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

Design and synthesis of three novel [2 + 2] self-assembled molecular rectangles 1-3via coordination driven self-assembly of predesigned Pd(ii) ligands is reported. 1,8-Diethynylanthracene was assembled with trans-Pd(PEt3)2Cl2 in the presence of CuCl catalyst to yield a neutral rectangle 1via Pd-C bond formation. Complex 1 represents the first example of a neutral molecular rectangle obtained via C-Pd coordination driven self-assembly. A new Pd2II organometallic building block with 180° bite-angle 1,4-bis[trans-(ethynyl) Pd(PEt3)2(NO3)]benzene (M2) containing ethynyl functionality was synthesized in reasonable yield by employing Sonagashira coupling reaction. Self-assembly of M2 with two organic clip-type donors (L2-L3) afforded [2 + 2] self-assembled molecular rectangles 2 and 3, respectively [L2 = 1,8-bis(4-pyridylethynyl)anthracene; L3 = 1,3-bis(3-pyridyl) isophthalamide]. The macrocycles 1-3 were fully characterized by multinuclear NMR and ESI-MS spectroscopic techniques, and in case of 1 the structure was unambiguously determined by single crystal X-ray diffraction analysis. Incorporation of Pd-ethynyl bonds helped to make the assemblies π-electron rich and fluorescent in nature. Complexes 1-2 showed quenching of fluorescence intensity in solution in presence of nitroaromatics, which are the chemical signatures of many commercially available explosives. © 2011 The Royal Society of Chemistry.

World University root node

Department of Chemistry

Dalton Transactions

Self-assembly of neutral and cationic PdII organometallic molecular rectangles: Synthesis, characterization and nitroaromatic sensing

Coordination-driven self-assembly of oxalato-bridged half-sandwich p-cymene ruthenium complex [Ru2(μ-η4-C2O 4)(MeOH)2(7eta;6-p-cymene)2](O 3SCF3)2 (1a) with several ditopic donors (La-Ld) in methanol affords a series of bi- and tetranuclear metallamacrocycles (2a and 3-5). Similarly, the combination of 2,5-dihydroxy-1,4-benzoquinonato (dhbq)-bridged binuclear complex [Ru 2(μ-η4-C6H2O 4)(MeOH)2(η6-p-cymene)2](O 3SCF3)2 (1b) with a flexible bidentate amide linker (La) in 1:1 molar ratio gave the corresponding tetranuclear complex 2b. All the macrocycles were isolated as their triflate salts in high yields and were fully characterized by various spectroscopic techniques. Finally, the molecular structures of all the assemblies were determined unambiguously by single-crystal X-diffraction analysis. Interestingly, the combination of acceptor 1a or 1b with an unsymmetrical linear ditopic donor La results in a self-sorted linkage isomeric (head-to-tail) macrocycle (2a or 2b) despite the possibility of formation of two different isomeric macrocycles (head-to-head or head-to-tail) due to different connectivity of the donor. Molecular structures of the complexes 2a and 2b showed tetranuclear rectangular geometry with dimensions of 5.51 Å × 13.29 Å for 2a and 7.91 Å × 13.46 Å for 2b. In both cases, two binuclear RuII2 building blocks are connected by a μ-N-(4-pyridyl)isonicotinamide donor in a head-to-tail fashion. Surprisingly, the macrocycle 2a loses one counteranion and cocrystallizes with monodeprotonated 1,3,5-trihydroxybenzene via strong intermolecular π-π stacking and hydrogen bonding. The tweezer complex 3 showed strong fluorescence in solution, and it showed fluorescence sensing toward nitroaromatic compounds. A fluorescence study demonstrated a marked quenching of the initial fluorescence intensity of the macrocycle 3 upon gradual addition of trinitrotoluene and exhibits significant fluorescence quenching response only for nitroaromatic compounds compared to various other aromatic compounds tested. © 2011 American Chemical Society.

Organometallics

Constructions of 2D-metallamacrocycles using half-sandwich Ru II2 precursors: Synthesis, molecular structures, and self-selection for a single linkage isomer

A dinuclear organometallic acceptor 4,4′-bis[trans-Pt(PEt 3)2(O3SCF3)(ethynyl)]biphenyl (1) containing Pt-ethynyl functionality is synthesized. Multinuclear NMR ( 1H, 31P, and 13C), infrared (IR), and electrospray ionization mass spectrometry (ESI-MS) including single-crystal X-ray diffraction analysis established the formation of 1. Equimolar treatment of acceptor 1 separately with three different "clip" type ditopic donors (La-Lc) yielded [2 + 2] self-assembled three metallamacrocycles 2a-2c, respectively. These macrocycles were characterized by various spectroscopic techniques, and their sizes/shapes were obtained through geometry optimization using molecular mechanics universal force field (MMUFF) simulations. Attachment of unsaturated ethynyl functionality to biphenyl building unit helped to make the macrocycles (2a-2c) π-electron rich and thereby fluorescent in nature. Furthermore, 2c in solution has been examined to be suitable for sensing electron-deficient nitroaromatic like picric acid, which is often considered as a secondary chemical explosive. The fluorescence study of 2c showed a marked quenching of initial emission intensity upon titrating with picric acid (PA), and it exhibited the largest fluorescence quenching response with high selectivity among various other electron deficient aromatic compounds tested. © 2011 American Chemical Society.

Inorganic Chemistry

Self-assembly of metallamacrocycles using a dinuclear organometallic acceptor: Synthesis, characterization, and sensing study

Communication between two molecules, one confined and excited (triplet or singlet) and one free and paramagnetic, has been explored through quenching of fluorescence and/or phosphorescence by nitroxides as paramagnetic radical species. Quenching of excited states by nitroxides has been investigated in solution, and the mechanism is speculated to involve charge transfer and/or exchange processes, both of which require close orbital interaction between excited molecule and quencher. We show in this report that such a quenching, which involves electron-electron spin communication, can occur even when there is a molecular wall between the two. The excited state molecule is confined within an organic capsule made up of two molecules of a deep cavity cavitand, octa acid, that exists in the anionic form in basic aqueous solution. The nitroxide is kept free in aqueous solution. 1H NMR and EPR experiments were carried out to ascertain the location of the two molecules. The distance between the excited molecule and the paramagnetic quencher was manipulated by the use of cationic, anionic, and neutral nitroxide and also by selectively including the cationic nitroxide within the cavity of cucurbituril. Results presented here highlight the role of the lifetime of the encounter complex in electron-electron spin communication when the direct orbital overlap between the two molecules is prevented by the intermediary wall. © 2011 American Chemical Society.

Langmuir

Interaction between encapsulated excited organic molecules and free nitroxides: Communication across a molecular wall

Ultrafast forster resonance energy transfer (FRET) in a RTIL-P123 gel is studied by femtosecond up-conversion technique. The mixed gel consists of a tri-block copolymer, (PEO)20-(PPO)70-(PEO)20 and a room temperature ionic liquid (RTIL) (1-pentyl-3-methyl-imidazolium bromide, [pmim][Br]). The acceptor rhodamine 6G (R6G) being ionic, stays in the peripheral corona region of the micellar aggregates of the gel. We use two donor dyes of different hydrophobicity. The hydrophobic neutral donor coumarin 153 (C153) resides in the core while the hydrophilic ionic donor coumarin 343 (C343) is located in the corona. As a result donor-acceptor distances are different for the two donors. Thus by varying the donor one can study region dependent FRET processes in the RTIL-P123 gel.

Journal of the Indian Chemical Society

Region dependent ultrafast FRET in an ionic liquid-P123 gel: A femtosecond study

Thermodynamic properties of the troposphere, particularly water vapor content and temperature, change in response to physical mechanisms, including frictional drag, evaporation, transpiration, heat transfer, pollutant emission and flow modification due to terrain. The planetary boundary layer (PBL) is characterized by a greater rate of change in its thermodynamic state than higher tropospheric altitudes. Such changes in the PBL typically occur on time scales of less than one hour; whereas the upper troposphere exhibits much longer time constants. Large horizontal gradients in vertical wind speed and steep vertical gradients in water vapor and temperature in the PBL result in high-impact weather, including severe thunderstorms. Observation of these gradients in the PBL with improved vertical resolution is important for improvement of weather prediction. Additionally high vertical resolution and accuracy of measured thermodynamic profiles, especially water vapor and temperature, are important for initialization of numerical weather prediction models. Satellite remote sensing in the visible, infrared and microwave bands provides qualitative and quantitative measurements of many atmospheric properties, including cloud cover, precipitation, liquid water content and precipitable water vapor in the atmosphere above the PBL. However, its ability to characterize thermodynamic properties of the PBL is limited by the confounding factors of ground emission in microwave channels and of cloud cover in visible and IR channels, as well as limitations in the vertical resolution of the remote sensing instruments onboard the satellite. Ground-based microwave radiometers are routinely used to estimate thermodynamic profiles, but the accuracy and resolution of vertical profiles may be improperly estimated. Here a new technique has been used to improve the vertical resolution of retrieved water vapor density profiles, based on the design of the Compact Microwave Radiometer for Humidity Profiling (CMR-H) [1]. The CMR-H operates at four frequencies near the weak water vapor absorption line, namely 22.12, 22.67, 23.25, and 24.5 GHz. © 2011 IEEE.

Department of Electrical Engineering

2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011

Trade-off between vertical resolution and accuracy in water vapor retrievals from ground-based microwave brightness temperature measurements

Over the last decade, Si1-xGex has increasingly been used as a channel material in MOSFETs. Though many studies have dealt with the real bandstructure of Si1-xGex, the effect of germanium mole fraction x on complex bandstructure has been unexplored. Complex bands fundamentally determine band to band tunneling (BTBT) current. For example, using the orientation dependent complex bandstructure of silicon [1], it has been shown [2] that the BTBT current in the [110] direction is an order of magnitude larger than that along the [100] direction. BTBT contributes significantly to off-current Ioff in conventional MOSFETs, via the mechanism of gate induced drain leakage (GIDL). Additionally, BTBT determines the on current Ion in tunneling FETs, which have been suggested as next generation devices. Further, BTBT is more dominant in Si 1-xGex than silicon, owing to a narrower bandgap. In this work, we determine the orientation dependent complex bandstructure of Si 1-xGex along common crystallographic directions and predict trends in BTBT current. © 2011 IEEE.

Device Research Conference - Conference Digest, DRC

Orientation dependent complex bandstructure of Si1-xGe x alloys

Zero-crossing rate (ZCR) is one of the most important acoustic feature that has been widely used in voice activity detection, voiced/unvoiced speech classification, music/speech classification image processing, optics, biomedical engineering, radar and fluid mechanics. The conventional time-domain ZCR measurement is sensitive to nonstationary noise. In this paper, we present a noise robust zerocrossing rate computation method. The number of zerocrossings is computed in autocorrelation-domain rather than in time-domain. The accuracy of the proposed measurement method is evaluated using both sinusoidal and speech waveforms under different signal-to-noise ratios (SNRs). Experimental results show that the proposed ZCR measurement method achieves better accuracy than the conventional ZCR measurement methods in the literature. © 2011 IEEE.

3rd International Conference on Trendz in Information Sciences & Computing …

Noise robust zerocrossing rate computation for audio signal classification

Biological Sciences and Engineering

Science

Indian science: Steps to excellence

Despite remarkable progress in the control of infectious diseases through vaccination, better delivery systems have been poorly explored. There is renewed interest in the discovery of novel vaccines and adjuvants owing to emerging and reemerging diseases and the burden and complexity of chronic infectious diseases. Conversely, the need for rapid local, regional, mucosal or parenteral bioavailability has led to advances in delivery systems and devices. Here, we present recent developments in the field of non-invasive cutaneous delivery of vaccines for infectious diseases. Transdermal delivery using microneedles could revolutionize the way prophylactic interventions for infectious diseases are carried out in the future. © 2011 Elsevier Ltd. All rights reserved.