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Latest Paper:
Gulnara A Gainanova,
Guzalia I Vagapova,
Victor V Syakaev,
Alsu R Ibragimova,
Farida G Valeeva,
Elena V Tudriy,
Irina V Galkina,
Olga N Kataeva,
Lucia Ya Zakharova,
Shamil K Latypov,
Alexander I Konovalov
A.E. Arbuzov Institute of Organic and Physical Chemistry of the Russian Academy of Sciences, 8, ul. Akad. Arbuzov, Kazan 420088, Russia.
A systematic study of the aggregation behavior of alkyltriphenylphosphonium bromides (TPPB-n; n=8, 10, 12, 14, 16, 18; here n is the number of carbon atoms in alkyl groups) in aqueous solutions has been carried out and compared with trimethyl ammonium bromides (TMAB-n). Critical micelle concentrations (cmcs) of TPPB-n and TMAB-n decrease with the number of carbon atoms with the slope parameter of ca.0.3. The low cmcs and effective solubilization power toward Orange OT indicate high micellization capacity of phosphonium surfactants. The low counterion binding parameter β is revealed for TPPB-10 and TPPB-12, while high counterion binding of ⩾80% is observed for high TPPB-n homologs. Values of the surface potential ψ calculated on the basis of pK(a) shifts of p-nitrophenols is similar for both series and monotonously increase with alkyl chain length. Several points indicate non-monotonic changes within TPPB-n series. There are peculiarities of the tensiometry and solubilization plots for high homologs and above mentioned increases in counterion binding on transiting from low to high molecular weight surfactants. Differences in aggregation behavior between TPPB and TMAB series and between low and high homologs can be due to the specific structural character of the TPP(+) cation, which is supported by X-ray data.
Asiya Mustafina,
Rustem Zairov,
Margit Gruner,
Alsu Ibragimova,
Dmitry Tatarinov,
Irek Nizameyev,
Nataliya Nastapova,
Vitaly Yanilkin,
Marcil Kadirov,
Vladimir Mironov,
Alexander Konovalov
AE Arbuzov Institute of Organic and Physical Chemistry, Kazan, Russia. asiyamust@mail.ru
The luminescent colloids have been synthesized through the layer-by-layer assembly of poly(sodium 4-styrenesulfonate)(PSS) and polyethyleneimine (PEI) onto the luminescent core. The latter has been obtained by the reprecipitation of complex Eu[(TTA)(3)1](where TTA(-) and 1 are thenoyltrifluoroacetonate and 2-(5-chlorophenyl-2-hydroxy)-2-phenylethenyl-bis-(2-methoxyphenyl)phosphine oxide, respectively) from organic solvent to aqueous solution. The variation of Eu(III) complexes indicates the role of the complex core in the development of such core-shell colloids. Complex Eu[(TTA)(3)1] is most convenient precursor of Eu-doped luminescent nanocomposites. The fluorometric measurements at each step of the layer-by-layer polyelectrolyte assembly onto Eu[(TTA)(3)1] core, at various pHs and additives reveal the quenching of Eu-centered luminescence as a result of the interfacial interaction of the core and the dye. The AFM images and electrochemical behavior of PSS-(PEI-PSS)(n)-Eu[(TTA)(3)1] colloids deposited on the surface indicate the stability of the polyelectrolyte multilayer in the dried state.
Lucia Zakharova,
Victor Syakaev,
Mikhail Voronin,
Vyacheslav Semenov,
Farida Valeeva,
Alsu Ibragimova,
Azat Bilalov,
Rashit Giniyatullin,
Shamil Latypov,
Vladimir Reznik,
Alexander Konovalov
A.E. Arbuzov Institute of Organic and Physical Chemistry of the Russian Academy of Science, Ul. Akad. Arbuzov 8, 420088 Kazan, Russia; Kazan State Technological University, Ul. K. Marx 68, 420015 Kazan, Russia.
New amphiphilic pyrimidinic (AP) compounds with two ammonium head groups and different kinds of counterions, inorganic bromide anions (APB) and hydrophobic tosylate anions (APT) were synthesized. Self-organization in these systems has been studied by methods of tensiometry, conductometry, potentiometry and NMR spectroscopy. The critical micelle concentrations (cmc's) of bola-type surfactants are only a little lower than those of cetyltrimethylammonium (CTA) analogues. For both pairs APB/CTAB and APT/CTAT the counterion binding is stronger for the conventional cationic surfactants as compared to 'bola' pyrimidinic surfactants. Unlike the CTAT micelles no sharp micellar growth occurs with the APT concentration. The geometry of AP compounds is assumed to be mainly responsible for the above finding. A branched molecular architecture prevents a close packing of the monomers in the bulk solution and at the interface producing a steric hindrance around the head groups.
Ia A Shimakha,
O K Pozdeev,
A A Ibragimova,
N K Minullina,
Zh P Fedorova,
A A Khasanov,
O N Il'inskaia
Campylobacter fetus subspecies fetus is a cause of different obstetric-gynecological diseases. It is a first time when rate of infection with Campylobacter was studied and connection between the infection and development of chronic gynecologic diseases and pathology of labor was established. Bacteria were isolated and identified in 36.0%+/- 0.7 of studied women admitted to inpatient clinics. It was established that Campylobacter fetus subspecies fetus can cause abnormalities in placenta functions as well as different inflammatory processes during pregnancy.
J Phys Chem B. 2007 Dec 5;:
18052275
Lucia Zakharova,
Vyacheslav Semenov,
Mikhail Voronin,
Farida Valeeva,
Alsu Ibragimova,
Rashid Giniatullin,
Alla Chernova,
Sergey Kharlamov,
Lyudmila Kudryavtseva,
Shamil Latypov,
Vladimir Reznik,
Alexander Konovalov
New amphiphilic pyrimidinic macrocycles (APMs) with two (APM-1) and three (APM-2) decyl tails have been synthesized by quaternization of the bridged N. Complex examination of the APM-based systems with the help of tensiometry, conductometry, dynamic light scattering, and UV and NMR spectroscopy provides evidence for their aggregation. Calculations based on surface tension isotherms and on packing parameter considerations make it possible to assume a lamellar packing of macrocycles when aggregating. Marked differences in the aggregation behavior of APM-1 and APM-2 have been found. The additives of polyethylenimine (PEI) exert little influence on the critical micelle concentration (cmc) of APM-1, while in the APM-2/PEI systems there occurs a pronounced decrease in the cmc and also a ca. 2-fold decrease in the surface area per molecule. The APM-based assemblies are explored as nanoreactors for the hydrolysis of O-alkyl O-p-nitrophenyl (chloromethyl)phosphonates (alkyl = ethyl, hexyl). The kinetic study reveals a minor rate effect of the APM-1-based systems. In the APM-2-based systems an acceleration of the hydrolysis of both phosphonates occurs as compared to the uncatalyzed process. Within the APM-2 --> APM-2/PEI --> APM-2/PEI/La(III) series, due to the cooperative contributions of the supramolecular, polymer, and homogeneous catalysis, an increase in the catalytic effect is observed from 30 times to 3 orders of magnitude as compared to that of the basic hydrolysis of the substrates.
Langmuir. 2007 Feb 10;:
17291018
Lucia Zakharova,
Alsu Ibragimova,
Farida Valeeva,
Andrey Zakharov,
Asiya Mustafina,
Lyudmila Kudryavtseva,
Harlampy Harlampidi,
Alexander Konovalov
A.E. Arbuzov Institute of Organic and Physical Chemistry of the Russian Academy of Sciences, 8, ul. Akad. Arbuzov, Kazan, 420088, Russia; and Kazan State Technological University, Kazan, 420015, Russia.
Effective nanoreactors based on polyethyleneimines (PEIs) for the hydrolytic cleavage of O-alkyl O-p-nitrophenyl chloromethylphosphonates (alkyl = ethyl, hexyl) and di(p-nitrophenyl)phosphate were developed in conformity with the idea of modeling the polyfunctional catalytic mechanism of enzymes. A step-by-step modification of the single PEI solution by additives with their own catalytic activities (sodium dodecyl sulfate and lanthanum salt) gave rise to a marked improvement in the reaction efficiency. A 104-106-fold acceleration of the reaction compared to the aqueous basic hydrolysis of the substrates was achieved in the sodium dodecyl sulfate-polyethyleneimine-La(III) ternary system. This system can be considered to be metallomicelles immobilized on a hydrophilic polymer matrix. When the PEI immobilized on silica gel was used as a catalyst, the full completion of the reaction was achieved for 100 min under mild conditions, while the half-life of the reaction in a comparable homogeneous regime exceeds 100 h.
Lucia Zakharova,
Farida Valeeva,
Andrey Zakharov,
Alsu Ibragimova,
Ludmila Kudryavtseva,
Harlampy Harlampidi
A.E. Arbuzov Institute of Organic and Physical Chemistry of the Russian Academy of Sciences, 8, ul. Akad. Arbuzov, Kazan 420088, Russia. lucia@iopc.knc.ru
Surface tension measurements and the kinetic study of the basic hydrolysis of ethyl p-nitrophenyl chloromethyl phosphonate were used to examine the structural behavior and catalytic activity of the cethyltrimethylammonium bromide (CTAB)-polyoxyethylene (10) oleyl ether, C(18)H(35)(OCH(2)CH(2))(10)OH (Brij 97)-water mixed micellar system. Application of the regular solution model to the experimental data yields the value of the interaction parameter beta as -4.6, which indicates an attractive interaction of the surfactants in the mixed micelle and reflects synergistic solution behavior of the mixture. The mixed micellar composition is found to be enriched in the surfactant with the lower critical micelle concentration (cmc). In the kinetic study a nonmonotonic change in the pseudo-first-order rate constant of basic hydrolysis of the substrate is observed with increasing mole fraction of nonionic surfactant. The pseudophase micellar model reveals that the concentration factor mainly contributes to the catalytic effect, while the microenvironmental factor plays a negative role.
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