Browsing by Author "Singh V.D."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Artificial light harvesting gel based on saponification-triggered gelation of aggregation-induced emissive BODIHYs
    (Royal Society of Chemistry, 2024) Yadav D.; Singh V.D.; Kushwaha A.K.; Kumar A.; Singh R.S.
    The present work provides a detailed study on saponification-triggered gelation of ester-based BODIHYs (B1 and B2) derived from ethyl 4-(2-(benzo[d]thiazol-2-yl(cyano)methylene)-hydrazinyl)-benzoate (L1) and diethyl 5-(2-(benzo[d]thiazol-2-yl(cyano)methylene)hydrazinyl)-isophthalate (L2). The ligands and BODIHYs display good emission in the solution and solid states. This study describes the gelation of BODIHYs for the first time, wherein stable gels GL2 and GB2 were prepared via saponification-triggered gelation of L2 and B2, respectively. The gelation and optical properties of the ligands and BODIHYs were compared through single-crystal X-ray diffraction studies. This work further explores the prospect of artificial light harvesting (ALH) via fabrication of ALHSs in the solution {B1/rhodamine B (RhB) and B2/RhB} and gel states (GB2/RhB). It was observed that in the presence of RhB, the emission intensities of BODIHYs and the gel decreased but those of RhB increased. The significant overlapping between the absorption spectrum of RhB and emission spectra of aggregates/gel suggests the possibility of energy transfer via noncovalent interactions. In these systems, B1, B2 and GB2 served as donors, whereas RhB served as an acceptor. � 2024 The Royal Society of Chemistry.
  • Thumbnail Image
    Item
    Intermolecular hydrogen bonding-assisted aggregation induced emission in quinolone-quinazoline conjugates and their potential use in acidochromism
    (Royal Society of Chemistry, 2024) Ali I.; Dwivedi B.K.; Singh V.D.; Pandey D.S.
    The effects of intermolecular hydrogen bonding on the aggregation behaviour for quinolone-quinazoline based D-A systems (Q1-Q3) have been reported. These compounds (Q1-Q3) have been strategically designed, synthesized and carefully characterized by spectral studies (IR, 1H, 13C-NMR, HRMS, UV/Vis, fluorescence) and their structures explicitly determined by X-ray single crystal analyses. Inclusion of apt electron donating groups (-H, Q1; -CH3, Q2 and -OCH3, Q3) enables these to display solvent-dependent emission indicative of a polarized excited state, probably due to enhanced intramolecular charge transfer (ICT). The occurrence of aggregation-induced emission enhancement (AIEE) in Q1-Q3 has been attributed to the restriction of the intramolecular rotation (RIR) and vibrations (RIV) via intermolecular hydrogen bonding. A possible role of the solvent and substituent in the photophysical behaviour and morphology of Q1-Q3 has been investigated by UV/Vis, emission, scanning electron microscopy (SEM) and dynamic light scattering (DLS) measurements. In addition, lowering of the energy gap between the HOMO and LUMO by electron donating substituents -CH3 (Q2) and -OCH3 (Q3) has been supported by DFT studies. Furthermore, they display reversible acid/base induced �ON-OFF-ON�-type signalling. The acidochromic behaviour upon exposure to acid/base has been supported by various studies. � 2024 The Royal Society of Chemistry.