Abstract
Two neutral ligands, carbonyl (CO) and phosphine, were cooperatively incorporated into half-metallocene iron(II) complexes (CpFeBr(CO)(PR3); Cp=C5H5; PR3=PPh3, P(OPh)3, PMePh2, PMe2Ph, P(n-Bu)3) for more active and versatile systems in transition metal-catalyzed living radical polymerization. For methyl methacrylate (MMA) with a bromide initiator [Me2C(CO2Me)CH2C(Me)-(CO2Me)Br; Me=CH3] [H-(MMA)2-Br], these hetero-ligated catalysts are superior, in terms of catalytic activity and molecular weight control, to similar homo-ligated half-metallocenes carrying two identical ligands such as CpFeBr(CO)2 and CpFeBr(PR3)2. Among the CpFeBr(CO)(PR3) complexes examined, CpFeBr(CO)(PMePh2) showed the highest activity and the best controllability (>90% conversion within 24 h; Mw/Mn=1.29), and the ‘living’ character of the polymerizations therewith was proved by sequential monomer addition experiments. In spite of the high activity, the Fe(II) complex is stable and robust enough to be handled under air, rendering it suitable for practical use. The concomitant high activity and high stability were attributed to the in situ generation of a real active catalyst with a 16-electron configuration by the irreversible release of the CO group from CpFeBr(CO)(PR3) on the activation of a terminal C–Br bond, as confirmed by the Fourier transform infrared monitoring of model reactions with the initiator as a dormant-end model compound.
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References
Crabtree, R. H. The Organometallic Chemistry of the Transition Metals (John Wiley & Sons, Inc., New York, USA, 2001).
Kamigaito, M., Ando, T. & Sawamoto, M. Metal-catalyzed living radical polymerization. Chem. Rev. 101, 3689–3745 (2001).
Kamigaito, M., Ando, T. & Sawamoto, M. Metal-catalyzed living radical polymerization: discovery and developments. Chem. Rec. 4, 159–175 (2004).
Ouchi, M., Terashima, T. & Sawamoto, M. Precision control of radical polymerization via transition metal catalysis: from dormant species to designed catalysts for precision functional polymers. Acc. Chem. Res. 41, 1120–1132 (2008).
Matyjaszewski, K. & Xja, J. Atom transfer radical polymerization. Chem. Rev. 101, 2921–2990 (2001).
Kato, M., Kamigaito, M ., Sawamoto, M. & Higashimura, T. Polymerization of Methyl Methacrylate with the Carbon Tetrachloride/Dichlorotris(triphenylphosphine)ruthenium(II)/Methylaluminum Bis(2,6-di-tert-butylphenoxide)Initiating System: Possibility of Living Radical Polymerization. Macromolecules 28, 1721–1723 (1995).
Ando, T., Kato, M., Kamigaito, M. & Sawamoto, M. Living radical polymerization of methyl methacrylate with ruthenium complex: formation of polymers with controlled molecular weights and very narrow distributions. Macromolecules 29, 1070–1072 (1996).
Wang, J. S. & Matyjaszewski, K. Controlled/’living’ radical polymerization. Atom transfer radical polymerization in the presence of transition-metal complexes. J. Am. Chem. Soc. 117, 5614–5615 (1995).
Ando, T., Kamigaito, M. & Sawamoto, M. Iron(II) chloride complex for living radical polymerization of methyl methacrylate. Macromolecules 30, 4507–4510 (1997).
Matyjaszewski, K., Wei, M., Xia, J. & McDermott, N. E. Controlled/’Living’ radical polymerization of styrene and methyl methacrylate catalyzed by iron complexes. Macromolecules 30, 8161–8164 (1997).
Kotani, Y., Kamigaito, M. & Sawamoto, M. FeCp(CO)2I: a phosphine-free half-metallocene-type iron(II) catalyst for living radical polymerization of styrene. Macromolecules 32, 6877–6880 (1999).
Kotani, Y., Kamigaito, M. & Sawamoto, M. Living radical polymerization of styrene by half-metallocene iron carbonyl complexes. Macromolecules 33, 3543–3549 (2000).
Zhu, S. & Yan, D. Atom transfer radical polymerization of methyl methacrylate catalyzed by ironII chloride/isophthalic acid system. Macromolecules 33, 8233–8238 (2000).
Louie, Y. & Grubbs, R. H. Highly active iron imidazolylidene catalysts for atom transfer radical polymerization. Chem. Commun. 1479–1480 (2000).
Gibson, V. C., O’Reilly, R. K., Reed, W., Wass, D. F., White, A. J. P. & Williams, D. J. Four-coordinate iron complexes bearing α-diimine ligands: efficient catalysts for atom transfer radical polymerisation (ATRP). Chem. Commun. 1850–1851 (2002).
Göbelt, B. & Matyjaszewski, K. Diimino- and diaminopyridine complexes of CuBr and FeBr2 as catalysts in atom transfer radical polymerization (ATRP). Macromol. Chem. Phys. 201, 1619–1624 (2000).
O’Reilly, R. K., Gibson, V. C., White, A. J. P. & Williams, D. J. Design of highly active iron-based catalysts for atom transfer radical polymerization: tridentate salicylaldiminato ligands affording near ideal nernstian behavior. J. Am. Chem. Soc. 125, 8450–8451 (2003).
Xue, Z., Lee, B. W., Noh, S. K. & Lyoo, W. S. Pyridylphosphine ligands for iron-based atom transfer radical polymerization of methyl methacrylate and styrene. Polymer 48, 4704–4714 (2007).
Niibayashi, S., Hayakawa, H., Jin, R. -H. & Nagashima, H. Reusable and environmentally friendly ionic trinuclear iron complex catalyst for atom transfer radical polymerization. Chem. Commun. 1855–1857 (2007).
Uchiike, C., Terashima, T., Ouchi, M., Ando, T., Kamigaito, M. & Sawamoto, M. Evolution of iron catalysts for effective living radical polymerization: design of phosphine/halogen ligands in FeX2(PR3)2 . Macromolecules 40, 8658–8662 (2007).
Ferro, R., Milione, S., Bertolasi, V., Capacchione, C. & Grassi, A. Iron complexes of Bis(oxazoline) ligand as novel catalysts for efficient atom transfer radical polymerization of styrene. Macromolecules 40, 8544–8546 (2007).
Uchiike, C., Ouchi, M., Ando, T., Kamigaito, M. & Sawamoto, M. Evolution of iron catalysts for effective living radical polymerization: P–N chelate ligand for enhancement of catalytic performances. J. Polym. Sci., Part A: Polym. Chem. 46, 6819–6827 (2008).
Ishio, M., Katsube, M., Ouchi, M., Sawamoto, M. & Inoue, Y. Active, versatile, and removable iron catalysts with phosphazenium salts for living radical polymerization of methacrylates. Macromolecules 42, 188–193 (2009).
Bolm, C., Legros, J., Paih, J. L. & Zani, L. Iron-catalyzed reactions in organic synthesis. Chem. Rev. 104, 6217–6254 (2004).
Takahashi, H., Ando, T., Kamigaito, M. & Sawamoto, M. Half-metallocene-type ruthenium complexes as active catalysts for living radical polymerization of methyl methacrylate and styrene. Macromolecules 32, 3820–3823 (1999).
Watanabe, Y., Ando, T., Kamigaito, M. & Sawamoto, M. Ru(Cp*)Cl(PPh3)2: a versatile catalyst for living radical polymerization of methacrylates, acrylates, and styrene. Macromolecules 34, 4370–4374 (2001).
Treichel, P. M., Shubkin, R. L., Barnett, K. W. & Reichard, D. Chemistry of the cyclopentadienylmetal carbonyls. II. cyclopentadienyliron carbonyl derivatives. Inorg. Chem. 5, 1177–1181 (2001).
Holland, K. A. & Rae, I. D. Thermal degradation of polymers. III thermal degradation of a compound which models the head-to-head linkage in poly(methyl methacrylate). Aust. J. Chem. 40, 687–692 (1987).
Ando, T., Kamigaito, M. & Sawamoto, M. Design of initiators for living radical polymerization of methyl methacrylate mediated by ruthenium(II) complex. Tetrahedron 53, 15445–15457 (1997).
Fischer, E. O. & Moser, E. Inorg. Synth 12: (ed. Parry, R. W.) Ch. 2, 35–36 (Wiley, 1970).
Hallam, B. F. & Pauson, P. L. Ferrocene derivatives.3. cyclopentadienyliron carbonyls. J. Chem. Soc. 3030–3037 (1956).
Lehmkuhl, H. & Mehler, G. Organyleisen-komplexe des typs Cp(Ph2P[CH2]nPPh2)Fe-R. Chem. Ber 118, 2407–2417 (1985).
Ando, T., Kamigaito, M. & Sawamoto, M. Metal alkoxides as additives for ruthenium(II)-catalyzed living radical polymerization. Macromolecules 33, 6732–6737 (2000).
Fuji, Y., Ando, T., Kamigaito, M. & Sawamoto, M. Iron-catalyzed suspension living radical polymerizations of acrylates and styrene in water. Macromolecules 35, 2949–2954 (2002).
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This research was partially supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Creative Scientific Research (18GS0209).
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Ishio, M., Terashima, T., Ouchi, M. et al. Carbonyl-phosphine hetero-ligated half-metallocene iron(II) catalysts for living radical polymerization: concomitant activity and stability. Polym J 42, 17–24 (2010). https://doi.org/10.1038/pj.2009.315
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DOI: https://doi.org/10.1038/pj.2009.315
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