OCH CH Research Articles

Regioselective ring opening of [(perfluoroalkyl)methyl] oxiranes with N-nucleophiles

The reactions of ▪ with some primary and secondary aliphatic amines affording selective ring opening at C β are reported. The reactions with secondary amines HNR 1R 2 (R 1 = R 2 = Et; R 1 = Bu t, R 2 = CH 2CH 2O(CO)C(CH 3) CH 2; R 1 = Et, R 2 = CH 2CH 2OH; R 1 = R 2 = CH 2CH 2OH) gave the corresponding C 8F 17CH 2 CH(OH) CH 2 NR 1R 2 derivatives. For R 1 = Et, R 2 = CH 2CH 2OH; R 1 = R 2 = CH 2CH 2OH, the reactions proceed through the selective nucleophilic attack of the NH moiety with no evidence of reactivity of the OH group. The reactions with the primary amines, allylamine and n-hexamethylenediamine, gave different products depending on reaction conditions.

Cobalt hexafluoroacetylacetonate polyether adducts for thin films of cobalt oxides

The novel [Co(C 5F 6HO 2) 2 · 2H 2O · CH 3(OCH 2CH 2) 2OCH 3] and [Co(C 5F 6HO 2) 2 · 2H 2O · CH 3(OCH 2CH 2) 3OCH 3] low-melting adducts have been synthesized and characterized by elemental analysis, IR spectroscopy, mass spectra and TG–DTG thermal measurements. The former adduct is liquid at room temperature, whilst very mild heating of the latter results in a thermal stable liquid compound. Both adducts can easily be evaporated. Deposition experiments, in a low-pressure horizontal hot-wall reactor, on optical transparent SiO 2 substrates, using these precursors, result in CoO or Co 3O 4 films, depending on the deposition conditions. XRD measurements provide evidence that CoO and Co 3O 4 consist of cubic, highly oriented, (2 0 0) and (3 1 1) crystals, respectively. The mean crystallite sizes were evaluated from the XRD line broadening. Both optical spectra and resistivity measurements of Co 3O 4 films show that they are semi-conducting and their band-gap was determined from the optical induced transitions. The film cross section and the surface atomic composition were investigated by SEM and XPS analyses, respectively.

Effect of subcritical CO 2 on ionic conductivity of {Al[O(CH 2CH 2O) 8.7] ρ/(LiClO 4) z} n hybrid inorganic–organic networks

The aim of this work is to study the effect of CO 2 under pressure on hybrid inorganic–organic polymer electrolytes, by using broad band dielectric spectroscopy (BDS) in the frequency interval 40 Hz–10 MHz and in the temperature range of −80 to 120 °C. Eleven inorganic–organic hybrid materials of the ORMOCERs type, with general formula {Al[O(CH 2CH 2O) 8.7] ρ /(LiClO 4) z } n were treated by applying CO 2 at 293 K and 5 MPa. The results demonstrated that the CO 2 treatment generally depressed the conductivity of about one order of magnitude. The decreased conductivity in treated complexes is explained in terms of a smaller anion-trapping ability of the Al centers. Residual CO 2 molecules are likely to inhibit the interaction of the perchlorate anions with Al centers within the structure. Segmental motion of the polymer chains plays a crucial role in the conductivity of investigated samples, while the ion-hopping phenomenon is the most important charge transfer mechanism both in the pristine and CO 2 treated materials. Equivalent conductivity studies have elucidated the different ionic species present at various salt concentrations and gave insight about the role of CO 2 in modifying the transport properties of the samples.

Photochemical synthesis and spectroscopic characteristic of the first vinylsilane carbonyl complexes of tungsten(0)

A series of new vinylsilane complexes of the type [W(CO) 5(η 2-H 2C CHSiR 3)] ( 1a– e) and trans-[W(CO) 4(η 2-H 2C CHSiR 3) 2] ( 2a– e) (R = Me, OMe, OCH 2CH 2OMe, and Cl) have been synthesized photochemically and characterized by IR and 1H, 13C and 29Si NMR spectroscopy. The values of the coordination shifts of the vinylic protons and carbons, Δ δ = δ (free vinylsilane) − δ (coordinated vinylsilane), strongly suggest that trimethylvinylsilane ( a) is coordinated more loosely to the tungsten atom in compounds of type 1 and 2 than other vinylsilanes ( b– e). The strongest dπ–π* interaction takes place between the carbonyltungsten moiety and trichlorovinylsilane. Analysis of 13C NMR data of vinylsilane compounds revealed that the electron-donating methyl substituents and the electron-withdrawing chlorine substituents at the silicon atom cause opposite deviations from the ideal symmetrical η 2-coordination of vinylsilane to the tungsten atom. The bis(vinylsilane) complexes 2a– e are shown to exist in several isomeric forms, whose solution dynamics were investigated by variable-temperature 1H NMR studies.

On the permittivity and density of the systems {tetraglyme + ( n-nonane or n-dodecane)} at various temperatures

Relative permittivity and density on mixing from T = (288.15 to 328.15) K and atmospheric pressure have been measured over the whole composition range for {(CH 3O)(CH 2CH 2O) m CH 3 polyoxyethyleneglycol dimethyl ether with m = 4 (also called 2,5,8,11,14-pentaoxapentadecane or tetraglyme) + ( n-nonane or n-dodecane)}. Relative permittivity increments and excess molar volumes on mixing for the above systems have been calculated. The Redlich–Kister equation has been used to estimate the binary fitting parameters and standard deviations from the regression lines were calculated. The density and excess molar volumes were fitted as a function of the mole fraction and temperature to a polynomial equation. The temperature dependence of derived magnitudes, as isobaric thermal expansibility, α , ( ∂ V m E / ∂ T ) P , x were computed, due to its importance in the study of specific molecular interactions. Different mixing rules have been applied to predict the permittivity of these mixtures and the results indicate that the predictions are better when the volume change on mixing is incorporated in calculations. The work concludes with an interpretation of the sign of the permittivity increment and of the behaviour with temperature of that permittivity increment and of excess molar volume.

Photodegradation catalyst screening by combinatorial methodology

In this work, a combinatorial methodology was developed for photodegradation catalyst screening. A fluorescence imaging detection system was designed for high throughput analysis, 1,6-hexamethylenediamine was used as the probe molecule for catalyst testing. The photodegradation activity of catalysts was evaluated by 1,6-hexamethylenediamine consumption during the photodegradation reaction. The methodology could provide reliable results. We found that pure TiO 2, ZrO 2, Nb 2O 5, MoO 3, and WO 3 did not show much activity for 1,6-hexamethylenediamine photodegradation under visible light. TiO 2 catalysts doped with different metal ions were tested. When TiO 2 was doped with Ta 2O 5, Nb 2O 5, V 2O 5, MoO 3, or WO 3, higher activity for photodegradation was observed. The doping of La 3+, Ba 2+, and Br − to TiO 2 did not improve the catalytic activities. When doping TiO 2 with Mn 2+, Cl −, Al 3+, Cu 2+, Fe 3+, Na +, Mg 2+, Li +, F −, Co 2+, or K +, catalytic activity was lower than that of pure TiO 2. After elaborate catalysts screening, we discovered new catalysts, such as 50–70% TiO 2/0–20% WO 3/20–40% VO 2.5 and 20–30% TiO 2/30–50% MoO 3/40–60% VO 2.5 as well as 30% WO 3/20% ZrO 2/50% NbO 2.5 (synthesized from ZrCl 4, NbCl 5, and (NH 4) 5H 5[H 2(WO 4) 6]·H 2O in ethanol solution or suspension) and 60–70% WO 3/Nb 2O 5 (synthesized from WCl 6 and NbCl 5 in ethanol solution). We observed that the catalytic activity is sensitive to preparation methods and catalyst specific surface areas. When P123 (HO(CH 2CH 2O) 20(CH 2CH(CH 3)O) 70(CH 2CH 2O) 20H, designated EO 20PO 70EO 20) was used as template to synthesize mesoporous materials, the mesoporous catalysts showed higher activity than regular catalytic materials.

Theoretical investigation of para-substituted phenyl selenobenzoates

The structural and electronic properties of eight para- substituted phenyl selenobenzoates have been investigated theoretically by performing semi-empirical molecular orbital theory at the level of PM3 of theory. The substituents include: C(O)OCH 2CH 3, C(O)CH 3, F, Cl, CH 3, OCH 3 and N(CH 3) 2. The optimized structures, relative binding energies, atomic charges, position of HOMO and LUMO and the electrostatic potential of the molecules are obtained.

The interface between electrode and poly(ethylene oxide) electrolytes

Impedance spectroscopy has been used for characterization of the interface between an ideally polarizable electrode and poly(ethylene oxide) electrolytes containing lithium salts. The solvent contribution to the inner layer capacitance, C s, for CH 3O(CH 2CH 2O) n CH 3 for ( n = 4, 8, 10) and oxymethylene-linked poly(oxyethylene), PMEO was evaluated by subtracting the contribution of the metal ( C m) from the inner layer capacitance. The position of the maximum in the bell-shaped curves C s( σ) depends on the molecular mass of the solvent. The influence of the external electric field on the condition of the solvent molecules at the inner layer has been characterized by a dipolar capacitance as a function of effective charge density, C dip( σ*) for PEO( n = 4, 8, 10) and solid PMEO. Polyethers with shorter chain have been found to be more sensitive to the external electric field for a negative electrode charge, the slopes of the C dip( σ*) curves are changing in sequence: PEO( n = 4) > PEO( n = 8, n = 10) > PMEO.

Compatibility of lyotropic liquid crystals with viruses and mammalian cells that support the replication of viruses

We report a study that investigates the biocompatibility of materials that form lyotropic liquid crystals (LCs) with viruses and mammalian cells that support the replication of viruses. This study is focused on aqueous solutions of tetradecyldimethyl-amineoxide (C 14AO) and decanol (D), or disodium cromoglycate (DSCG; C 23H 14O 11Na 2), which can form optically birefringent, liquid crystalline phases. The influence of these materials on the ability of vesicular stomatitis virus (VSV) to infect human epitheloid cervical carcinoma (HeLa) cells was examined by two approaches. First, VSV was dispersed in aqueous C 14AO+D or DSCG, and then HeLa cells were inoculated by contacting the cells with the aqueous C 14AO+D or DSCG containing VSV. The infectivity of VSV to the HeLa cells was subsequently determined. Second, VSV was incubated in LC phases of either C 14AO+D or DSCG for 4 h, and the concentration (titer) of infectious virus in the LC was determined by dilution into cell culture medium and subsequent inoculation of HeLa cells. Using these approaches, we found that the LC containing C 14AO+D caused inactivation of virus as well as cell death. In contrast, we determined that VSV retained its infectivity in the presence of aqueous DSCG, and that greater than 74–82% of the HeLa cells survived contact with aqueous DSCG (depending on concentration of DSCG). Because VSV maintained its function (and we infer structure) in LCs formed from DSCG, we further explored the influence of the virus on the ordering of the LC. Whereas the LC formed from DSCG was uniformly aligned on surfaces prepared from self-assembled monolayers (SAMs) of HS(CH 2) 11(OCH 2CH 2) 4OH on obliquely deposited films of gold in the absence of VSV, the introduction of 10 7–10 8 infectious virus particles per milliliter caused the LC to assume a non-uniform orientation and a colorful appearance that was readily distinguished from the uniformly aligned LCs. Control experiments using cell lysates with equivalent protein concentrations but no virus did not perturb the uniform alignment of the LC.

Effect of subcritical CO 2 on the structural and electrical properties of ORMOCERS-APE systems based on Zr and Al

Two series of hybrid inorganic–organic polymer electrolytes of the organically modified ceramics as polymer electrolytes (ORMOCERS-APE) type with formulas {Al[O(CH 2CH 2O) 8.7] ρ /(LiClO 4) z } n (1.85 ≤ ρ ≤ 2.24, 0 ≤ z ≤ 1.06) and {Zr[O(CH 2CH 2O) 8.7] ρ /(LiClO 4) z } n (1.80 ≤ ρ ≤ 1.99, 0 ≤ z ≤ 0.90) were treated with CO 2 in subcritical conditions (293 K and 5 MPa). The effect of CO 2 on the samples was investigated by using ESEM, thermal analysis (TG and DSC) and broad band dielectric spectroscopy (BDS). Both complexes {Al[O(CH 2CH 2O) 8.7] ρ /(LiClO 4) z } n and {Zr[O(CH 2CH 2O) 8.7] ρ /(LiClO 4) z } n after CO 2 treatment exhibited a change in the segmental relaxation with respect to the untreated samples. This phenomenon has been interpreted in terms of higher portion of free volume in the samples. The CO 2 treatment primarily lowered the conductivity of {Al[O(CH 2CH 2O) 8.7] ρ /(LiClO 4) z } n complexes of about one order of magnitude, as opposed to {Zr[O(CH 2CH 2O) 8.7] ρ /(LiClO 4) z } n complexes, where an increment of two orders of magnitude was observed. In both cases the conductivity of the treated and untreated materials versus the reciprocal absolute temperature presents the typical Vogel–Tamman–Fulcher (VTF) behavior. The different effects on the conductivities of the treated complexes are explained in terms of the modified anion-trapping ability of Al centers and in terms of the interactions of subcritical CO 2 with the host polymer and the salt. Insight about the conductivity mechanisms were provided by the study of the VTF parameters and the relaxation times determined from the Debye peaks of the imaginary resistivity, the imaginary permittivity and the correlated motion analysis.

Excess molar enthalpies and volumes of binary mixtures of nonafluorobutylmethylether with ethylene glycol ethers at T = 298.15 K

Excess molar enthalpies, H m E and volumes, V m E were reported for binary mixtures of {nonafluorobutylmethylether, (NFBME, C 4F 9–O–CH 3)} + [five ethylene glycol ethers, EGE n, m-R, {C m H 2 m + 1 -(OCH 2CH 2) n -R, n = 1 and 2, m = 1 to 4, R = OH and OCH 3}] at 298.15 K. Results of excess molar enthalpies and volumes were positive over whole range of concentrations for all the mixtures. The magnitude was in order: EGE1,4-OH > EGE1,3-OH > EGE1,2-OH > EGE1,1-OH > EGE2,1-OH > EGE2,1-OCH 3 for H m E and EGE2,1-OCH 3 > EGE1,4-OH > EGE1,3-OH > EGE1,2-OH > EGE1,1-OH > EGE2,1-OH for V m E at the maximum point. The curves of H m E and V m E for the EGE2,1-OH system were depressed in the middle mole fraction of NFBME, x 1 suggesting a quasi-stable state in the solution. We observed occurrences of the stable emulsification state in solutions in concentrations range of 0.35 < x 1 < 0.55. From these results, excess partial molar enthalpies, H m , 2 E , ∞ , and volumes, V m , 2 E , ∞ , of EGE n, m-R at infinite dilution, apparent molar enthalpies of solvation, Δ solv H 2, of the EGE n, m-R in NFBME were evaluated. The dependence of these thermodynamic quantities on the number of carbon atoms in the alkyl group, m, the number of the ethylene oxide group, n, and the difference of R group were discussed in consideration of various kinds of intermolecular interactions in pure component liquids and solutions.

Synthesis of a novel type of hybrid fluorocarbon ionic surfactants containing polyoxyethlene chain

A novel type of hybrid ionic surfactants containing oxyethylene chain and fluorocarbon chain in one molecule, n-C 8F 17SO 3 −N +(C 2H 5) 3(CH 2CH 2O) n H ( n = 4.0, ∼4.1, 8.7, 13.2, 17.8, 22.3), were prepared. The compounds were achieved from the reaction of polyethylene glycol and perfluorooctanesulfonyl fluoride in the presence of Et 3N. The evaluation of their behavior at the air–water interface has been studied from measurements of surface tension versus variation of concentration, and the properties of the hybrid surfactants are not consistent with the empirical rule observed from the fluorinated nonionic surfactant.

Quantum chemical study of group 14 elements pentacoordinated derivatives—metallatranes

The structures of a series of metallatranes, N(CH 2CH 2O) 3M–X ( I– IV), where M=Si, Ge, Sn and Pb, and X=H, F, Cl, Br, HO, CH 3, (CH 3) 2N, (CH 3) 3N + were studied using DFT calculations with full geometry optimization. The obtained results are in good agreement with gas electron diffraction data. The transannular bond M←N length depends on the nature of M and axial X substituent and the strength of M←N bond increases in Si<Ge<Sn order. The structures of tetracoordinated species, HC(CH 2CH 2O) 3M–X and N(CH 2CH 2O) 3C–X, were calculated for comparison. Possible mechanisms of transannular bond formation in I– IV are also discussed.

Comparison of Sm complexes with Sn compounds for syntheses of copolymers composed of lactide and cyclic carbonates and their biodegradabilities

The comparison of organolanthanide complexes, (C 5Me 5) 2SmMe(THF) (Sm1) and [(C 5Me 5) 2Sm] 2(PhC C C CPh) (Sm2), with tin compounds, Bu 2Sn(OMe) 2 (Sn1) and Bu 2Sn(OCH 2CH 2CH 2O) (Sn2), in the preparation of random, diblock, and triblock copolymers composed of l-lactide ( l-LA) or d, l-LA and cyclic carbonates, trimethylene carbonate (TMC) or 2,2-dimethyltrimethylene carbonate (DTC) is reported. The biodegradabilities of the resulting copolymers with proteinase K and a compost were examined. The copolymerization of l-LA with cyclic carbonates by Sm1 or Sm2 afforded copolymers with relatively low melting points (<160 °C) due to the accompanying epimerization in comparison with those obtained with Sn1 or Sn2. In the degradation of the polymers with a compost, the copolymers based on d, l-LA were more degradable than those based on l-LA. On the other hand, the effect of the incorporated cyclic carbonate on its degradability was more drastic in the copolymers based on l-LA than those in the copolymers based on d, l-LA. The introduction of only a small amount of the cyclic carbonates into PLLA significantly enhanced the degradability of PLLA with a compost or proteinase K. In the enzymatic degradation of l-LA-containing polymers, the copolymerization of l-LA with TMC was also quite effective to improve the degradability of PLLA. Triblock copolymerization tends to be effective to enhance the degradability of PLLA.

Liquid crystalline phthalocyanine spun films for organic vapour sensing

Vapour sensing properties of spin-coated films of mesogenic octa-substituted phthalocyanine derivatives MPcR 8, where M = Ni(II), R = –S(CH 2) 11CH 3, –SCH(CH 2OC 12H 25) 2, –S(CH 2CH 2O) 3CH 3 were investigated using spectroscopic ellipsometry, Raman spectroscopy and surface plasmon resonance (SPR) technique. Solvent molecules with saturated C C bonds such as chloroform are found to have formed hydrogen bonds with alkyl chains of the substituents of phthalocyanine molecules. The sensor response to aromatic compounds such as benzene is, on the other hand, believed to be the consequence of their π–π interaction with the conjugated phthalocyanine ring.

Synthesis of proton conducting tungstosilicate mesoporous materials and polymer composite membranes

Tungstosilicate mesoporous materials (WMM) were synthesized using the ionic surfactant cetyltrimethylammonium bromide (C 16H 33N +(CH 3) 3Br −, CTMABr) and non-ionic surfactants, including C 12H 25(OCH 2CH 2) 10OH (Brij 22, C 12EO 10OH), C 16H 33(OCH 2CH 2) 10OH (Brij 56, C 16EO 10OH), and C 18H 37(OCH 2CH 2) 10OH (Brij 76, C 18EO 10OH). Using CTMABr, the highest W/Si ratio achieved for the molecular sieve product was 0.03. The proton conductivity ranged from 0.5 to 2.2 × 10 −2 S/cm, where the highest conductivity was observed with the H 3PO 4 based preparation. Non-ionic surfactants produced materials with a W/Si ratio as high as 0.05 without any dense WO 3 impurities. These samples showed thicker pore walls (39 Å), higher thermal stability, and higher proton conductivity (4.0 × 10 −2 S/cm). The WMMs were also employed to make a composite membrane with linear polyethyleneimine (PEI)-3-glycidoxypropyl-trimethoxysilane (GLYMO)-bis(trifluoromethanesulfonyl)imide (HTFSI). At 100 °C and 100% relative humidity, the composite membrane with 30 wt.% calcined (at 500 °C) WMM showed the highest conductivity of 6.1 × 10 −2 S/cm. At 130 °C and 20% relative humidity, the highest conductivity of 6.4 × 10 −3 S/cm was obtained for the composite membrane with 30 wt.% as-synthesized WMM.

Epoxidation of dibenzocycloalkenes on Ti–Ge-MCM-41 and Ti-SBA-15 catalysts

Epoxidation of a series of dibenzocycloalkenes: phenanthrene, 5H-dibenzo[ a, e]cycloheptene, 5H-dibenzo[ a, c] cycloheptene, 5,6-dihydrodibenzo[ a, e]cyclo-octene, and dibenzo[ a, e]cyclooctene with hydrogen peroxide was investigated on Ti- and Ge-modified Ti-incorporated-type mesoporous catalysts including MCM-41 and SBA-15 structures looking for the effect of the porous texture and Ge-promoting on both activity and selectivity to epoxide and H 2O 2 efficiency. Ti–Ge-MCM-41 catalysts (Si/Ti = 43; Si/Ge = 85 and Si/Ti = 41; Si/Ge = 62) were prepared by a one-pot surfactant-assisted procedure based on the use of a cationic surfactant (CTAB, cetyltrimethylammonium bromide), as structure directing agent, and a complexing polyalcohol (2,2′,2″-nitriletriethanol), able to harmonize the hydrolysis and co-condensation reaction rates of the different heteroelements and the self-assembling processes between the inorganic precursors and the surfactant micelles. Ti-SBA-15 catalysts were prepared in a strong acidic medium (2 M HCl solution) using Pluronic P-123 (HO(CH 2CH 2O) 20(CH 2CH(CH 3)O) 70(CH 2CH 2O) 20H),as surfactant and tetraethyl orthosilicate and tetrapropyl orthotitanate as silicon and titanium sources. All these materials were characterized by N 2 adsorption–desorption isotherm measurements, XRD, TEM and DR–UV–Vis, both as fresh and used catalysts.

X-ray diffraction studies of three 1-phenylethynylgermatranes with two phenyl groups in atrane skeleton

Single crystal structures of treo-N(CH 2CH 2O) 2(CHPhCHPhO)GeC CPh ( 1), erythro-N(CH 2CH 2O) 2(CHPhCHPhO)GeC CPh ( 2) and N(CH 2CH 2O) 2(CH 2CPh 2O)GeC CPh ( 3) were determined by X-ray diffraction studies. These compounds show transannular N→Ge interactions; the strength of this interaction depends on the Ph groups position in atrane skeleton ( 1, d(N→Ge)=2.210(4) Å; 2, d(N→Ge)=2.166(4) Å; 3, d(N→Ge)=2.138(3) Å). The structures of these compounds are discussed along with performed DFT calculations data. General trends for molecular structures of the group 14 elements (Si, Ge) metallatranes containing carbon substituents in atrane framework are reviewed.

Synthesis and styrene polymerization behavior of new titanium complexes Cp *TiCl(OCHRCH 2NAr)

A series of titanium complexes Cp *TiCl(OCHRCH 2NAr) (Cp * = C 5Me 5, R = H, Ar = phenyl ( 2a); R = H, Ar = 2,6-dimethylphenyl ( 2b); R = Me, Ar = phenyl ( 2c); R = Me, Ar = 2,6-dimethylphenyl ( 2d)) was prepared by the reaction of corresponding 2-phenylamino-ethanol derivatives with Cp *TiCl 3 in the presence of excessive triethylamine. All the titanium complexes display higher catalytic activity towards the syndiospecific polymerization of styrene in the presence of modified methylaluminoxane (MMAO) as a cocatalyst, yielding higher molecular weight polystyrenes with higher syndiotacticities and melting temperatures ( T m) than their mother complex Cp *TiCl 3. When 2-(2,6-diisopropyl-phenylamino)-ethanol was reacted with Cp *TiCl 3, an unexpected monodentate complex Cp *TiCl 2(OCH 2CH 2NHC 6H 3 i Pr 2-2,6) 3 was obtained. The complex 3 displays relative low catalytic activity towards styrene polymerization, but produces higher molecular weight polystyrene with higher syndiotacticities.

Lithium-selective potentiometric sensor based on a second generation carbosiloxane dendrimer

A second generation triethylene glycolmonomethylether end-grafted carbosiloxane dendrimer ( III) has been synthesized by the reaction of Si(OCH 2CH 2CH 2SiMe(OCH 2CH 2CH 2SiMe 2Cl) 2) 4 ( I) with triethylene glycolmonomethylether ( II). PVC-based membranes of dendrimer III as electroactive material with sodium tetraphenylborate (NaTPB) as anion excluder and with plasticising solvent mediators have been prepared and used for Li (I) ion determination. The membrane having a composition of PVC: III:NaTPB:chloronaphthalene (150:21.5:3:150) exhibited the best result with linear potential response in the concentration range of 2.5 × 10 −5 to 1.0 × 10 −1 M of Li + with a slope of 52.0 mV per decade of Li + activity. The membrane can be used over a period of 2 months in aqueous as well as in non-aqueous medium with good reproducibility. The electrode works excellent in the pH range of 3.7–8.0. The selectivity coefficient values for mono-, bi-, and tri-valent cations indicate good selectivity for Li + over a large number of cations.