Cyclopolymerization Of Diethyl Dipropargylmalonate Research Articles

Electro-optical and electrochemical properties of poly(1,6-heptadiyne) derivative with a bulky (t-butyldiphenylsiloxy)methyl substituents

ABSTRACTA conjugated cyclocopolymer with a bulky substituents was synthesized via the MoCl5-catalyzed cyclopolymerization of diethyl dipropargylmalonate and 4,4′-bis[(tert-butyldiphenylsiloxy)methyl]-1,6-heptadiyne. The chemical structure of polymer was characterized by NMR (1H-, 13C-), IR, and UV-visible spectroscopies to have a conjugated backbone system with the designed substituents. The polymer showed characteristic UV-visible absorption band and absorption maximum value of 507 nm. Photoluminescence spectrum exhibited maximum peak at 594 nm, which corresponds to the photon energy of 2.09 eV. Band gap of cyclic copolymer was 2.01 eV.

Electro-Optical and Electrochemical Properties of a Conjugated Polymer Prepared by the Cyclopolymerization of Diethyl Dipropargylmalonate

The electro-optical and electrochemical properties of poly(diethyl dipropargylmalonate) were measured and discussed. Poly(diethyl dipropargylmalonate) prepared by (NBD)PdCl2catalyst was used for study. The chemical structure of poly(diethyl dipropargylmalonate) was characterized by such instrumental methods as NMR (1H-,13C-), IR, and UV-visible spectroscopies to have the conjugated cyclopolymer backbone system. The microstructure analysis of polymer revealed that this polymer have the six-membered ring moieties majorly. The photoluminescence peak of polymer was observed at 543 nm, which is corresponded to the photon energy of 2.51 eV. The cyclovoltamograms of the polymer exhibited the irreversible electrochemical behaviors between the doping and undoping peaks. It was found that the kinetics of the redox process of this conjugated cyclopolymer might be controlled by the diffusion-control process from the experiment of the oxidation current density of polymer versus the scan rate.

Novel metathesis catalysts based on ruthenium 1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidenes: synthesis, structure, immobilization, and catalytic activity.

The synthesis of novel ruthenium-based metathesis catalysts containing the saturated 1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene ligand, that is, [RuCl2(NHC)[=CH-2-(2-PrO)-5-NO(2)-C6H3]] (1) and [Ru(CF3COO)2(NHC)[=CH-2-(2-PrO)-5-NO2-C6H3]] (2) (NHC=1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) is described. Both catalysts are highly active in ring-closing metathesis (RCM) and ring-opening cross-metathesis (ROCM). Compound 1 shows moderate activity in enyne metathesis. Compound 2 is not applicable to enyne metathesis since it shows high activity in the cyclopolymerization of diethyl dipropargylmalonate (DEDPM). Poly(DEDPM) prepared by the action of 2 consists of 95% five-membered rings, that is, poly(cyclopent-1-enevinylene)s, and 5 % of six-membered rings, that is, poly(cyclohex-1-ene-3-methylidene)s. The polymerization proceeds in a nonliving manner and results in polyenes with broad polydispersities (1.9< or =PDI< or =2.3). Supported analogues of 2 were prepared by immobilization on hydroxymethyl-Merrifield resin and a monolithic support derived from ring-opening-metathesis polymerization (ROMP). Catalyst loadings of 1 and 2.5%, respectively, were obtained. Both supported versions of 2 showed excellent reactivity. With 0.24-2% of the supported catalysts, yields in RCM and ROCM were in the range of 76-100%. Leaching of ruthenium was low and resulted in Ru contaminations of the products of less than 0.000014% (0.14 ppm).

Stereoselective Cyclopolymerization of Diynes: Smart Materials for Electronics and Sensors

AbstractA series of heptadiynes was cyclopolymerized by Schrock initiators to produce poly(ene)s exclusively based on one single repetitive unit, i.e. 1,2‐cyclopent‐2‐enylenvinylenes. Polymers containing virtually solely 1,2‐cyclopent‐2‐enylenvinylene units were obtained by various routes, e.g. by low‐temperature‐initiated cyclopolymerization of diethyldipropargyl malonate (DEDPM). A chiral poly(ene) was prepared from 4‐(ethoxycarbonyl)‐4‐(1S, 2R, 5S)‐(+)‐menthoxycarbonyl‐1,6‐heptadiyne (ECMHD) to determine the configuration of the double bonds and the tacticity of the poly(ene) backbone. Poly(ECMHD) consisted of &gt;96% 5‐membered rings and possessed a tactic, alternating cis‐trans structure. Alternatively, poly(DEDPM) exclusively based on 1,2‐(cyclopent‐1‐enylene)vinylene units was prepared using MoCl5‐n‐Bu4Sn‐EtOH‐quinuclidine (1:1:5:1) and MoOCl4‐n‐Bu4Sn‐EtOH‐quinuclidine (1:1:2:1). The initiator efficiency of MoOCl4‐n‐Bu4Sn‐EtOH‐quinuclidine (1:1:2:1) was as high as 91%, the highest value ever reported for such systems. Multistage polymerizations of DEDPM indicated for both initiator systems that the catalytic species were active for at least 6 hours in the presence of monomer yet did not fulfill the criteria of a truly living polymerization. Finally, a new modification of the Grubbs‐Hoveyda catalyst, Ru(CF3COO)2(CH‐2‐(2,4,5‐(MeO)3‐C6H3)(SIMes) (SIMes=1,3‐dimesityl‐4,5‐dihydroimidazol‐2‐ylidene) allowed the first ruthenium alkylidene‐catalyzed living cyclopolymerization of DEDPM. The different initiators, their properties, the resulting polymerization systems as well as the physical properties of the resulting poly(ene)s are summarized.

Factors relevant for the ruthenium-benzylidene-catalyzed cyclopolymerization of 1,6-heptadyines.

Fourteen metathesis initiators that had been designed for use in the living polymerization of diethyl dipropargylmalonate (DEDPM), including the Hoveyda catalyst [RuCl(2)(IMesH(2))([double bond]CH-2-(2-PrO)[bond]C(6)H(4))] (1 a), as well as [Ru(CF(3)COO)(2)(IMesH(2))([double bond]CH-2-(2-PrO)[bond]C(6)H(4))] (1 b), [Ru(CF(3)CF(2)COO)(2)(IMesH(2))([double bond]CH-2-(2-PrO)[bond]C(6)H(4))] (1 c), [Ru(CF(3)CF(2)CF(2)COO)(2)(IMesH(2))([double bond]CH-2-(2-PrO)[bond]C(6)H(4))] (1 d), [RuCl(2)(IMesH(2))([double bond]CH-2,4,5-(MeO)(3)[bond]C(6)H(2))] (2 a), [Ru(CF(3)COO)(2)(IMesH(2))([double bond]CH-2,4,5-(MeO)(3)[bond]C(6)H(2))] (2 b), [Ru(CF(3)CF(2)COO)(2)(IMesH(2))([double bond]CH-2,4,5-(MeO)(3)[bond]C(6)H(2))] (2 c), [Ru(CF(3)CF(2)CF(2)COO)(2)(IMesH(2))([double bond]CH-2,4,5-(MeO)(3)[bond]C(6)H(2))] (2 d), [RuCl(2)(IMes)([double bond]CH-2-(2-PrO)[bond]C(6)H(4))] (3 a), [Ru(CF(3)COO)(2)(IMes)([double bond]CH-2-(2-PrO)[bond]C(6)H(4))] (3 b), [RuCl(2)(IMesH(2))([double bond]CH-2-(2-PrO)-5-NO(2)[bond]C(6)H(3))] (4 a), [Ru(CF(3)COO)(2)(IMesH(2))([double bond]CH-2-(2-PrO)-5-NO(2)[bond]C(6)H(3))] (4 b), [Ru(CF(3)CF(2)COO)(2)(IMesH(2))([double bond]CH-2-(2-PrO)-5-NO(2)[bond]C(6)H(3))] (4 c), and [Ru(CF(3)CF(2)CF(2)COO)(2)(IMesH(2))([double bond]CH-2-(2-PrO)-5-NO(2)[bond]C(6)H(3))] (4 d) (IMes=1,3-dimesitylimidazol-2-ylidene; IMesH(2)=1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) were prepared. Living polymerization systems could be generated with DEDPM by careful tuning of the electronic nature and steric placement of the ligands. Although 1 a, 2 a, 3 a, 3 b, and 4 a were inactive in the cyclopolymerization of DEDPM, and initiators 1 b-d did not allow any control over molecular weight, initiators 2 b-d and 4 b-d offered access to class VI living polymerization systems. In particular, compounds 2 b and 4 d were superior. The livingness of the systems was demonstrated by linear plots of M(n) versus the number of equivalents of monomer added (N). For initiators 2 b-d and 4 b-d, values for k(p)/k(i) were in the range of 3-7, while 1 b, 1 c, and 1 d showed a k(p)/k(i) ratio of >1000, 80, and 40, respectively. The use of non-degassed solvents did not affect these measurements and underlined the high stability of these initiators. The effective conjugation length (N(eff)) was calculated from the UV/Vis absorption maximum (lambda(max)). The final ruthenium content in the polymers was determined to be 3 ppm.

Regio- and stereospecific cyclopolymerization of 1,6-heptadiynes

The synthesis of poly(ene)s exclusively based on one single repetitive unit, i.e. 1,2-cyclopent-2-enylenvinylenes is described. Polymers containing >96% 1,2-cyclopent-2-enylenvinylene units were obtained by low-temperature-initiated cyclopolymerization of diethyl dipropargylmalonate (DEDPM) by Mo(N-2,6-i-Pr2-C6H3)(CHCMe2Ph)(OCH(CH3)2)2. In the presence of quinuclidine, 100% five-membered ring structures were realized at room temperature, e.g. using Mo(N-2,6-Me2-C6H3)(CHCMe2Ph)(OC(CH3)3)2. 4-(Ethoxycarbonyl)-4-(1S,2R,5S)-(+)-menthyl-1,6-heptadiyne was cyclopolymerized to determine the configuration of the double bond (i.e. the cis/trans ratio) and the tacticity of the poly(ene) backbone. Poly(4-(ethoxycarbonyl)-4-(1S,2R,5S)-(+)-menthyl-1,6-heptadiyne) again consisted of >96% five-membered rings and possessed an all-trans tactic, presumably isotactic structure. A linear plot of number of monomers added (N) versus molecular weights suggested that the cyclopolymerization of DEDPM proceeded in a living manner. At least a class V living system was confirmed by the stepwise synthesis of poly(DEDPM). Molecular weight distributions (PDIs) of 1.16–1.37 result from ratios of the rate constants for polymerization (kp) to initiation (ki), kp/ki>1. Influences of temperature, the base and steric and electronic effects of the arylimido and alkoxy ligand are presented. Complementary to the use of well-defined Schrock initiators, poly(DEDPM) containing exclusively five-membered rings was accessible by the use of the quaternary systems MoCl5–n-Bu4Sn–EtOH–quinuclidine and MoOCl4–n-Bu4Sn–EtOH–quinuclidine. Though virtually identical polymers were obtained, the polymerization systems themselves were controlled, yet not living as is the case with Schrock initiators. Selected polymer properties such as stability, degradation behavior, conductivity, and thermoresponsive behavior will be discussed.

Regio- and stereospecific cyclopolymerization of 1,6-heptadiynes and 1,5-hexadiynes

The synthesis of poly(ene)s exclusively based on one single repetitive unit, i.e., 1,2- cyclopent-2-enylenvinylenes, is described. Polymers containing >96% 1,2-cyclopent-2-enylenvinylene units were obtained by low-temperature-initiated cyclopolymerization of diethyl dipropargylmalonate (DEDPM) by Mo(N-2,6-i-Pr2-C6H3)(CHCMe2Ph)(OCH(CH3)2)2. In the presence of quinuclidine, >96% 5-membered ring structures were realized at room temperature, e.g., using Mo(N-2,6- Me2-C6H3)(CHCMe2Ph)(OC(CH3)3)2. 4-(Ethoxycarbonyl)-4-(1S,2R,5S)-(+)-menthyl-1,6-heptadiyne was cyclopolymerized to determine the configuration of the double bond (i.e., the cis/trans ratio) and the tacticity of the poly(ene) backbone. Poly(4-(ethoxycarbonyl)-4-(1S,2R,5S)-(+)-menthyl-1,6- heptadiyne) again consisted of >96% 5-membered rings and possessed an all-trans tactic, presumably isotactic structure. A linear plot of number of monomers added (N) vs. molecular weight suggested that cyclopolymerization of DEDPM proceeded in a living manner. At least a class-V living system was confirmed by the stepwise synthesis of poly(DEDPM). Molecular weight distributions (PDIs) of 1.16-1.37 resulted from ratios of the rate constants for polymerization (kp) to initiation (k i), k p/k i >> 1. Influences of temperature, the base and steric and electronic effects of the arylimido and alkoxy ligand are presented. Complementary to the use of well-defined Schrock initiators, poly(DEDPM) containing exclusively 5-membered rings was accessible by the use of the quaternary systems MoCl5-n-Bu4Sn-EtOH-quinuclidine and MoOCl4-n-Bu4Sn-EtOH-quinuclidine. Though virtually identical polymers were obtained, the polymerization systems themselves were controlled, yet not living, as is the case with Schrock initiators. Selected polymer properties such as stability, degradation behavior, conductivity, and thermoresponsive behavior will be discussed. Finally, the polymerization behavior of other monomers such as N,N-dipropargylaniline (1), dipropargyl sulfide (2), 1,8-diethynylnaphthalene (3) and 1,2-diethynyltetramethyldisilane (4) is presented.

Mo(CO)6-catalyzed cyclopolymerization of diethyl dipropargylmalonate to give a polyene containing only five-membered rings

Mo(CO)6-catalyzed cyclopolymerization of diethyl dipropargylmalonate to give a polyene containing only five-membered rings

Cyclopolymerization of Diethyl Dipropargylmalonate and Triethyl Dipropargylphosphonoacetate by Molybdenum Pentachloride

The cyclopolymerization of two dipropargyl monomers having different functionality (diethyl dipropargylmalonate, triethyl dipropargylphosphoneacetate) was carried out by molybdenum (V) chloride catalyst system in chlorobenzene at 60°C. The polymerizations were well proceeded to give a high polymer yield (85–98%). The number average molecular weights (An of poymers were in the range of 46000–97000. These polymers were completely soluble in aromatic and halogenated hydrocarbon solvents and easily casted into a homogeneous polymer film. Various instrumental analyses such as NMR (1H- and 13C-), IR, GPC, and UV-visible spectroscopies indicated that the present polymers have a highly conjugated polymer backbone structure. The tensile strength and failure strain of polymer film generally increased as the feed ratio of diethyl dipropargylmalonate in copolymer increased. On the other hand, the char yield of polymers increased significanly as the feed ratio of triethyl dipro-pargylphosphonoacetate in copolymer increased.

Cyclopolymerization of diethyl dipropargylmalonate by transition metal catalysts

Cyclopolymerization of diethyl dipropargylmalonate by transition metal catalysts