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 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

Folic acid (FA), vitamin B9, is a good receptor of drugs triggering cellular uptake via endocytosis. FA is sparingly soluble in water. Herein, a new approach for the formation of FA hydrogel by the hydrolysis of glucono-δ-lactone in PBS buffer under physiological conditions has been reported. The gel has a fibrillar network morphology attributable to intermolecular H-bonding and π-stacking interactions. The thixotropic property of the gel is used for the encapsulation of both hydrophilic [doxorubicin (DOX)] and hydrophobic [camptothecin (CPT)] drugs. The loading of DOX and CPT into the gel is attributed to the H-bonding interaction between FA and drugs. The release of DOX is sustainable at pH 4 and 7, and the Peppas model indicates that at pH 7 the diffusion of the drug is Fickian but it is non-Fickian at pH 4. The release of CPT is monitored by fluorescence spectroscopy, which also corroborates the combined release of both drugs. The metylthiazolyldiphenyltetrazolium bromide assay of FA hydrogel demonstrates nontoxic behavior and that the cytotoxicity of the DOX-loaded FA hydrogel is higher than that of pure DOX, with a minimal effect on normal cells. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

World University root node

ChemMedChem

Injectable Hydrogel of Vitamin B9 for the Controlled Release of Both Hydrophilic and Hydrophobic Anticancer Drugs

Metal halide perovskites based on formamidinium (FA) show interesting properties compared to methylammonium (MA) compounds. The larger molecular size of FA compared to that of MA leads, however, to a structural instability in FAPbI3, placing FA at the border of tolerance factor for three-dimensional (3D) lead iodide perovskites. Because of the huge interest in mixed Sn/Pb perovskites, here we investigate FAPb1-xSnxBr3 perovskites in a full compositional range (0 ≤ x ≤ 1). We find a non-monotonic band gap evolution with increasing Sn content, which, through first-principles computational analyses, we relate to a distorted structure that dynamically averages to a cubic phase, as determined by X-ray diffraction. The large FA cation induces an instantaneous structure made by partly decoupled SnBr3 units, which leads to the observed band gap opening. FASnBr3 thus likely represents a limit compound of 3D perovskites. Intermediate FAPb1-xSnxBr3 compositions maintain a band gap of ∼1.8 eV up to 85% Sn content, making them interesting candidates for applications in tandem devices. © 2018 American Chemical Society.

ACS Energy Letters

Exploring the Limits of Three-Dimensional Perovskites: The Case of FAPb1- xSnxBr3

We report the preparation of alkali and alkaline earth (Ae) metal complexes supported by 2-picolylamino-diphenylphosphane chalcogenide [(Ph2P(=E)NHCH2(C5H4N)] [E = S (1-H); Se (2-H)] ligands. The treatment of the protic ligand, 1-H or 2-H, with alkali metal hexamethyldisilazides at room temperature afforded the corresponding alkali metal salts [M(THF)2(Ph2P(=E)NCH2(C5H4N)] [M = Li, E = S (3a), Se (3b)] and [{M(THF)n(Ph2P(=E)NCH2(C5H4N)}2] [M = Na, E = S (4a), Se (4b); M = K, E = Se (5b)] in good yield. The homoleptic Ae metal complexes [κ2-(Ph2P(=Se)NCH2(C5H4N)Mg(THF)] (6b) and [κ3-{(Ph2P(=Se)NCH2(C5H4N)}2M(THF)n] (M = Ca (7b), Sr (8b), Ba (9b)] were synthesized by the one-pot reaction of 2-H with [KN(SiMe3)2] and MI2 in a 2:2:1 molar ratio at room temperature. The molecular structures of the protic-ligands 1-H and 2-H, as well as complexes 3a,b-5a,b and 6b-9b were established using single-crystal X-ray analysis. The Ae metal complexes 6b-9b were tested for ring-opening polymerization (ROP) of racemic lactide (rac-LA) and copolymerization of rac-LA and ϵ-caprolactone (ϵ-CL) at room temperature. In the ROP of rac-LA, the calcium complex 7b exhibited high isoselectivity, with Pi = 0.89, whereas both the barium and strontium complexes showed lower isoselectivity with Pi = 0.78-0.62. In the copolymerization of rac-LA and ϵ-CL, both barium and strontium complexes proved to be efficient precatalysts for the formation of the block copolymer rac-LA-CL, but the reactivity of 9b was found to be better than that of 8b. All the polymers were fully characterized using differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography analyses. Kinetic studies on the ROP reaction of LA confirmed that the rate of polymerization followed the order Ba ≥ Sr ≈ Ca. © 2018 American Chemical Society.

Inorganic Chemistry

Ring Opening Polymerization and Copolymerization of Cyclic Esters Catalyzed by Group 2 Metal Complexes Supported by Functionalized P-N Ligands

We report the reactions of imidazolin-2-iminato titanium complexes [(Im R N)Ti(NMe 2 ) 3 ] (R = Mes, 2b; R = Dipp, 2c; Mes = mesityl, Dipp = 2,6-diisopropylphenyl) with 2,6-diisopropylaniline in a 1:3 molar ratio to yield the titanium imido complexes of composition [(Im R NH)Ti = N( Dipp )(HN Dipp ) 2 ] (R = Mes, 3b; R = Dipp, 3c) in good yield by the Ti-Niminato bond cleavage at 60 °C. In contrast, the reaction of [(Im R N)Ti(NMe 2 ) 3 ] with 2,6-diisopropylaniline in a 1:1 molar ratio afforded mono-substituted products [(Im R N)Ti(NMe 2 ) 2 (HN Dipp )] (R = Mes, 4b; R = Dipp, 4c) in good yield. The reaction of [(Im R N)Ti(NMe 2 ) 3 ] with the iminopyrrole ligand [2-(2,6-iPr 2 C 6 H 3 -N = CH)C 4 H 3 NH] (N Dipp PyH) in a 1:1 ratio afforded mixed ligands, titanium complexes [(Im R N)Ti(NMe 2 ) 2 (N Dipp -Py)] (R = tBu, 5a; R = Dipp, 5c) with imidazolin-2-iminato and iminopyrrolide ligands. Molecular structures of 3b, 3c, 4c, 5a, and 5c were determined by single-crystal X-ray analysis. The solid-state structures of 3b and 3c clearly indicate the formation of true Ti = N double bonds, measuring 1.730(2) Å and 1.727(1) Å, respectively. The solid-state structures of 5a and 5c reveal the formation of five-coordinate titanium complexes. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.

Journal of Coordination Chemistry

Reactivity of titanium imidazolin-2-iminato complexes with 2,6-diisopropylaniline and 2-{(2,6-diisopropylphenyl)-iminomethyl}pyrrole

We report here reactions between the N-adamantyliminopyrolyl ligand 2-(AdNCH)-C4H3NH (L-H) and alkali metal hexamethyldisilazides [MN(SiMe3)2] (M = Li, Na and K) to afford the dimeric [{2-(AdNCH)-C4H3NLi(THF)}2] (1), [{2-(AdNCH)-C4H3N}{Na(THF)1.5}2] (2) and polymeric [{2-(AdNCH)-C4H3NK(THF)}n] (3) complexes at ambient temperature. A one-pot reaction between L-H, [KN(SiMe3)2] and alkaline earth metal diiodide (AeI2) in a 2 : 2 : 1 molar ratio, which resulted in the formation of a heteroleptic Ae metal complex [κ2-{2-(AdNCH)-C4H3N}2Ae(THF)2] [Ae = Mg (4), Ca (5)], is also reported. The solid-state structures of complexes 1, 3 and 4 were established through single-crystal X-ray diffraction analysis. The alkali and alkaline earth metal complexes 1-5 were utilised as precatalysts for the catalytic hydroboration of pinacolborane (HBpin) with aldehydes and ketones, and potassium complex 3 was identified as a competent catalyst under mild conditions. Additionally, cyanosilylation of carbonyl compounds was explored with trimethylsilyl cyanide and aldehydes/ketones, using the alkali metal precatalyst 3 under mild conditions. In both catalytic processes, the potassium catalyst 3 exhibited high tolerance towards a number of functional groups. © 2018 The Royal Society of Chemistry.

Dalton Transactions

Alkali metal complexes as efficient catalysts for hydroboration and cyanosilylation of carbonyl compounds

Presently, great attention is being directed toward the development of promising electrode materials for non-lithium rechargeable batteries which have the advantages of low cost, high energy storage density, and high rate capacity for substantial renewable energy applications. In this study, we have predicted that the C3N monolayer is a potential electrode material for Na- and K-ion batteries by first-principle calculations. The diffusion barriers are calculated to be as small as 0.03 eV for Na and 0.07 eV for K, which could lead to a very fast diffusion on the C3N monolayer surface, implying high mobility and cycle stability for batteries. The C3N monolayer is predicted to allow a high storage capacity of 1072 mAh/g by the inclusion of multilayer adsorption with an average voltage of 0.13 V for Na2C3N and 0.26 V for K2C3N systems, which is more promising than previously studied anode materials. All of these results ensure that the C3N monolayer could serve as an excellent anode material for Na- and K-ion batteries. © 2018 American Chemical Society.

Journal of Physical Chemistry C

Graphene-like Carbon-Nitride Monolayer: A Potential Anode Material for Na- and K-Ion Batteries

Pyrido-oxazine derivatives have been synthesized by employing tandem S N2 and S NAr reaction between 2,4,6-tribromo-3-(2-bromoethoxy)pyridine or 2,4,6-tribromo-3-(3-bromopropoxy)pyridine and a variety of primary amines. Moderate to good regioselectivity in favor of cyclization at the 2-position is observed. Pyrido-oxazine products thus generated are converted into biarylated pyrido-oxazine and terpyridine ligands. © 2018 SynOpen. All rights reserved.

Fulltext

SynOpen

Synthesis of Substituted Pyrido-oxazine through Tandem S N2 and S NAr Reaction

Anilines are one of the important chemical feedstocks and are utilized for the preparation of a variety of pharmaceuticals, agrochemicals, pigments, and dyes. In this context, the catalytic reduction of nitro functionality is an industrially vital process for the synthesis of aniline derivatives. Herein, we report an efficient nanosized bimetallic Pd-Au/TiO2 nanomaterial which is proved to be quite efficient for rapid catalytic hydrogen transfer reduction of nitroarenes into corresponding amines. Significantly, the reduction process is successful under solvent-free and mild green atmospheric conditions. Bimetallic Pd-Au nanoparticles served as the active center, and TiO2 played as a support in hydrogen transfer from the source hydrazine monohydrate. Typical results highlighted that the reactions were very rapid and the products were obtained in good to excellent yields. Significantly, the process was successful in the presence of a very low amount catalyst (0.1 mol %). Furthermore, the reaction showed good chemoselectivity and compatiblity with double or triple bond, aldehyde, ketone, and ester functionalities on the aromatic ring. Typical results indicated the true heterogeneous nature of the Pd-Au/TiO2 nanocatalyst, where the catalyst retained the activity, without loss of its activity. Copyright © 2018 American Chemical Society.

ACS Omega

Bimetallic Pd-Au/TiO2 Nanoparticles: An Efficient and Sustainable Heterogeneous Catalyst for Rapid Catalytic Hydrogen Transfer Reduction of Nitroarenes

In this article, we have studied 34 S = 1/2 complexes of first-row transition-metal complexes in d1, d5, d7, and d9 configurations in an attempt to determine the intrinsic accuracy of the scalar-relativistic complete active space self-consistent field (CASSCF) and N-electron valence perturbation theory (NEVPT2) methods, with respect to predicting molecular g-values. CASSCF calculations based on active spaces that contain only metal-based orbitals largely overestimate the g-values, compared to experiment and often fail to provide chemically meaningful results. Incorporation of dynamic correlation by means of the NEVPT2 method significantly improves the transition energies, with a typical error, relative to the experiment, of 2000-3000 cm-1. As a result, a lowering in the g-shift by almost an order of magnitude is obtained, relative to the CASSCF results. However, the g-shifts are still overestimated, compared to the experiment, since CASSCF leads to an overly ionic description of the metal-ligand bond and, hence, to spin-orbit coupling matrix elements that are too large. Inclusion of the double d-shell, along with appropriate bonding counterparts to the antibonding d-orbitals in the active space, led to the correct trends in the g-values for all studied complexes, with the linear regression coefficient (R) equal to 0.93 over the entire dataset. Various technical aspects of the calculations such as the influence of relativity, importance of picture change effects, solvation effects, and comparison between second-order perturbation and effective Hamiltonian-based theories have also been systematically studied. In addition, g-tensor calculations were performed with five popular density functional theory (DFT) methods (B3LYP, M06L, M06, TPSSh, and PBE0) to compare with wave function (WF) methods. Our results suggest that WF-based methods are remarkably better than DFT methods. However, despite the fact that WF theory has come a long way in computing the properties of large, open-shell transition-metal complexes, methodological work is still necessary for truly high accuracies to be reached. © 2018 American Chemical Society.

Journal of Chemical Theory and Computation

Challenges in Multireference Perturbation Theory for the Calculations of the g-Tensor of First-Row Transition-Metal Complexes

Conventional graphite anodes can hardly intercalate sodium (Na) ions, which poses a serious challenge for developing Na-ion batteries. This study details a novel method that involves single-step laser-based transformation of urea-containing polyimide into an expanded 3D graphene anode, with simultaneous doping of high concentrations of nitrogen (≈13 at%). The versatile nature of this laser-scribing approach enables direct bonding of the 3D graphene anode to the current collectors without the need for binders or conductive additives, which presents a clear advantage over chemical or hydrothermal methods. It is shown that these conductive and expanded 3D graphene structures perform exceptionally well as anodes for Na-ion batteries. Specifically, an initial coulombic efficiency (CE) up to 74% is achieved, which exceeds that of most reported carbonaceous anodes, such as hard carbon and soft carbon. In addition, Na-ion capacity up to 425 mAh g−1 at 0.1 A g−1 has been achieved with excellent rate capabilities. Further, a capacity of 148 mAh g−1 at a current density of 10 A g−1 is obtained with excellent cycling stability, opening a new direction for the fabrication of 3D graphene anodes directly on current collectors for metal ion battery anodes as well as other potential applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim