligation of metal‐sandwich complexes

Photochemical generation of cationic lewis acids via deligation of metal‐sandwich complexes

Ferrocene as an effective initiator for copolymerization of styrene with maleic anhydride

Photoinitiation of multifunctional acrylates via ferrocene-alkyl chloride charge transfer complexes

Contact Info

Product

Resources

About