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Mushtaq, I., Mushtaq, I., Akhter, Z., Murtaza, I., Qamar, S., Ayub, S., . . . Zaman, F. (2020). Engineering electroactive and biocompatible tetra(aniline)-based terpolymers with tunable intrinsic antioxidant properties in vivo. Materials science & engineering. C, biomimetic materials, sensors and systems, 108, Article ID 110456.
Open this publication in new window or tab >>Engineering electroactive and biocompatible tetra(aniline)-based terpolymers with tunable intrinsic antioxidant properties in vivo
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2020 (English)In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 108, article id 110456Article in journal (Refereed) Published
Abstract [en]

Under different pathological conditions, high levels of reactive oxygen species (ROS) cause substantial damage to multiple organs. To counter these ROS levels in multiple organs, we have engineered highly potent novel terpolymers. We found that combination of FDA-approved polyethylene glycol, fumaric acid moieties and electroactive tetra(aniline) by varying the content of tetra(aniline) results into a novel drug composition with biologically active tunable intrinsic antioxidant properties. To test tunable intrinsic antioxidative properties of these engineered novel terpolymers, we used alloxan to induce diabetes in rats where ROS generation is known to be higher. The systemic administration of terpolymers to the diabetic rats showed strong electroactive antioxidant behavior which normalized ROS levels, enzymatic antioxidants including superoxide dismutase, catalase, but also reduced glutathione. As a proof-of-principle, we here show TANI based novel drug composition of terpolymers with tunable intrinsic antioxidant effects confirmed in multiple organs.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Tetra(aniline), Electroactive terpolymers, Thermal stability, Antioxidant, Biocompatible, Diabetes
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-76829 (URN)10.1016/j.msec.2019.110456 (DOI)2-s2.0-85075739838 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-12-09 (johcin)

Available from: 2019-11-23 Created: 2019-11-23 Last updated: 2019-12-10Bibliographically approved
Filippov, A., Bhattacharyya, S. & Shah, F. U. (2019). CO2 absorption and ion mobility in aqueous choline-based ionic liquids. Journal of Molecular Liquids, 276, 748-752
Open this publication in new window or tab >>CO2 absorption and ion mobility in aqueous choline-based ionic liquids
2019 (English)In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 276, p. 748-752Article in journal (Refereed) Published
Abstract [en]

CO2 absorption and ion mobility are investigated in a series of 50/50 wt% aqueous solutions of choline-based ionic liquids with different cations and anions: [N1,1,4,2OH][Threo], [N1,1,5,2OH][Threo], [N1,1,6,2OH][Threo], [N1,1,5,2OH][β-ala] and [N1,1,5,2OH][Tau]. The process of CO2 absorption was completed in an hour reaching maximum of absorption capacity 0.07–0.10 wt% to ionic liquid (by 0.4–0.6 molar ratios). A rapid CO2 absorption is observed by the formation of solid product as a result of reaction between CO2 molecule and the ionic liquid. Diffusion coefficients of the cation and anion in the mixture are comparable while the diffusivity of water molecules is found to be quite different from the ions. In the process of CO2 absorption, an increase in the diffusivity of ions is observed due to the precipitation of solid products and depletion of ions contents in the liquid phase of the system. 13C NMR measurements of diffusivity of CO2 enriched with 13C isotope showed that a part of the absorbed CO2 remained in the liquid phase being physically and chemically bound to ions. The ionic liquid is re-cycled by evaporating water and releasing CO2 molecules using vacuum and temperature.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Ionic liquids, CO2 absorption, Nuclear magnetic resonance, Diffusivity of ions, Phase transformations
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-72056 (URN)10.1016/j.molliq.2018.12.045 (DOI)000459528600083 ()2-s2.0-85058405735 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-01-03 (svasva)

Available from: 2018-12-16 Created: 2018-12-16 Last updated: 2019-04-12Bibliographically approved
Nazir, U., Akhter, Z., Naveed Zafar, A. & Shah, F. U. (2019). Experimental and theoretical insights into the corrosion inhibition activity of novel Schiff bases for aluminum alloy in acidic medium. RSC Advances, 9(62), 36455-36470
Open this publication in new window or tab >>Experimental and theoretical insights into the corrosion inhibition activity of novel Schiff bases for aluminum alloy in acidic medium
2019 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 62, p. 36455-36470Article in journal (Refereed) Published
Abstract [en]

Three novel Schiff bases, namely N-(4-((4-((phenylimino)methyl)phenoxy)methoxy)benzylidene)benzenamine (UA), N-(3-methoxy-4-((2-methoxy-4-((phenylimino)methyl)phenoxy)methoxy)benzylidene)benzenamine (UB), and N-(3-ethyl-4-((2-ethyl-4-((phenylimino)methyl)phenoxy)methoxy)benzylidene)benzenamine (UC), were synthesized and their structures were elucidated through diverse spectroscopic techniques such as FT-IR, GC-MS, 1H NMR and 13C NMR. The corrosion inhibition effect of these Schiff bases on aluminum alloy AA2219-T6 in acidic medium was explored using weight loss, Tafel polarization, and electrochemical impedance spectroscopy. Theoretical quantum chemical calculations using density functional theory were employed to determine the adsorption site. It was found that inhibition efficiencies increase with an increase in the inhibitor concentration. Tafel plots showed that these Schiff bases function as mixed inhibitors. Adsorption of the Schiff bases on aluminum followed the Langmuir adsorption isotherm and the value of  showed a dominant chemical mechanism. FT-IR and SEM techniques were used to investigate the surface morphology. The compounds showed a substantial corrosion inhibition for aluminum alloy in 0.1 M HCl at 298 K. UB and UC exhibited superior anticorrosion efficiency compared to UA originating from the electron-donating methoxy and ethoxy group substitutions, respectively. There was found to be good correlation between molecular structure and inhibition efficiencies.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-76679 (URN)10.1039/c9ra07105a (DOI)2-s2.0-85074967548 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-11-15 (johcin)

Available from: 2019-11-11 Created: 2019-11-11 Last updated: 2019-11-27Bibliographically approved
An, R., Wu, M., Li, J., Qiu, X., Shah, F. U. & Li, J. (2019). On the Ionic Liquid Film ‘Pinned’ by Core-Shell Structured Fe3O4@Carbon Nanoparticles and Their Tribological Properties. Physical Chemistry, Chemical Physics - PCCP
Open this publication in new window or tab >>On the Ionic Liquid Film ‘Pinned’ by Core-Shell Structured Fe3O4@Carbon Nanoparticles and Their Tribological Properties
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2019 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084Article in journal (Refereed) Epub ahead of print
Abstract [en]

A strongly ‘pinned’ ionic liquid (IL, [BMIM][PF6]) film onto silicon (Si) surface via carbon capsuled Fe3O4 core-shell (Fe3O4@C) nanoparticles is achieved, revealing excellent friction-reducing ability at a high load. The adhesion force is measured as ~ 198 nN at the Fe3O4@C-Si interface by Fe3O4@C colloidal AFM tip, which is stronger than that at both Fe3O4@C-Fe3O4@C (~ 60 nN) and IL-Si (~ 10 nN) interfaces, indicating a strong ‘normal pin-force’ towards the Si substrate. The resulting strengthened force enables the formation of lateral IL networks via the dipole-dipole attractions among Fe3O4 cores. The observed blue shift of the characteristic band related to the IL anion in ATR-FTIR spectra confirmed the enhanced interaction. The N-Si, P-O chemical bonds formed as a result of the IL interactions with the Si substrate confirmed by XPS spectroscopy suggested that the IL lay on the Si plane. This orientation is favorable for Fe3O4@C nanoparticles to exert ‘normal pin-force’ and press the IL film strongly onto surfaces. The IL ios/clusters are thus anchored by these Fe3O4@C ‘pins’ onto the substrate to form a dense film, resulting in a smaller interaction size parameter, which is responsible for the reduced friction coefficient μ.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-76830 (URN)10.1039/C9CP05905A (DOI)
Available from: 2019-11-23 Created: 2019-11-23 Last updated: 2019-12-10
Filippov, A., Antzutkin, O. & Shah, F. U. (2019). Rapid carbene formation increasing ion diffusivity in an imidazolium acetate ionic liquid confined between polar glass plates. Physical Chemistry, Chemical Physics - PCCP, 21(40), 22531-22538
Open this publication in new window or tab >>Rapid carbene formation increasing ion diffusivity in an imidazolium acetate ionic liquid confined between polar glass plates
2019 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 21, no 40, p. 22531-22538Article in journal (Refereed) Published
Abstract [en]

1-Ethyl-3-methyl-imidazolium acetate ([EMIM][OAc]) is one of the most widely used ionic liquids for various applications. This study is focussed on the chemical stability of [EMIM][OAc] on the surfaces of polar glass plates. 1H and 13C NMR spectroscopy and NMR diffusometry of [EMIM][OAc] IL confined between glass plates with a specific surface area 105–106 m−1 are thoroughly investigated. A rapid and spontaneous reaction took place on the surfaces of glass plates leading to the formation of neutral chemical moieties as evident by the appearance of new signals in the 1H NMR spectra. These new products are assigned as N-heterocyclic carbene (NHC) and acetic acid. These neutral chemical moieties have significantly increased the ion diffusivity by dissociation of the cation and the anion in [EMIM][OAc] IL. The yield and rate of formation of NHC and acetic acid are found to increase with the increasing surface area of polar glass plates and the time of contact between the IL and glass surfaces. Based on NMR spectroscopy, a dissociative reaction mechanism is proposed for the formation of free NHC in the neat [EMIM][OAc] IL.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Natural Sciences Chemical Sciences Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-76117 (URN)10.1039/C9CP04504J (DOI)31588443 (PubMedID)2-s2.0-85073483050 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-10-25 (johcin)

Available from: 2019-09-25 Created: 2019-09-25 Last updated: 2019-11-04Bibliographically approved
Filippov, A., Antzutkin, O. & Shah, F. U. (2019). Reactivity of CO2 with aqueous choline-based ionic liquids probed by solid-state NMR spectroscopy. Journal of Molecular Liquids, 286, Article ID 110918.
Open this publication in new window or tab >>Reactivity of CO2 with aqueous choline-based ionic liquids probed by solid-state NMR spectroscopy
2019 (English)In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 286, article id 110918Article in journal (Refereed) Published
Abstract [en]

CO2 absorption in a series of choline-based ionic liquids is investigated using solid-state 13C and 15N MAS NMR spectroscopy. Natural abundance and 13C enriched CO2 gas was purged through 50 wt% aqueous solutions of alkyldimethyl(2-hydroxyethyl)ammonium threonine, [N1,1,n,2OH][Threo], (alkyl = butyl, pentyl and hexyl) and pentyldimethyl(2-hydroxyethyl)ammonium taurine [N1,1,5,2OH][Tau]. The process of CO2 absorption results in precipitation of a solid sediment, which stays in equilibrium with the liquid phase. Upon degassing of the sample, the sediment is dissolved back into the IL-aqueous phase. Solid state 13C and 15N MAS NMR data suggest that the solid sediment is composed of neutral threonine (or taurine) in the zwitterionic forms and the liquid phase contained the products of reactions between the ionic liquids and CO2 molecules. A plausible mechanism for formation of the solid sediments and the reaction products in liquid phases is suggested.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
CO2 absorption, Aqueous choline-based ionic liquids, Liquid-solid equilibrium, 13C and 15N MAS, CP-MAS NMR
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-73873 (URN)10.1016/j.molliq.2019.110918 (DOI)000474308400033 ()2-s2.0-85065237523 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-14 (johcin)

Available from: 2019-05-07 Created: 2019-05-07 Last updated: 2019-08-16Bibliographically approved
Hafeez, A., Akhter, Z., Gallagher, J. F., Khan, N. A., Gul, A. & Shah, F. U. (2019). Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines. Polymers, 11(9), Article ID 1498.
Open this publication in new window or tab >>Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines
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2019 (English)In: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, no 9, article id 1498Article in journal (Refereed) Published
Abstract [en]

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
Polyazomethines, single crystals, bis-aldehydes, spectroscopic characterization, conductivity, poly(Schiff base)s
National Category
Polymer Chemistry Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-75995 (URN)10.3390/polym11091498 (DOI)000489104300123 ()31540265 (PubMedID)2-s2.0-85072514470 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-09-18 (johcin)

Available from: 2019-09-13 Created: 2019-09-13 Last updated: 2019-10-29Bibliographically approved
Mushtaq, I., Akhter, Z. & Shah, F. U. (2019). Tunable Self-Assembled Nanostructures of Electroactive PEGylated Tetra(Aniline) Based ABA Triblock Structures in Aqueous Medium. Frontiers in Chemistry, 7, 1-10, Article ID 518.
Open this publication in new window or tab >>Tunable Self-Assembled Nanostructures of Electroactive PEGylated Tetra(Aniline) Based ABA Triblock Structures in Aqueous Medium
2019 (English)In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, p. 1-10, article id 518Article in journal (Refereed) Published
Abstract [en]

PEGylated tetra(aniline) ABA triblock structure PEG-TANI-PEG (2) consisting of tetra(aniline) (TANI) and polyethylene glycol (PEG) was synthesized by coupling the tosylated-PEG to boc-protected NH2/NH2 TANI (1) through a simple nucleophilic substitution reaction. Deprotection of 2 resulted in a leucoemeraldine base state of TANI (2-LEB), which was oxidized to stable emeraldine base (2-EB) state. 2-EB was doped with 1 M HCl to emeraldine salt (2-ES) state. FTIR, 1H and 13C NMR and UV-Vis-NIR spectroscopy, and MS (ESI) was used for structural characterization. The synthesized triblock structure exhibited good electroactivity as confirmed by CV and UV-Vis-NIR spectroscopy. Self-assembling of the triblock structure in aqueous medium was assessed by DLS, TEM, and SEM. Spherical aggregates were observed with variable sizes depicting the effect of concentration and oxidation of 2-LEB. Further, the aggregates showed acid/base sensitivity as evaluated by doping and dedoping of 2-EB with 1 M HCl and 1 M NH4OH, respectively. Future applications in drug delivery and sensors are envisaged for such tunable self-assembled nanostructures in aqueous media.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
triblock nanostructures, PEGylation, redox activity, aqueous self-assembly, tunable self-assembled structures
National Category
Polymer Chemistry Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-75367 (URN)10.3389/fchem.2019.00518 (DOI)000477062400001 ()31403042 (PubMedID)2-s2.0-85072212160 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-06 (johcin)

Available from: 2019-07-29 Created: 2019-07-29 Last updated: 2019-09-23Bibliographically approved
Kim, I., Karlsson, O., Antzutkin, O., Shah, F. U., Jones, D. & Sandberg, D. (2019). Wood modification with maleic anhydride and sodium hypophosphite. In: Proceedings of the 20th International Symposium on Wood, Fiber and Pulping Chemistry, ISWFPC20, September 9-11, 2019, Tokyo, Japan, 4 pp.: . Paper presented at Proceedings of the 20th International Symposium on Wood, Fiber and Pulping Chemistry, ISWFPC20, September 9-11, 2019, Tokyo, Japan, 4 pp. (pp. 1-4). Tokyo: The University of Tokyo
Open this publication in new window or tab >>Wood modification with maleic anhydride and sodium hypophosphite
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2019 (English)In: Proceedings of the 20th International Symposium on Wood, Fiber and Pulping Chemistry, ISWFPC20, September 9-11, 2019, Tokyo, Japan, 4 pp., Tokyo: The University of Tokyo , 2019, p. 1-4Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Tokyo: The University of Tokyo, 2019
National Category
Wood Science
Identifiers
urn:nbn:se:ltu:diva-76121 (URN)
Conference
Proceedings of the 20th International Symposium on Wood, Fiber and Pulping Chemistry, ISWFPC20, September 9-11, 2019, Tokyo, Japan, 4 pp.
Available from: 2019-09-26 Created: 2019-09-26 Last updated: 2019-10-22
Filippov, A., Azancheev, N., Gibaydullin, A., Bhattacharyya, S., Antzutkin, O. N. & Shah, F. U. (2018). Dynamic Properties of Imidazolium Orthoborate Ionic Liquids Mixed with Polyethylene Glycol Studied by NMR Diffusometry and Impedance Spectroscopy. Magnetic Resonance in Chemistry, 56(2), 113-119
Open this publication in new window or tab >>Dynamic Properties of Imidazolium Orthoborate Ionic Liquids Mixed with Polyethylene Glycol Studied by NMR Diffusometry and Impedance Spectroscopy
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2018 (English)In: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 56, no 2, p. 113-119Article in journal (Refereed) Published
Abstract [en]

We used 1H pulsed field gradient (PFG) NMR to study the self-diffusion of polyethylene glycol (PEG) with average molecular mass of 200 and ions in mixtures of PEG with imidazolium bis(mandelato)borate (BMB) and imidazolium bis(oxalato)borate (BOB) ionic liquids (ILs). The ionic liquid was mixed with PEG in the concentration range of 0–100 wt%. Within the temperature range of 295 to 353 K, the diffusion coefficient of BMB is slower than that of the imidazolium cation. The diffusion coefficients of PEG, as well as the imidazolium cation and BMB anions, differ under all experimental conditions tested. This demonstrates that the IL in the mixture is present in at least a partially dissociated state. Generally, increasing the concentration of PEG leads to an increase in the diffusion coefficients of PEG and both the ions, and decreases their activation energy for diffusion. NMR chemical shift alteration analysis showed that the presence of PEG changes the chemical shifts of both ions but in different directions. Impedance spectroscopy was used to measure the ionic conductivity of the ionic liquids mixed with PEG.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Chemical Sciences Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-64929 (URN)10.1002/mrc.4636 (DOI)000419519200009 ()28752526 (PubMedID)2-s2.0-85040248332 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-01-09 (svasva)

Available from: 2017-07-31 Created: 2017-07-31 Last updated: 2018-12-14Bibliographically approved
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