201
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Allan LEN, Shaver MP, White AJP, Gibson VC. Correlation of Metal Spin-State in α-Diimine Iron Catalysts with Polymerization Mechanism. Inorg Chem 2007; 46:8963-70. [PMID: 17854185 DOI: 10.1021/ic701500y] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The alpha-diimine iron complexes, (R',R'')[N,N]FeCl(2) ((R',R'')[N,N] = R'-N=CR' '-CR' '=N-R', where R' = tert-butyl (tBu), cyclohexyl (Cy) and R' ' = phenyl (Ph), para-fluorophenyl (F-Ph), para-bromophenyl (Br-Ph), para-methylphenyl (Me-Ph), or para-methoxyphenyl (MeO-Ph)), are found to polymerize styrene through a catalytic chain transfer (CCT) mechanism. Magnetic moment measurements indicate that Fe(III) complexes containing these ligands possess intermediate (S = 3/2) spin-state iron centers. In contrast, Fe(III) complexes bearing proton (R' ' = H) and para-dimethylaminophenyl (R' ' = NMe(2)-Ph) substituents are high-spin and are efficient atom transfer radical polymerization (ATRP) catalysts. Hammett plots show a linear correlation of the substituent constant, sigma, with polymerization rate and polymer molecular weight, respectively.
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Affiliation(s)
- Laura E N Allan
- Contribution from the Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK
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202
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Stolzenberg AM, Workman SR, Gutshall JE, Petersen JL, Akhmedov N. Syntheses and characterization of organo-group 14 cobaloxime compounds. Inorg Chem 2007; 46:6744-54. [PMID: 17616181 DOI: 10.1021/ic070251+] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reactions of cobaloxime Na[(t-BuPy)Co(DH)2] with Ph3ECl (E = Si, Ge, Sn, and Pb) were investigated. Metal-metal bonded complexes (t-BuPy)Co(DH)2EPh3 were isolated for E = Sn and Pb. (t-BuPy)Co(DH)2SnPh3.(C2H5)2O, C39H52CoN5O5Sn, crystallized in the monoclinic space group P21/c (Z = 4) with unit cell dimensions a = 11.6443(6) A, b = 15.6085(8) A, c = 22.6354(12) A, beta = 96.634(1) degrees , and V = 4086.4(4) A3 at 295(2) K. The structure resembled those of six-coordinate alkyl cobaloxime complexes and had Co-NPy and Co-Sn distances of 2.056(2) and 2.5568(3) A, respectively. (t-BuPy)Co(DH)2PbPh3, C35H42CoN5O4Pb, crystallized in the monoclinic space group P21/n (Z = 4) with unit cell dimensions a = 15.0104(7) A, b = 15.7693(8) A, c = 16.6230(8) A, beta = 114.348(1) degrees , and V = 3584.8(3) A3 at 295(2) K. The complex was nearly isostructural with the Sn analogue and had Co-NPy and Co-Pb distances of 2.049(2) and 2.6191(4) A, respectively. Coupling of the ortho phenyl protons to the spin 1/2 isotopes of Sn and of Pb was a characteristic feature of the 1H NMR spectrum. Additional, longer range couplings were observed for the Pb complex and for both complexes in the 13C NMR. Metal-metal bonded complexes were not obtained for E = Si or Ge. The products isolated in the latter case were the hydride Ph3GeH and the cobalt(II) complex (t-BuPy)Co(DH)2,C17H27CoN5O4, which crystallized in the orthorhombic space group Pbcn (Z = 8). Unit cell dimensions were a = 17.9821(11) A, b = 9.7449(6) A, c = 22.7374(15) A, and V = 3984.4(4) A3 at 295(2) K. The five-coordinate complex had Co-NPy = 2.096(2) A and was dimeric in the lattice.
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Affiliation(s)
- Alan M Stolzenberg
- Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA.
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203
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Kurmaz SV, Grachev VP, Kochneva IS, Perepelitsina EO, Estrina GA. Synthesis, structure, and properties of branched polymethacrylates. POLYMER SCIENCE SERIES A 2007. [DOI: 10.1134/s0965545x07080044] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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204
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205
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Cheng TY, Szalda DJ, Zhang J, Bullock RM. Synthesis and structure of CpMo(CO)(dppe)H and its oxidation by Ph3C+. Inorg Chem 2007; 45:4712-20. [PMID: 16749835 DOI: 10.1021/ic060111k] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction of CpMo(CO)(dppe)Cl (dppe = Ph2PCH2CH2PPh2) with Na+[AlH2(OCH2CH2OCH3)2]- gives the molybdenum hydride complex CpMo(CO)(dppe)H, the structure of which was determined by X-ray crystallography. Electrochemical oxidation of CpMo(CO)(dppe)H in CH3CN is quasi-reversible, with the peak potential at -0.15 V (vs Fc/Fc+). The reaction of CpMo(CO)(dppe)H with 1 equiv of Ph3C+BF4- in CD3CN gives [CpMo(CO)(dppe)(NCCD3)]+ as the organometallic product, along with dihydrogen and Gomberg's dimer (which is formed by dimerization of Ph3C.). The proposed mechanism involves one-electron oxidation of CpMo(CO)(dppe)H by Ph3C+ to give the radical-cation complex [CpMo(CO)(dppe)H].+. Proton transfer from [CpMo(CO)(dppe)H].+ to CpMo(CO)(dppe)H, loss of dihydrogen from [CpMo(CO)(dppe)(H)2]+, and oxidation of Cp(CO)(dppe)Mo. by Ph3C+ lead to the observed products. In the presence of an amine base, the stoichiometry changes, with 2 equiv of Ph3C+ being required for each 1 equiv of CpMo(CO)(dppe)H because of deprotonation of [CpMo(CO)(dppe)H].+ by the amine. Protonation of CpMo(CO)(dppe)H by HOTf provides the dihydride complex [CpMo(CO)(dppe)(H)2]+OTf-, which loses dihydrogen to generate CpMo(CO)(dppe)(OTf).
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Affiliation(s)
- Tan-Yun Cheng
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
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206
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Choi J, Tang L, Norton JR. Kinetics of hydrogen atom transfer from (eta(5)-C(5)H(5))Cr(CO)(3)H to various olefins: influence of olefin structure. J Am Chem Soc 2007; 129:234-40. [PMID: 17199304 DOI: 10.1021/ja066325i] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Treating (etha(5)-C(5)H(5))Cr(CO)3H (1) or (etha(5)-C(5)H(5))Cr(CO)3D (1-d(1)) with an excess of olefin containing the opposite isotope generally leads to H/D exchange, although hydrogenation is also observed in some cases. Application of an appropriate statistical correction to the observed exchange rate gives kH and kD, the rate constants for H* (D*) transfer from (etha(5)-C(5)H(5))Cr(CO)(3)H (D) to various olefins. The values of kH and kD vary appreciably with the substituents on the double bond. Phenyl-substituted olefins accept H* more readily than do carbomethoxy-substituted olefins, although the latter accept H* more readily than do alkyl-substituted olefins. A methyl substituent on the incipient radical site increases k(H) at 323 K by a factor between 5 and 50. A methyl substituent on the carbon to which the H* is being transferred decreases kH substantially. On the whole, the rate constants for H* transfer reflect steric effects as well as the stability of the resulting carbon-centered radicals.
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Affiliation(s)
- Jongwook Choi
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA
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207
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Makio H, Fujita T. Synthesis of Chain-End Functionalized Polyolefins with a Bis(phenoxy imine) Titanium Catalyst. Macromol Rapid Commun 2007. [DOI: 10.1002/marc.200600853] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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208
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Camerlynck S, Cormack PAG, Sherrington DC, Saunders G. Control of Branching Vs. Cross‐Linking in Conventional Free Radical Copolymerization of MMA and EGDMA Using CoBF as a Catalytic Chain Transfer Agent. J MACROMOL SCI B 2007. [DOI: 10.1080/00222340500324464] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- S. Camerlynck
- a Department of Pure & Applied Chemistry , University of Strathclyde , Glasgow, UK
| | - P. A. G. Cormack
- a Department of Pure & Applied Chemistry , University of Strathclyde , Glasgow, UK
| | - D. C. Sherrington
- a Department of Pure & Applied Chemistry , University of Strathclyde , Glasgow, UK
| | - G. Saunders
- b Polymer Laboratories Limited , Shropshire, UK
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209
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Kurmaz SV, Kochneva IS, Perepelitsina EO, Korolev GV, Grachev VP, Aldoshin SM. Photochromic transformations of 6-nitrospiropyran in matrices of linear and branched polymers. Russ Chem Bull 2007. [DOI: 10.1007/s11172-007-0033-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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210
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Affiliation(s)
- Deborah M Smith
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA
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211
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212
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Synthesis and reactivity of metal-containing monomers 64. Synthesis, structure, polymerization, and catalytic properties of the palladium and cobalt vinylporphyrin complexes. Russ Chem Bull 2007. [DOI: 10.1007/s11172-007-0026-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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213
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YAMADA T, IIDA K, YAMAGO S. Living Radical Polymerization. KOBUNSHI RONBUNSHU 2007. [DOI: 10.1295/koron.64.329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Takeshi YAMADA
- Pioneering Research Unit for Next Generation, Kyoto University
| | - Kazunori IIDA
- Polymer Division, National Institute of Standards and Technology
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214
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Beuermann S, Buback M, Gadermann M, Jürgens M, Saggu DP. Tubular reactor synthesis of styrene–methacrylate copolymers in solution with supercritical carbon dioxide. J Supercrit Fluids 2006. [DOI: 10.1016/j.supflu.2006.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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215
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Zwolak G, Lucien FP. Effect of Bulk Viscosity on the Catalytic Chain Transfer Polymerization of CO2-Expanded Butyl Methacrylate and Styrene. Macromolecules 2006. [DOI: 10.1021/ma061370w] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Grzegorz Zwolak
- School of Chemical Sciences and Engineering, The University of New South Wales, UNSW Sydney, NSW 2052, Australia
| | - Frank P. Lucien
- School of Chemical Sciences and Engineering, The University of New South Wales, UNSW Sydney, NSW 2052, Australia
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216
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Wayland BB, Peng CH, Fu X, Lu Z, Fryd M. Degenerative Transfer and Reversible Termination Mechanisms for Living Radical Polymerizations Mediated by Cobalt Porphyrins. Macromolecules 2006. [DOI: 10.1021/ma061643n] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bradford B. Wayland
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
| | - Chi-How Peng
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
| | - Xuefeng Fu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
| | - Zhi Lu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
| | - Michael Fryd
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
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217
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Tang L, Norton JR. Measurement of the Rate Constant for H• Abstraction from Methylisobutyryl Radical by (C5Ph5)Cr(CO)3•. Macromolecules 2006. [DOI: 10.1021/ma0615755] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lihao Tang
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
| | - Jack R. Norton
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
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218
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Tang L, Norton JR. Factors Affecting the Apparent Chain Transfer Rate Constants of Chromium Metalloradicals: Mechanistic Implications. Macromolecules 2006. [DOI: 10.1021/ma061574c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lihao Tang
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
| | - Jack R. Norton
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
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219
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Yamada B, Zetterlund PB, Sato E. Utility of propenyl groups in free radical polymerization: Effects of steric hindrance on formation and reaction behavior as versatile intermediates. Prog Polym Sci 2006. [DOI: 10.1016/j.progpolymsci.2006.08.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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220
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221
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Zwolak G, Jayasinghe NS, Lucien FP. Catalytic chain transfer polymerisation of CO2-expanded methyl methacrylate. J Supercrit Fluids 2006. [DOI: 10.1016/j.supflu.2005.12.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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222
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Poli R. Einelektronenreaktionen von Übergangsmetallkomplexen in der radikalischen Polymerisation. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200503785] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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223
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Poli R. Relationship between One-Electron Transition-Metal Reactivity and Radical Polymerization Processes. Angew Chem Int Ed Engl 2006; 45:5058-70. [PMID: 16821230 DOI: 10.1002/anie.200503785] [Citation(s) in RCA: 237] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Controlled radical polymerization has come along in leaps and bounds following the development of efficient transition-metal catalysts for atom-transfer radical polymerization. Another type of controlled radical polymerization process, namely organometallic radical polymerization, uses the reversible formation of metal-carbon bonds. Metals are also implicated in catalytic chain transfer, a process that involves the abstraction of hydrogen atoms. This Minireview discusses the importance of one-electron transition-metal reactivity in metal-mediated controlled radical polymerization processes.
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Affiliation(s)
- Rinaldo Poli
- Laboratoire de Chimie de Coordination, CNRS UPR 8241, 205 Route de Narbonne, 31077 Toulouse cedex, France.
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224
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Rota C, Tomasi A, Iannone A. Alpha-tocopherol amplifies benzoyl peroxide free radical decomposition in a chemical system. Free Radic Res 2006; 40:637-45. [PMID: 16753842 DOI: 10.1080/10715760600654895] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Benzoyl peroxide is commonly used in the treatment of acne, even though some adverse effects have been reported, probably mediated by the formation of peroxide-derived free radicals and the depletion of antioxidants. In the present work we have studied, in a chemical system, the effect of alpha-tocopherol on benzoyl peroxide radical decomposition to analyse the presence of an interaction between these two compounds, leading to an enhanced peroxide-cytotoxicity, as we have previously reported. Under our experimental conditions alpha-tocopherol strongly amplified the peroxide free radical decomposition occurring either in the presence or in the absence of UV irradiation, and lead to the formation of an unknown radical species in addition to benzoyloxy, phenyl and tocopheroxyl free radicals. The results of this study show that the enhancement of benzoyl peroxide toxicity in cells exposed simultaneously to this peroxide and alpha-tocopherol, is likely due to the generation of the detected radical species.
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Affiliation(s)
- Cristina Rota
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy
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225
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Kurmaz SV, Bubnova ML, Perepelitsina EO, Estrina GA. Control of crosslinking free-radical copolymerization of ethylene glycol dimethacrylate with alkyl methacrylates of various structures and macromolecular design of copolymers. POLYMER SCIENCE SERIES A 2006. [DOI: 10.1134/s0965545x06070054] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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226
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Braunecker WA, Matyjaszewski K. Recent mechanistic developments in atom transfer radical polymerization. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.molcata.2006.01.076] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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227
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Kurmaz SV, Perepelitsina EO. Cross-linking radical polymerization of di(meth)acrylates in the presence of cobalt(II) porphyrin. Russ Chem Bull 2006. [DOI: 10.1007/s11172-006-0340-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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228
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THE EVOLUTION OF THE CHAIN TRANSFER CONSTANT DURING THE CATALYTIC CHAIN TRANSFER POLYMERIZATION OF 2-HYDROXYPROPYL METHACRYLATE. ACTA POLYM SIN 2006. [DOI: 10.3724/sp.j.1105.2006.00308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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229
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230
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Romack TJ, Kaur G, Weaver SF, Harrelson SK, Kenward AG. Catalytic chain-transfer synthesis of 1,1,2,2-tetrahydroperfluoroalkyl methacrylate macromonomers. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/pola.21466] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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231
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Telechelic Oligomers and Macromonomers by Radical Techniques. OLIGOMERS # POLYMER COMPOSITES # MOLECULAR IMPRINTING 2006. [DOI: 10.1007/12_2006_101] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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232
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Morrison DA, Davis TP, Heuts JPA, Messerle B, Gridnev AA. Free radical polymerization with catalytic chain transfer: Using NMR to probe the strength of the cobalt–carbon bond in small molecule model reactions. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/pola.21662] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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233
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Heuts JP, Russell GT. The nature of the chain-length dependence of the propagation rate coefficient and its effect on the kinetics of free-radical polymerization. 1. Small-molecule studies. Eur Polym J 2006. [DOI: 10.1016/j.eurpolymj.2005.09.022] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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234
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Gupta BD, Yamuna R, Mandal D. Cobaloximes with Mixed Dioximes of Glyoxime and Diphenylglyoxime: Synthesis, Characterization, CV, X-ray Studies, and Crystal Packing. Organometallics 2005. [DOI: 10.1021/om050919x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. D. Gupta
- Department of Chemistry, Indian Institute of Technology, Kanpur, India 208016
| | - R. Yamuna
- Department of Chemistry, Indian Institute of Technology, Kanpur, India 208016
| | - Debaprasad Mandal
- Department of Chemistry, Indian Institute of Technology, Kanpur, India 208016
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235
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Zhang J, Grills DC, Huang KW, Fujita E, Bullock RM. Carbon-to-Metal Hydrogen Atom Transfer: Direct Observation Using Time-Resolved Infrared Spectroscopy. J Am Chem Soc 2005; 127:15684-5. [PMID: 16277493 DOI: 10.1021/ja0555724] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the direct spectroscopic observation of hydrogen atom transfer reactions from carbon to metals, in which homolytic cleavage of a C-H bond is accomplished at a single metal center. Laser flash photolysis (355 nm) of a solution of [Cp(CO)2Os]2 leads to homolysis of the Os-Os bond and formation of the osmium-centered radical, Cp(CO)2Os*, as observed by time-resolved infrared (TRIR) spectroscopy. DFT computations on Cp(CO)2Os* support this assignment. Continuous photolysis (lambda > 300 nm) of [Cp(CO)2Os]2 in the presence of excess 1,4-cyclohexadiene produces the osmium hydride Cp(CO)2OsH. The kinetics of this carbon-to-metal hydrogen atom transfer were examined by TRIR spectroscopy. The second-order rate constant for hydrogen atom transfer from 1,4-cyclohexadiene to Cp(CO)2Os* in hexane at 23 degrees C is kH = (2.1 +/- 0.2) x 106 M-1 s-1. The pKa of Cp(CO)2OsH was determined as 32.7 in CH3CN, and use of a thermochemical cycle provided an estimated lower limit of 82 kcal/mol for the Os-H bond dissociation energy, indicating that it is an exceptionally strong M-H bond. Photolysis of [Tp(CO)2Os]2 (Tp = hydridotris(pyrazolyl)borate) results in carbon-to-metal hydrogen atom transfers from even stronger C-H bonds (THF or toluene) and produces Tp(CO)2OsH.
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Affiliation(s)
- Jie Zhang
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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236
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Chiefari J, Jeffery J, Krstina J, Moad CL, Moad G, Postma A, Rizzardo E, Thang SH. Binary Copolymerization with Catalytic Chain Transfer. A Method for Synthesizing Macromonomers Based on Monosubstituted Monomers. Macromolecules 2005. [DOI: 10.1021/ma0501949] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- John Chiefari
- CSIRO Molecular Science, Bag 10, Clayton South, Victoria 3169, Australia
| | - Justine Jeffery
- CSIRO Molecular Science, Bag 10, Clayton South, Victoria 3169, Australia
| | - Julia Krstina
- CSIRO Molecular Science, Bag 10, Clayton South, Victoria 3169, Australia
| | - Catherine L. Moad
- CSIRO Molecular Science, Bag 10, Clayton South, Victoria 3169, Australia
| | - Graeme Moad
- CSIRO Molecular Science, Bag 10, Clayton South, Victoria 3169, Australia
| | - Almar Postma
- CSIRO Molecular Science, Bag 10, Clayton South, Victoria 3169, Australia
| | - Ezio Rizzardo
- CSIRO Molecular Science, Bag 10, Clayton South, Victoria 3169, Australia
| | - San H. Thang
- CSIRO Molecular Science, Bag 10, Clayton South, Victoria 3169, Australia
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237
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Dreos R, Siega P, Scagliola S, Randaccio L, Nardin G, Tavagnacco C, Bevilacqua M. Synthesis, Characterization, and Electrochemical Properties of Dinuclear Complexes Assembled from Asymmetric CoIII Bis(dioximates) and Boronic Acids. Eur J Inorg Chem 2005. [DOI: 10.1002/ejic.200500179] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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238
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Kaneyoshi H, Matyjaszewski K. Effect of Ligand and n-Butyl Acrylate on Cobalt-Mediated Radical Polymerization of Vinyl Acetate. Macromolecules 2005. [DOI: 10.1021/ma051433v] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hiromu Kaneyoshi
- Center for Macromolecular Engineering, Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Krzysztof Matyjaszewski
- Center for Macromolecular Engineering, Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
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239
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Wang W, Irvine DJ, Howdle SM. Dispersion Catalytic Chain Transfer Polymerizations of Methyl Methacrylate in Supercritical Carbon Dioxide. Ind Eng Chem Res 2005. [DOI: 10.1021/ie0502638] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wenxin Wang
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom, and Uniqema Limited R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, United Kingdom
| | - Derek J. Irvine
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom, and Uniqema Limited R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, United Kingdom
| | - Steven M. Howdle
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom, and Uniqema Limited R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, United Kingdom
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240
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Mahanthappa MK, Bates FS, Hillmyer MA. Synthesis of ABA Triblock Copolymers by a Tandem ROMP−RAFT Strategy. Macromolecules 2005. [DOI: 10.1021/ma051535l] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mahesh K. Mahanthappa
- Department of Chemical Engineering and Materials Science, Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
| | - Frank S. Bates
- Department of Chemical Engineering and Materials Science, Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
| | - Marc A. Hillmyer
- Department of Chemical Engineering and Materials Science, Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
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241
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Debuigne A, Caille J, Jérôme R. Highly Efficient Cobalt‐Mediated Radical Polymerization of Vinyl Acetate. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200461333] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Antoine Debuigne
- Center for Education and Research on Macromolecules (CERM), University of Liège, Sart‐Tilman, B6, 4000 Liège, Belgium, Fax: (+32) 4‐366‐3497
| | | | - Robert Jérôme
- Center for Education and Research on Macromolecules (CERM), University of Liège, Sart‐Tilman, B6, 4000 Liège, Belgium, Fax: (+32) 4‐366‐3497
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242
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Debuigne A, Caille JR, Jérôme R. Highly Efficient Cobalt‐Mediated Radical Polymerization of Vinyl Acetate. Angew Chem Int Ed Engl 2005; 44:1101-1104. [PMID: 15645465 DOI: 10.1002/anie.200461333] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Antoine Debuigne
- Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman, B6, 4000 Liège, Belgium, Fax: (+32) 4-366-3497
| | | | - Robert Jérôme
- Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman, B6, 4000 Liège, Belgium, Fax: (+32) 4-366-3497
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243
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Weiser MS, Mülhaupt R. Cobalt(II) octanoate and cobalt(II) perfluorooctanoate catalyzed atom transfer radical polymerization of styrene in toluene and fluorous media—A versatile route to catalyst recycling and oligomer formation. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/pola.20873] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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244
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Probing mechanistic features of conventional, catalytic and living free radical polymerizations using soft ionization mass spectrometric techniques. POLYMER 2004. [DOI: 10.1016/j.polymer.2004.09.017] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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245
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Wang W, Stenson PA, Marin-Becerra A, McMaster J, Schröder M, Irvine DJ, Freeman D, Howdle SM. New Thiolate−Cobalt(II) Complexes for Catalytic Chain Transfer Polymerization of Methyl Methacrylate. Macromolecules 2004. [DOI: 10.1021/ma049267z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wenxin Wang
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K., and Uniqema R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, U.K
| | - Philip A. Stenson
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K., and Uniqema R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, U.K
| | - Armando Marin-Becerra
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K., and Uniqema R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, U.K
| | - Jonathan McMaster
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K., and Uniqema R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, U.K
| | - Martin Schröder
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K., and Uniqema R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, U.K
| | - Derek J. Irvine
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K., and Uniqema R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, U.K
| | - David Freeman
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K., and Uniqema R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, U.K
| | - Steven M. Howdle
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K., and Uniqema R&D Department, The Wilton Research Centre, Wilton, Redcar, TS10 4RF, U.K
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246
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Hutson L, Krstina J, Moad CL, Moad G, Morrow GR, Postma A, Rizzardo E, Thang SH. Chain Transfer Activity of ω-Unsaturated Methacrylic Oligomers in Polymerizations of Methacrylic Monomers. Macromolecules 2004. [DOI: 10.1021/ma049813o] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lillian Hutson
- CSIRO Molecular Science, Bag 10, Clayton South, Clayton, Victoria 3169, Australia
| | - Julia Krstina
- CSIRO Molecular Science, Bag 10, Clayton South, Clayton, Victoria 3169, Australia
| | - Catherine L. Moad
- CSIRO Molecular Science, Bag 10, Clayton South, Clayton, Victoria 3169, Australia
| | - Graeme Moad
- CSIRO Molecular Science, Bag 10, Clayton South, Clayton, Victoria 3169, Australia
| | - Gregory R. Morrow
- CSIRO Molecular Science, Bag 10, Clayton South, Clayton, Victoria 3169, Australia
| | - Almar Postma
- CSIRO Molecular Science, Bag 10, Clayton South, Clayton, Victoria 3169, Australia
| | - Ezio Rizzardo
- CSIRO Molecular Science, Bag 10, Clayton South, Clayton, Victoria 3169, Australia
| | - San H. Thang
- CSIRO Molecular Science, Bag 10, Clayton South, Clayton, Victoria 3169, Australia
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247
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Yang P, Chan BCK, Baird MC. Is FeEt2(2,2‘-dipyridyl)2 a Ziegler Catalyst for Polymerization of the Polar Monomer Acrylonitrile? Organometallics 2004. [DOI: 10.1021/om0499613] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ping Yang
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6
| | - Bryan C. K. Chan
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6
| | - Michael C. Baird
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6
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248
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Gupta BD, Vijaikanth V, Singh V. Synthesis, Characterization, and Variable-Temperature 1H NMR Behavior of Organo-Bridged Dicobaloximes. Organometallics 2004. [DOI: 10.1021/om034273p] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- B. D. Gupta
- Department of Chemistry, Indian Institute of Technology, Kanpur, 208 016, India
| | - V. Vijaikanth
- Department of Chemistry, Indian Institute of Technology, Kanpur, 208 016, India
| | - Veena Singh
- Department of Chemistry, Indian Institute of Technology, Kanpur, 208 016, India
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249
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Sato E, Zetterlund PB, Yamada B. Macromonomer synthesis using ?-(2-methyl-2-phenylpropyl)acrylates as addition-fragmentation chain-transfer agents expelling the cumyl radical. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/pola.20332] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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250
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Kurmaz SV, Perepelitsina EO, Bubnova ML, Estrina GA. High-efficiency approach to control network structure formation in the cross-linking radical copolymerization of ethylene glycol dimethacrylate. MENDELEEV COMMUNICATIONS 2004. [DOI: 10.1070/mc2004v014n03abeh001858] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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