Eugene Sh. Finkelshtein

Ring-opening metathesis polymerization of substituted norbornenes

Abstract Ring-opening metathesis polymerization of a series of substituted norbornenes was carried out. Special attention was paid to the polymerization of monomers bearing silicon-containing groups, e.g., trimethylsilylnorbornene. Various heterogeneous and homogeneous tungsten-, rhenium- and ruthenium-based systems were used as catalysts. It was possible to obtain polymers of some norbornenes having reactive SiCl and SiOR bonds as well as groups capable of polymerizing via different mechanisms. The latter remained unchanged during the ring-opening of the norbornenes and could be used for the further modification of these polymers. Some data on the polymerization of various cycloolefin pairs are presented. It was found that some of the new silicon-containing polynorbornenes belong to the group of the most permeable and rather permselective polymers.

Synthesis of Z-isomeric insect sex pheromone components via ethenolysis of 1,5-cyclooctadiene

Abstract A novel syntheses of Z-5-decenol, Z-5-decenyl acetate, Z-7-dodecenol, Z-7-dodecenyl acetate, Z-9-tricosene, Z-7,8-epoxy-2-methyloctadecane which are sex pheromone components of Lepidoptera and Diptera orders, have been realized via stereoselective cometathesis of 1,5-cyclooctadiene with ethylene in the presence of MoCl 5 /SiO 2 -SnMe 4 as a key reaction. The main cometathesis product, 1,Z-5,9-decatriene, has been converted into pheromone components mentioned above by regioselective partial hydroboration or hydrozirconation with help of 9-BBN and Cp 2 ZrHCl, correspondingly. The protonolysis of the obtained zirconosene derivative gave 1,Z-5-decadiene. Hydroboration-oxidation or hydroboration-C 2 -homologation of the latter led to Z-5- or Z-7 monoene pheromone components. Hydroboration-iodination of terminal double bond in 1,Z-5,9-decatriene, and further cross-coupling of the obtained iodine derivative with convenient lithium cuprates resulted in Z-9-tricosene, the main sex pheromone component of House Fly ( Musca Domestica ), or in 2-methyl-Z-7-octadecene, the precursor of Gypsy Moth ( Lymantria Dispar ) sex attractant.

Cross-metathesis of polynorbornene with polyoctenamer: a kinetic study

Summary The cross-metathesis of polynorbornene and polyoctenamer in d-chloroform mediated by the 1st generation Grubbs’ catalyst Cl2(PCy3)2Ru=CHPh is studied by monitoring the kinetics of carbene transformation and evolution of the dyad composition of polymer chains with in situ 1H and ex situ 13C NMR spectroscopy. The results are interpreted in terms of a simple kinetic two-stage model. At the first stage of the reaction all Ru-benzylidene carbenes are transformed into Ru-polyoctenamers within an hour, while the polymer molar mass is considerably decreased. The second stage actually including interpolymeric reactions proceeds much slower and takes one day or more to achieve a random copolymer of norbornene and cyclooctene. Its rate is limited by the interaction of polyoctenamer-bound carbenes with polynorbornene units, which is hampered, presumably due to steric reasons. Polynorbornene-bound carbenes are detected in very low concentrations throughout the whole process thus indicating their higher reactivity, as compared with the polyoctenamer-bound ones. Macroscopic homogeneity of the reacting media is proved by dynamic light scattering from solutions containing the polymer mixture and its components. In general, the studied process can be considered as a new way to unsaturated multiblock statistical copolymers. Their structure can be controlled by the amount of catalyst, mixture composition, and reaction time. It is remarkable that this goal can be achieved with a catalyst that is not suitable for ring-opening metathesis copolymerization of norbornene and cis-cyclooctene because of their substantially different monomer reactivities.

Experimental and Theoretical Study of [2σ + 2σ + 2π]–Cycloaddition of Quadricyclane and Ethylenes Containing Three Silyl-Groups

The reaction of [2σ + 2σ + 2π]-cycloaddition of quadricyclane with olefins is an attractive way for regio- and sterospecific synthesis of norbornene derivatives (exo-tricyclononenes) with desired substituents. The presence of Cl3Si-containing groups in such compounds permits different monomer modifications for the development of new materials. Herein, for the first time the theoretical and experimental study of the behavior of different ethylenes containing three silyl-groups in the reaction of [2σ + 2σ + 2π]-cycloaddition with quadricyclane was systematically performed. Based on the data obtained for this reaction the activity scale of the ethylene derivatives was established, and the explanations for an ethylene activity were suggested. As a result, a new family of Si-containing tricyclononenes was successfully synthesized. As an example of a possible modification, the methylation of the sterically hindered cycloadducts was investigated and the conditions for full methylation were found. Considering that gas permeability of polymers increases with the increase of a number of the side Me3Si-groups, the compounds are interesting monomers for synthesis of membrane polymers possessing high gas permeability values.

New composites based on poly(3-trimethylsilyltricyclononene-7) and organic nature fillers (calixarenes & cyclodextrins)

Herein we describe new materials for membrane gas separation process with improved selectivities towards different pairs of gases. Organic nature fillers (modified calix[4]arenes, calix[8]arenes and modified α-, β-, γ-cyclodextrins) were used as additives to poly(trimethylsilyltricyclononene-7) (PTCNSi1)in order to study correlations between structure of the filling agent and gas transport parameters of the composite membranes. It was shown a positive influence of calixarenes and cyclodextrins as additives on permselectivity of the membranes. For instance, selectivity towards H2/CH4 gas pair increased almost in 2.4 times when calix[4]arene with Et- and tert-Bu- group was introduced into polymeric matrix. Detailed study of the PTCNSi1 adsorbtion/desortion data is presented. The obtained composites were characterized by TEM, WAXD, PALS and BET analysis.

Binary and Ternary Catalytic Systems for Olefin Metathesis Based on MoCl 5 /SiO 2

Kinetics of α-olefin metathesis in the presence of binary (MoCl5/ SiO2-Me4Sn) and ternary catalytic systems (MoCl5/SiO2-Me4Sn-ECl4, E = Si or Ge) was studied. Specifically, kinetics and reactivity of 1-decene, 1-octene, and 1-hexene in the metathesis reaction at 27°C and 50°C in the presence of MoCl5/ SiO2-SnMe4 were examined and evaluated in detail. It was shown that experimental data comply well with the simple kinetic equation for the rate of formation of symmetrical olefins with allowance for the reverse reaction and catalyst deactivation: \(r = \left( {k_1 \cdot c_\alpha - k_{ - 1} \cdot c_s } \right) \cdot e^{ - k_d \cdot \tilde n_{tot} } \). The coefficients for this equation were determined, and it was shown that these α-olefins had practically the same reactivity. It was found that reactivation in the course of metathesis took place due to the addition of a third component (silicon tetrachloride or germanium tetrachloride in combination with tetramethyltin) to a partially deactivated catalyst. The number of active centers was determined (5–6% of the amount of Mo) and the mechanisms of formation, deactivation, and reactivation were proposed for the binary and ternary catalytic systems. The role of individual components of the catalytic systems was revealed.

Janus tricyclononene polymers bearing tri(n-alkoxy)silyl side groups for membrane gas separation

A series of polymers of a new type, which contain rigid polymer main chains (glassy nature) and long flexible side substituents (rubbery nature), were prepared from norbornene derivatives with (AlkO)3Si-groups of a different length (Alk = Me, Et, n-Pr, n-Bu) as promising materials for membrane separation of gaseous hydrocarbons. The 1st generation Grubbs complex and Pd–N-heterocyclic carbene complex in combination with Na+[(3,5-(CF3)2C6H3)4B]− and PCy3 were used as catalysts of metathesis and addition polymerization in the synthesis of high-molecular weight polymers (Mw ≤ 1.1 × 106) with good or high yields (up to 99%). The prepared addition polymers were glassy, while the glass transition temperature of metathesis polymers depended on the length of the alkyl-group in (AlkO)3Si-substituents and it varied in the range of −44 to 61 °C. The dramatic tuning of polymer gas-transport properties was demonstrated by the change of the polymer main chain structure and the length of tri(n-alkoxy)silyl side groups. For example, we have succeeded for the first time in obtaining metathesis polynorbornenes, which turned out to be more permeable than their addition isomers. Not being large free volume polymers, all studied metathesis and addition polytricyclononenes exhibited solubility controlled permeation of hydrocarbons (P(n-C4H10) up to 8100 barrer) and high C4/C1 selectivity (22–49).

Synthesis and properties of polynorbornenes containing trialkoxysilyl groups

In this work we report the synthesis and polymerization of new norbornenes containing trialkoxysilyl groups. These monomers were reactive both in ROMP and in addition polymerization. Obtained polymers possessed interesting properties. So despite of low surface area they were good permeable, and some of them exhibited a low tendency to aging. The solubility controlled selectivity for hydrocarbons was observed. These properties would allow finding industrial application of obtained polymers for the membrane gas separation of hydrocarbon mixtures.In this work we report the synthesis and polymerization of new norbornenes containing trialkoxysilyl groups. These monomers were reactive both in ROMP and in addition polymerization. Obtained polymers possessed interesting properties. So despite of low surface area they were good permeable, and some of them exhibited a low tendency to aging. The solubility controlled selectivity for hydrocarbons was observed. These properties would allow finding industrial application of obtained polymers for the membrane gas separation of hydrocarbon mixtures.

Cross-linking of addition copolymers based on 3-trimethylsilyltricyclo[4.2.1.02,5]non-7-ene

Herein we report a new approach to cross-link substituted addition polynorbornenes. The cross-linking was realized by the copolymerization of SiMe3-containing tricyclononene with low amounts of tricyclononene bearing triethoxysilyl groups followed by the hydrolysis of Si(OEt)3-groups with the formation of interchain siloxane bonds. The amount of cross-links proved to depend on the composition of copolymers and cross-linking conditions, which allowed to perform controlled cross-linking of polynorbornenes. The insoluble polymers with good film forming properties were obtained by cross-linking. The developed method could find further application for the modification of polynorbornenes.Herein we report a new approach to cross-link substituted addition polynorbornenes. The cross-linking was realized by the copolymerization of SiMe3-containing tricyclononene with low amounts of tricyclononene bearing triethoxysilyl groups followed by the hydrolysis of Si(OEt)3-groups with the formation of interchain siloxane bonds. The amount of cross-links proved to depend on the composition of copolymers and cross-linking conditions, which allowed to perform controlled cross-linking of polynorbornenes. The insoluble polymers with good film forming properties were obtained by cross-linking. The developed method could find further application for the modification of polynorbornenes.

Synthesis and metathesis polymerization of fluorine-containing tricyclononenes

Herein the synthesis of a new series of fluorine containing tricyclononenes using [2σ+2σ+2π]-cycloaddition of quadricyclane with fluorine containing alkenes is described. According to the experiment the reactivity of fluorine containing alkenes in [2σ+2σ+2π]-cycloaddition reaction was established. The obtained cycloadducts were successfully involved in ring-opening metathesis polymerization on Ru-based catalytic systems. The obtained polymers were glassy and amorphous. The investigation of gas-transport properties of the new materials with improved selectivity towards different pairs of gases was executed.Herein the synthesis of a new series of fluorine containing tricyclononenes using [2σ+2σ+2π]-cycloaddition of quadricyclane with fluorine containing alkenes is described. According to the experiment the reactivity of fluorine containing alkenes in [2σ+2σ+2π]-cycloaddition reaction was established. The obtained cycloadducts were successfully involved in ring-opening metathesis polymerization on Ru-based catalytic systems. The obtained polymers were glassy and amorphous. The investigation of gas-transport properties of the new materials with improved selectivity towards different pairs of gases was executed.