Supramolecular Catalysts Based on Novel Pyrimidinophane: Influence of Additives of Polymer and Lanthanum Ions

Abstract

Supramolecular systems based on the novel tetracationic amphiphilic pyrimidinophane, their mixtures with polymer (polyethyleneimine) and lanthanum ions were formed. Using spectrophotometry technique a catalytic activity of these systems was studied on the example of hydrolysis reaction of O-p-nitrophenyl-O-alkylchloromethylphosphonates (alkyl = ethyl (P1) and n-hexyl (P2)). At the first step the catalytic effect of individual solutions of pyrimidinophanes was examined. Pronounced substrate specificity for two different phosphonates was revealed: inhibition of hydrolysis for phosphonate with ethyl residue and catalysis of hydrolysis for phosphonate with n-hexyl moiety. Similar unusual effect for organized systems based on cationic surfactants could be a result of the influence of two opposite factors. On the one hand, pH decrease with the pyrimidinophane concentration was found. It corresponds to reducing of OH -ions concentration in reaction medium and, therefore inhibition of hydrolysis occurs. On the other hand, aggregation in aqueous solutions of pyrimidinophane induces reactant concentrating in surfactant aggregates that accelerates the reaction. Thereby depending on the domination of the first or the second factor inhibition or catalysis may be observed. Experimental kinetic data allow us to assume that phosphonate P2 because of its higher hydrophobicity and affinity to nonpolar core of micellar pseudophase possesses the higher capability to binding with pyrimidinophane aggregates in comparison with P1. Quantitative treatment of obtained kinetic data in terms of pseudophase model has revealed that binding ability of P2 with pyrimidinophane aggregates is almost 2 times greater than in the case of P1. Moreover, hydrolysis in catalytic complex proceeds more than 5 times faster for substrate with n-hexyl residue. This fact is also due to the high capability of P2 to concentrate within hydrophobic core of pyrimidinophane aggregates. Thus it can be concluded that in the case of P2 the domination of positive contribution over the negative contribution of pH decrease with surfactant concentration is achieved due to high capability of substrate to bind with pyrimidinophane aggregates and high rate of hydrolysis in catalytic complex. It results in catalysis of reaction. At the same time, moderate ability of P1 to bind with aggregates is not enough to compensate pH decrease, which results in inhibition of reaction. Upon the transition from individual solutions of pyrimidinophane to its binary mixture with polyethyleneimine the difference of kinetic constants between P1 and P2 tends to be preserved. However absolute values of these constants are much lower than in the case of individual solutions of pyrimidinophane. Probably, it is due to the fact that cooperative aggregation between surfactant and polymer prevents reactant concentration in surfactant/polymer aggregates. However, resulting catalytic effect of binary system for both phosphonates is higher than in the case of individual solutions of pyrimidinophane. It ...

Supramolecular Nanocontainers Based on Hydrophobized Calix[4]resorcinol: Modification by Gemini Surfactants and Polyelectrolyte

“…Соотношение интенсивностей первого и третьего пиков в спек-Рисунок 1. Структурные формулы каликс [4]резорцина (КР), геминальных ПАВ, полиакриловой кислоты (ПАК), спектрального зонда Судан I и лекарственного препарата куркумин. тре пирена I 1 /I 3 чувствительно к полярности среды, поэтому широко используется для идентификации образования мицелл, содержащих области с различной микрополярностью.…”

“…[4][5][6][7][8][9] В данной работе при выборе соеди-нений руководствовались критериями, применяемыми к биотехнологическим разработкам: экологичность, низкие концентрации компонентов, биосовместимость, низкая токсичность и пр. В качестве макроциклической матрицы использовали новый амфифильный каликс [4] резорцин (КР), функционализированный природными (аминокислотными) остатками по верхнему ободу. Со-любилизацию КР проводили в водных мицеллярных растворах геминальных (дикатионных) ПАВ различной гидрофобности 16-12-16(ОН) и 12-6-12(ОН) (Рисунок 1).…”

“…Геминальные ПАВ -это димерные амфифильные со-единения, содержащие две головные группы с присо-единенными к ним алкильными радикалами, соединен-ные спейсерным фрагментом. [10,11] Геминальные ПАВ имеют низкие значения критической концентрации ми-целлообразования (ККМ), что позволяет значительно Supramolecular Nanocontainers Based on Calix [4]resorcinol снижать их дозировки. В случае менее гидрофобного ПАВ 12-6-12(ОН) использовали тройную систему КР-12-6-12(ОН)-полиакриловая кислота (ПАК).…”

Amphiphilic Macrocyclic Derivative of Pyrimidine: Self-Assembly, Solubilization and Interaction with DNA Decamer

“…В наших ранних работах было показано, что пиримидинофаны обладают рядом уникальных особенностей, в частности, способны к концентрационно зависимому гелеобразова-нию [15] и являются субстрат-специфичными катализато-рами расщепления экотоксикантов различной гидрофоб-ности. [16] Поэтому их дальнейшая модификация и изуче-ние функциональной активности представляет интерес и является актуальным. В рамках данной работы, про-должающей цикл исследований агрегационных харак-теристик и функциональной активности пиримидинсо-держащих ПАВ, [17][18][19][20][21][22][23] сформированы и изучены супра-молекулярные системы на основе макроциклического пиримидинсодержащего амфифила, в составе которого имеется аллильный заместитель (Рисунок 1а, ПФ-1).…”

Aggregation and Solubilization Properties of System Based on Glycine-Calix[4]resorcinol and Sodium Dodecyl Sulfate in Aqueous Medium

“…Mixed compositions based on the building blocks of rigid (calixarenes, cyclodextrins) and soft (surfactant, polymers) structures invariably appear in the focus of scientific research, since they allow the development of multifunctional and smart materials, systems and structures to be promoted due to aggregation ability. [1][2][3][4][5][6] The formation of these mixed compositions can reduce the consumption of reagents [1,7] and connect the factors of morphology control of functional aggregates. [8][9][10] A review of the literature shows that in recent years a significant number of calix [4]resorcinol derivatives have been synthesized, and their aggregation properties in the absence and in the presence of surfactants have been studied.…”