Indian Institute of Technology Indore

About: Indian Institute of Technology Indore is a education organization based out in Indore, Madhya Pradesh, India. It is known for research contribution in the topics: Fading & Support vector machine. The organization has 1606 authors who have published 4803 publications receiving 66500 citations.

Graphene Oxide as Metal-Free Catalyst in Oxidative Dehydrogenative C–N Coupling Leading to α-Ketoamides: Importance of Dual Catalytic Activity

Abstract: A heterogeneous, inexpensive, and environmentally friendly carbocatalyst, graphene oxide (GO) enables the formation of α-ketoamides from activated aldehydes and amines through a cross-dehydrogenative coupling pathway. The oxygenated functionalities (e.g., carboxyl, hydroxyl, ketonic, and epoxides) on the surface of graphene oxide impart acidic as well as oxidizing properties to the material. This dual catalytic property of graphene oxide is explored toward the generation of α-ketoamides where surface acidity of graphene oxide favors the initial formation of hemiaminal intermediate followed by oxidation leading to the desired final product. The hemiaminal intermediate could be isolated and confirmed by NMR and mass analysis. A few control experiments confirmed that both acidic and oxidizing catalytic activities of graphene oxide were instrumental in the coupling reaction. Use of benzoic acid and p-toluene sulfonic acid as catalysts resulted in the formation of only hemiaminal intermediate as the major prod...

An iterative approach for decomposition of multi-component non-stationary signals based on eigenvalue decomposition of the Hankel matrix

Abstract: The decomposition of multi-component signals finds use in signal analysis. A new iterative approach to decompose a multi-component non-stationary signal into amplitude–frequency modulated (AM–FM) mono-component signals is presented in this paper. The proposed iterative approach is based on repeatedly performing eigenvalue decomposition (EVD) of the Hankel matrix, initially constructed from the samples of the multi-component signal. The components corresponding to significant eigenvalue pairs of the Hankel matrix are extracted. The process of constructing the Hankel matrix, performing EVD of the Hankel matrix and extraction of components corresponding to significant eigenvalue pairs, which we refer to as ‘Iteration’ is repeated till all the extracted components satisfy the defined mono-component signal criteria (MSC). The proposed decomposition approach being adaptive is suitable for analysis of non-stationary signals. The experimental results obtained by decomposing different kinds of synthetic and natural multi-component signals using the proposed iterative approach are presented and compared with the results obtained by empirical mode decomposition (EMD) and singular spectrum analysis (SSA). It is shown that unlike EMD, the ability of the proposed iterative approach to separate constituent mono-component signals is neither affected by the ratio of their mean frequencies nor by their relative amplitudes.

Design and synthesis of donor–acceptor pyrazabole derivatives for multiphoton absorption

Abstract: A series of ferrocenyl substituted pyrazaboles were prepared, which have an electron-withdrawing pyrazabole moiety as the central core, with a D–π–A–π–D structural motif (D = donor, A = acceptor) and containing a variety of π bridges. A crystallographic study reveals that the pyrazabole central core was observed in planar geometry. Strong two-photon absorption in the visible region and three-photon absorption in the near IR region were observed in the ferrocenyl substituted pyrazaboles. It was observed that the 2PA absorption cross-section increases with the conjugation length.