Determination of excited singlet-state dipole moments of hydroxy and methoxy coumarins using solvatochromic method

Husain, M.; Sindhu, Rajeev; Tandon, H.C.

doi:10.5155/eurjchem.3.1.75-80.498

Cited by 12 publications

(2 citation statements)

References 47 publications

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“…5×10 -3 M), the absorption spectra exhibit two bands with maxima around 205 and 230 nm. The first band showed a strong nature, indicating the character of δ → δ* transition, and the second band with a longer wavelength has a weak nature related to the n → δ* transition of the nitrogen or oxygen atom in the morpholine skeleton [25]. With increasing solvent polarity, the two bands showed a positive (red) bathochromic shift with stabilization of the solute excited state rather than the ground state.…”

Section: Electronic Absorption Spectramentioning

confidence: 97%

Spectroscopic study of solvent effects on the electronic absorption spectra of morpholine and its complexes

et al. 2023

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The electronic absorption spectra of morpholine and its five morpholine complexes have been studied in different solvents of various polarities. The regression and correlation coefficients have been calculated with the SPSS program. Solvation energy relationships were deduced from spectral shifts and correlated with solvent parameters α (solvent hydrogen bond donor acidity), β (solvent hydrogen bond acceptor basicity), and π* (dipolarity/polarizability). The percentage contributions of the calculated solvatochromic parameters show that classic solvation effects play a major role in explaining the spectral shifts in all investigated complexes. The blue shift of [Fe(MOR)3Cl3]·4H2O, [Ni(MOR)4Cl2]·4H2O, and [Cu(MOR)4Cl2]·6H2O complexes is due to the formation of hydrogen bonds, which suggests the stabilization of the ground electronic state compared with the excited state. [CuNi(MOR)2Cl4]·4H2O and [CuZn(MOR)3Cl4]·2H2O are mixed metal complexes that suffer a red shift due to the solute-solvent interactions, which causes stabilization of the excited solute state with increasing solvent polarity. The bands are affected by specific solute-solvent interactions including hydrogen bond donor ability (acidity) and hydrogen bond acceptor ability (basicity) and nonspecific solute-solvent interactions including electromagnetic interaction between the dipole moments of solute and polar solvents.

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Section: Electronic Absorption Spectramentioning

confidence: 97%

Spectroscopic study of solvent effects on the electronic absorption spectra of morpholine and its complexes

et al. 2023

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“…17 Those are modeled by analytical expressions, 18,19 which are frequently used to derive ground and excited state dipole moments of dyes in solution. 20 In Ref. 21 the deviation of measured data from the models is clearly discerned for fluorescein in protic solvents, whereas with aprotic solvents good compliance was found.…”

Section: Solvatochromismmentioning

confidence: 99%

Indicating pressure and environmental effects by means of the spectral shift with rhodamine B and fluorescein

Johann

2015

AIP Advances

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Fluorescence absorption and emission wavelengths can be influenced by environmental conditions, such as pressure, temperature and concentration. Here those effects are explored with an emphasis on determining the potential of rhodamine B and fluorescein as high-pressure indicators. The red shift of the emission peak maxima of rhodamine B and fluorescein are investigated in dependence of pressure up to 200 MPa using as the solvents water, ethanol and poly(dimethylsiloxane) (PDMS) with rhodamine B and water, polystyrene beads and melamine resin beads with fluorescein. Emission spectra recording and peak fitting is done automatically at time intervals of down to a second and with 0.3 nm wavelength resolution. The wavenumber-pressure relation for rhodamine B reveals increasing divergence from linear behavior in the sequence of the solvents water, ethanol and silicone rubber. Graphical correlation of the data diverging only slightly from linearity with a selection of polarity functions is enabled using the concept of 'deviation from linearity (DL)' plots. Using the example of rhodamine B dissolved in PDMS elastomer it is shown that there is a temperature induced irreversible molecular reordering, when scanning between 3 and similar to 50 degrees C, and a polarity change in the proximity of the embedded dye molecule. Swelling studies are performed with PDMS containing rhodamine B, where the elastomer is first put in water, then in ethanol and again in water. There a complex solvent exchange process is revealed in the elastomer demonstrating the feasibility of fluorescence spectroscopy, when observing variations in wavelength, to indicate and enlighten molecular rearrangements and swelling dynamics in the polymer, and polarity changes and solvent exchange processes in the dye solvation shell

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A New Candidate Laser Dye Based 1,4-Bis[β-(2-Naphthothiazolyle)Vinyl]Benzene. Spectroscopic Behavior, Laser Parameters and Excitation Energy Transfer

Al-Romaizan

Hussein

2018

J Fluoresc

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A new candidate laser dye based 1,4-bis[β-(2-naphthothisolyl) vinyl] benzene (BNTVB) were prepared, and characterized in various organic solvents. The center polarity is less sensitive than electronic absorption. A red shift was noticed in the fluorescence spectra (ca. 40 nm) with increment in the solvent's polarity, this means that BNTVB's polarity appreciates upon excitation. The dipole moment of ground state (μ) and the excited singlet state dipole moment (μ) are determined from Kawski - Chamma and Bakshiev-Viallet equations using the disparity of Stokes shift with solvent polarity function of ε (dielectric constant) and n (refractive index) of the solvent. The result was found to be 0.019D and 5.13D for ground and exited state, in succession. DFT/TD-DFT manners were used to understand the electronic structures and geometric of BNTVB in other solvents. The experimental and theoretical results showed a good agreement. The photochemical quantum yield (Ф) of BNTVB was calculated in variable organic reagents such as Dioxane, CHCl, EtOH and MeOH at room temperature. The values of φ were calculated as 2.3 × 10, 3.3 × 10, 9.7 × 10 and 6.2 × 10 in Dioxane, CHCl, EtOH and MeOH, respectively. The dye solutions (2 × 10 M) in DMF, MeOH and EtOH give laser emission in the blue-green region. The green zone is excited by nitrogen pulse 337.1 nm. The tuning range, gain coefficient (α) and cross - section emission (σ) of laser were also estimated. Excitation energy transfer from BNTVB to rhodamine-6G (R6G) and N,N-bis(2,6-dimethyphenyl)-3,4:9,10-perylenebis-(dicarboximide) (BDP) was also studied in EtOH to increase the laser emission output from R6G and BDP when excited by nitrogen laser. The dye-transfer power laser system (ETDL) obeys the Foster Power Transmission (FERT) mechanism with a critical transmission distance, R of 40 and 32 Ả and k equals 2.6 × 10 and 1.06 × 10 M s for BNTVB / R6G and BNTVB / BDP pair, respectively.

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Determination of excited singlet-state dipole moments of hydroxy and methoxy coumarins using solvatochromic method

Cited by 12 publications

References 47 publications

Spectroscopic study of solvent effects on the electronic absorption spectra of morpholine and its complexes

Spectroscopic study of solvent effects on the electronic absorption spectra of morpholine and its complexes

Indicating pressure and environmental effects by means of the spectral shift with rhodamine B and fluorescein

A New Candidate Laser Dye Based 1,4-Bis[β-(2-Naphthothiazolyle)Vinyl]Benzene. Spectroscopic Behavior, Laser Parameters and Excitation Energy Transfer

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