DFT and TD-DFT study on quadratic NLO response and optoelectronic activity in novel Y-shaped imidazole-based push-pull chromophores

Theoretical calculations of nonlinear optical responses for interpreting nonconjugated molecular systems to affect non-optimal properties

Understanding the intricacies of polymorphic origins in nonconjugated crystal systems is crucial for optimizing their properties. This study focuses on the crystal growth, characterization, and nonlinear optical (NLO) responses of a system analyzed using single crystal X-ray analysis, revealing a monoclinic geometry. Hirschfeld surface analysis emphasized the significance of intermolecular interactions in driving polymorph development, shedding light on the structural nuances influencing the material's properties. Through the evaluation of density functional theory parameters, the research found that the NLO responses of the system were as efficient as those of widely recognized materials like urea and KDP. Moreover, the stability of the system was confirmed through (NBO) analysis, showcasing its potential for practical applications. By manipulating the polymorphic crystal forms, researchers can potentially unveil new crystalline materials with tailored properties suitable for applications in optical and optoelectronic devices. This work underscores the importance of exploring novel crystal engineering strategies to harness the full potential of materials in the realm of advanced technologies.

Unraveling the structure-property relationship of novel thiophene and furan-fused cyclopentadienyl chromophores for nonlinear optical applications

Development of organic nonlinear optical materials has become progressively more important due to their emerging applications in new-generation photonic devices. A novel series of chromophores based on innovative thiophene and furan-fused cyclopentadienyl bridge with various powerful donor and acceptor moieties were designed and theoretically investigated for applications in nonlinear optics. To unravel the structure-property relationship between this new push-pull conjugated systems and their nonlinear optical property, multiple methods, including density of states analysis, coupled perturbed Kohn-Sham (CPKS) method, sum-over-states (SOS) model, the two-level model (TSM), hyperpolarizability density analysis, and the (hyper)polarizability contribution decomposition, were performed to comprehensively investigated the nonlinear optical and electronic properties of this new π-system. Due to excellent charge transfer ability of new bridge and distinctive structure of donor and acceptor, the designed chromophores exhibit deep HOMO levels, low excitation energy, high dipole moment difference and large hyperpolarizability, indicating the appealing air-stable property and remarkable electrooptic performance of them. Importantly, THQ-CS-A3 and PA-CS-A3 shows outstanding NLO response properties with βtot value of 6953.9 × 10-30 and 5066.0 × 10-30 esu in AN, respectively. The influence of the push-pull strength, the heterocycle and the π-conjugation of new bridge on the nonlinear optical properties of this novel powerful systems are clarified. This new series of chromophores exhibit remarkable electro-optical Pockels and optical rectification effect. More interestingly, PA-CS-A3 and THQ-CS-A2 also show appealing SHG effect. This study will help people understand the nature of nonlinear optical properties of innovative heteroarene-fused based cyclopentadienyl chromophores and offer guidance for the rational design of chromophores with outstanding electrooptic (EO) performance in the future.

Synthesis, characterization, biological activities, and computational studies of pyrazolyl-thiazole derivatives of thiophene

This study reports the synthesis, characterization, and biological evaluation of a series of pyrazolyl-thiazole derivatives of thiophene. Seven compounds were synthesized and characterized using NMR spectroscopy and mass spectrometry. The antimicrobial activities of these derivatives were evaluated against various bacterial (Escherichia coli, Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus) and fungal strains (Aspergillus niger, Aspergillus oryzae, Rhizopus, Candida albicans), demonstrating significant inhibition zones and low minimum inhibitory concentrations (MIC). In addition, the compounds exhibited notable antioxidant activities in DPPH and hydroxyl radical scavenging assays. Computational studies, including density functional theory (DFT) calculations and molecular docking simulations, were performed to understand the electronic properties and binding interactions of the synthesized compounds with biological targets. The molecular docking results supported the experimental findings, highlighting the potential of these pyrazolyl-thiazole derivatives as multifunctional therapeutic agents with both antimicrobial and antioxidant properties.

Theoretical study of the Tetraaminelithium and Tetraaminesodium molecules complexed with H-, Li- and Na- anions: static and dynamic NLO parameters

CONTEXT

This work focuses on the study of six molecules composed of the TetraAmineLithium (TALi+) and TetraAmineSodium (TANa+) structures linked with the anions H-, Li- and Na-. The NLO results obtained by these calculations showed significant values of static first hyperpolarizabilities (βtot) ranging from 8.74 * 10-30 to 691.99 * 10-30 esu. The two molecules TALi-Li and TALi-Na gave the highest values of static βtot equal to 563.20 and 691.99 * 10-30 esu respectively and static second hyperpolarizabilities (γav) of 680.02 and 779.05 * 10-35 esu. The highest dynamic first hyperpolarizabilities (β||) values are around 1474080.00 * 10-30 esu and 6,145,080.00 * 10-30 esu at 720 nm lasers and which are attributed to the two molecules TANa-Li and TANa-Na respectively. Four molecules have push-pull behavior where the anions are donor groups, the Li+-NH3 and Na+-NH3 groups are acceptor groups and a bridge composed by the three remaining NH3 ligands. The maximum wavelengths (λmax) in vacuum and in the presence of solvents for all molecules are in the range 240 to 870 nm.

METHOD

The software used in this study is Gaussian 16. The optimizations of the molecules were calculated by B3LYP-D3/6-31 +  + G(d,p). The static first hyperpolarizability (βtot) was calculated by different functionals: CAM-B3LYP, LC-wPBE, LC-BLYP, M11, wB97X, HSEh1PBE and M06-2X and the MP2 method, the basis-set used is 6-31 +  + G(d,p). Other calculations of static βtot were carried out by the CAM-B3LYP functional combined with several basis-sets: 6-31G(d,p), 6-31 +  + G(d,p), cc-pVDZ, AUG-cc- pVDZ, 6-311G(d,p), 6-311 +  + G(d,p), cc-pVTZ and AUG-cc-pVTZ. The calculations of the first (β||) and second (γ||) hyperpolarizabilities in second harmonic generation (SHG) were calculated by CAM-B3LYP/6-31 +  + G(d,p). The delocalization energies (E(2)) were determined by the NBO approach and calculated by the same functional and basis-set cited before. The solvation Gibbs energies (ΔGsolv) were calculated using the implicit SMD model. Maximum wavelengths (λmax) and oscillator strengths ([Formula: see text]) were calculated by TD-CAM-B3LYP/6-31 +  + G(d,p) in the presence of the implicit CPCM model.