Indian Journal of Chemistry

Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical

 

CODEN: ICACEC; ISSN: 0376-4710 (Print), 0975-0975 (Online)

 

http://www.niscair.res.in; http://nopr.niscair.res.in

Total visitors: 6045 since 09-01-2012

 

Perspectives & Challenges

 

 

VOLUME 51A

NUMBER 1-2

JAN-FEB 2012

 

CONTENTS

 

 

15

 

Potential of nanocarbons and related substances as adsorbents and chemical storage materials for H2, CO2 and other gases

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C N R Rao*, Urmimala Maitra, K S Subrahmanyam , K Gopalakrishnan, Nitesh Kumar, Ram Kumar &
A Govindaraj

 

 

 

 

Carbon nanotubes, graphene, BN nanotubes and graphene-like BCN are potential chemical and adsorptive storage material for H2, CO2 and methane.

 

 

 

 

 

32

 

Selective synthesis of metallic and semiconducting single-walled carbon nanotubes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rakesh Voggu, A Govindaraj & C N R Rao*

 

 

 

 

Traditional methods for the synthesis of SWNTs yield metallic and semiconducting nanotubes. Methods for selective synthesis and separation of particular electronic type and chirality are of paramount importance.

 

 

 

 

 

 

 

47

 

Molecular logic gates: Recent advances and perspectives

 

 

 

 

 

 

 

 

 

 

 

 

Sivaramapanicker Sreejith &
Ayyappanpillai Ajayaghosh
*

 

 

 

 

 

 

 

57

 

Molecular engineering of novel low band gap conducting polymers

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A K Bakhshi*, Avneet Kaur & Vinita Arora

 

 

 

 

Current efforts to design novel conducting polymers with the desired conduction properties are reviewed. Some recent results on the electronic structure and conduction properties of tailored conducting polymers, including investigations based on efficient artificial intelligence techniques, are discussed.

 

 

 

 

 

69

 

Photocytotoxic organometallic compounds

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Basudev Maity & Akhil R Chakravarty*

 

 

 

The emerging chemistry of organometallic complexes showing light-induced DNA cleavage activity and photocytotoxicity in various cancer cells is reviewed. Bimetallic ferrocenyl-conjugates of 3d metal ions show photocytotoxicity in visible  light.

 

 

 

 

83

 

Conformational properties of the bis-μ-(thiolato) dicopper center in cytochrome c oxidase

 

 

 

 

 

 

 

 

Jitumani Rajbongshi, Manas Kumar Ghosh,
Nusrat J M Sanghamitra, Sayan Gupta & Shyamalava Mazumdar*

 

 

 

 

 

 

 

 

99

 

NO- and CO-donors: An emerging class of pharmaceuticals in current medicine

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pradip K Mascharak

 

 

 

 

Design and development of exogenous NO- and CO-donors have gained momentum in recent years following the discovery of physiological and pathological effects of NO and CO.

 

 

 

108

 

Coordination chemistry of 2-aminothioethers and their unusual chemical transformations

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sutanuva Mandal, Suman Kr Roy &
Sreebrata Goswami
*

 

 

 

 

The ligand, 2-aminothioether, upon coordination undergoes unusual metal mediated chemical transformations leading to formation of different organic compounds. Coordination chemistry of the transformed compounds has been discussed.

 

 

 

118

 

Cyclophosphazene- and cyclocarbophosphazene-based supported ligands

 

 

 

 

 

 

 

 

 

 

 

Vadapalli Chandrasekhar*, Atanu Dey &
Subrata Kundu

 

 

 

 

Cyclophosphazene and cyclocarbophosphazene-based multisite coordination ligands and their metalation behaviour are described.

 

 

 

 

 

130

 

Structural comparisons of the species of recognition of Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Ag+ with
1,3-di-conjugates of calix[4]arene by DFT computations

 

 

 

 

 

 

 

 

 

 

Balaji Ramanujam, Jugun Prakash Chinta & Chebrolu P Rao*

 

 

 

 

Coordination chemistry of the interactions between the host calix[4]arene receptor and guest metal ion species have been studied by computational modeling studies.

 

 

 

 

 

145

 

Anion doped binary oxides, SnO2, TiO2 and ZnO: Fabrication procedures, fascinating properties and future prospects

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R Nagarajan*, Vinod Kumar & Shahzad Ahmad

 

 

 

 

Various synthetic approaches to dope the oxygen in SnO2, TiO2 and ZnO with other anions as well as the emergence of interesting and useful properties as a consequence of anion doping are reviewed.

 

 

 

155

 

Polyaniline-supported metal catalysts for
green synthesis

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pravin R Likhar, M Lakshmi Kantam* &
Suresh Bhargava

 

 

 

 

Conducting and redox properties of polyaniline coupled with ease of preparation from inexpensive starting materials, high environmental stability and easy acid doping/base dedoping has prompted its use as a support to hold metal complexes during catalytic reactions. Polyaniline-supported palladium, indium, and iron catalysts are evaluated for use in coupling, addition and acylation reactions.

 

 

 

 

166

 

Reflections on the electrochemical reduction of carbon dioxide on metallic surfaces

 

 

 

 

 

 

 

 

 

 

B Viswanathan

 

 

 

The constrained geometry of activation of carbon dioxide on metallic surfaces and its electrocatalytic reduction are discussed.

 

 

 

174

 

Challenges and opportunities in biofuels production

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Darbha Srinivas* & Jitendra Kumar Satyarthi

 

 

 

 

The current state-of-art processes for the production of biofuels from vegetable oils are reviewed. The opportunities and future challenges in this area are discussed.

 

 

 

 

186

 

Design of novel ceria-based nano-oxides for CO oxidation and other catalytic applications

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D Devaiah, Lankela H Reddy, K Kuntaiah & Benjaram M Reddy*

 

 

 

 

Doped ceria-based nanosized solid solutions have been examined for CO oxidation. Ceria-hafnia mixed oxide exhibits highest oxygen storage/release capacity and excellent CO oxidation activity.

 

 

 

196

 

Electrochemical reactions and phase transitions investigated by in situ scanning tunneling microscopy

 

 

 

 

 

 

 

 

 

 

 

Bo Cui, Dong Wang & Li-Jun Wan*

 

 

 

 

 

 

 

 

 

205

 

Surface modification in electroanalysis: Past, present and future

 

 

 

 

 

 

 

 

 

 

 

 

 

Rajendra N Goyal* & Sunita Bishnoi

 

 

 

The catalytic effect on the performance of sensors and biosensors, due to surface modification of working electrodes by nanomaterials are presented.

 

 

 

226

 

Hydrogen storage: An overview with current insights based on a conceptual DFT approach

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Arindam Chakraborty, Soma Duley &
Prat
im K Chattaraj*

 

 

 

 

Hydrogen has been conceived as a future fuel alternative for mobile applications. Various molecular materials, ranging from nanosheets and cages to metal-based bulky covalent frameworks, are reviewed as potential templates for hydrogen adsorption and storage.

 

 

 

245

 

Design of anisotropic nanostructures using microemulsions

 

 

 

 

 

 

 

 

 

 

 

 

 

Ashok K Ganguli*, Sonalika Vaidya &
Aparna Ganguly

 

 

 

 

Microemulsion-based synthesis is used to synthesize nanomaterials with varied morphology.

 

 

 

Authors for correspondence are indicated by (*)

 

 

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 15-31

 

Potential of nanocarbons and related substances as adsorbents and
chemical storage materials for H2, CO2 and other gases

C N R Rao*, Urmimala Maitra, K S Subrahmanyam, K Gopalakrishnan, Nitesh Kumar, Ram Kumar &
A Govindaraj

International Centre for Material Sciences, Chemistry and Physics of Materials Unit, and New Chemistry Unit Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India

Email: cnrrao@jncasr.ac.in

Received 15 December 2011

Solid materials which can adsorb and store hydrogen, carbon dioxide and methane are gaining importance because of the challenges faced in the energy and environment sectors. Several materials have been examined for the adsorption and storage of hydrogen. There is a notion that a material comprising light elements may be better for the adsorption and storage of hydrogen. In this context, carbon nanotubes and graphene would be expected to be suitable materials for the purpose. However, the adsorption of hydrogen on these materials reaches maximum values up to 3 to 4 wt%, that too under high pressure. Chemical storage of hydrogen in nanotubes by hydrogenation goes up to ~3wt%, but reaches a much higher value of 5 wt% or more in the case of few-layer graphenes. The sp3 carbon-hydrogen bonds formed by the hydrogenation of graphene decompose readily on heating to ~500 ºC or on exposure to UV or laser radiation giving out all hydrogen, making few-layer graphenes attractive as possible hydrogen storage materials. Chlorine can be chemically stored in few-layer graphenes in a similar manner. Adsorption of CO2 on activated charcoal is well known. Few-layer graphenes also adsorb CO2 substantially, specially at low temperatures and reach values of 45 wt% at 195 K and 0.11 MPa, and 51 wt% at 298 K and 5 MPa. Graphene analogues containing B, C and N with the composition BxCyNz on the other hand, adsorb CO2 up to 128 wt% at 195 K and 0.1 MPa and 64 wt% at room temperature, making them probably some of the best materials known for adsorption of CO2. Interestingly, these BCN materials are equally good for the adsorption of methane and exhibit an adsorption of nearly 15 wt% at room temperature.

Keywords: Nanocarbons, Carbon nanotubes, Graphenes, Borocarbonitrides, Hydrogen storage, Hydrogen adsorption,Carbon dioxide adsorption, Methane adsorption, Halogen storage

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 32-46

 

Selective synthesis of metallic and semiconducting
single-walled carbon nanotubes

Rakesh Voggua, A Govindaraja, b & C N R Raoa, b, *

aCSIR Centre of Excellence in Chemistry, Chemistry and Physics of Materials Unit, and

International Centre for Materials Science,

Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P O, Bangalore 560 064, India

bSolid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India

Email: cnrrao@jncasr.ac.in.

Received 12 November 2011

As-prepared single-walled carbon nanotubes (SWNTs) are generally mixtures of semiconducting and metallic species, the proportion of the former being around 67%. Since most applications of SWNTs are best served by semiconducting or metallic nanotubes, rather than by mixtures of the two, methods which would directly yield semiconducting and metallic SWNTs in pure form are desirable. In this article, we present the available methods for the direct synthesis of such SWNTs along with the methods available to separate semiconducting and metallic SWNTs from mixtures. We also discuss the synthesis of Y-junction carbon nanotubes.

Keywords: Carbon nanotubes, Nanocarbons, Selective synthesis, Y-junction, Semiconducting SWNT, Metallic SWNT

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 47-56

 

Molecular logic gates: Recent advances and perspectives

Sivaramapanicker Sreejith & Ayyappanpillai Ajayaghosh*

Photosciences and Photonics Group, Chemical Sciences and Technology Division,
CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695 019, India

Email: ajayaghosh62@gmail.com

Received 22 December 2011

The capacity and miniaturization of information storage and processing technology are rapidly approaching a limit. Alternative materials and operating principles for the elaboration and communication of data in electronic circuits and optical networks must be identified. Molecular level computing is predicted as the ultimate solution to overcome the present limitation of computing devices in terms of storage capacity and processing speed. Their attractive features are the miniaturized dimensions and the high degree of control on molecular design through chemical synthesis. In recent years a variety of molecules that respond to various chemical inputs have been synthesized and demonstrated as molecular logic gates. This review covers the recent developments and future perspectives of molecular logic gates with particular emphasis on fluorescent organic molecules.

Keywords: Molecular logic, Molecular switches, Logic gates, Boolean logic, Chemical switches, Fluorescence, Fluorophores

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 57-68

 

Molecular engineering of novel low band gap conducting polymers

A K Bakhshia, b, *, Avneet Kaura & Vinita Aroraa

aDepartment of Chemistry, University of Delhi, Delhi 110 007, India

bUP Rajarshi Tandon Open University, Shantipuram (Sector F), Phaphamau, Allahabad 211 013, India

Email: akbakhshi2000@yahoo.com

Received 22 November 2011

Conducting polymers have infiltrated our day to day life with a wide range of products extending from the most common consumer goods to highly specialized applications in space, aeronautics and electronics. In this article, current efforts to design novel conducting polymers with the desired conduction properties are reviewed. Some recent results on the electronic structure and conduction properties of tailored conducting polymers are discussed. The application of search algorithms in obtaining the optimal solution for a copolymer with minimum band-gap and maximum delocalization has been discussed. Finally, the importance of theoretical study of conducting polymers has been outlined.

Keywords: Conducting polymers, Electronic structures, Copolymers, Donor-acceptor polymers, Band gap, Artificial intelligence, Genetic algorithm, Ant algorithm

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 69-82

 

Photocytotoxic organometallic compounds

Basudev Maity & Akhil R Chakravarty*

Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India

Email: arc@ipc.iisc.ernet.in

Received 15 November 2011

Organometallic compounds have recently found applications in medicinal chemistry and as diagnostic tools in chemical biology. Naturally occurring biomolecules, viz., cobalamine, NiFe hydrogenase, Acetyl-CoA synthase, etc., also contain metal-carbon bonds. Among organometallic compounds having medicinal importance, (arene)ruthenium complexes, radioactive technetium complexes and ferrocene conjugates are notable ones. Applications of photoactive organometallic complexes or metal complexes conjugated with an organometallic moiety are of recent origin. Photodynamic therapy (PDT) is a promising method to treat cancer cells in presence of light. This review primarily focuses on different aspects of the chemistry of organometallic complexes showing photocytotoxic activities. Half-sandwich tungsten, iron or ruthenium complexes are known to show photonuclease and/or photo-crosslinking activity. Photoinduced organometallic CO releasing molecules also exert photocytotoxic activity. Attempts have been made in this review to highlight the photocytotoxic behavior of various metal complexes when conjugated with a photoactive organometallic moiety, viz., ferrocene.

Keywords: Medicinal chemistry, Organometallic compounds, Ferrocene, DNA photocleavage,      Photocytotoxicity

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 83-98

 

Conformational properties of the bis-μ-(thiolato) dicopper center in
cytochrome c oxidase

Jitumani Rajbongshia, b, Manas Kumar Ghoshb, Nusrat J M Sanghamitrab, Sayan Guptab & Shyamalava Mazumdarb, *

aDepartment of Chemistry, Gauhati University, Guwahati 781 014, India

bDepartment of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India

Email: shyamal@tifr.res.in

Received 14 December 2011

The novel bis-μ(thiolato) dicopper center (CuA) forms the electron entry site in the respiratory enzyme, cytochrome c oxidase. While most of the electron transfer copper proteins consist of a mono-nuclear copper center, the presence of a dinuclear copper in cytochrome c oxidase has attracted immense interest. The CuA center from the mesophilic organism, P. denitrificans (PdCuA) and from the thermophilic organism T. thermophilus (TtCuA) have very similar spectroscopic and electronic properties, albeit the stability of the two proteins are significantly different from each other. This dinuclear copper center undergoes interesting conformational change induced by change in the pH of the solution, which involves equilibrium conversion of the purple ‘charge-delocalized’ form to a ‘valance-trapped’ form of the metal center. The pH dependent conformational changes in the PdCuA and TtCuA show different pKa values indicating involvement of different amino acids in the process. The conformation change near the dinuclear center in the mesophilic protein PdCuA is extremely fast while that in the thermophilic protein TtCuA is very slow. The results of recent studies on the conformational properties of this novel metal center in the protein have been outlined in this mini-review in the light of understanding their implications in biology.

Keywords: Bioinorganic chemistry, Electron transfer proteins, Cytochrome c oxidase, Time-resolved fluorescence, Protein electrochemistry, Conformational changes, Dinuclear copper, Copper

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 99-107

 

NO- and CO-donors: An emerging class of pharmaceuticals in
current medicine

Pradip K Mascharak

Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA

Email: pradip@ucsc.edu

Received 22 August 2011

In recent years, two small diatomic molecules namely, nitric oxide (NO) and carbon monoxide (CO) have been shown to play key roles in human physiology. Depending on their concentration (in the nano-to-micro molar range), these two molecules exhibit distinct physiological or pathological effects. Several exogenous NO-donors have found use as medication for blood pressure control and as anti-infective agents. CO-donating compounds have shown promises in controlling tissue damage. Demand for new and efficient NO- and CO-donors for controlled delivery of these two messenger molecules to biological targets has grown over the years and the market for such drugs is expanding at a fast rate. Inorganic and bioinorganic chemists have already contributed significantly in this area. It is expected that they will play an important role in the future design and development of these drugs.

Keywords: Nitric oxide, Carbon monoxide, NO-drugs, CORM, Heme oxygenase, Nitrosyl compounds, Carbonyl compounds, Signal transduction, Cytoprotective activity

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 108-117

 

Coordination chemistry of 2-aminothioethers and their unusual
chemical transformations

Sutanuva Mandal, Suman Kr Roy & Sreebrata Goswami*

Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India

Email: icsg@iacs.res.in

Received 11 November 2011

Versatile coordination chemistry of 2-aminothioether ligands and their unusual chemical reactivities upon coordination have been primarily discussed with special emphasis on S-C bond activation and N-C bond formation processes. Chemical transformations have been followed via successful isolation and complete characterization of the products. Biological activities of the complexes along with their spectral properties are collected.

Keywords: Coordination chemistry, Aminothioethers, Thioethers, S-C bond activation, Non-innocent ligands

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 118-129

 

Cyclophosphazene- and cyclocarbophosphazene-based ligands

 

Vadapalli Chandrasekhar*, Atanu Dey & Subrata Kundu

Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India

Email: vc@iitk.ac.in

Received 7 December 2011

In this review the utility of the inorganic ring systems, cyclophosphazenes and cyclocarbophosphazenes, to support multisite coordination platforms is described. Different types of ligands based on these ring systems and their metalation behavior is described.

Keywords:   Coordination chemistry, Cyclophosphazenes, Cyclocarbophosphazenes, Multisite coordination ligands, Metalation

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 130-144

 

Structural comparisons of the species of recognition of Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Ag+ with 1,3-di-conjugates of calix[4]arene
by DFT computations

Balaji Ramanujam, Jugun Prakash Chinta & Chebrolu P Rao*

Bioinorganic Laboratory, Department of Chemistry, Indian Institute of Technology Bombay, Powai,
Mumbai 400 076, India

Email: cprao@iitb.ac.in

Received 22 August 2011

Calixarenes are versatile macromolecular systems, which would exhibit better host-guest chemistry upon appropriate derivatization. Our group has been involved in the synthesis of a variety of calix[4]arene conjugates, which were found to selectively recognize metal ions. Though such recognitions have been demonstrated, based on different experimental studies, the qualitative and semi-quantitative understanding of the coordination aspects are still lacking owing to the non-availability of the crystal structures of the species of recognition. Hence, in order to understand the coordination chemistry of the interactions between the host calix[4]arene receptor and the guest metal ion species, computational modelling studies have been carried out. In this regard, five conjugates of calix[4]arene, which are 1,3-di-O-derivised at the lower-rim and appended over an amide as well as Schiff  base linker have been studied. The computational modelling studies have been carried out at the level of density functional theory to yield coordination geometries, which are intune with the experimental observations and comparable to those reported in the literature in the case of similar receptor systems. The species of recognition obtained with the metal ions are found to have some structural resemblances with the metal sites present in metalloproteins. The modelling studies and the coordination geometries are discussed in this article.

Keywords: Density functional calculations, Calix[4]arene conjugates, Macromolecules,
Species of recognition, Coordination core, Computational modelling

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 145-154

 

Anion doped binary oxides, SnO2, TiO2 and ZnO: Fabrication procedures, fascinating properties and future prospects

 

R Nagarajan*, Vinod Kumar & Shahzad Ahmad

Materials Chemistry Group, Department of Chemistry, University of Delhi, Delhi 110 007, India

Email: rnagarajan@chemistry.du.ac.in

Received 14 November 2011

Doping the oxygen in the three technologically important binary oxides SnO2, TiO2, and ZnO, with other anions such as nitrogen, carbon, fluorine, sulfur and chlorine by various synthetic procedures are described. The crystal structures of these oxides along with their electronic structures are summarized. The evolution of many useful properties, such as efficient photocatalysis, high electrical conductivity with high optical transparency on doping with some of these anions, is discussed. An important milestone achieved by our research group for the synthesis of F-doped SnO2 and ZnO powders is highlighted. Heavily F-doped SnO2, obtained by the safe, simple, reliable and reproducible synthetic approach developed by us is the first example among oxide semiconductors to show Moss-Burstein effect, and consequently the defect states are produced in the system on injection of extra charge carriers. These trapped defect states give rise to glow curves in the thermoluminescence spectrum. This observation suggests the use of SnO2:F as a thermal UV sensors in high radiation environments. In the concluding part, the need for the investigation in to the interesting structural, electronic and optical properties, especially in the heavily doped regime, are portrayed as part of the future directions of research in these oxides.

Keywords: Oxides, Binary oxides, Doping, Anion doping, Tin dioxide, Titania, Zinc oxide, Photocatalysis, Sensors,Electrical conductivity

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 155-165

 

Polyaniline-supported metal catalysts for green synthesis

Pravin R Likhara, M Lakshmi Kantama, b, * & Suresh Bhargavab, c

aI&PC Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 607, India

bRMIT-IICT Centre, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 607, India

Email: mlakshmi@iict.res.in

cSchool of Applied Sciences, RMIT University, Melbourne, Australia

Received 14 November 2011

The conducting and redox properties of polyaniline coupled with its easy preparative protocol from inexpensive starting materials, high environmental stability, and easy acid doping/base dedoping has prompted its use as a support to hold metal complexes securely during catalytic reactions. Synthesis of polyaniline-supported palladium, indium, and iron catalysts, their characterization and use in coupling, addition and acylation reactions have been reviewed in this article.

 

Keywords: Catalysts, Conducting polymers, Polyaniline support, Palladium, Indium, Iron

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 166-173

 

Reflections on the electrochemical reduction of carbon dioxide
on metallic surfaces

B Viswanathan

National Centre for Catalysis Research, Indian Institute of Technology Madras,
Chennai 600 036, India

Email: bvnathan@iitm.ac.in

Received 1 November 2011

It is known that carbon dioxide undergoes electrochemical reduction to a variety of products like CO, hydrocarbons and alcohols on metallic surfaces and that the nature of the metal has a role to play in the observed selectivity of products. Rationalization of the results obtained on different metallic surfaces and accounting for the selectivity have been the points of contention in literature. This presentation examines these aspects from the point of view of surface activation of carbon dioxide and proposes a site specific and geometry constrained adsorption of carbon dioxide as the possible reason for the variation in the results reported in literature.

Keywords: Electrochemical reduction, Reduction, Carbon dioxide, Selectivity, Surface activation, Adsorption

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 174-185

 

Challenges and opportunities in biofuels production

Darbha Srinivas* & Jitendra Kumar Satyarthi

Catalysis Division, CSIR-National Chemical Laboratory, Pune 411 008, India

Email: d.srinivas@ncl.res.in

Received 21 November 2011

Biofuels are attractive alternative to petroleum diesel. They are renewable, non-toxic, biodegradable, carbon neutral and lead to reduced tailpipe emissions. This article presents the current state-of-art processes of their production and discusses the opportunities and future challenges in this area of research.

Keywords: Biodiesel, Biofuels, Renewable fuels, Solid catalysts, Transesterification (fatty acid glycerides), Deoxygenation, Hydrotreatment, Vegetable oils/fats

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 186-195

 

Design of novel ceria-based nano-oxides for CO oxidation and
other catalytic applications

D Devaiah, Lankela H Reddy, K Kuntaiah & Benjaram M Reddy*

Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology
Uppal Road
, Hyderabad
500 607, India

Email: bmreddy@iict.res.in/ mreddyb@yahoo.com

Received 17 November 2011

Carbon monoxide oxidation over various ceria-based solid solutions has been reviewed. The advantageous incorporation of various dopants in the ceria lattice (CexM1–xO2; M = Zr and Hf, and CexM1–xO2-d; M = La and Pr) to improve oxygen storage capacity and CO oxidation activity have been addressed. Nanosized doped ceria solid solutions are synthesized by a newly developed coprecipitation method from ultrahigh dilute aqueous solutions. To establish the thermal stability, the synthesized materials have been calcined at 773 and 1073 K and thoroughly characterized by various state-of-the-art techniques. The structural features have been investigated by X–ray diffraction, transmission electron microscopy, Raman spectroscopy, UV–visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and BET surface area. X-ray differaction and Raman Spectroscopic studies establish the formation of solid solutions and the TEM analysis specifies the nanosized nature of the mixed oxides. Further, the XPS and UV–vis DRS studies establish the existence of cerium in both 3+ and 4+ oxidation states and the presence of oxygen vacancies, respectively. Among various combinations, the ceria-hafnia solid solution exhibits the best oxygen storage capacity and excellent CO oxidation activity. As revealed by this model study, there is ample scope to design better materials for CO oxidation and related pollution abatement applications.

Keywords: Catalysts, Ceria, CO oxidation, Oxygen storage capacity, Solid solutions, Defective fluorite structure

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 196-204

 

Electrochemical reactions and phase transitions investigated by
in situ scanning tunneling microscopy

Bo Cuia, b, Dong Wanga & Li-Jun Wana, *

aInstitute of Chemistry, Chinese Academy of Sciences, and Beijing National Laboratory for Molecular Sciences, Beijing 100190, China

Email: wanlijun@iccas.ac.cn

bGraduate University of Chinese Academy of Sciences, Beijing 100049, China

The reaction and adsorption of organic molecules at electrode-electrolyte interfaces have been intensively studied to understand the fundamental processes at the electrochemical interface. Electrochemical scanning tunneling microscopy (ECSTM) has been recognized as a powerful tool to investigate potential-induced structural transition and reaction at the solid/liquid interface with atomic and molecular resolution. This review article presents some recent progress in ECSTM application for exploring potential-dependent chemical reactions and phase transitions. Details of the molecular adsorption structure and structural transition controlled by electrode potential are revealed by high resolution STM images. The ability to control the adlayer structure is important for modulating the structure and function of the electrode surfaces.

Keywords: Electrochemical scanning tunneling microscopy, Potential-induced phase transitions, Potential-induced structural transition

 

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 205-225

 

Surface modification in electroanalysis: Past, present and future

Rajendra N Goyal* & Sunita Bishnoi

Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667, India

Email: rngcyfcy@iitr.ernet.in

Received 27 October 2011

This review discusses the electrochemical sensors and biosensors based on carbon nanotubes, fullerenes, metal nanoparticles and ionic liquid/composite modified electrodes. Subsequently, recent developments and major strategies for enhancing sensing performance, the challenges and prospects of further developments in the future are debated. Besides a brief exposition of the properties of ionic liquids and their general applications based on these properties, this review focuses on the application of ionic liquids in electroanalytical sensors. Emphasis is given to direct electron-transfer reaction, origin of electrocatalysis effect of nanomaterials and use of these sensors to determine the level of biomolecules, drugs/doping agents in human body fluids. This review aims to expand on these aspects by covering the most recent trends and advances in the utilization of nanomaterials in electroanalytical techniques during the last decade or so.

Keywords: Electrochemistry, Electroanalysis, Modified electrodes, Surface modification, Electrode modification, Sensors, Biosensors, Nanomaterials, Carbon nanotubes, Fullerenes, Ionic liquids

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 226-244

 

Hydrogen storage: An overview with current insights based on a
conceptual DFT approach

 

Arindam Chakraborty, Soma Duley & Pratim K Chattaraj*

Department of Chemistry and Center for Theoretical Studies

Indian Institute of Technology, Kharagpur 721 302, India

Email: pkc@chem.iitkgp.ernet.in

Received 29 September 2011

Importance of various conceptual density functional theory based reactivity descriptors and nucleus independent chemical shift in analyzing the hydrogen adsorption potential of a wide variety of systems is reviewed. The charges on the different atomic sites in a molecule also play a crucial role in this regard.

Keywords: Theoretical chemistry, Density functional calculations, Hydrogen storage, Aromaticity, Conceptual DFT, Nucleus independent chemical shift, Chemical shift

 

Indian Journal of Chemistry

Vol. 51A, Jan-Feb 2012, pp. 245-251

 

Design of anisotropic nanostructures using microemulsions

Ashok K Gangulia, *, Sonalika Vaidyab & Aparna Gangulyc

aDepartment of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016, India

Email: ashok@chemistry.iitd.ernet.in

bDepartment of Chemistry, Hindu College, University of Delhi, Delhi 110 007. India

cDepartment of Chemistry, Central University of Rajasthan, Kishangarh, Rajasthan 305 802, India

Received 31 October 2011

Water-in oil microemulsions can be intelligently designed to form organized assemblies which can then be used as nanoreactors for synthesizing a variety of nanomaterials. The size and morphology of the desired product is controlled by manipulating the parameters involved in the formation of a microemulsion like Wo ([H2O]/[Surfactant]), and the nature of solvent, surfactant and co-surfactant. This review focuses on understanding the controlled growth of anisotropic nanostructures using microemulsions emphasizing on the recent contributions by our group on synthesis of nickel and copper oxalate nanorods and silica nanostructures. We believe that this review will espouse the ability of the microemulsion method to control the shape and size of nanostructures.

Keywords: Microemulsions, Nanomaterials, Anisotropic nanostructures