Department of Chemistry

Indian Institute of Technology Hyderabad (IITH) is a premier institute of science and technology established in 2008. IITH has been consistently ranked in the&nbsp;<a href="https://iith.ac.in/reports/" rel="noopener noreferrer">top 10 institutes</a>&nbsp;in India for Engineering&nbsp;<a href="https://www.nirfindia.org/2021/EngineeringRanking.html" rel="noopener noreferrer" target="_blank">according to NIRF</a>&nbsp;making it one of the most coveted schools for science and technology in the country.

IITH offers&nbsp;<a href="https://iith.ac.in/academics/under-graduate/">undergraduate programs</a>&nbsp;in all the classical engineering disciplines, applied sciences, design, as well as several modern interdisciplinary areas. Students are given a flexibility to explore a broad set of areas, and potentially pursue a minor or double major in a discipline that is not their own. Students who wish to seek a deeper understanding of their own discipline are strongly encouraged to get involved in cutting-edge research with the help of a faculty to mentor them, and earn an Honors in their own field.

The very foundation of IIT Hyderabad is based on&nbsp;<a href="https://iith.ac.in/research/">research and innovation</a>. The vibrant research culture is evident from the number of patents and publications that IITH produces consistently every year. IITH offers&nbsp;<a href="https://iith.ac.in/academics/programmes-offered/">graduate programs</a>&nbsp;at both a masters, and a doctoral level, in several diverse areas. There are separate programs for technology, design, science, and liberal arts. The&nbsp;<a href="https://iith.ac.in/academics/post-graduate/">MTech program</a>&nbsp;is offered in various modes and durations to cater to the ever-growing need of postgraduate level professionals in the country.

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IITH enjoys a very special relationship with Japanese universities and industries that goes beyond academic and research collaborations. In fact, some of the iconic buildings in IITH campus will carry the signature of Japanese architecture.

IITH creates a unique holistic ecosystem for education that offers interactive learning, a very flexible academic structure, cutting-edge research, strong industry collaboration, and entrepreneurship. This is an environment which enables students and faculty to translate their dreams into realities.

IIT Hyderabad

Current and future developments in the emerging field of nanobiotechnology are closely linked to the rational design of novel fluorescent nanomaterials, e.g. for biosensing and imaging applications. Here, the synthesis of bright near infrared (NIR)-emissive nanoparticles based on the grafting of silica nanoparticles (SNPs) with 3-aminopropyl triethoxysilane (APTES) followed by covalent attachment of Alexa dyes and their subsequent shielding by an additional silica shell are presented. These nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. TEM studies revealed the monodispersity of the initially prepared and fluorophorelabelled silica particles and the subsequent formation of raspberry-like structures after addition of a silica precursor.Measurements of absolute fluorescence quantum yields of these scattering particle suspensions with an integrating sphere setup demonstrated the influence of dye labelling density-dependent fluorophore aggregation on the signaling behaviour of such nanoparticles. © Springer Science+Business Media B.V. 2012.

World University root node

Journal of Nanoparticle Research

Synthesis and characterisation of highly fluorescent core-shell nanoparticles based on Alexa dyes

Reactions of N-aryliminopyrrolyl ligand 1a, 2-(2,6- iPr 2C 6H 3N=CH)-C 4H 3NH (Imp Dipp-H), with dibenzylcalcium gave two types of pyrrolylcalcium complexes, bis(iminopyrrolyl)calcium (2a) and (amidopyrrolyl)calcium (3a), via alkane elimination and ligand alkylation reaction, respectively. Preparation of a mono(iminopyrrolyl) complex, (iminopyrrolyl)Ca[N(SiMe 3) 2](THF) 2 (4a), was accomplished by the addition of 1 equiv of 1a to Ca[N(SiMe 3) 2] 2(THF) 2. A series of group 2 metal bis(iminopyrrolyl) complexes, [(Imp Dipp) 2M(THF) 3] (M = Sr (5a), Ba, (6a)) and [(Imp Me) 2Ca(THF) 2] (2b) (2-(4-MeC 6H 4N=CCH 3)-C 4H 3NH (Imp Me-H)), was selectively prepared via amine elimination reactions, and their molecular structures were clarified by X-ray diffraction studies. © 2012 American Chemical Society.

Organometallics

Preparation and structure of iminopyrrolyl and amidopyrrolyl complexes of group 2 metals

Exciting assemblies: A metal-organic self-assembly of pyrenebutyric acid (PBA), 1,10-phenanthroline (o-phen), and Mg II shows solid-state fluorescence originating from a 1:1 PBA-o-phen exciplex. This exciplex fluorescence is sensitized by another residual PBA chromophore through an excited-state energy-transfer process. The solvent polarity modulates the self-assembly and the corresponding exciplex as well as the energy transfer, resulting in tunable emission of the hybrid (see figure). Copyright © 2012 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Chemistry - A European Journal

Exciplex formation and energy transfer in a self-assembled metal-organic hybrid system

Light-harvesting hybrids have gained much importance as they are considered as potential mimics for photosynthetic systems. In this Concept article we introduce the design concepts involved in the building up of light-harvesting hybrids; these resemble the well-studied organic-based assemblies for energy transfer. We have structured this article into three parts based on the strategies adopted in the synthesis of hybrid assemblies, as covalent, semicovalent, and noncovalent procedures. Furthermore, the properties and structural features of the hybrids and analogous organic assemblies are compared. We also emphasize the challenges involved in the processability of these hybrid materials for device applications and present our views and results to address this issue through the design of soft-hybrids by a solution-state, noncovalent, self-assembly process. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Light-harvesting hybrid assemblies

A dielectric barrier discharge reactor was designed and tested for the degradation of a model aqueous pollutant crystal violet (CV). The specific advantage of the present configuration is the effective utilization of reactive species generated in the discharge plasma. The reactive species formed in the discharge, particularly the OH - radicals, may cause strong oxidizing effects in the degradation of CV. Mineralization of the dye was confirmed by TOC analyzer and infrared gas analyzer. It was observed that both degradation efficiency and TOC removal increased with increasing the input energy; however, the energy yield decreased. The highest energy yield achieved was 86.3 (g/kWh). Formation of hydrogen peroxide was quantified and addition of Fe 2+ increased the performance of the reactor. The dye degradation followed first-order kinetics. © 2012 American Chemical Society.

Industrial and Engineering Chemistry Research

Green approach for wastewater treatment-degradation and mineralization of aqueous organic pollutants by discharge plasma

Hydrogen production by non-thermal plasma (NTP) assisted direct decomposition of hydrogen sulfide (H2S) was carried out in a dielectric barrier discharge (DBD) reactor with stainless steel inner electrode and copper wire as the outer electrode. The specific advantage of the present process is the direct decomposition of H2S in to H2 and S and the novelty of the present study is the in-situ removal of sulfur that was achieved by operating DBD plasma reactor at ∼430 K. Optimization of various parameters like the gas residence time in the discharge, frequency, initial concentration of H2S and temperature was done to achieve hydrogen production in an economically feasible manner. The typical results indicated that NTP is effective in dissociating H2S into hydrogen and sulfur and it has been observed that by optimizing various parameters, it is possible to achieve H2 production at 300 kJ/mol H2 that corresponds to ∼3.1 eV/H2, which is less than the energy demand during the steam methane reforming (354 kJ/mol H2 or ∼3.7 eV/H2). © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

International Journal of Hydrogen Energy

Production of hydrogen from hydrogen sulfide assisted by dielectric barrier discharge

An efficient three-step strategy for the synthesis of functionalized flavans, starting from readily available 2-bromoiodobenzenes and aryl vinyl alcohols, is presented and successfully extended to benzoxepine. An intermolecular [Pd]-catalyzed C-C and an intramolecular [Cu]-catalyzed C-O bond formations have been employed as key transformations of the strategy. © 2012 Elsevier Ltd. All rights reserved.

Tetrahedron Letters

An efficient intermolecular [Pd]-catalyzed C-C and intramolecular [Cu]-catalyzed C-O bonds formation: Synthesis of functionalized flavans and benzoxepine

Polymer electrolytes were synthesized by two different approaches and applied to electrochromic devices based on electrodeposited tungsten oxide (WO3) or poly(3,4-ethylenedioxythiophene) (PEDOT) films as the cathode, and a Prussian blue (PB) film as the anode. The first method involved the entrapping of an ionic liquid in a polymer host (poly(methylmethacrylate) or PMMA) and the second approach relied on the in situ thermal polymerization of methylmethacrylate (MMA) in the hydrophobic ionic liquid, yielding a solidified transparent gel. The effect of in situ solid polymer electrolyte formation on device performance characteristics was realized in terms of a larger coloration efficiency of 119 cm2 C-1 (λ = 550 nm) achieved for the WO3-PB (MMA) device, as compared to a value of 54 cm2 C-1 obtained for the WO3-PB (PMMA) device. Similar enhancements in electrochromic coloring efficiency, reflectance contrast, and faster switching kinetics were obtained for the PEDOT-PB (MMA) device. The strategy of introducing an electrolyte to the electrochromic device in a liquid state and then subjecting the same to gradual polymerization allows greater accessibility of the electrolyte ions to the active sites on the electrochromic electrodes and superior interfacial contact. As a consequence, larger optical contrast and faster kinetics are achieved in the MMA based devices. While PEDOT films were amorphous, PB films were semi-crystalline but only in the case of WO3; the hexagonal structure of WO3, equipped with three/four/six-coordinated voids was found to affect bleaching kinetics favorably. The performance of PMMA based electrolyte is limited by high resistance at the electrode-electrolyte interface, and a smaller number of ions available for oxidation and reduction. Large area (∼10 cm × 4 cm) devices were also fabricated using this simple wet chemistry method and their ability to color uniformly without any pinholes was demonstrated. © 2012 The Royal Society of Chemistry.

Fulltext

RSC Advances

Electrochromic device response controlled by an in situ polymerized ionic liquid based gel electrolyte

A photoactive electrode of cadmium sulfide (CdS) quantum dots and fullerene (C 60) nanowhiskers (NW), free of a wide-gap semiconducting oxide support, has been fabricated for the first time, by growing CdS quantum dots using the successive ionic layer adsorption and reaction (SILAR) method over a layer of C 60 nanowhiskers. Enhanced excited electron injection efficiency from the CdS quantum dots to C 60 nanowhiskers was ascertained on the basis of maximum fluorescence quenching and shortest emission decay lifetimes in the CdS/C 60 (NW) electrode compared to conventional CdS/C 60 and CdS electrodes. Conducting atomic force microscope (C-AFM) revealed the larger nanoscale electronic conductivity for the CdS/C 60 (NW) electrode relative to CdS/C 60 or neat CdS electrodes. Kelvin probe force microscopy (KPFM) furnished an insight into how the downshift of the quasi Fermi level toward more positive potentials in the C 60 nanowhiskers as compared to neat C 60, is capable of providing an additional driving force for rapid electron transport within the photoanode. Photoelectrochemical cells based on the CdS/C 60 (NW) and CdS/C 60 electrodes were formed by employing a thin film of carboxylate functionalized multiwalled carbon nanotubes (MWCNTs)/ poly(dimethyldiallylammonium chloride) (PDDA) as the counter electrode. Rapid electron transport and high effective surface area of the C 60 nanowhiskers manifested in higher photocurrents, photovoltage, and incident photon to current conversion efficiency (IPCE) for the cell based on the CdS/C 60 (NW) electrode. The advantage of using MWCNT/PDDA electrode as the counter electrode was realized in terms of an overall enhancement in short circuit current (J SC), open-circuit voltage (V OC), and IPCE attained for the CdS/C 60 (NW)-MWCNT/PDDA cell as opposed to cells based on platinum (Pt) as the counter electrode. Our method of combining CdS quantum dots with C 60 nanowhiskers to yield an electrode that is superior to C 60-based traditional electrodes on all counts is easily applicable to other visible light absorbing quantum dots and thus opens up exciting possibilities for a plethora of yet unexplored donor-acceptor architectures for high performance photoelectrochemical solar cells. © 2012 American Chemical Society.

Journal of Physical Chemistry C

Facile charge propagation in CdS quantum dot cells

Poly(3, 4-ethylenedioxythiophene) (PEDOT) films have been synthesized by a facile electropolymerization route by using poly(-diallyldimethylammonium) chloride (PDDA) as the counter-ion source. To enhance their efficacy, the fullerene derivative N-methyl fulleropyrrolidine (N-FP) was embedded in the PEDOT/PDDA films; the electron-conducting ability of the N-FP came to the fore, as the conductivity, optical contrast, and ion-storage capacity were greater in the PEDOT/PDDA/N-FP film than in the PEDOT/PDDA film. Both the PEDOT/PDDA and PEDOT/PDDA/N-FP films showed an unprecedented dramatic digression from the expected optical response of conventional PEDOT, exhibiting distinct π-π * absorptions in the visible region in air, corresponding to a bandgap of 1.1-1.3 eV, which is outside the established range (1.6-1.7 eV). The neutral state of these films showed split components, which was simultaneously accompanied by a reversible color change from bright blue (in oxidized form) to deep brown (in reduced form). This is a most unusual color transition for PEDOT, as it opposes the well-established colors that vacillate between dark blue (reduced) and sky blue (oxidized) tones. Atomic force microscopy and Kelvin probe force microscopy provided evidence for the higher nanoscale current-carrying capacity and lower localized work function for PEDOT/PDDA/N-FP than for PEDOT/PDDA; both the energetics and conductivity are conducive for fast redox switching. The serendipitous but easily reproducible synthesis method and results for PEDOT/PDDA and PEDOT/PDDA/N-FP pave the way for the utilization of this material for electronic, electrochemical, and optical functions. This is different from what is currently known about the molecular-level feature control of macroscopic properties. © 2012 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.