Pavel S. Gribanov

An unprecedentedly simple method of synthesis of aryl azides and 3-hydroxytriazenes

Fischers approach towards the synthesis of aryl azides and triazinoles from diazonium salts and hydroxylammonium chloride (phenylhydraxylamine) was reinvestigated and optimized. The new methodology enables the preparation of aryl azides and triazinoles in high yields in water at room temperature. The procedure is very simple, robust, easily scalable, reproducible, and “green”.

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.

Addition polymerization of 5-vinyl-2-norbornene and 5-ethylidene-2-norbornene

Herein we described addition polymerization of 5-ethylidene-2-norbornene and 5-vinyl-2-norbornene in the presence of N-heterocyclic carbene Pd-complexes. After activation with B- or/and Al-organic compounds, these complexes were found to be selective and highly active catalysts for polymerization of these bifunctional norbornenes. The studied catalytic systems were active even at very high monomer/Pd ratios (up to 250 000/1) and their catalytic activity was in the range of 5·106-3·107 gpolymer/(molPd·h). Some interesting relationships between the structure of Pd-complexes and the catalyst activity in polymerization were found. In the presence of these complexes, amorphous, glassy and soluble polynorbronenes containing side alkenyl groups were prepared and characterized by means of IR and NMR spectroscopy.Herein we described addition polymerization of 5-ethylidene-2-norbornene and 5-vinyl-2-norbornene in the presence of N-heterocyclic carbene Pd-complexes. After activation with B- or/and Al-organic compounds, these complexes were found to be selective and highly active catalysts for polymerization of these bifunctional norbornenes. The studied catalytic systems were active even at very high monomer/Pd ratios (up to 250 000/1) and their catalytic activity was in the range of 5·106-3·107 gpolymer/(molPd·h). Some interesting relationships between the structure of Pd-complexes and the catalyst activity in polymerization were found. In the presence of these complexes, amorphous, glassy and soluble polynorbronenes containing side alkenyl groups were prepared and characterized by means of IR and NMR spectroscopy.

Addition Polymerization of 5-Ethylidene-2-Norbornene in the Presence of Pd N-Heterocyclic Carbene Complexes

New high-performance catalytic systems based on Pd N-heterocyclic carbene complexes for the selective addition polymerization of 5-ethylidene-2-norbornene (ENB) were proposed. With these catalysts, polymerization can be conducted at unprecedentedly high monomer/catalyst ratio (up to 5 × 105/1) and gives high-molecular-weight soluble polymers with good film-forming properties. Varying the polymerization conditions (reaction temperature, monomer and catalyst concentrations, monomer/Pd ratio) makes it possible to prepare soluble ENB-based addition polymers with specified molecular weights in reasonable yields.