Wyniki wyszukiwania - BazTech

1

Synthesis and self-assembly of a simple CO2-responsive diblock polymer

Zhang Pengfei, Jing Xianwu, Zhou Lang, Liu Qiang, Zhang Yadong

Polish Journal of Chemical Technology

|

2024

|

Vol. 26, nr 3

16--20

EN

Methoxypolyethylene glycol 1900 and α-bromoisobutanoyl bromide were utilized for alcoholysis reaction to obtain a macromolecular initiator. Then, a simple amphiphilic diblockpolymer (mPEG-PDMAEMA) based on the initiator and dimethylaminoethyl methacrylate was synthesized through the atomic transfer radical polymerization (ATRP) method. The structures of the initiator and diblock polymer were accurately characterized using infrared spectrum and proton nuclear magnetic resonance spectroscopy (1H NMR). Cryo-transmission electron microscopy revealed the self-assembly of mPEG-PDMAEMA into vesicle-like structures in water. Upon injection of CO2 into the solution, the tertiary amine structure within PDMAEMA underwent protonation, resulting in the mPEG-PDMAEMA adopting a hydrophilic structure. Consequently, the vesicles dissociated and dispersed, forming a network-like structure in water. The protonation phenomenon was confi rmed by 1H NMR, as evidenced by the shifting of alkyl hydrogen atoms near nitrogen atoms toward downfi eld positions.

2

Multifunctional interphases for polymeric engineering products and smart devices

Gutowski V. S., Toikka G., Liu M. S., Li S.

Advances in Manufacturing Science and Technology

|

2015

|

Vol. 39, nr 1

5--15

EN

The ability to control interactions between polymeric substrate and single molecules including successful placement of molecules in desired location at technologically useful conformation and spatial architecture provides a platform for designing functional surfaces for high-tech engineered products and smart devices. Subsequent ability to control interactions between arrays of immobilized molecules in the form of molecular brushes and interacting materials such as fluids, solids or bioactive materials such as cells and tissues facilitates the control of adhesion and fracture properties of interfaces for structurally bonded or coated materials or enables control of other properties such as surface conductivity of flexible films, fibres and fabrics for electronic or energy harvesting applications, live cells propagation in biomedical sensors or devices and for restorative medicine applications. This paper discusses theoretical and practical aspects of surface grafted molecular brushes at controlled surface density, spatial geometry and chemical functionality which facilitate more than 1000-fold strength increase of bonded assemblies in comparison with unmodified substrates to the point of achieving 100% cohesive fracture of substrates or adhesives, as detailed in our earlier publications. The same molecules exhibiting an in-built electron conductivity facilitate achieving a 108-fold increase in polymer surface conductivity.

PL

Analiza oddziaływania podłoża polimerowego i pojedynczych cząsteczek dotyczy ich rozmieszczenia dla ustalonego położenia w celu uzyskania korzystnej technologicznie konfiguracji. Stanowi ona podstawę do projektowania struktury geometrycznej powierzchni zaawansowanych technologicznie wyrobów i urządzeń inteligentnych. Określenie stopnia wzajemnego oddziaływania pomiędzy układami cząsteczek w postaci „szczotek molekularnych” – substancjami w stanie ciekłym i stałym lub materiałami bioaktywnymi, m.in. komórkami i tkankami, umożliwia kontrolę przylegania i pękania materiałów połączonych. Także kontrolę innych właściwości m.in. przewodnictwa powierzchniowego wytworzonych warstw lub włókien oraz rozprzestrzeniania się komórek w czujnikach i urządzeniach biomedycznych. W pracy przedstawiono teoretyczne i praktyczne zagadnienia z obszaru „szczotek molekularnych”. Uwzględniono kontrolę ich gęstości powierzchniowej, geometrii i właściwości chemicznych. Umożliwi to zwiększenie wytrzymałości łącznych elementów ponad 1000-krotnie w porównaniu z podłożem niemodyfikowanym. Zapewni także pękanie kohezyjne podłoża lub warstwy klejów.

3

Experimental Evidence, Stability and Proposed Structure of Protonated Tetramethyl p-tert-Butylcalix[4]arene Tetraketone

Makrlík E., Dybal J., Budka J., Vaoura V.

Polish Journal of Chemistry

|

2008

|

Vol. 82, nr 7

1441-1441

EN

From extraction experiments and gamma-activity measurements, the extraction constant corresponding to the equilibrium H3O+(aq) + 1×Na+(nb) 1.H3O+ (nb) + Na+(aq) taking place in the two-phase water–nitrobenzene system (1 = tetramethyl p-tert-butylcalix[4]arene tetraketone; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex(H3O+,1.Na+) = –0.6š0.1. Fur ther, the sta bil ity con stant of the 1×H3O+ complex in water saturated nitrobenzene corresponding to the equilibrium 1(nb) + H3O+(nb) 1×H3O+ (nb) was calculated for a temperature of 25°C as log beta nb (1×H3O+) = 9.7š0.2. Finally, by means of DFT cal cu la tions, three dif fer ent struc tures of this com plex spe cies were in di cated. The cal culated stabilization energy of 1×H3O+, –406.7 kJ mol–1, is the same for of all three optimized structures.

4

Accurate Gas Phase Basicities of Hydroxyl Radical Modified Purines Estimated by Advanced Quantum Chemistry Methods

Cysewski P., Kozłowska K.

Polish Journal of Chemistry

|

2008

|

Vol. 82, nr 12

2255-2268

EN

The gas phase basicities (GPB) of purines and their hydroxyl radical modified analogs were characterized by different methods and diverse basis sets. The macroscopic and microscopic protolytic properties of six derivatives were analyzed in details. Most of studied model purine analogs, namely 8-oxo-adenosine (AB), 8-oxo-guanosine (GA), xanthosine (GB) and fapy-guanosine (GC) have reduced basicities from 2.0 kcal/mol (AB) to 6.4 kcal/mol (GA) compared to non-modified model purine nucleosides. The fapy-adenosine (AC) and 2-OH-adenosine (AA) are characterized by higher basic character compared to non-modified adenosine. Besides, it is presented the detailed analysis of GPB in accuracies estimated by means of HF, MP2, B3LYP, G3MP2 and G3MP2B3 methods. The B3LYP/aug-cc-pvdz approach seems to be the most accurate among studied methods and precise enough for estimation of GPB. However, the microscopic protonation features are much more sensitive to applied method since the difference in energies between some tautomers are often less than 1 kcal/mol with method dependent succession. The correct sequence of neutral and cationic forms may be however obtained using one of the model composite chemistry approaches, e.g. G3MP2B3. In the cases where B3LYP/aug-cc-pvdz and G3MP2B3 methods lead to contradictory predictions of order of neutral or protonated tautomers the latter is suggested to be used in the interpretation of microscopic protonation properties. Nevertheless, if only macroscopic property is necessary the B3LYP/aug-cc-pvdz level is sufficient since it provides GPB values with 1.0 kcal/mol accuracy.

5

The Protonation Equili rium and Decomposition of Amino- and Hydroxyphosphonates, Phos phine Ox ides and Phosphonic Acid

Doskocz M., Gancarz R., Roszak S.

Polish Journal of Chemistry

|

2007

|

Vol. 81, nr 11

2013-2021

EN

Protonation states of amino and hydroxyl phosphoroorganic derivatives have been studied. Based on the presented calculations we can state that mono- and di-protonated species on nitrogen are dominating states in solution. The protonation on phosphoryl oxygen occurs only as an effect of dynamic equilibrium between protonated species. The double and tripple protonation lead to very strong acid and thus such states are rather not present even in strong acidic media.

6

NMR Evidence for Protonated Tetraethyl p-tert-Butylcalix[4]arene Tetraacetate

Kriz J., Dybal J., Makrlik E., Vanura P.

Polish Journal of Chemistry

|

2007

|

Vol. 81, nr 7

1321-1326

EN

In addition to well-known complexes of tetraethyl p-tert-butylcalix[4]arene tetraacetate (abbrev. 1) with alkali metal cations, an equimolar complex of this compound with H3O+, i.e. 1źH3O+, was found to be formed slowly in acetonitrile, however, with a very high equilibrium constant, the value ofwhich is beyond the possibilities of exact determination by NMR. Hydrogen bis(1,2-dicarbollyl) cobaltate (HDCC) was used as a proton source. Further, by a combination of 1D and 2D 1H NMR with 13C NMR spectra, it was proved that the ester carbonyls of 1 are not strongly involved in coordination of H3O+. It means that the most probable structure of the 1źH3O+ complex is obviously that with H3O+ bound by strong hydrogen bonds to the phenoxy oxygen atoms of 1.

7

Spectroscopic 1H NMR, 13C NMR and Theoretical DFT Study of Isoguanine and 8-Oxoadenine in Water and DMSO-d6 Solutions

Dybiec K., Gryff-Keller A.

Polish Journal of Chemistry

|

2006

|

Vol. 80, nr 11

1831-1843

EN

1Hand 13CNMRspectra of isoguanine (2-hydroxyadenine) and 8-oxoadenine inH2Oand DMSO-d6 solutions of various acidity have been interpreted using arguments based on the results of several 1D and 2D NMR experiments and theoretical DFT-based calculations. The collected data for H2O solutions can serve for identification of these compounds in body fluids during medical analysis. The 1H and 13C NMR spectra of the investigated compounds in DMSO-d6 solutions have provided information on their tautomeric forms and the mobility of their exchangeable protons.

8

The Pronotation Site in Aminophosp

Doskocz M., Miziak P., Gancarz R.

Polish Journal of Chemistry

|

2005

|

Vol. 79 / nr 3

547-552

EN

The protonation equilibria in aminophosphonates: protonation on nitrogen vs phosphoryl oxygen has been calculated. The calculated energy differences explain satisfactory experimentally observed tendency toward nonstability of aminophoshonates in acidic media.

9

Modyfikacja budowy i właściwości poliketanili - polimerów do zastosowań w optoelektronice

Iwan A., Sęk D.

Polimery

|

2005

|

T. 50, nr 7-8

581-586

PL

Otrzymano szereg różniących się budową chemiczną poliketanili [wzór (II)] stanowiących produkty polikondensacji diaminy z diketonem [równanie (1)]. Budowę tych polimerów, odznaczających się dobrą odpornością cieplną, scharakteryzowano metodami analizy elementarnej oraz spektroskopii 13C NMR, FT-IR i UV-VIS. Zbadano wpływ protonowania atomu azotu w ich wiązaniu ketiminowym za pomocą estru 1,2-(di-2-etyloheksylowego) kwasu 4-sulfoftalowego [DEHEPSA o wzorze (I)] (schemat B) na temperaturę zeszklenia (Tg) i właściwości fotoluminescencyjne poliketanili. Stwierdzono, że w wyniku protonowania centrów iminowych zachodzą zmiany w delokalizacji elektronów p w łańcuchu poliketanilowym, co przyczynia się do batochromowego przesunięcia pasm zarówno absorpcyjnych, jak i emisyjnych. Ponadto, zastosowany czynnik protonujący wykazuje właściwości plastyfikujące, co przejawia się znacznym obniżeniem wartości Tg. Określono również wywołane oddziaływaniem polimeru z rozpuszczalnikiem aprotonowym (dimetyloacetamidem) lub protonowym (m-krezolem, schemat A) przesunięcie maksimum pasma emisji. Podano interpretację mechanizmu oddziaływania tego drugiego rozpuszczalnika.

EN

Polyketanils [Formula (II)] being the products of polycondensation of diamines with diketones [equation (1)] and differing in chemical structure have been obtained. The structures of these polymers, showing good thermal stability (Fig. 1), were characterized using elemental analysis, 13C NMR, FT-IR and UV-VIS methods. Effects of ketimine bond nitrogen atom protonation with 1,2-(di-2-ethylhexyl) ester of 4-sulfophthalic acid [DEHEPSA, Formula (I)] (Scheme B) on glass transition temperature (Tg, Fig. 2) and photoluminescence properties (Fig. 3) of polyketanils were investigated. It was found that changes in delocalization of p-electrons in polyketanil chain occur as a result of imino centers' protonation. This contributes to bathochromic shifts of both absorption and emission bands. Additionally, the protonating agent used shows plastifying properties resulting in significant decrease in Tg. Shift of maximum emission band, caused by interaction of polymer with aprotic solvent (dimethylacetamide) or protogenic one (m-cresol, Scheme A), has been also determined along with interpretation of the mechanism of the latter solvent interaction.

10

Creatinine and Creatininium Cation in Water Solution. Tautomerism and Quantitative Interpretation of the Solution Acidity Effect on 1H, 13C and 14 N NMR Chemical Shifts

Kotsyubynskyy D., Molchanov S., Gryff-Keller A.

Polish Journal of Chemistry

|

2004

|

Vol. 78 / nr 2

239-248

EN

1H, 13C and 14N NMR chemical shifts for creatinine in water solutions of various acidity have been measured. Analysis of these data enabled determination of the acidity constant of creatininium cation and the chemical shifts of the neutral and protonated forms of creatinine. Molecular energies and carbon and nitrogen magnetic shielding constants for various tautomeric structures of the investigated species have been calculated using the quantum chemistry method GIAO DFT B3LYP/6-311++G(2d,p). Compilation of the available experimental and theoretical results has provided additional information on the problem of tautomerism of this important biological molecule.

11

Badanie wpływu protonowania na właściwości poliketanili

Iwan A., Sęk D., Fryczkowski R.

Prace Naukowe Instytutu Technologii Organicznej i Tworzyw Sztucznych Politechniki Wrocławskiej. Konferencje

|

2003

|

Vol. 52, nr 25

350-353

PL

Poliketanile zawierające w łańcuchu głównym grupy iminowe, będące produktami polikondensacji diketonów i diamin mogą być domieszkowane zarówno kwasami Lewisa jak i protonowymi. W prowadzonej pracy jako dopant zastosowano 1,2-(di-2-etyloheksylo)ester kwasu 4-sulfoftalowego (DEHEPSA). Związek ten dzięki swojej budowie spełnia podwójną rolę: -protonuje azot grupy iminowej oraz działa plastyfikująco co ułatwia przetwórstwo polimerów. Celem niniejszej pracy było określenie wpływu protonowania (domieszkowania) na właściwości poliketanili, zarówno termiczne jak i spektroskopowe.

EN

New polyketanils have been synthesized from diamines and diketones by melt condensation polymerization (180C, 24 hours). Physical properties of these polymers can be conveniently tuned either by an appropriate design of the repeat sub-unit originating from the diamine or by protonation of imine nitrogen with a protonating agent exhibiting plasticizing properties, for example with 1,2-(di-2-ethylhexyl)ester of 4-sulfophthalic acid (DEHEPSA). In the base (non-protonated) from the synthesized polymers emit either blue radiation or green radiation depending on the mutual presence of conjugated and saturated chain segments. Protonation with DEHEPSA transforms blue radiation emitters into the green radiation ones. Simultaneously it results in a large decrease of the polymer glass transition (Tg) from the values exceeding 373K to the values close to room temperatures, improving by consequence the flexibility of the polymers.

12

Właściwości porfiryn i ftalocjanin

Makarska M., Polska K., Gerasymchuk Y.S., Radzki S.

LAB Laboratoria, Aparatura, Badania

|

2003

|

R. 8, nr 4

6-12

PL

W artykule omówiono budowę pierścienia porfirynowego i jego analogu - pierścienia ftalocjaninowego. Omówiono najważniejsze reakcje tych makrocykli: protonowania, kompleksowania metali, aglomeracji, przyłączania podstawników oraz redukcji i utleniania.

13

Hyperpolarizalities of pyridine derivatives and their protonated species: ab initio studies

Latajka Z., Gajewski G., Ratajczak H., Venturini J.

Bulletin of the Polish Academy of Sciences. Chemistry

|

2003

|

Vol. 51, No. 1

1-4

EN

The first hyperpolarizability values of pyridine derivatives and their proto-nated species have been calculated using ab intio (STO-3G) method. The effect of proto-nation on these values is discussed.

14

Acid-Catalyzed Cleavage of Some Chromone, Coumarin and Pyrone Derivaties of Aminomethylphosphonic Acid. Products and Kinetics of the ReactionB

Boduszek B., Latajka R., Walkowiak U.

Polish Journal of Chemistry

|

2001

|

Vol. 75, nr 1

63-69

EN

Treatment of chromone-2, coumarin-4 and pyrone-2 derivatives of N-benzylaminomethylphosphonic acid with strong mineral acids leads to formation of the corresponding heterocyclic amines and phosphoric acid. Kinetic studies of this cleavage reaction demonstrate that protonation has a remarkable influence on a cleavage of C-P bonds. In aq. H2SO4, cleavage of the acids 1-3 exhibits a kinetic dependence on [H+]. The measured solvent isotope effect (kH/kD) was about 1.5 for the 1 and 2 and only 1.1 for the 3. The existence of the isotope effect shows that protons are involved on the rate-determining step. The data obtained suggest that the protonated phosphonate molecule is split by a dissociative mechanism with A-SE2 character and this is combined with an elimination of the phosphonate group as a positive-charged phosphorus moiety.