A white colour IL-SiWA hybrid molecular material has been synthesized using 1-butyl 3-methyl imidazolium bromide ionic liquid and silicotungstic acid. The material is found to dissolve in polar organic solvent such as DMSO, but not in water. It is characterized by CHN analysis, FTIR, XRD, UV-vis DRS, TGA and SEM. The FTIR spectra indicate the formation of a hybrid compound showing fingerprint vibrational bands of both Keggin ions of silicotungstic acid and imidazolium ions. There is a strong evidence of interaction between the Keggin anions and imidazolium cations from the UV-vis DR spectra and the splitting of imidazolium C-H bands in the IR spectrum of the IL-SiWA. The near IR shows loss of crystallization water from heteropoly acid when it reacts with ionic liquid forming the hybrid molecular material. © 2008 Elsevier B.V. All rights reserved.

Gangavarapu Ranga Rao

Department Of Chemistry

Dimethyl Sulfoxide

Electric load management

Electrolysis

Forming

Fourier transform infrared spectroscopy

Ionic liquids

Ions

Organic compounds

Organic solvents

Photolithography

Reconnaissance aircraft

CHN ANALYSIS

FTIR SPECTRUMS

HETEROPOLY ACIDS

HYBRID COMPOUNDS

HYBRID MOLECULAR MATERIAL

HYBRID MOLECULAR MATERIALS

Imidazolium

IMIDAZOLIUM BROMIDES

IMIDAZOLIUM CATIONS

IMIDAZOLIUM IONS

ir spectrum

KEGGIN ANIONS

KEGGIN IONS

KEGGIN UNIT

NEAR IR

POLAR ORGANIC SOLVENTS

SILICOTUNGSTIC ACID

SILICOTUNGSTIC ACIDS

Synthesis and characterizations

vibrational bands

Ionization of liquids

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Materials Chemistry and Physics

Polyoxometalate-based materials are gaining importance in the fields of heterogeneous catalysis and materials chemistry. In this context, we have synthesized (H(CL)2)3PMo and (H(CL)2)3PW novel hybrid materials using phosphomolybdic acid (PMoA) and phosphotungstic acid (PWA) as a source of Keggin anions, respectively, and ε-caprolactam (CL). The caprolactam molecules have undergone lactam–lactim tautomerisation in the presence of heteropolyacids forming cationic dimers. The hybrid materials are characterized by FTIR, XRD analyses, TGA, DSC, SEM and UV–DRS techniques. From single crystal X-ray analysis of (H(CL)2)3PMo, we find that the protonated caprolactam dimers replaced the protonated water molecules (H5O2+) from hexahydrated state of heteropolyacids. These materials show increased band gaps in the semiconducting region, due to decrease in the crystallite size. The cyclic voltammograms recorded by immobilizing these materials on 6 mm glassy carbon electrodes have shown three consecutive two-electron redox couples. © 2017 Elsevier Ltd

Polyhedron

Hydrophobic supramolecular assemblies of Keggin anions with lactam-lactim cationic tautomers

A solid hybrid molecular material containing 1-butyl 3-methyl imidazolium cations and Keggin anions of phosphotungstic acid has been synthesized. It is fully characterized by CHN analysis, FTIR, XRD, UV-Vis-NIR DRS, 31P MAS NMR, TGA and SEM. The FTIR spectrum of the compound shows the fingerprint vibrational bands of both Keggin molecular anions and imidazolium cations. The aromatic C-H stretch region (2700-3250 cm-1) of imidazolium cation is split due to the interaction between the ring C-H and bulky Keggin anion. The red-shift in the UV-Vis spectra and the downfield 31P MAS NMR chemical shift also confirm the electrostatic interaction between the ions in the compound. Near IR spectral region (1000-2500 nm) shows the elimination of water in the compound which is hydrophobic. © Indian Academy of Sciences.

Fulltext

Journal of Chemical Sciences

Investigation of hybrid molecular material prepared by ionic liquid and polyoxometalate anion

A molecular salt with formula [BmIm]3[PMo12O40]3- has been prepared using room temperature ionic liquid and phosphomolybdic acid. The material is characterized by single-crystal X-ray diffraction. The compound crystallizes in orthorhombic system with space group Pca21. It is also characterized by CHN analysis, 31P MAS NMR, UV-vis DRS and near-IR methods. Thermal stability of the compound is investigated by TGA, IR and PXRD methods. Near-IR shows the loss of water of crystallization by the Keggin ions of phosphomolybdic acid bonded with ionic liquid. © 2008 Elsevier Masson SAS. All rights reserved.

Solid State Sciences

Synthesis and characterization of 1-butyl 3-methyl imidazolium phosphomolybdate molecular salt

The nature of the Keggin ions of tungstophosphoric acid interacting with Ce0.5Zr0.5O2 solid solution has been investigated. The vibrational study shows additional IR features at 1051 and 957 cm-1 which are correlated to the primary Keggin anions interacting with Lewis sites involving Ce4+ and Zr4+ ions, and thus affecting the P-O and W=Oterminal bonds. The IR study indicates the formation of interfacial Ce4+-O-W and Zr4+-O-W bonds. The chemisorbed Keggin molecular layers on Ce0.5Zr0.5O 2 show activity towards conversion of acetophenone to styrene by Meerwein-Ponndorf-Verley reduction followed by dehydration. The activity is correlated with the relative intensities of IR peaks at 1051 and 957 cm -1 of the perturbed Keggin molecular layers. © 2007 Springer Science+Business Media, LLC.

Catalysis Letters

Investigation of 12-tungstophosphoric acid supported on Ce 0.5Zr0.5O2 solid solution

The interaction of 20 wt% 12-tungstophosphoric acid with Cex Zr1 - x O2 solid solutions has been studied by PXRD, FTIR, FT-Raman, H2-TPR, NH3-TPD, diffuse reflectance UV-vis-NIR, and 31P MAS NMR techniques. The study indicates that the Keggin anions are attached to Lewis metal ion centres and anion vacancies on Cex Zr1 - x O2 supports through W{double bond, long}O terminal bonds. The Keggin units at the interface are chemically perturbed as indicated by non-intrinsic IR bands observed at 958 cm-1 (W{double bond, long}Oter bond), and 1052, 1102 cm-1 (P{single bond}O bond). NH3-TPD shows that the Keggin anions fixed to Lewis sites and/or oxygen ion vacancies decrease the ammonia uptake on Cex Zr1 - x O2 solid solutions. H2-TPR shows modified redox behaviour of Cex Zr1 - x O2 solid solutions due to the simultaneous reduction of ceria, decomposition of Keggin anions and the reduction of WO3. The broadening of 31P MAS NMR and DR-UV-vis-NIR spectra demonstrate the existence of chemical interactions between the Keggin anions and Cex Zr1 - x O2 supports. © 2008 Elsevier Inc. All rights reserved.

Journal of Colloid and Interface Science

Interaction of Keggin anions of 12-tungstophosphoric acid with Cex Zr1 - x O2 solid solutions

The Journal of Physical Chemistry B

Structures of Ionic Liquids with Different Anions Studied by Infrared Vibration Spectroscopy

Electrochimica Acta

Ionic conductivity, infrared and Raman spectroscopic studies of 1-methyl-3-propylimidazolium iodide ionic liquid with added iodine

Synthesis and characterization of hybrid molecular material prepared by ionic liquid and silicotungstic acid

Journal	Materials Chemistry and Physics
ISSN	02540584
Open Access	No