01747nas a2200169 4500008004100000022001400041245009800055210006900153260007100222300001400293490000700307520107100314100002201385700002601407700001601433856012801449 2008 eng d a0022-326300aIntramolecular Diels-Alder reaction in ionic liquids: effect of ion-specific solvent friction0 aIntramolecular DielsAlder reaction in ionic liquids effect of io a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcNOV a9075-90830 v733 a

The present work aims at understanding the role of viscosity or solvent friction in ionic liquids for an intramolecular Diels-Alder (IMDA) reaction of (E)-1-phenyl-4-[2-(3-methyl-2-butenyloxy)benzylidene]-5-pyrazolone (1). The results have been analyzed on the basis of the current theoretical models, and their failure to account for the observed trends is discussed in terms of ``effective'' viscosity or microviscosity. The rates of the reaction decrease with the increasing viscosity of the ionic liquids. As evident from the anionic effect, the solute-solvent specific interactions play a role in governing the kinetics of the reaction. The lower viscosities of the bistrifluoromethanesulfonimide [NTf(2)](-) based ionic liquids as compared to those based on tetrafluoroborate [BF(4)](-) anion fail to result in a corresponding acceleration in the rates of the reaction. These contradictory results indicate that solvent microviscosity, rather than the bulk macroscopic viscosity, should be the criteria for selecting the ionic liquids as reaction media.

1 aTiwari, Shraeddha1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/intramolecular-diels-alder-reaction-ionic-liquids-effect-ion-specific-solvent-friction-001800nas a2200205 4500008004100000022001400041245009300055210006900148260007500217300001200292490000700304520104700311653001801358653002301376653001801399653001401417100002601431700001601457856012101473 2009 eng d a0095-978200aDramatic change in viscosities of pure ionic liquids upon addition of molecular solvents0 aDramatic change in viscosities of pure ionic liquids upon additi a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScMAY a589-6000 v383 a

Viscosities of binary mixtures of pyridinium based ionic liquids (1-butyl pyridinium tetrafluoroborate, [BP][BF(4)], 1-butyl 3-methyl pyridinium tetrafluoroborate [3-MBP][BF(4)], 1-butyl 4-methyl pyridinium tetrafluoroborate, [4-MBP][BF(4)]), and phosphonium based ionic liquids, (tetrabutyl phosphonium alaninate, [TBP][Ala]; tetrabutyl phosphonium valinate, [TBP][Val]) with the molecular solvents, water, methanol and dichloromethane, have been measured at 298.15 K. A Brookfield ultra-rheometer was employed to measure the reported viscosities. The drop in viscosity in the close vicinity of pure ionic liquid is more prominent in polar solvents like water compared to less polar solvents. The temperature dependence of this observation was also studied for binary mixtures of [4-MBP][BF(4)] with water in range of 298.15-323.15 K. The Vogel-Fulcher-Tamman (VFT) equation was employed to investigate the temperature dependence of the viscosities of pure pyridinium-based ionic liquids in the temperature range from 298.15-323.15 K.

10aionic liquids10aMolecular solvents10aVFT equations10aviscosity1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/dramatic-change-viscosities-pure-ionic-liquids-upon-addition-molecular-solvents-001633nas a2200157 4500008004100000022001400041245011200055210006900167260007100236300001200307490000800319520097800327100002601305700001601331856012801347 2010 eng d a1520-610600aContrasting thermosolvatochromic trends in pyridinium-, pyrrolidinium-, and phosphonium-based ionic liquids0 aContrasting thermosolvatochromic trends in pyridinium pyrrolidin a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJAN a376-3810 v1143 a

Thermosolvatochromism has been studied in three series of ionic liquids, pyridinium-based 1-butylpyridinium, 1-hexylpyridinium, and 1-octylpyridinium with bis(trifluoromethylsulfonyl)imide [NTf2] and tetrafluoroborate [BF4] anions, pyrrolidinium-based ionic liquids 1-methyl-1-butylpyrrolidium, 1-methyl-1-hexylpyrrolidium, 1-methyl-1-octylpyrrolidium with bis(trifluoromethylsulfonyl) imide anion and phosphonium-based ionic liquids tetrabutylphosphonium with alanate and valinate anions. The effect of increase in alkyl chain length and temperature on normalized polarity E-T(N), Kanilet-Taft parameters, hydrogen bond donor ability (alpha), hydrogen bond acceptor ability (beta), and polarizability (pi*) was investigated in the temperature range of 298-353 K. Interestingly, the polarity decreases with temperature in the case of pyridinium- and pyrrolidinium-based ionic liquids, and it increases with temperature in the case of phosphonium-based ionic liquids.

1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/contrasting-thermosolvatochromic-trends-pyridinium-pyrrolidinium-and-phosphonium-based-001162nas a2200229 4500008004100000022001400041245005600055210005500111260011000166300001200276490000700288520037100295653002300666653002800689653001800717653003100735653002300766653001400789100002600803700001600829856008700845 2010 eng d a0376-471000aIonic liquids: new materials with wide applications0 aIonic liquids new materials with wide applications aDR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIAbNATL INST SCIENCE COMMUNICATION-NISCAIRcMAY a635-6480 v493 a

Ionic liquids have emerged as possible substitutes for volatile organic solvents and have found many applications in a variety of research areas. In this review, an effort has been made to discuss the special properties of ionic liquids that render these unique solvent media useful in chemical transformations, electrochemical applications, extractions, etc.

10aChemical processes10aElectrochemical devices10aionic liquids10aPhysicochemical properties10aSolvent properties10aviscosity1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/ionic-liquids-new-materials-wide-applications-001465nas a2200193 4500008004100000022001400041245006600055210006300121260007500184300000900259490000700268520081400275653001801089653001201107653001401119100002601133700001601159856009601175 2010 eng d a0369-820300aSolvent-induced viscosity changes in ionic liquids - a review0 aSolventinduced viscosity changes in ionic liquids a review a5 LAJPATRAI RD, ALLAHABAD 211002, INDIAbNATL ACAD SCIENCES INDIAcJAN a1-120 v803 a

The high viscosity of several ionic liquids is an undesirable property for their applications in a variety of chemical reactions and electrochemical devices. Addition of a solvent in an ionic liquid is known to reduce its high viscosity to a great extent. In this review, an attempt has been made to examine the published data on the reduction in viscosities of many ionic liquids upon the addition of molecular solvents, including water. A tentative description has been provided for the drop in viscosities under these conditions. Analysis of the viscosity data with the help of empirical equations has been summarized. This critical review also outlines the future outlook of the required studies that might be useful to those who are interested in using ionic liquids for a variety of applications.

10aionic liquids10asolvent10aviscosity1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/solvent-induced-viscosity-changes-ionic-liquids-review-001197nas a2200193 4500008004100000022001400041245009100055210006900146260011000215300001200325490000700337520043900344653001800783653001400801100002600815700002700841700001600868856011900884 2010 eng d a0376-471000aTemperature dependent viscosity of mixtures of ionic liquids at different compositions0 aTemperature dependent viscosity of mixtures of ionic liquids at  aDR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIAbNATL INST SCIENCE COMMUNICATION-NISCAIRcMAY a727-7300 v493 a

This work presents experimental investigations of viscosities of the mixtures of ionic liquids, viz., [bmim][BF(4)] + [bmim][PF(6)] and [hmim][BF(4)] + [hmim][PF(6)] at different temperatures. The temperature dependence of viscosities of these mixtures has been analysed in the light of Vogel-Fulcher-Tammann (VFT) equation with excellent accuracy. The viscosities of the mixtures have been analysed using a simple mixing rule.

10aionic liquids10aviscosity1 aKhupse, Nageshwar, D.1 aKurolikar, Shabana, R.1 aKumar, Anil uhttps://library.ncl.res.in/content/temperature-dependent-viscosity-mixtures-ionic-liquids-different-compositions-001751nas a2200157 4500008004100000022001400041245006100055210005900116260007100175300001600246490000800262520118600270100002601456700001601482856009501498 2011 eng d a1089-563900aCosolvent-directed diels-alder reaction in ionic liquids0 aCosolventdirected dielsalder reaction in ionic liquids a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP a10211-102170 v1153 a

The rate constants of a bimolecular Diels-Alder reaction in binary mixtures of ionic liquids prepared in molecular solvents were analyzed to investigate the effect of viscosity of the medium and solvent effect. In this connection, we have carried out the Diels-Alder reaction of anthracene 9-carbinol with N-ethyl maleimide in binary mixtures of pyridinium-based ionic liquids, 1-butyl-pyridinium tetrafluoroborate, 1-buty1-3-pyridinium tetrafluoroborate, and 1-butyl-4-methyl pyridinium tetrafluoroborate in water, methanol, and chloroform at 298.15 K. The rates of reaction decreased, caused by gradually increasing the volume fraction of ionic liquids in solvents for all three ionic liquids. The kinetic results demonstrate a successful application of the pairwise interaction model built upon the concept of enforced hydrophobic hydration. A temperature-dependent study of kinetics of the Diels-Alder reaction was carried out in the binary mixtures of ionic liquids in water and was explained by the entropy-enthalpy compensation effect based upon activation parameters. Kinetics of the Diels-Alder reaction in highly aqueous medium was noted to be entropically driven.

1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/cosolvent-directed-diels-alder-reaction-ionic-liquids-001878nas a2200157 4500008004100000022001400041245013800055210006900193260007100262300001200333490000800345520119500353100002601548700001601574856013001590 2011 eng d a1520-610600aDelineating solute-solvent interactions in binary mixtures of ionic liquids in molecular solvents and preferential solvation approach0 aDelineating solutesolvent interactions in binary mixtures of ion a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB a711-7180 v1153 a

The effect of solute-solvent and solvent-solvent interactions on the preferential solvation of solvatochromic indicators in binary mixtures of ionic liquids with molecular solvents has been investigated. The binary mixtures of the pyridinium-based ionic liquids 1-butylpyridinium tetrafluoroborate ([BP][BF4]), 1-butyl-3-methylpyridinium tetrafluoroborate ([3-MBP][BF4]), and 1-butyl-4-methylpyridinium tetrafluoroborate ([4-MBP][BF4]) with molecular solvents like water, methanol, and dichloromethane have been selected for this investigation. The effect of addition of ionic liquids to molecular solvents on the polarity parameters E-T(N), Kamlet-Taft parameters, hydrogen bond donor ability (HBD) (alpha), hydrogen bond acceptor ability (HBA) (beta), and polarizability (pi*) was obtained. The polarity parameters of the mixture display nonideality on addition of ionic liquids to water and dichloromethane. On the other hand, strong synergetic effects were seen in the ionic liquid-methanol binary mixtures. The preferential solvation models have been employed to analyze the collected data in order to achieve information on solute-solvent interactions in these binary mixtures.

1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/delineating-solute-solvent-interactions-binary-mixtures-ionic-liquids-molecular-solvents-001862nas a2200169 4500008004100000022001400041245006200055210006100117260011000178300001400288490000700302520122500309100002501534700002601559700001601585856009101601 2012 eng d a1463-907600aDo anions influence the polarity of protic ionic liquids?0 aDo anions influence the polarity of protic ionic liquids aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcDEC a2754-27610 v143 a

Polarity studies in two classes of imidazolium-based protic ionic liquids (PILs) possessing [HSO4](-), [HCOO](-),[CH3COO](-) and [CH3CH2COO](-) anions were carried out using a solvatochromic method from 298.15 to 353.15 K. For 1-methylimidazolium class of PILs, ET(30) was found to be independent over the entire range of temperature, while ET(30) was noted to decrease with a rise in temperature in the case of 1-butylimidazolium class of PILs containing [CH3COO](-) and [CH3CH2COO](-) anions. The ET(30) value decreases in both the classes upon varying the anions ([HSO4](-), [HCOO](-), [CH3COO](-) and [CH3CH2COO](-)). The E-T(30) value is controlled by hydrogen bond acceptor basicity, b, and dipolarity/polarizability, pi*. The E-T(30) value for PILs varies inversely to the strength of the coulombic interaction between ions in PILs. Strong interactions between ions lead to lower E-T(30) values. Unlike the poor thermal effect on E-T(30), the Kamlet-Taft parameters i.e. alpha, beta and pi* have pronounced thermal effect in the imidazolium-based PILs. Variation in the Kamlet-Taft parameters is controlled by the stabilization of ions and the degree of proton transfer from Bronsted acid to Bronsted base.

1 aShukla, Shashi, Kant1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/do-anions-influence-polarity-protic-ionic-liquids-001783nas a2200169 4500008004100000022001400041245006400055210006300119260011000182300001200292490000700304520114000311100002201451700002601473700001601499856009801515 2015 eng d a1463-907600aSolvent-mediated molar conductivity of protic ionic liquids0 aSolventmediated molar conductivity of protic ionic liquids aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcNOV a475-4820 v173 a

The molar conductivity, A(m), of protic ionic liquids (PILs) in molecular solvents is measured at 298.15 K. The decrease in the A(m) values of PILs is observed with an increase in the concentration of PILs. The limiting molar conductivities, A(m)(0), were obtained for each PIL in different molecular solvents using a least squares method. The A(m)(0) data for PILs were correlated with the structural aspects of PILs and solvent properties. The polar protic solvents show poor ionic association as compared to the polar aprotic solvents, which is discussed on the basis of the hydrogen bond donating (HBD) ability of solvents and PILs. The alkyl chain substitution of anions plays a significant role in the ionic association of the PILs. The diffusion coefficient D-0 and the transport number t were determined, which were consistent with the A(m)(0) values of PILs in water. The A(m)(0) and D-0 values are dependent on the hydrodynamic radius of anions of these ionic liquids. The extent of ionic association for each PIL was discussed using temperature dependent A(m) data for aqueous PIL systems in terms of the Walden plot.

1 aThawarkar, Sachin1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/solvent-mediated-molar-conductivity-protic-ionic-liquids-002007nas a2200229 4500008004100000022001400041245014800055210006900203260007500272300001400347490000700361520110400368653002501472653002101497653003101518653001401549653001801563100002201581700002601603700001601629856013201645 2016 eng d a1439-423500aComparative investigation of the ionicity of aprotic and protic ionic liquids in molecular solvents by using conductometry and NMR spectroscopy0 aComparative investigation of the ionicity of aprotic and protic  aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcAPR a1006-10170 v173 a

Electrical conductivity (sigma), viscosity (), and self-diffusion coefficient (D) measurements of binary mixtures of aprotic and protic imidazolium-based ionic liquids with water, dimethyl sulfoxide, and ethylene glycol were measured from 293.15 to 323.15K. The temperature dependence study reveals typical Arrhenius behavior. The ionicities of aprotic ionic liquids were observed to be higher than those of protic ionic liquids in these solvents. The aprotic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, [bmIm][BF4], displays 100% ionicity in both water and ethylene glycol. The protic ionic liquids in both water and ethylene glycol are classed as good ionic candidates, whereas in DMSO they are classed as having a poor ionic nature. The solvation dynamics of the ionic species of the ionic liquids are illustrated on the basis of the (HNMR)-H-1 chemical shifts of the ionic liquids. The self-diffusion coefficients D of the cation and anion of [HmIm][CH3COO] in D2O and in [D-6]DMSO are determined by using H-1 nuclei with pulsed field gradient spin-echo NMR spectroscopy.

10aconducting materials10aElectrochemistry10aelectrostatic interactions10aIon pairs10aionic liquids1 aThawarkar, Sachin1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/comparative-investigation-ionicity-aprotic-and-protic-ionic-liquids-molecular-solvents-using01310nas a2200193 4500008004100000245015700041210006900198260000800267300001400275490000600289520055900295100002400854700001900878700001900897700002400916700002600940700001900966856013100985 2016 eng d00aESP promoted "on water" click reaction: a highly economic and sustainable protocol for 1,4-disubstituted-1H-1,2,3-triazole synthesis at room temperature0 aESP promoted on water click reaction a highly economic and susta cNOV a6016-60190 v13 aA highly economic and green protocol for azide-alkyne cyclo-addition reactions in water has been developed which offers a mild, practical and inexpensive basic alternative to the conventional protocols. The protocol uses readily available, considered as waste material, Egg Shell Powder (ESP) as an additive for CuAAC reaction. The reactions proceeded in water in presence of this basic waste material derived additive under 'external base/ligand/reducing agent/organic solvent' free conditions affording good to excellent yields of the desired products.1 aKonwar, Manashjyoti1 aAli, Abdul, A.1 aChetia, Mitali1 aSaikia, Prakash, J.1 aKhupse, Nageshwar, D.1 aSarma, Diganta uhttps://library.ncl.res.in/content/esp-promoted-water-click-reaction-highly-economic-and-sustainable-protocol-14-disubstituted01863nas a2200157 4500008004100000245015100041210006900192260000800261300001400269490000600283520122300289100002601512700002601538700001601564856012501580 2017 eng d00aKinetic profile and catalytic activity of transition metal-based ionic liquids for reduction of nitroarenes via in situ formation of nanoparticles0 aKinetic profile and catalytic activity of transition metalbased  cAUG a6833-68430 v23 a

The experimentally determined apparent rate constant (k(app)) shows that the [BmIm](2)[PdCl4] and [BmIm](2)[NiCl4] act as effective catalysts for the reduction of nitroarenes to aminoarenes in the presence of NaBH4. The TEM, XPS, XRD and dynamic light scattering studies show that there is in situ formation of Pd and Ni metal Nanoparticles (NPs) from the reduction of [BmIm](2)[PdCl4] and [BmIm](2)[NiCl4], respectively which are responsible for the enhancement in the catalytic activity. Thus, in the presence of the ionic liquid stabilized metal NPs show higher catalytic activity in comparison to the NPs stabilized with other capping agents as reported. The order of k(app) as 1) PNP > 2-BrPNP > 2-APNP and 2) PNP > ONP > 2-NR for reduction of nitroarenes using [BmIm](2)[PdCl4] and [BmIm](2)[NiCl4] and its correlation explained on the basis of electronic structure and hydrogen bonding ability of nitroarenes. The thermodynamic parameters such as E-a, Delta H-#, Delta S-# and Delta G(#) are in agreement with the surface catalyzed reduction reaction of PNP in the presence of NPs as catalyst. The kapp values illustrated the reduction reaction follow the LangmuirHinshelwood (L-H) mechanism.

1 aThawarkar, Sachin, R.1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/kinetic-profile-and-catalytic-activity-transition-metal-based-ionic-liquids-reduction02383nas a2200157 4500008004100000245009200041210006900133260000800202300001600210490000700226520180500233100002202038700001902060700002602079856012002105 2017 eng d00a Plasmonic behavior of ionic liquid stabilized gold nanoparticles in molecular solvents0 aPlasmonic behavior of ionic liquid stabilized gold nanoparticles cNOV a12989-129950 v413 aIn this paper, we have demonstrated the facile synthesis of stable gold nanoparticles (AuNPs) using imidazolium ionic liquids (ImILs) as a stabilizer as well as a surfactant and their surface plasmon resonance (SPR) in different molecular solvents with varying dielectric properties. The preparation of AuNPs capped with N,N'-dialkyl ImILs of different chain lengths (denoted as [C-4, C-n-im]Br, n = carbon number of the alkyl chain) has been investigated. With one long alkyl chain (n >= 14), these AuNPs could be stably dispersed in solution over a month. The amphiphilic nature of the imidazolium salt dictates the stability and dispersion of these AuNPs in organic or aqueous solvents. Alkyl chain lengths (n >= 14) and the amount of ImILs have insignificant effect on the size of AuNPs and they possess an average size of 5 nm. These ionic liquid stabilized AuNPs were exploited to examine their optical properties when exposed to various solvent systems by measuring the change in the SPR spectrum. It was seen that the position of the SPR band of AuNPs is greatly influenced by the solvents under consideration. The shift in the SPR absorption band is observed to be in the range of 520 nm to 605 nm for AuNP@[C-4,C-16-im]Br from nonpolar to highly polar solvents. The considerable discovery presented here is that the lambda(SPR) of the SPR shifts to the blue with the increase of carbon atom in the alcohol chain from methanol to 1-decanol. Also for polyethylene glycols (PEGs), the lambda(SPR) shifts to the blue with the increase in molecular weight from PEG 200 to PEG 600. In above both cases, the variation in SPR of AuNPs is observed according to the dielectric properties of the medium in addition to the steric factor of alcohols and PEGs during their interaction with AuNP surfaces.1 aThawarkar, Sachin1 aThombare, Balu1 aKhupse, Nageshwar, D. uhttps://library.ncl.res.in/content/plasmonic-behavior-ionic-liquid-stabilized-gold-nanoparticles-molecular-solvents01751nas a2200229 4500008004100000022001400041245012000055210006900175260000800244300001200252490000700264520096000271653001901231653001701250653001301267653002701280653002201307100002201329700002601351700001601377856012801393 2020 eng d a0095-978200aBinary mixtures of aprotic and protic ionic liquids demonstrate synergistic polarity effect: an unusual observation0 aBinary mixtures of aprotic and protic ionic liquids demonstrate  cFEB a210-2210 v493 a

In this communication, we demonstrate the solute-solvent and solvent-solvent interactions in the binary mixtures of two aprotic ionic liquids, namely 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, with the protic ionic liquid 1-methylimidazolium acetate. The synergistic effects as expressed by the solvatochromic parameter are noted. This observation is in contrast to the mixing of protic ionic liquids 1-methylpyrrolidium acetate and 4-methylmorpholine acetate with 1-methylimidazolium acetate, respectively. It appears that the synergistic effects in the binary mixtures of aprotic and protic ionic liquids are caused by the formation of hydrogen bonds, since cations are dominant H-bond donors while anions are dominant H-bond acceptors. Preferential solvation models are used to describe the solute-solvent interactions in the binary ionic liquid mixtures.

10abinary mixture10aIonic liquid10apolarity10aPreferential solvation10asynergetic effect1 aThawarkar, Sachin1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/binary-mixtures-aprotic-and-protic-ionic-liquids-demonstrate-synergistic-polarity-effect