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: Computer science & Chemistry. The organization has 1606 authors who have published 4803 publications receiving 66500 citations.

Synthesis and Structural Characterization of New Divanada‐ and Diniobaboranes Containing Chalcogen Atoms

Abstract: The reaction of [CpnMCl4−x] (M=V: n=2, x=2; M=Nb: n=1, x=0; Cp=η5-C5H5) with LiBH4⋅THF followed by thermolysis in the presence of dichalcogenide ligands E2R2 (E=S, Te; R=2,6-(tBu)2-C6H2OH, Ph) and 2-mercaptobenzothiazole (C7H5NS2) yielded dimetallaheteroboranes [{CpV(μ-TePh)}2(μ3-Te)BH⋅thf] (1), [(CpV)2(BH3S)2] (2), [(CpNb)2B4H10S] (3), [(CpNb)2B4H11S(tBu)2C6H2OH] (4), and [(CpNb)2B4H11TePh] (5). In cluster 1, the V2BTe atoms define a tetrahedral framework in which the boron atom is linked to a THF molecule. Compound 2 can be described as a dimetallathiaborane that is built from two edge-fused V2BS tetrahedron clusters. Cluster 3 can be considered as an edge-fused cluster in which a trigonal-bipyramidal unit (Nb2B2S) has been fused with a tetrahedral core (Nb2B2) by means of a common Nb2 edge. In addition, thermolysis of an in-situ-generated intermediate that was produced from the reaction of [Cp2VCl2] and LiBH4⋅THF with excess BH3⋅THF yielded oxavanadaborane [(CpV)2B3H8(μ3-OEt)] (6) and divanadaborane cluster [(CpV)2B5H11] (7). Cluster 7 exhibits a nido geometry with C2v symmetry and it is isostructural with [(Cp*M)2B5H9+n] (M=Cr, Mo, and W, n=0; M=Ta, n=2; Cp*=η5-C5Me5). All of these new compounds have been characterized by 1H NMR, 11B NMR, and 13C NMR spectroscopy and elemental analysis and the structural types were established unequivocally by crystallographic analysis of compounds 1–4, 6, and 7.

An Automatic Subject Specific Intrinsic Mode Function Selection for Enhancing Two-Class EEG-Based Motor Imagery-Brain Computer Interface

Abstract: The electroencephalogram (EEG) signals tend to have poor time-frequency localization when analysis techniques involve a fixed set of basis functions such as in short-time Fourier transform and wavelet transform. These signals also exhibit highly non-stationary characteristics and suffer from low signal-to-noise ratio (SNR). As a result, there is often poor task detection accuracy and high error rates in designed brain-computer interfacing (BCI) systems. In this paper, a novel preprocessing method is proposed to automatically reconstruct the EEG signal by selecting the intrinsic mode functions (IMFs) based on a median frequency measure. Multivariate empirical mode decomposition is used to decompose the EEG signals into a set of IMFs. The reconstructed EEG signal has high SNR and contains only information correlated to a specific motor imagery task. The common spatial pattern is used to extract features from the reconstructed EEG signals. The linear discriminant analysis and support vector machine have been utilized in order to classify the features into left hand motor imagery and right hand motor imagery tasks. Our experimental results on the BCI competition IV dataset 2A show that the proposed method with fifteen channels outperforms bandpass filtering with 22 channels (>1%) and by >9 % $(p = 0.0078)$ with raw EEG signals, >13% $(p = 0.0039)$ with empirical mode decomposition-based filtering and >17 % $(p = 0.0039)$ with discrete wavelet transform-based filtering.

Mechanochromism and electroluminescence in positional isomers of tetraphenylethylene substituted phenanthroimidazoles

Abstract: The study of aggregation-induced emission (AIE) luminogens has gained momentum due to their remarkable luminogenic properties and applications in mechano-sensors and organic light-emitting diodes (OLEDs). In this article we have studied three positional isomers (ortho, meta, and para) of phenanthroimidazoles 3a–3c and explored their AIE, mechanochromic and electroluminescence behavior. The phenanthroimidazoles 3a–3c were synthesized by the Suzuki cross-coupling reaction of (2-bromo/3-bromo/4-bromo)phenathroimidazoles 2a–2c with 4-(1,2,2-triphenylvinyl)phenylboronic acid pinacol ester in good yields. The phenanthroimidazoles 3a–3c exhibit strong AIE. The mechanochromic study reveals reversible mechanochromism with good color contrast between blue and green colors. The ortho (3a) and meta (3b) isomers exhibit a grinding induced spectral shift of 98 nm while the para-isomer (3c) exhibits a spectral shift of 43 nm. Moreover, 3a–3c were explored as non-doped blue emitters in efficient organic light-emitting diodes. Among the three emitters, 3c provided a high quantum efficiency of 4.0% in a non-doped blue device.