- Email: [email protected]
Characterization of network polymers by fluorescence techniques
302 enable reversible oxygenation. This system shows a brilliant reddish color like blood pigment, and reversibly binds oxygen molecules quantitatively. A typical example was seen in a poly-lipid liposome system containing lipid-heme in its interlayer structure. This system enables reversible oxygen transport better than that of human blood under the same physicochemical conditions as biological ones. Analytical parameters for F e - O 2 binding are: IR spectroscopy: 1161 cm -x (~o-o); MiSssbauer parameters: ~ and AEQ are 0.28 and 2.15 mm s -1, respectively. These results strongly indicate that the oxygen is considerably charge-separated ( F e ( I I l ) - O 2 ) as is the case in hemoglobin. This success is due to the contribution of the environment provided by the polymer matrix. An oxygen-enriching membrane can also be prepared by fixing these heme derivatives to solid polymer membranes. This topic is touched upon briefly. See: J.
Chem. Soc. Jpn., 6 (1988) 845.
Selective Oxidations and Reductions with Polymer-supported Anionic Reagents G . G e l b a r d , T. B r u n e l e t a n d O . L o u i s - A n d r e , CNRS, BP 24, Lyon-Vernaison, France The usefulness of polymer-supported reagents (PSR) is illustrated in the case of two important chemical transformations in organic chemistry. The purpose is to devise new supported reagents, i.e. new reactive species to be put onto polymers later on; the design of PSR is achieved by preliminary knowledge of the soluble species. Thus, new (and old) complex chromates of the general formula "" / N +X(CrO3) ~ were studied in solution and fixed onto polypyridine and anion exchange resins; the resulting polymer ( ~ ) - N + X(CrO3) ~ was studied in the oxidation of various alcohols to the corresponding aldehyde or ketone. The properties of the dithionite anion $2O2- were checked in PTC conditions and then on various anion exchange resins. Reductions of carbonyl derivatives were found to be very chemo- and highly regioselective. The efficiency of this PSR is better than that of the borohydride analogue.
Characterization of Network Polymers by Fluorescence Techniques K e n n e t h J. S h e a , University of California, Irvine, CA, U.S.A. The utifization of highly crosslinked network polymers as reagents and catalysts requires materials with a high degree of penetrability towards solvents. This need is particularly acute when template polymerization is employed as the method of functionalization. We will discuss the utility of fluorescence diagnostics as a means of evaluating solvent and reagent penetrability in network polymers. Specifically, correlations will be developed between the solvatochromic shifts of the 1-dimethylamino-5-naphthalenesulfonamide probes embedded in various network polymers and the facility with which solvents penetrate the network. In related studies we will develop protocols for evaluating the relative degree of transport of ionic reagents through network polymers. The fluorescence diagnostics allow selection of materials that are most suitable for use in creating functionalized sites by template polymerization. To be published as "Fluorescence Probes for Evaluating Polymer Chain Solvation in Network Polymers. An Analysis of the Solvatochromic Shift of the Dansyl Probe in Macroporous Styrene-Divinylbenzene and Styrene-Diisopropenylbenzene Copolymers", Macromolecules, 21 (1989), and " O n the Control of Microenvironment Shape of Functionalized Network Polymers Prepared by Template Polymerization", J. Amer. Chem. Soc., 111 (1989).
Influence of a Spacer on the Kinetics of Reduction of Carbonyl Compounds with Macroporous Borohydride Exchange Resin M . B a c q u e t , M . M . S a l u n k h e , D . L e m a g u e r a n d C. C a z e , Universit~ de Lille 1, Villeneuve d'Ascq, France, and Northwestern University, Evanston, IL, U.S.A. Borohydride exchange resin is a well-known reducing agent. Recently it has been shown that starting from a gel-type support an increase in the kinetics of reduction could be obtained by use of a porous polymer as the support or by introduction of a spacer. In this work we have studied the influence of a spacer on the kinetics of reduction via a
Chem. Soc. Jpn., 6 (1988) 845.
Selective Oxidations and Reductions with Polymer-supported Anionic Reagents G . G e l b a r d , T. B r u n e l e t a n d O . L o u i s - A n d r e , CNRS, BP 24, Lyon-Vernaison, France The usefulness of polymer-supported reagents (PSR) is illustrated in the case of two important chemical transformations in organic chemistry. The purpose is to devise new supported reagents, i.e. new reactive species to be put onto polymers later on; the design of PSR is achieved by preliminary knowledge of the soluble species. Thus, new (and old) complex chromates of the general formula "" / N +X(CrO3) ~ were studied in solution and fixed onto polypyridine and anion exchange resins; the resulting polymer ( ~ ) - N + X(CrO3) ~ was studied in the oxidation of various alcohols to the corresponding aldehyde or ketone. The properties of the dithionite anion $2O2- were checked in PTC conditions and then on various anion exchange resins. Reductions of carbonyl derivatives were found to be very chemo- and highly regioselective. The efficiency of this PSR is better than that of the borohydride analogue.
Characterization of Network Polymers by Fluorescence Techniques K e n n e t h J. S h e a , University of California, Irvine, CA, U.S.A. The utifization of highly crosslinked network polymers as reagents and catalysts requires materials with a high degree of penetrability towards solvents. This need is particularly acute when template polymerization is employed as the method of functionalization. We will discuss the utility of fluorescence diagnostics as a means of evaluating solvent and reagent penetrability in network polymers. Specifically, correlations will be developed between the solvatochromic shifts of the 1-dimethylamino-5-naphthalenesulfonamide probes embedded in various network polymers and the facility with which solvents penetrate the network. In related studies we will develop protocols for evaluating the relative degree of transport of ionic reagents through network polymers. The fluorescence diagnostics allow selection of materials that are most suitable for use in creating functionalized sites by template polymerization. To be published as "Fluorescence Probes for Evaluating Polymer Chain Solvation in Network Polymers. An Analysis of the Solvatochromic Shift of the Dansyl Probe in Macroporous Styrene-Divinylbenzene and Styrene-Diisopropenylbenzene Copolymers", Macromolecules, 21 (1989), and " O n the Control of Microenvironment Shape of Functionalized Network Polymers Prepared by Template Polymerization", J. Amer. Chem. Soc., 111 (1989).
Influence of a Spacer on the Kinetics of Reduction of Carbonyl Compounds with Macroporous Borohydride Exchange Resin M . B a c q u e t , M . M . S a l u n k h e , D . L e m a g u e r a n d C. C a z e , Universit~ de Lille 1, Villeneuve d'Ascq, France, and Northwestern University, Evanston, IL, U.S.A. Borohydride exchange resin is a well-known reducing agent. Recently it has been shown that starting from a gel-type support an increase in the kinetics of reduction could be obtained by use of a porous polymer as the support or by introduction of a spacer. In this work we have studied the influence of a spacer on the kinetics of reduction via a