Estimation of Dipole Moments and Quantum Yield of 5-chloro-2-methoxyphenyl Boronic Acid in Different Solvents Environment

Experimental and Theoretical Spectroscopic Investigation on Coumarin Based Derivatives for Non-Linear Optoelectronics Application

The spectral properties of MBTC (4-((4-((Benzo[d]oxazol-2-ylthio)methyl)-1H-1,2,3-triazol-1-yl)methyl)-7-methoxy-2H-chromen-2-one), CBTC (4-((4(((5Chlorobenzo[d]oxazol-2-yl)thio)methyl)-1H-1,2,3-triazol-1-yl)methyl)-2H-benzo[h]chromen-2-one) and TBTC (4-((4-((Benzo[d]oxazol-2-ylthio)methyl)-1H-1,2,3-triazol-1-yl)methyl)6(tertbutyl)2Hchromen-2-one) were studied in series of solvents with different polarity at room temperature to explore their solvatochromic effect and dipole moment. Stokes shift revealed a bathochromic shift with varying solvent polarity for all molecules which implies π-π^*transition. The ground state and excited state dipole moment of the molecules are calculated experimentally using salvatochromic methods like Lippert-Mataga, Bakhshiev, Kawaski-chamma-viallet, and Reichardt's microscopic solvent polarity functions and computationally by density functional theory (DFT) method. It is observed that the excited state dipole moment is higher than the ground state so synthesized molecules are more polar in the excited state than in the ground state. Using the DFT method HOMO and LUMO energy values were obtained and compared with values obtained by the cyclic voltammetry. Using the values of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) we have estimated energy gap, chemical hardness (ɳ), chemical softness (s), ionization potential (IP), electron affinity (EA), electronegativity (χ), electrophilicity (ω), and chemical potential (μ) of the molecules were estimated. The energy gap of MBTC, CBTC, and TBTC were found to be low, that is 3.861 eV, 3.822 eV, and 3.801 eV respectively, this indicates molecules are more reactive and it has the easiest π-π^* transition. Further electrophilic and nucleophilic sites were figured out using molecular electrostatic potential (MESP) which is useful in photochemical reactions. Hence the quantum chemical calculation and spectroscopic properties of the molecules can give a better understanding of their use in an optoelectronic device.

Quantum chemical computations and photophysical spectral features studies of two coumarin compounds

An attempt was made to determine the ground state and excited state dipole moments and quantum chemical computations of two coumarin compounds, namely 3-hydroxy-3-[2-oxo-2-(2-oxo-2H-chromen-3-yl)-ethyl]-1,3-dihydro-indol-2-one (3HOCE) and 3-[2-(8-methoxy-2-oxo-2H-chromen-3-yl)-2-oxo-ethylidene]-1,3-dihydro-indol-2-one (3MOCE). Both compounds displayed a red shift with enhancement in solvent polarity. The larger excited state dipole moment indicated the more polar nature of the selected compounds in the excited state than in the ground state. Kinetic stability and chemical reactivity of the selected compounds were studied with help of the quantum chemical properties of the compounds such as frontier molecular orbital analysis using density functional theory calculations with B3LYP/6-311+G (d, p) basis sets. Molecular electrostatic potential, Mulliken charges, natural bond orbital, and nonlinear optical properties were further studied. NBO analysis showed proton transfer within the selected donor-acceptor, depicting the large energy of stabilization for the compounds. The calculated Fukui function inferred the local softness and electrophilicity indices of used solute compounds.

Synthesis, Characterization and Solvatochromic Studies Using the Solvent Polarity Parameter, ENT on 2-Chloro-3-Ethylamino-1,4-Naphthoquinone

Quinones are molecules with varied biological activities and electronic properties which are used for important applications [1, 2]. Quinone with a heteroatom substituted, namely 2-chloro-3-ethylamino-1,4-naphthoquinone (N-CAN) was synthesized and characterized by various techniques such as H¹-NMR, C¹³-NMR, Mass spectroscopy and FT-IR spectroscopy. In this study, the solvatochromic effects on the spectral properties of 2-chloro-3-ethylamino-1,4-naphthoquinone have been investigated in different solvents taking into consideration, the solvent parameters like dielectric constant (ε) and refractive index (η) of different solvent polarities. Using Lippert-Mataga, Bakshiev's, Kawski-Chamma-Viallet and Reichardt equations, the ground state (μ_g) and excited state (μ_e) dipole moments were calculated. The angle between the excited state and ground state dipole moments were also calculated. Graphical Abstract ᅟ.