Novel electrophilic trisubstituted ethylenes, methyl and methoxy ring-trisubstituted butyl 2-cyano-3-phenyl-2-propenoates, RPhCHDC(CN)CO 2 C 4 H 9 where R is 2,4,5-trimethyl, 2,4,6-trimethyl, 2,3-dimethyl-4-methoxy, 2,5-dimethyl-4-methoxy, 2,4-dimethoxy-3-methyl, 2,3,4-trimethoxy, 2,4,5-trimethoxy, 2,4,6-trimethoxy, 3,4,5-trimethoxy were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-trisubstituted benzaldehydes and butyl cyanoacetate, and characterized by CHN analysis, IR, 1 H and 13 C-NMR. All the ethylenes were copolymerized with styrene (M 1 ) in solution with radical initiation (ABCN) at 70 C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, 1 H and 13 C-NMR. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200-500 C range with residue (2-5% wt), which then decomposed in the 500-800 C range.

With respect to the increasing need for fully characterizing surface-tethered polymer brushes, the capacity of quantitative IR-Fourier transform infrared (FTIR) spectroscopy using a multiple-internal-reflection Si prism as the attenuated total reflection (ATR) element is investigated to directly characterize the surface chemical modifications occurring during a surface-initiated controlled polymerization. A simple two-step strategy is used involving first the covalent grafting of atom transfer radical polymerization (ATRP) initiators on a hydrogenated silicon surface and the subsequent polymerization of styrene. Three prefunctionalized surfaces designated Si-Br1, Si-Br2, and Si-Br3 are obtained by different procedures. The initiator grafting densities obtained by quantitative IR are 1.7 ± 0.3 nm–2 for Si-Br1, 1.5 ± 0.3 nm–2 for Si-Br2, and 0.9 ± 0.2 nm–2 for Si-Br3. After the polymerization of styrene under the same experimental conditions (grafting from without sacrificial initiators) and a careful Soxhlet rinse to remove physisorbed polymers formed in solution, almost no polymerization is observed using Si-Br1 with a value of the density in polymerized styrene units of 12 ± 2 nm–2, which is probably due to the chelating effect of the amino linkers used for grafting the initiators in Si-Br1. In contrast, the densities in styrene units are 54 ± 11 nm–2 using Si-Br2 and 141 ± 28 nm–2 using Si-Br3. The degree of polymerization (DP) has been evaluated by measuring the polymer thickness (by ellipsometry and atomic force microscopy, AFM) and using a scaling law relating the latter to DP for dry polymer brushes. High DP values of 200 and 1000 are found in the case of Si-Br2 and Si-Br3, respectively. The fraction of active polymerization initiators is found to be 15–18%, independent of the initiator surface density. In contrast, polymerization kinetics appear affected by steric hindrance and conformational disorder among grafted initiators. This approach for determining surface densities of grafted initiators and grafted polymer chains and DPs is fully generalizable to any other polymer system.

Copolymers are valuable supports for obtaining heterogeneous catalysts that allow their recycling and therefore substantial savings, particularly in the field of asymmetric catalysis. This contribution reports the use of two comonomers: Azido-3-propylmethacrylate (AZMA) bearing a reactive azide function was associated with 2-methoxyethyl methacrylate (MEMA), used as a spacer, for the ATRP synthesis of copolymers, and then post-functionalized with a propargyl chromium salen complex. The controlled homopolymerization of MEMA by ATRP was firstly described and proved to be more controlled in molar mass than that of AZMA for conversions up to 63%. The ATRP copolymerization of both monomers made it possible to control the molar masses and the composition, with nevertheless a slight increase in the dispersity (from 1.05 to 1.3) when the incorporation ratio of AZMA increased from 10 to 50 mol%. These copolymers were post-functionalized with chromium salen units by click chemistry and their activity was evaluated in the asymmetric ring opening of cyclohexene oxide with trimethylsilyl azide. At an equal catalytic ratio, a significant increase in enantioselectivity was obtained by using the copolymer containing the largest part of salen units, probably allowing, in this case, the more favorable bimetallic activation of both the engaged nucleophile and electrophile. Moreover, the catalytic polymer was recovered by simple filtration and re-engaged in subsequent catalytic runs, up to seven times, without loss of activity or selectivity.