03200nas a2200289   4500008004100000022001400041245009400055210006900149260006700218300001400285490000700299520215700306653000602463653001602469653005502485653002202540653002702562653004802589653001802637653003602655653002402691653003102715653001202746100001502758700001602773856012102789       2005                        eng d  a0887-624X00aNovel tridentate nitrogen donor as ligand in copper catalyzed ATRP of methyl methacrylate0 aNovel tridentate nitrogen donor as ligand in copper catalyzed AT  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcNOV  a4996-50080 v433 a<p>A tridentate ligand, BPIEP: 2,6-bis[1-(2,6-diisopropyl phenylimino) ethyl] pyridine, having central pyridine unit and two peripheral imine coordination sites was effectively employed in controlled/''living'' radical polymerization of MXU at 90 degrees C in toluene as solvent, (CuBr)-Br-I as catalyst, and ethyl-2-bromoisobutyrate (EBiB) as initiator resulting in well-defined polymers with polydispersities M-W/M-n &lt;= 1.23. The rate of polymerization follows first-order kinetics, k(app) = 3.4 x 10(-5) s(-1), indicating the presence of low radical concentration ([P*] &lt;= 10(-8)) throughout the reaction. The polymerization rate attains a maximum at a ligand-to-metal ratio of 2:1 in toluene at 90 degrees C. The solvent concentration (v/v, with respect to monomer) has a significant effect on the polymerization kinetics. The polymerization is faster in polar solvents like, diphenylether, and anisole, as compared to toluene. Increasing the monomer concentration in toluene resulted in a better control of polymerization. The molecular weights (M-n,M-SEC) increased linearly with conversion and were found to be higher than predicted molecular (M-n,M-Cal). However, the polydispersity remained narrow, i.e., &lt;= 1.23. The initiator efficiency at lower monomer concentration approaches a value of 0.7 in 110 min as compared to 0.5 in 330 min at higher monomer concentration. The aging of the copper salt complexed. with BPIEP had a beneficial effect and resulted in polymers with narrow polydispersitities and higher conversion. PMMA obtained at room temperature in toluene (33%, v/v) gave PDI of 1.22 (Mn = 8500) in 48 h whereas, at 50 degrees C the PDI is 1.18 (Ma = 10,300), which is achieved in 23 h. The plot of In kapp versus 1/T gave an apparent activation energy of polymerization as (Delta E-app(not equal)) 58.29 KJ/mol and enthalpy of equilibrium (Delta H-eq(0)) to 28.8 KJ/mol. Reverse ATRP of MMA was successfully performed using AIBN in bulk as well as solution. The controlled nature of the polymerization reaction was established through kinetic studies and chain extension experiments. (c) 2005 Wiley Periodicals, Inc.</p>10a210a6-bis [1-(210a6-diisopropyl phenylimino) ethyl] pyridine (BPIEP)10aActivation energy10aapparent rate constant10aAtom transfer radical polymerization (ATRP)10adiphenylether10aethyl-2-bromoisobutyrate (EBiB)10amethyl methacrylate10apolydispersity index (PDI)10aToluene1 aMittal, A.1 aSivaram, S.  uhttp://library.ncl.res.in/content/novel-tridentate-nitrogen-donor-ligand-copper-catalyzed-atrp-methyl-methacrylate-100656nas a2200157   4500008004100000022001400041245010400055210006900159260007200228300001400300490000700314100001500321700001600336700001700352856012900369       2006                        eng d  a0024-929700aUnfavorable coordination of copper with methyl vinyl ketone in atom transfer radical polymerization0 aUnfavorable coordination of copper with methyl vinyl ketone in a  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAUG   a5555-55580 v391 aMittal, A.1 aSivaram, S.1 aBaskaran, D.  uhttp://library.ncl.res.in/content/unfavorable-coordination-copper-methyl-vinyl-ketone-atom-transfer-radical-polymerization-0