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Pareek Y.,IITBombay | Ravikanth M.,IITBombay
European Journal of Organic Chemistry | Year: 2011

A series of mono-functionalized core-modified expanded porphyrin building blocks such as thiasapphyrin, thiarubyrin, oxasmaragdyrin, and BF 2-oxasmaragdyrin have been synthesized by simple condensation of readily available precursors. The mono-functionalized core-modified expanded porphyrin building blocks were used to synthesize the first three examples of covalently linked diphenylethyne-bridged dyads containing two different expanded porphyrin macrocycles, namely thaisapphyrin-BF 2-oxasmaragdyrin, thiarubyrin-BF 2-oxasmaragdyrin, and thiasapphyrin-thiarubyrin, by coupling appropriate mono-functionalized expanded porphyrin building blocks under mild Pd 0 coupling reaction conditions. The three dyads were freely soluble in common organic solvents and characterized by MS, NMR, absorption, electrochemical, and fluorescence techniques. The NMR, absorption, and electrochemical studies indicated that the two macrocycles in the dyads interact weakly with each other and maintain their independent characteristic features. The steady-state fluorescence studies of the dyads showed that the thiasapphyrin and thiarubyrin units are nonfluorescent but fluorescence was observed from the BF 2-oxasmaragdyrin unit. However, the quantum yield of the BF 2-oxasmaragdyrin unit in the dyads was less than that of monomeric BF 2-oxasmaragdyrin because of an enhancement of nonradiative decay channels operating in the dyads. The potential use of two of the three dyads containing the BF 2-smaragdyrin subunit as fluorescent sensors for anions was explored. The studies showed that the binding of the anion at the protonated sapphyrin and rubyrin sites in the respective dyads can be followed by the clear changes in the fluorescence band of the BF 2-oxasmaragdyrin unit, which indicates that these dyads can be used as fluorescent anion sensors. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Karamchandani S.H.,IITBombay | Mustafa H.D.,IITBombay | Mustafa H.D.,Tulane University | Merchant S.N.,IITBombay | Desai U.B.,IITHyderabad
Proceedings of the IEEE | Year: 2012

The paper presents a new paradigm from the perspective of pervasive on-body computing through an innovative polymerized textile, which exhibits sensing and radiation properties. A radical, first of its kind, sensor fabricated from unsaturated polymer resin textile, establishes a dynamic link connecting human thermodynamics to electrical ambiance. A dynamic fabrication process of esterification and $\eta$-polymerization is developed, which is articulately arrested using an innovatively formulated retardant, yielding a permanent thermally unstable partially oriented yarn (tuPOY). A prudently established nontrivial interchange phenomenon is founded, presenting an inimitable calibration mechanism of the sensors and charting a novel relationship of exuberated energy to lattice kinetics of tuPOY. This meticulously researched conducting medium of tuPOY, fabricated from aromatic polyamides, also presents an avant-garde architecture for proliferation of electrical and thermal signals concomitantly between the sensors and its transmission circuit. A power generating unit (PGU) delineates the power mining from thermal energy dissipated from the body, presenting a new dimension in operational power dynamics. A textile composite antenna is premeditated exclusively from radiating tuPOY-based patch and substrate, an archetype reporting in published literature. The judiciously designed antenna, with tuPOY coupled as its patch, and substrate operate as shields against the radiations directed towards the body leading to a self-sustained sculpt. The back-end hardware of the test setup conceptualizes an automated physician machine (APM) presenting a standalone architecture. The artificial intelligence core of APM is modeled on weighted multiclass support vector machines (wmSVMs). The capturing of signal variations, devoid of any metallic components, presents a singular facet of research and amalgamates various interdisciplinary fields, while providing a robust architecture with minimum tradeoffs. © 1963-2012 IEEE.

Patnaik P.,IITBombay | Mukhopadhyay G.,IITBombay | Singh P.P.,IITBombay
AIP Conference Proceedings | Year: 2011

We report here our study on SiC doped with transition metals using first principle density functional theory calculations. We have considered cubic SiC with 3d transition metals as substitutional impurities for Si and C site separately. Cubic SiC doped with Cr, Mn, show ferromagnetism whereas with Sc, Ti, V and Co show site dependency of magnetic properties. Rests of the impurities are found to be non-magnetic. © 2011 American Institute of Physics.

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