研究目的
Investigating the unusual emission spectrum of BBTP due to double ESIPT processes and resolving inconsistencies in previous theoretical studies.
研究成果
The double ESIPT process in BBTP is stepwise, not concerted, with EE* as the least stable tautomer and EK* and KK* being more stable. The refined computational model (LR+cLR/CC2) accurately reproduces experimental data, resolving previous inconsistencies. Substitutions with electron-withdrawing groups can redshift emission, while electron-donating groups may inhibit ESIPT. The study emphasizes the need for state-specific solvation approaches in theoretical analyses.
研究不足
The study relies on computational models which may have inherent approximations, such as the choice of functionals and basis sets affecting accuracy. The VEM-UD approach is computationally expensive and did not converge for some transition states. Experimental quantum yields are not available, limiting quantitative comparisons. The findings are specific to BBTP and its derivatives in chloroform solvent.
1：Experimental Design and Method Selection:
The study uses computational methods including Time-Dependent Density Functional Theory (TD-DFT) with functionals like B3LYP, M06-2X, and oB97X-D, and post-Hartree–Fock methods such as ADC(2) and CC2. Solvent effects are incorporated using polarizable continuum models (PCM) with linear-response (LR), corrected linear-response (cLR-PCM), and vertical excitation model (VEM-UD) schemes. Geometry optimizations, frequency calculations, and vibronic spectra simulations are performed to analyze ESIPT processes and optical properties.
2：Solvent effects are incorporated using polarizable continuum models (PCM) with linear-response (LR), corrected linear-response (cLR-PCM), and vertical excitation model (VEM-UD) schemes. Geometry optimizations, frequency calculations, and vibronic spectra simulations are performed to analyze ESIPT processes and optical properties.
Sample Selection and Data Sources:
2. Sample Selection and Data Sources: The molecule studied is 2,5-bis(benzoxazol-2-yl)thiophene-3,4-diol (BBTP) and its substituted derivatives. Data sources include computational outputs from software like Gaussian and Turbomole, with comparisons to experimental data from literature.
3：List of Experimental Equipment and Materials:
Computational software: Gaussian 16, Turbomole
4：6, FCclasses program for vibronic spectra. Basis sets:
6-31G(d), cc-pVTZ, 6-311+G(2d,p), aug-cc-pVTZ. Solvent: Chloroform modeled using PCM.
5：Experimental Procedures and Operational Workflow:
Optimize ground state and excited state geometries in gas phase and solvent using DFT and post-HF methods. Calculate vibrational frequencies to confirm minima or transition states. Compute absorption and emission energies with solvent corrections. Simulate vibronic spectra using Franck-Condon approximation. Analyze electron density differences and barriers for ESIPT processes.
6：Data Analysis Methods:
Statistical analysis of bond length deviations (MAD, MSD, MaxD, MinD). Comparison of relative energies and barriers between tautomers. Use of composite protocols combining different methods for accuracy. Validation against experimental emission spectra.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
