Department of Chemistry

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

A modular platform for the synthesis of tunable aza-oxa-based macrocycles was established. Modulations in the backbone and the side-chain functional groups have been rendered to achieve the tunable property. These aza-oxa-based macrocycles can also differ in the number of heteroatoms in the backbone and the ring size of the macrocycles. For the proof of concept, a library of macrocycles was synthesized with various hanging functional groups, different combinations of heteroatoms, and ring sizes in the range of 17–27 atoms and was characterized by NMR and mass spectrometry. In light of the importance of the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction and the significance of triazole groups for various applications, we employed the click-reaction-based macrocyclization. The competence of the synthesized macrocycles in various biomedical applications was proven by studying the interactions with the serum albumin proteins; bovine serum albumin and human serum albumin. It was observed that some candidates, based on their hanging functional groups and specific backbone atoms, could interact well with the protein, thus improving the bioactive properties. On the whole, this work is a proof-of-concept to explore the backbone-and side-chain-tunable macrocycle for different properties and applications. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

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Molecules

Aza-Oxa-Triazole Based Macrocycles with Tunable Properties: Design, Synthesis, and Bioactivity

Structural diversity and tunable properties achieved by a defined monomeric sequence are the trademarks of a sequence-defined polymer (SDP). Herein, we report a modular synthetic platform where, in addition to the provision of changing the side chain, the backbone functional groups of the SDP can also be tuned among three key functional groups, namely dithiocarbamate (DTC), ester and amide. An efficient synthetic strategy has been developed to incorporate DTC into the SDP backbone without the need for separate design of the monomer. This unique strategy with the potential to vary both the backbone as well as the side chain is, to the best of our knowledge, the first report in the field of man-made SDPs. Three different classes of sequence-defined oligomers (SDOs) have been synthesized: (i) SDO1 with DTC alone in the backbone; (ii) SDO2 with DTC and ester in the backbone; and (iii) SDO3 with DTC and ester in the backbone and amide in the side-chain linkage. The structure-activity relationships of the three SDOs were investigated, which is important for their biomedical and material applications. This led to the conclusion that SDO1 with DTC functionality was stable under conditions of hydrolysis, heat and acid treatment, whereas SDO2 (DTC and ester) and SDO3 (DTC, ester and amide) are not stable under those conditions. On the other hand, for applications related to toxic Hg2+ removal, SDO3, which contained all three functional groups (DTC, ester and amide), was the most efficient, followed by SDO2 (DTC and ester) with medium efficiency and SDO1 (DTC) with the lowest efficiency. The investigation of the protein binding affinity with serum albumin concluded that all three SDOs are transportable via serum proteins. Taken together, this is a proof-of-concept to explore SDOs with tunable backbones and side-chains to modulate their properties and employ the best suited SDO for any given application. © 2022 The Royal Society of Chemistry.

Polymer Chemistry

Backbone and side chain-linker tunability among dithiocarbamate, ester and amide in sequence-defined oligomers: synthesis and structure–property–function relationship

We report the very first example of a self-assembled p-cymene-Ru(ii) metallocycle based on a green emitting 4-amino-1,8-naphthalimide Tröger's base (TBNap) supramolecular scaffold. A new cleft-shaped TBNap-derived di-4-picolyl donor was synthesized and reacted in a 2 : 2 stoichiometry ratio with a dinuclear Ru(ii) acceptor (Ru-A) to generate a [2 + 2] self-assembled metallocycle (TBNap-Ru-MC) in good yield. Both TBNap and TBNap-Ru-MC showed positive solvatochromism in different solvents with varying polarities. In addition, the binding propensity of cationic TBNap-Ru-MC toward the heparin polyanion was determined using fluorescence titration studies. The initial fluorescence emission of TBNap-Ru-MC was quenched upon the gradual addition of the heparin polyanion, and the Stern-Volmer quenching constant (KSV) was calculated to be 3.97 × 105 M−1 © 2022 The Royal Society of Chemistry.

Dalton Transactions

Synthesis, characterization, and heparin-binding study of a self-assembled p-cymene-Ru(ii) metallocycle based on a 4-amino-1,8-naphthalimide Tröger's base supramolecular scaffold

A unique V-shaped "chiral" supramolecular scaffold, N-(4-pyridyl)-4-amino-1,8-naphthalimide Tröger's base (TBNap), was synthesized in good yield from a precursor N-(4-pyridyl)-4-amino-1,8-naphthalimide (Nap). TBNap was characterized using different spectroscopic methods and the molecular structure was elucidated by diffraction analysis. A new p-cymene-Ru(II)-curcumin conjugate (TB-Ru-Cur) was designed by reacting TBNap dipyridyl donor and ruthenium-curcuminato acceptor [RuCur = (p-cymene)Ru-(curcuminato)Cl] in the presence of silver triflate. TB-Ru-Cur was isolated in quantitative yield and characterized using Fourier transform infrared (FT-IR), NMR (1H, 13C, and 19F), and electrospray ionization mass spectrometry (ESI-MS), and the molecular structure has been predicted using a computational study. Both TBNap and TB-Ru-Cur exhibited intramolecular charge transfer (ICT)-based fluorescence emission. Furthermore, the anticancer properties of TBNap, Ru-Cur, and TB-Ru-Cur were assessed in different cancer cell lines. Gratifyingly, the conjugate TB-Ru-Cur displayed fast-cellular internalization and good cytotoxicity against HeLa, HCT-116, and HepG2 cancer cells and the estimated IC50value was much lower than that of the precursors (TBNap and Ru-Cur) and the well-known chemotherapeutic drug cisplatin. © 2022 American Chemical Society. All rights reserved.

Inorganic Chemistry

Design, Synthesis, and Anticancer Studies of a p-Cymene-Ru(II)-Curcumin Organometallic Conjugate Based on a Fluorescent 4-Amino-1,8-naphthalimide Tröger's Base Scaffold

The design of suitable fluorescent chemosensors for the trace detection of emerging organic pollutants attracted great research interest because of their serious menace to the environment and health hazards. Herein, we report two 1,8-naphthalimide-based fluorescent chemosensors, N-phenyl-4-amino-1,8-naphthalimide (Nap-1) and N-phenyl-3-amino-1,8-naphthalimide (Nap-2), for the discriminative fluorescent sensing of nitro-containing antibiotics. Nap-1 and Nap-2 have been synthesized in two steps from their respective nitro-1,8-naphthalic anhydride precursors and they were fully characterized using standard spectroscopic techniques such as FT-IR, and NMR (1H, and 13C), and HRMS. Both Nap-1 and Nap-2 are highly emissive due to internal-charge transfer (ICT) transition and exhibited a positive solvatochromism in different solvent mediums. The fluorescence titration studies of Nap-1 and Nap-2 with various antibiotics showed high selectivity and strong binding affinity for nitro-containing antibiotics with a parts-per-billions (ppb) level of sensitivity. The initial fluorescence emission intensity of Nap-1 and Nap-2 was quenched upon the addition of nitro-antibiotics such as Nitrofurazone (NFZ) and Dimetridazole (DMZ). Notably, the co-existence of other competing antibiotics showed negligible to moderate fluorescence quenching. The observed discriminative fluorescence sensing was also reflected by sharp visual colour changes. The Stern-Volmer quenching constants (KSV) were calculated to be in the order of 104 M−1. These studies suggest that Nap-1 and Nap-2 can be used as potential “turn-off” fluorescent chemosensors for the selective, sensitive, and fast detection of nitro-antibiotics. © 2022 The Author(s)

Results in Chemistry

Discriminative fluorescent sensing of nitro-antibiotics at ppb level using N-phenyl-amino-1,8-naphthalimides chemosensors

This work reports a unique ZrO2-Ag2O heterojunction nanocomposite uniformly dispersed on a macro-/meso-porous polymer monolithic template to serve as simple and effective visible light-driven heterogeneous plasmonic photocatalysts for water decontamination. The monolithic photocatalysts' structural properties and surface morphology are characterized using various surface and structural characterization techniques. The photocatalytic performance of the proposed photocatalysts is evaluated by optimizing multiple operational parameters. The photocatalytic properties of the fabricated monolithic nanocomposite are monitored through time-dependent photocatalytic disintegration of norfloxacin drug, a widely employed antimicrobial, with considerable aquatic persistence. The analytical results conclude that a (60:40) ZrO2-Ag2O nanocomposite embedded polymer monolith exhibits superior photocatalytic activity for the complete mineralization of norfloxacin molecules under optimized conditions of solution pH (3.0), photocatalyst quantity (100 mg), pollutant concentration (15 mg/L), photosensitizers (2.0 mM KBrO3), visible light intensity (300 W/cm(2) tungsten lamp) and irradiation time (<= 1 h). The proposed new-age inorganic-organic hybrid visible light photo-catalysts with superior structural and surface properties exhibit brilliant performance and fast responsiveness for water decontamination applications, in addition to their excellent chemical stability, high durability, multi-reusability, and cost-effectiveness. {[}GRAPHICS] .

PHOTOCHEMICAL \& PHOTOBIOLOGICAL SCIENCES

ZrO2-Ag2O nanocomposites encrusted porous polymer monoliths as high-performance visible light photocatalysts for the fast degradation of pharmaceutical pollutants

Data Mining is a powerful technology and is used to identify useful and understandable patterns by analyzing large sets of data. It gives a detailed view of various disease predictions. It will be more useful especially in pandemic times. During these days, doctors are in the front line and battling with the COVID-19 virus. It will be hard for people to immediately get medical guidance or appointments. Our proposed system, the smart health application will come in handy at these times. The system allows people to get medical guidance for their health issues. Also, the system is fed with symptoms and the disease-related with it which will give high accuracy for disease prediction. Our model aims to use Stacking Ensemble Classification Algorithms to give high accuracy and correct prediction than Naive Bayes, Random Forest, Support Vector Machine, K - Nearest Neighbor, Decision Tree, Logistic Regression for different types of 149 diseases. The GUI is designed which can be used easily to predict the different types of disease accurately.

INTERNATIONAL JOURNAL ON INFORMATION TECHNOLOGIES AND SECURITY

SMART HEALTH SYSTEM USING STACKING ENSEMBLE CLASSIFICATION ALGORITHM

Concrete-based construction provides enormous advantages by utilizing waste materials and by-products from various sources such as industries, power plants, etc. One of the significant waste materials from the coal-based power plants, pond ash (PA), is highly dumped into landfills, causing critical environmental issues. This study examined the strength, morphological and durability characteristics of coal pond ash concrete. In this investigation, the cement was replaced with 10\% of coal pond ash by weight of cement and water - binder ratio of 0.44 was used in all mix proportions. Strength properties were evaluated by using modulus of elasticity test. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) were also performed to evaluate its morphological characteristics. Durability properties such as rapid chloride penetration test, weathering resistance test, acid resistance test and chloride resistance test were conducted. The test results confirmed the efficiency of adding ash to cement material. Ten percent of coal pond ash in concrete had significant resistance against chloride penetration, weathering action, chloride and acid attack. SEM and EDAX analysis confirmed the presence of a higher amount of CSH gels at the increase in age, which promotes more - denser, less porous and compacted microstructure in concrete.

INTERNATIONAL JOURNAL OF COAL PREPARATION AND UTILIZATION

Performance study on strength, morphological, and durability characteristics of coal pond ash concrete

Rapid and reliable detection of organophosphorus (OP) threats is essential for facilitating efficient and timely countermeasures. This work describes the design and operation of a miniaturized electrochemical sensor array chip, based on strategic coupling of diverse MOF-based biomimetic and biocatalytic reagent layers (offering tunable OP target specificities) with different potentiometric, voltametric, and amperometric transducers to generate information-rich analytical data and robust discrimination power towards rapid field identification of key classes of OP threats. This uniquely integrated 4-electrode sensor array yields rich analytical data that enables rapid and efficient discrimination of P−F- and P−Cl-type OP nerve agents (NAs) and OP pesticides from coexisting environmental pollutants. The sensor array outputs lead to distinct binary codes for the target OP threats that enable their rapid digital identification. This sensor array chip thus presents a significant advance towards reliable OP threat-sensing hand-held devices that meet the urgent demands of different defense surveillance applications. © 2022 Wiley-VCH GmbH.

ChemElectroChem

Sensor Array Chip for Real-Time Field Detection and Discrimination of Organophosphorus Neurotoxins

Reaction of the 1,2-disilylene, [{ArC(NDip)2}Si]2 1 (Dip=2,6-diisopropylphenyl, Ar=4-C6H4But), with CO proceeds via insertion of CO into one Si−N bond and Si−Si bond cleavage, to cleanly give the bis(silylene), {ArC(NDip)2}Si(:)O (Formula presented.) Ar 2, under ambient conditions. The reaction can be partially reversed when solutions of 2 are subjected to UV irradiation. The five-membered heterocyclic fragment of 2 represents the first silicon analogue of an “abnormal” N-heterocyclic carbene (aNHC), a view which is substantiated by a computational analysis of the compound. Reaction of 2 with [Mo(CO)6] under UV light affords the chelate complex, [Mo(CO)4(κ2-Si,Si-2)] 3, while reaction with [Fe(CO)5] gives the unusual silyleneyl bridged complex, [{Fe2(CO)6}{μ-Si[(NDip)2CAr]}2] 4. The same coordination complexes can be accessed by reaction of 1 with [Mo(CO)6] or [Fe(CO)5] under UV light. As is the case for aNHCs, d-block metal complexes of bis(silylene) 2 could prove useful as bespoke catalysts for organic transformations. © 2022 Wiley-VCH GmbH.