Publication Date: 2003
Tetrahedron (14645416)59(41)pp. 8213-8218
Epoxides can be cleaved in a regio- and stereoselective manner under neutral conditions with alcohols and acetic acid in the presence of catalytic amounts of decatungstocerate(IV) ion, ([CeW10O36] 8-), affording the corresponding β-alkoxy and β-acetoxy alcohols in high yields. In water, ring opening of epoxides occurs with this catalyst to produce the corresponding diols in good yields. © 2003 Elsevier Ltd. All rights reserved.
Publication Date: 2000
Journal of Chemical Research - Part S (13645560)(11)pp. 515-517
Alkens are transformed to their corresponding epoxides in high yields and with high selectivity by ultrasonic irradiation and sodium periodate in the presence of catalytic amounts of manganese porphyrin supported on Amberlite IRA-400 ion-exchange resin (MnTPPS-Ad).
Publication Date: 2022
Applied Organometallic Chemistry (02682605)36(7)
Platinum-based drugs are an essential class of chemotherapy drugs in breast cancer. However, suffer from side effects and drug resistance; structural changes and applying drug carriers can lead to new drug candidates in this class. The metal-organic frameworks (MOFs) as porous carriers have recently attracted much attention in drug delivery. In this study, for the first time, hyaluronic acid (HA)-targeted MOF (NH2-MIL-101 (Fe)) nanoparticles (Pt-CUR@MIL@HA NPs) were evaluated in delivery of platinum-curcumin (Pt-CUR) prodrug to the MDA-MB-231 triple-negative breast cancer cell line; in this regard, the cytotoxicity, ROS production, and cellular uptake of designed NPs have been studied. Different analysis methods confirmed chemical structures, the prepared NPs had a uniform morphology, and the hydrodynamic size of the optimized non-targeted loaded particles increased to about 252 nm with a zeta potential of +26.9 mV, after targeting with HA, the size increased to 310 nm, and the zeta potential changed to −28 mV. Based on TGA and atomic absorption (ICP-MS) results, the drug loading percent was determined to be about 30%–35%. Drug release from the HA targeted Pt-CUR@MIL@HA system in the neutral condition was slow and sustained, and after 36 h, a maximum of 60% of the drug was released, but in acidic conditions, the release was increased, and by 18 h, the release was about 80%. The cytotoxicity of MOF NPs containing Pt-CUR was more significant than that of the free drug, and HA targeted has resulted in more cellular uptake than the non-targeted NPs. In conclusion, these new MOF- based HA-coated NPs of PT-CUR can be introduced to pre-clinical researches after completing in vitro and in vivo studies. © 2022 John Wiley & Sons Ltd.
Publication Date: 2018
Journal of Molecular Liquids (18733166)254pp. 137-144
The paper seeks to immobilize Candida rugosa lipase (CRL) on Chromium terephthalate MIL-101 (MIL-101(Cr)) and its three chemically modified forms: amino MIL-101(Cr) (NH2-MIL), trichlorotriazine amino MIL-101(Cr) (TCT@NH2-MIL) and glutaraldehyde amino MIL-101(Cr) (Glu@NH2-MIL). The synthesis process of these metal organic frameworks, CRL immobilization and the morphology of supports were verified using FTIR, PXRD, BET and FE-SEM techniques. The enzyme loading and the specific activity at different initial concentration of lipase for all the supports were measured and the obtained results were compared. The highest specific activity at any given point in the common range of enzyme loading belongs to CRL@Glu@NH2-MIL. While all the immobilized CRLs show no significant drop in residual activity after pH stress, the thermal stability is just substantially improved for CRL@TCT@NH2-MIL and CRL@Glu@NH2-MIL. About 80–90% of the initial enzymatic activity retained after 35 days for all of the supports indicating a significant storage stability of the immobilized CRLs. © 2018
Publication Date: 2020
Journal of Physics Condensed Matter (09538984)32(46)
Structural and optical properties of methylammonium iron iodide perovskite CH3NH3FeI3 are studied at DFT-PBE(mBJ)/FP-LAPW + lo level of theory to assess feasibility of the replacement of the toxic lead with the non-toxic iron in the perovskite layer of solar cells. Starting from experimental crystal structure of the Pb perovskite, volume and aspect ratio (c/a) and atomic positions are optimized for the CH3NH3FeI3 structure, and its electronic and optical characteristics are calculated. An index, measuring the raw optical performance of the light harvesting layer of a solar cell is introduced and calculated for the two Fe and Pb perovskites. Comparative values of this index shows that the iron perovskite CH3NH3FeI3 has an acceptable optical performance, ∼61% that of the Pb perovskite CH3NH3PbI3. Analysis of the Brewster angles (θ B) calculated for the TiO2/perovskite and perovskite/spiro interfaces shows that the Fe perovskite solar cell can have better optical harvesting performance by a factor of 1.32, which improves its comparative overall performance up to 80%. As a conclusion, application of iron perovskite CH3NH3FeI3 is promising, especially due to its much lower costs and significantly alleviated environmental hazards of the incorporating solar cells. © 2020 IOP Publishing Ltd.
Publication Date: 2020
Journal of Photochemistry and Photobiology A: Chemistry (18732666)389
Photooxidation of various 2-pyrazolines is studied experimentally and computationally. Experimental results show that the electron-donating/withdrawing substituents increases/decreases the rate of this photoreaction. The proposed light-induced electron-transfer mechanism explains the steric and electronic effects of the substituents, co-planarity of the aryl rings substitutions, orientations of the C3-aryl ring towards the C3=N2 double bond and the solvent on the irradiation time for completion of reaction. Computational (TD)B3LYP/6-311++G(d,p) results, including frontier orbital energies, UV–vis transitions, electrostatic potential, CHELPG charges, are used to find and describe tunneling electron-transfer process and its associated structural relaxations which form the rate-determining step of the reaction, and to justify the effect of substitutions on the rate of reaction. The intermediate complex formed after the first electron transfer proceeds the proton transfer step only in its triplet state. Triplet excited states of 2-pyrazolines may have little contribution to the electron transfer step. Cyclic voltammetric measurements support the photochemical results. © 2019 Elsevier B.V.
Publication Date: 2018
Journal of Molecular Structure (00222860)1173pp. 903-917
A series of aryl substituted 1-phenyl-2-pyrazolines containing electron-donating and electron-withdrawing substituents on different positions of the C3– or C5-aryl groups were synthesized and their steric and electronic effects on characteristic spectral data were investigated by experimental spectroscopic methods (UV–Vis, IR and NMR) and DFT computations. Whereas the C5-aryl group of the heterocyclic ring behaves as σ-donor/acceptor substituent, the π-donor/acceptor ability of the C3-aryl group depends on the co-planarity of the substituent with the aryl ring and also the extent of the orientation of this C3-aryl ring towards the C[dbnd]N double bond of the heterocyclic ring. A significant through conjugation of the lone pair on the N1-atom towards the C3-aryl ring is observed when the electron-withdrawing nitro group is located on the para-position of this aryl ring. The experimental spectroscopic results for the substitution effects are also supported by (TD)DFT/6-311++G(d,p) computed UV–Vis spectra. Experimental and theoretical NMR chemical shifts and spin-spin coupling constants obtained for these 2-pyrazolines validated by Karplus diagram approves the structures predicted for these compounds. © 2018 Elsevier B.V.
Publication Date: 2014
Match (03406253)72(2)pp. 359-373
An asymmetry index (AI) is introduced to measure deviation of the electron density distribution in a molecule from any given symmetry. This AI is calculated by summing all point-wise differences between electron density distributions before and after symmetry operation. A minimum asymmetry index (MAI) rule is also introduced to evaluate uniquely the extent of asymmetry of a molecule with respect to any reference symmetry operation. This MAI rule prescribes where to locate the reference element of symmetry. The overall MAI for a given molecule with respect to a certain symmetry point group is calculated by averaging over AIs of all symmetry elements appearing in its character table. The proposed AI and the MAI rule are used to measure electron density asymmetry of the NX3, NX2Y/NXY2 and NXYZ (X, Y, Z = H, F, Cl, Br) series of molecules referenced to the C3V symmetry.
Publication Date: 2012
Physical Review A - Atomic, Molecular, and Optical Physics (10502947)85(3)
The mechanism of the formation of doorway quasistates (transient species) prior to the start of ionization of the two-electron molecular H 2 system subjected to an eight-cycle ultrashort intense laser pulse is investigated by solving exactly the one-dimensional (1D) electronic time-dependent Schrödinger equation, including nuclear motion semiclassically. Space of the electron density of the two-electron 1D H 2 system around the nuclei is partitioned into four physicochemically significant partitions, including homolytic (e 1Hα+- Hβ+e 2)∼(e 2Hα+-Hβ+e 1) and ionic (Hα+-Hβ-)∼(Hα - Hβ+) transient species. The underlying mechanisms responsible for the formation and evolution of the homolytic and ionic transient species are explored based on probing variation of the two-electron norms of these states and their corresponding time-dependent high-order harmonic generation spectra. © 2012 American Physical Society.
Publication Date: 2011
Fluid Phase Equilibria (03783812)301(1)pp. 73-79
Configurational-biased Gibbs ensemble Monte Carlo simulations were performed to obtain the phase behavior of the homologous series of primary alcohols from ethanol to 1-heptanol. Molecular interactions in these systems are modeled by a newly developed exp-6 potential in combination with a Coulombic intermolecular potential. Some of exp-6 potential parameters required to describe these alcohols were taken from the previous literature data reported for methanol and n-alkanes. The oxygen's potential parameters were optimized to fit the coexistence curve of these alcohols to the experimental data. Simulated values of saturated liquid and vapor densities, vapor pressures and critical constants of the alcohols are in good agreement with experimental data. The efficiency of the new model in the prediction of binary phase diagram of water/ethanol and n-hexane/1-propanol mixtures is also evaluated. The calculated mole fractions in the vapor and liquid phases of these binary mixtures also show satisfactory agreement with the experimental data. © 2010 Elsevier B.V.
Publication Date: 2008
Chemical Physics (03010104)352(1-3)pp. 297-305
Contributions of the vibrational motions to the NMR shielding constants are calculated and studied theoretically for the isolated H2, HF and H2O molecules in the gas phase. Intramolecular potential energy surfaces (PES) and their corresponding wave functions have been calculated using B3LYP/6-311++G** method. Shielding constant surfaces for the 1H, 17O and 19F nuclei in these molecules have been calculated over their PES's using CSGT method. Distribution of the shielding constants and their corresponding averages are calculated for each vibrational state. Combination effects of the populated vibrational levels (and different vibrational modes in the case of H2O molecule) to the NMR shielding constants are also evaluated. From the results obtained for H2O, it can be concluded that for polyatomic molecules different vibrational modes may have opposite effects on the nuclear shielding constants and thus may partially cancel vibrational contributions to shielding constants. The zero-point vibrational contributions to the NMR shielding constant of the nuclei of the HF and H2O molecules calculated via our approach are comparable with those reported by Ruud et al. [K. Ruud, P.-O. Åstrand, P.R. Taylor, J. Chem. Phys. 112 (2000) 2668, K. Ruud, P.-O. Åstrand, P.R. Taylor, J. Am. Chem. Soc. 123 (2001) 4826]. © 2008 Elsevier B.V. All rights reserved.
Publication Date: 2023
Colloids and Surfaces A: Physicochemical and Engineering Aspects (18734359)677
Conjugation via covalent bonding on nanocarriers is an effective strategy to stabilize drugs and prodrugs, improve their efficiency and decrease their side effects. In this study, temozolomide (TMZ) is used as a prodrug and stabilized via covalent conjugation on folic acid−targeted−gold−thiol modified surface, and then, the physicochemical behavior of the integrated system towards cancer cells is studied by surface techniques, votammetric methods, electrochemical impedance spectroscopy (EIS), and quartz crystal microbalance (QCM). The voltammetric and ATR−FTIR studies revealed that the conjugated TMZ is stable at least for 48 h. The adsorption behavior of A2780 cancer cells onto the system is well described by Freundlich adsorption isotherm with adsorption capacity of 50.11 and adsorption intensity of 1/n = 0.15. The process is controlled by a first order kinetic model with rate constant of 0.036 ± 0.002 min−1 and t1/2 of 18 ± 1 min. To our knowledge, this is the first time that the physicochemical behavior of the TMZ prodrug integrated onto Au−thiol SAM nanostructures is studied by EIS and QCM concerning cancer cells. The results of this research are noteworthy and can improve our physicochemical insights into anticancer drugs in conjunction with gold targeted nanocarriers, regarding the stability of prodrugs, mixed molecular nanostructures, adsorption kinetics and isotherms for sensing and capture of cancer cells. © 2023
Publication Date: 2016
Electrochimica Acta (00134686)187pp. 646-654
Comparative electrochemical behavior of three types of proteins; cytochrome c (Cyt c), Agaricus Bisporus laccase (LacAB) and glucose oxidase (GOx) immobilized on gold mercaptopropionic acid self-assembled monolayer via three different methods, including (a) covalent attachment by using EDC/NHS organic activators, (b) electrostatic interactions, and (c) covalent-coordinate binding by using Zr(IV) ion glue is investigated. Immobilization steps and electrochemical behavior of the immobilized proteins are traced by means of cyclic and differential pulse voltammetry (CV and DPV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The results indicate that characteristics of the immobilized systems including; surface coverage, electrocatalytic activity and stability of the proteins are considerably affected by type of the bond formed between electrode and protein (the immobilization method), and nature of the protein. Immobilization via Zr(IV) ion resulted in higher activities for metalloproteins, i.e. Cytc with Heme active center and LacAB with T copper active center, while EDC/NHS method was more efficient for GOx having FAD cofactor. The experimental data will be presented and discussed from which the efficient immobilizing method for each case is introduced. © 2015 Elsevier Ltd. All rights reserved.
Publication Date: 2008
Electrochimica Acta (00134686)53(22)pp. 6293-6303
A new, simple, and easy method for introducing hydroxamic acid group onto the surface of polycrystalline gold electrode by means of in-situ layer-by-layer functionalization is described. The fabrication was performed in a four-step method: (i) modification of gold by cysteamine self-assembled monolayer, Au-CA SAM, (ii) activation of nitrilotriacetic acid (NTA) by 1-ethyl-3(3- (dimethylamino)propyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS), (iii) immobilization of activated NTA onto Au-CA to form Au-CA-NTA, and (iv) conversion of the remaining activated carboxylic acid groups of Au-CA-NTA (terminals) to hydroxamic acid groups by using hydroxylamine hydrochloride (HAH) to form Au-CA-NDHA modified electrode. The resulting modified electrode was successfully tested for accumulation of zirconium ion (Zr(IV)) from an aqueous acidic solution. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements were used to trace the events in each step, characterize the surface, determine the surface pKas, and find the affinity of the prepared electrode towards the Zr(IV). Surface pKas equal to 6.5 and 5.5 were estimated for Au-CA-NTA, and Au-CA-NDHA SAM electrodes, respectively. These values allowed estimating the charge-state of the surface at any pHs. The modified surface showed a large affinity for selective accumulation of Zr(IV) from acidic solution. © 2008 Elsevier Ltd. All rights reserved.
Publication Date: 2006
Analytica Chimica Acta (00032670)562(2)pp. 223-228
A phosphate functionalized cysteamine self-assembled monolayer based on gold electrode is designed for uranyl ion (UO22+) detection. The response of the modified electrode is studied by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The EIS data are approximated using constant phase element (CPE) model from which kinetic and analytical parameters are evaluated. Uranyl ion is recognized based on blocking effect against charge transfer between p-benzoquinone as a probe and the modified electrode. This effect is detected from linear variation of charge transfer resistance (Rct) as a function of UO2 2+ concentration. From the analysis of the EIS data and approximated parameters, a method is developed for UO22+ determination based on impedimetric measurements. © 2006 Elsevier B.V. All rights reserved.
Publication Date: 2025
Physical Chemistry Chemical Physics (14639084)27(30)pp. 15895-15905
Femtosecond transient absorption experiments and ab initio and nonadiabatic dynamics (NAD) simulations have helped to explicate the photophysical dynamics of two ubiquitous members of the flavonoid family, astragalin and kaempferol. Differences between their excited state deactivation mechanisms have been observed and explained. Astragalin exhibits an ultrashort (∼10 ps) S1 lifetime, whereas that of kaempferol extends approximately twice as long (∼20 ps), explained by the systems’ relative access to a S1/S0 conical intersection following excited state intramolecular proton transfer. These findings expound the unexpected role played by sugar substituents in photoprotective flavonoids and justify the use of similar natural derivatives for UV photothermal materials. © 2025 The Royal Society of Chemistry.
Publication Date: 2014
Physical Chemistry Chemical Physics (14639084)16(23)pp. 11679-11689
The potential energy profiles of neutral and protonated anisole and p-fluoroanisole at different electronic states have been investigated extensively by the RI-MP2 and RI-CC2 methods. The calculations reveal that the relaxation dynamics in protonated anisole and p-fluoroanisole are essentially different from those of the neutral analogues. In neutral anisole/p- fluoroanisole, the 1πσ* state plays a vital relaxation role along the O-CH3 coordinate, yielding the CH3 radical. For both of these molecules, the calculations indicate conical intersections (CIs) between the ground and excited state potential energy (PE) curves, hindered by a small barrier, and providing non-adiabatic gates for radiation-less deactivation to the ground state. Nevertheless, for the protonated cases, besides the prefulvenic deformation of the benzene ring, it has been predicted that the lowest 1(σ,n)π* state along the C-O-C bond angle plays an important role in photochemistry and the relaxation dynamics. The S1, S0 PE profiles of protonated anisole along with the former reaction coordinate (out-of-plane deformation) show a barrierless relaxation pathway, which can be responsible for the ultrafast deactivation of excited systems to the ground state via the low-lying S1/S0 conical intersection. Moreover, the later reaction coordinate in protonated species (C-O-C angle from 120°-180°) is consequently accompanied with the bond cleavage of C-OCH3 at the 1(σ,n)π* state, hindered by a barrier of ∼0.51 eV, and can be responsible for the relaxation of excited systems with significant excess energy (hν ≥ 5 eV). Furthermore, according to the RI-CC2 calculated results, different effects on the S1-S0 electronic transition energy of anisole and p-fluoroanisole upon protonation have been predicted. The first electronic transitions of anisole and p-fluoroanisole shift by ∼0.3 and 1.3 eV to the red respectively due to protonation. © 2014 the Partner Organisations.
Publication Date: 2009
Optics Communications (00304018)282(23)pp. 4552-4555
In this work, temporal evolution of two-photon laser optogalvanic signals of neon has been studied. Optogalvanic signals for four transitions from the metastable 2p53s[3/2]2 state to 2p54d′[3/2]1, 2p54d′[3/2]2, 2p54d′[5/2]3 and 2p54d′[5/2]2 states were recorded over a range of discharge currents (3.4-9 mA). It was found that the shape of the optogalvanic signal was strongly dependent on the discharge current so that its peak shifted to shorter times and its amplitude increased with the discharge current. The decay rates of the 4d states, calculated from the optogalvanic signals, were found to increase linearly with the discharge current in the range of 6.2-9 mA. However, for the range of 3.4-5.4 mA, the decay rates were observed to slightly decrease with the discharge current. © 2009 Elsevier B.V. All rights reserved.
Publication Date: 2020
Solar RRL (2367198X)4(12)
Low-cost carbon-based perovskite solar cells (C-PSCs) without a hole transport layer (HTL) and metal contact are highly promising for marketing. However, lower efficiency than conventional PSCs and instability during the penetration of moisture through the porous carbon electrode as well as the incoming of ultraviolet (UV) light from the glass side of the device remain challenges. Herein, a multifunctional triple-layer system containing TiO2/SiO2/CeO2 porous nanomaterials is numerically simulated and experimentally used on the glass side of HTL-free C-PSCs. This strategy is designed to increase cell efficiency by enhancing the antireflective feature and long-term stability via the UV light blocking and superhydrophobic properties introduced to the surface. Furthermore, this system is durable against environmental pollutants due to the photocatalytic self-cleaning effect of TiO2. A superhydrophobic carbon back contact is also used to sandwich the perovskite active layer between two superhydrophobic surfaces and further the humidity resilience of the device. The device with polydimethylsiloxane (PDMS)–TiO2/SiO2/CeO2/glass/meso-TiO2/MAPbI3/superhydrophobic-carbon configuration shows an efficiency of 16.60% among the HTL-free C-PSCs and superior long-term stability (maintaining 98.5% of the initial efficiency without encapsulation) against UV light and relative humidity of 90% at 50 °C. © 2020 Wiley-VCH GmbH
Publication Date: 2018
International Journal of Refrigeration (01407007)86pp. 139-153
In this work an equation of state which was previously given for the hard convex body chain molecules was modeled to n-alkanes and refrigerants. The equation of state parameters and the application ranges of density and temperature were determined through fitting with the experimental data. It was found that the collision diameter and the nonspherical geometry parameter are temperature dependent and the relations were also given for their temperature dependencies. The compressibility factor, the reduced bulk modulus and the reduced isobaric expansion coefficient were calculated using the obtained parameters and compared with their experimental values. It was shown that the errors in the properties prediction are within experimental uncertainty. The results show that the equation of state is applicable for alkanes and refrigerants in both subcritical and supercritical region, but the error increases a little in the region away from the critical point. © 2017 Elsevier Ltd and IIR
Publication Date: 2022
Journal of Molecular Structure (00222860)1257
A novel oxo–peroxo tungsten(VI) Schiff base complex, [WO(O2)L(CH3OH)], a homogeneous catalyst for sulfoxidation was synthesized by treating WO3 in the presence of H2O2 with a dibasic tridentate (ONO) Schiff base ligand. The complex was characterized by FT–IR, 1H NMR, and 13C NMR spectroscopy. Moreover, the structure of the crystalline tungsten(VI) complex was further investigated by single crystal X-ray diffraction analysis (SC-XRD). The crystal structure analysis revealed that the complex is hepta-coordinated, and metal ion is surrounded by ONO set of the coordinated doubly deprotonated ligand to adopt a distorted pentagonal–bipyramidal geometry. The theoratical calculations of the geometrical parameters, frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP), and natural bond orbital (NBO) analysis of the synthesized compounds utilizing DFT at the B3LYP level of theory at the Def2-TZVP basis set revealed that the predicted data match the experimental results. The main purpose of the current study is to employ the synthesized W complex for its homogeneous catalytic effectiveness for the oxidation of aryl and alkyl sulfides in ethanol by using 30% aqueous H2O2. © 2022
Publication Date: 2025
Advances in Colloid and Interface Science (0001-8686)344
Biopolymers are known as environmental materials with massive applications in various fields. Among biopolymers, polysaccharides are bioactive, renewable, bioresorbable, biocompatible, biodegradable, and hydrophilic. These brilliant properties have made them promising materials for use in emerging technologies. Three-dimensional (3D) printing of these green materials has extensive applications in clinical usage, novel electronic devices, developed resin and polymers, absorbents, etc. This review describes the recent development of employing polysaccharide-based nanomaterials in the construction of different bio-products by using extrusion, laser, inkjet 3D printing, and vat polymerization methods. The influence of incorporating nanoparticles (NPs) on the properties of the final 3D-printed composite comprising reinforcement effects, mechanical properties, viscosity, printability, shear-thinning property, biocompatibility, structural integrity, and interactions have been evaluated. This review helps researchers keep up with developments in polysaccharide-based 3D-printed composites, with the vision that NPs can potentially revolutionize the bioink issue in the future. © 2025 Elsevier B.V.
Publication Date: 2016
International Journal of Mass Spectrometry (13873806)396pp. 5-12
VX and its six other isomers which are potentially nerve agents with molecular weight of 267 were synthesized and their EI and CI MS spectra were studied. Although the major ions in the mass spectra for these isomers are similar, these chemicals could be distinguished based on some low abundance characteristic ions. Structures of fragments were assigned using EI-MS analysis of the deuterated analogs. Density functional theory was also applied to show preferred fragmentation pathways. This study is also focused on calculation of the electrophilicity index of VX and its structural isomers, in order to elucidate their reactive nature. © 2015 Elsevier B.V. All rights reserved.
Publication Date: 2018
Fluid Phase Equilibria (03783812)460pp. 135-145
To respond to the problems in experimental studies on the massive number of possible ionic liquids (ILs), the chemists and engineers try to develop the predictive models for different thermophysical properties of these compounds from the knowledge of their structures. In spite of monocationic ionic liquids (MILs), the available experimental data for multicationic ILs are scarce and often contradictory. In this work, simple group contribution methods (GCMs) were developed to estimate the density, surface tension and glass transition temperature of series of mono-, di-, and tri-cationic imidazolium-based ILs at ambient conditions. The studied ILs contain different anions and the number of carbon atoms in the alkyl chain of their cations vary from 2 to 12. The contribution of each of the structural groups in density and surface tension has been estimated based on the MILs with the lowest chain length i.e. MIL containing [C2mim]+ and also methyl and methylene groups based on the additivity of molar volumes and parachors. For glass transition temperature, the contributions proposed by Lazzus et al. for MILs (Thermochim. Acta 528 (2012) 38–44) were used. The results have been compared with the literature values where they exist. The proposed GCMs are easy to use and can extend to different mono- and multi-cationic ILs. Also, they can provide predictions of the property values for ILs which were never studied previously. The results showed that the method is successful in its predictions. The absolute average deviation, AAD%, for the density, surface tension and glass transition temperature of MILs are 0.31%, 2.48% and 0.56%, respectively. AAD% values of these properties for DILs are 0.71%, 5.37% and 3.07%, respectively. © 2017 Elsevier B.V.
Publication Date: 2021
Applied Physics A: Materials Science and Processing (14320630)127(1)
A multifunctional-aptamer (APT) nanoprobe, TOV6 APT-superparamagnetic iron oxide nanoparticle-carbon dots (APT-SPION-CDs), for fluorescence and magnetic resonance targeted imaging (FI/MRI) of human ovarian cancer cells (OVCAR-3) is introduced. The SPION-CDs were synthesized and conjugated with TOV6 APT recognizing the stress-induced phosphoprotein 1 (STIP1) overexpressed on OVCAR-3 cells. The capability of the nanoprobe as a contrast agent for MRI and simultaneously as a fluorescent probe for fluorescence microscopy was studied. TOV6 APTs were adsorbed on SPION-CDs and were confirmed with Fourier transform infrared spectrometer. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed higher cytotoxic effects for APT-SPION-CDs compared to SPION-CDs on STIP1-negative HeLa cells. But on OVCAR-3, as STIP1-positive cells, the cytotoxic effect was negligible. The fluorescence microscopic images confirmed that APT-SPION-CDs specifically targeted ovarian cancer cells due to the tumor-targeting effect of TOV6 APT. High spin–spin relaxivity value (r2 = 308.5 mM−1 s−1) and the signal enhancement in T2-weighted MRIs confirmed the capability of the nanoprobe as a T2-based contrast agent. In vitro cellular uptake and signal enhancement of this multimodal FI/MRI nanoprobe demonstrated the potential application of APT-SPION-CDs as a contrast agent for MRI and as a fluorescent probe for fluorescence microscopic imaging. © 2021, Springer-Verlag GmbH Germany, part of Springer Nature.
Publication Date: 2016
Journal Of The Iranian Chemical Society (1735207X)13(4)pp. 659-669
Cocaine, a powerful addictive stimulant drug, has a variety of adverse effects on the body, thus its sensitive detection is very important. Here, we report on a simple, label-free, and sensitive impedimetric sensor for determination of cocaine based on its affinity to form an inclusion complex with β-cyclodextrin (β-CD). First, we prepared nanostructured poly N-acetylaniline film via electropolymerization of its monomer on a glassy carbon electrode (PNAANI/GC), subsequently overoxidized it, and conjugated β-CD to the polymer backbone. The designed and synthesized nanostructured PNAANI film serves a dual function in the sensor: on one hand, it maintains a high effective surface area on a geometrically small electrode that significantly enhances the number of β-CD molecules immobilized on the electrode; on the other hand, it provides an upright-oriented β-CD conjugation to the polymer backbone, thus all the β-CD receptors are actively involved in responding to the target. Sensitivity of the sensor was further enhanced by preconcentration of cocaine on the modified electrode surface. We attributed the changes in the interfacial charge transfer resistance (R ct) of the electrode to cocaine concentration. Under optimized condition (pH 7.4, 5-min accumulation at an open circuit voltage), the sensor responded to cocaine concentration in the range of 100 nM-1.0 mM with a detection limit of 50 nM. Selectivity of the sensor for cocaine relative to some potential inferring compounds was also investigated, and the results were promising. The proposed approach exhibited an extended dynamic range, low detection limit, good sensitivity, and a desirable selectivity, which provides an efficient application prospect for on-field cocaine sensing. © 2015 Iranian Chemical Society.
