Solvatochromic studies on 4-Bromomethyl-7-methyl coumarins

Khanapurmath, Netravati; Kulkarni, Manohar V.; Pallavi, L.; Yenagi, Jayashree; Tonannavar, J.

doi:10.1016/j.molstruc.2018.01.070

Cited by 10 publications

(6 citation statements)

References 51 publications

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“…Solvent-mediated changes in the absorption or fluorescence spectrum of π-conjugated organic chromophores are well known. The polarity of the host solvent can modify the electronic structure of organic chromophores (i.e., solvatochromism) including coumarins, , indoles, hemicyanines, pyrazines, fluorescein, and many others. Whether the energy gap increases or decreases depends on the degree of stabilization of the ground and excited states. , Neglecting specific solvent interactions, the overall scale of the solvatochromic shift is related to the relative difference in the dipole moments associated with the levels involved in the luminescent transition .…”

Section: Introductionmentioning

confidence: 99%

“…11 Solvent-mediated changes in the absorption or fluorescence spectrum of π-conjugated organic chromophores are well known. The polarity of the host solvent can modify the electronic structure of organic chromophores (i.e., solvatochromism) including coumarins, 12,13 indoles, 14 hemicyanines, 15 pyrazines, 16 fluorescein, 17 and many others. Whether the energy gap increases or decreases depends on the degree of stabilization of the ground and excited states.…”

Section: ■ Introductionmentioning

confidence: 99%

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Metal–Organic Framework with Color-Switching and Strongly Polarized Emission

et al. 2019

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Hybrid fluorescent metal−organic frameworks (MOFs) use long-range intermolecular structural motifs in which the properties of the scaffold molecular system can be designed for specific applications. In this work, we constructed a MOF−chromophore system with a strongly polarized fluorescence and a large emission wavelength shift. To achieve this, we first devised a fluorophore with a linear conjugated backbone, bulky and noninteracting side chains, and easily accessible nitrogen atoms on its pyridine end groups. The linear nature of the conjugated backbone can lead to a strongly polarized luminescence, the side groups assist structural stability and minimize intermolecular interactions, and the sterically accessible pyridines provide a large fluorescence colorchanging ability. These features were demonstrated by synthesizing a planar Zn-based MOF in which the linear backbone of the chromophore molecules was highly aligned. The MOFs demonstrated a strong polarization effect and a color-shifting ability from green-yellow to orange. The results show that hybrid metal−organic materials can be designed to generate a strong command of the material luminescence, in terms of both emission color and polarization.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Metal–Organic Framework with Color-Switching and Strongly Polarized Emission

et al. 2019

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“…Synthesis of 4-Bromomethyl-6-Methyl Coumarin-Bromide Salt (3). 4-Bromomethyl-6-methylcoumarin (2) 18 (0.253 g, 1 mmol) and the triazole precursor (1) (0.125 g, 1 mmol) were dissolved in ample amount of 1,4−dioxane and kept for stirring for 2 days at 100 °C, which resulted in a white-off precipitate that was separated by Whatman filter paper and washed with excess 1,4-dioxane to remove the impurities. The obtained white-off solid was dried in an oven at 35 °C to produce the respective bromide salt 3 in pure form.…”

Section: Methodsmentioning

confidence: 99%

Augmenting the Electrocatalytic Activities of Metal–N-Heterocyclic Carbene Complexes as Bifunctional Electrocatalysts for Hydrogen and Oxygen Evolution Reactions by Carbon Composite Strategy

Vijayakumar,

Achar,

Yhobu

et al. 2024

Energy Fuels

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The pursuit of efficient transformation of green energy sources through water electrolysis necessitates the expansion of reasonable, earth-abundant, and robust bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this connection, N-heterocyclic carbenes (NHCs) coordinated metal complexes have become one of the most stimulating and ubiquitous classes of organometallics due to their ease of preparation and modularity in stereoelectronic possessions. Here, we report a series of metal NHC complexes synthesized by the reaction of an NHC precursor with an appropriate metal source and thoroughly characterized using spectral and analytical techniques. Both metal−NHC complexes and their carbon composites using multiwalled carbon nanotubes (MWCNT) and graphene plates (GP) were tested for their electrochemical HER and OER performances in acidic and basic electrolytes, respectively. The MWCNT and GP composites displayed improved HER activity compared with the bare complexes. Furthermore, a two-fold improved OER performance of the carbon composites was evident compared with the activity of the bare metal−NHC complexes to achieve the overpotential (η 10 ). Furthermore, the electrochemical impedance spectroscopic technique was used to bring out the key information required to justify the activity trend in HER and OER reactions and the nature of the electrode−electrolyte interaction of electrocatalysts.

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“…To a solution of 4-bromomethyl-7,8-benzocoumarin ( 2 ) 47 (0.578 g, 2 mmol) in 20 mL of 1,4-dioxane was added 1 H -methylallyl-1,2,4-triazole (0.246 g, 2 mmol) in a round bottom flask and the reaction mixture was stirred at 100 °C for 48 h. The obtained triazolium bromide salt was filtered using Whatman filter paper, washed with fresh 1,4-dioxane and air dried to afford bromide salt 4 as a stable beige solid. Yield: 84.5%.…”

Section: Methodsmentioning

confidence: 99%