Facile synthesis, single crystal analysis, and computational studies of sulfanilamide derivatives

Exploring key electronic and non-linear optical amplitute with bilateral intramolecular charge transfer into thieno[3,2-b]thiophene-based compounds: a DFT approach

Organic molecules are considered important NLO materials in the modern age because of their potential optoelectronic features. Therefore, a series of organic molecules (DBTD1-DBTD7) with a D-π-A architecture was designed from the reference compound (DBTR) by structurally tailoring it with effective donors and making significant modifications to the π-spacers. All derivatives and references were initially optimized at the M06 functional with a 6-311G(d,p) basis set. Furthermore, the optimized structures (DBTR and DBTD1-DBTD7) were used to determine the density of states (DOS), frontier molecular orbitals (FMOs), natural bond orbital (NBO), UV-Visible, transition density matrix (TDM) analyses, and the most significant NLO properties. Among the compounds, DBTD4 had the smallest band gap (2.882 eV) which was further supported by DOS analysis. The global reactivity parameters were also related to the HOMO-LUMO band gap, where the compound with the lowest band gap showed a lower hardness value and higher softness value. NBO analysis was used to explain the molecular stability and hyperconjugation. DBTD4 and DBTD5 demonstrated comparable low bandgaps with the highest comparable NLO parameter values. However, we also observed efficient NLO characteristics for DBTD6 and DBTD7. The highest μ tot value is observed in DBTD6 as 10.362 D, whereas the highest α tot (1.48 × 10-22 and 1.47 × 10-22 esu) is observed in DBTD6 and DBTD7. Further, β tot (6.68 × 10-28 and 6.23 × 10-28 esu) in DBTD4 and DBTD5 and γ tot (6.20 × 10-33 and 6.59 × 10-33 esu) values are observed in DBTD5 and DBTD6. To acquire favorable NLO responses in molecules, structural modelling utilizing efficient donor units played significant role. Thus, current research insights encourage researches to develop efficient NLO materials for optoelectronic applications.

Unveiling peripheral symmetric acceptors coupling with tetrathienylbenzene core to promote electron transfer dynamics in organic photovoltaics

Non-fullerene organic compounds are promising materials for advanced photovoltaic devices. The photovoltaic and electronic properties of the derivatives (TTBR and TTB1-TTB6) were determined by employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) analyses using the M06/6-311G(d,p) functional. To enhance the effectiveness of fullerene-free organic photovoltaic cells, modifications were applied to end-capped acceptors by using strong electron-withdrawing moieties. The structural tailoring showed a significant electronic impact for HOMO and LUMO for all chromophores, resulting in decreased band gaps (3.184-2.540 eV). Interestingly, all the designed derivatives exhibited broader absorption spectra in the range of 486.365-605.895 nm in dichloromethane solvent. Among all derivatives, TTB5 was observed to be the promising candidate because of its lowest energy gap (2.54 eV) and binding energy (0.494 eV) values, along with the bathochromic shift (605.895 nm). These chromophores having an A-π-A framework might be considered promising materials for efficient organic cells.

Unveiling the influence of end-capped acceptors modification on photovoltaic properties of non-fullerene fused ring compounds: a DFT/TD-DFT study

Herein, unique A-D-A configuration-based molecules (NBD1-NBD7) were designed from the reference compound (NBR) by utilizing the end-capped acceptor modification approach. Various electron-withdrawing units -F, -Cl, -CN, -NO2, -CF3, -HSO3, and -COOCH3, were incorporated into terminals of reference compound to designed NBD1-NBD7, respectively. A theoretical investigation employing the density functional theory (DFT) and time-dependent DFT (TD-DFT) was performed at B3LYP/6-311G(d,p) level. To reveal diverse opto-electronic and photovoltaic properties, the frontier molecular orbitals (FMOs), absorption maxima (λ max), density of states (DOS), exciton binding energy (E b), open-circuit voltage (V oc) and transition density matrix (TDM) analyses were executed at the same functional. Moreover, the global reactivity parameters (GRPs) were calculated using the HOMO-LUMO energy gaps from the FMOs. Significant results were obtained for the designed molecules (NBD1-NBD7) as compared to NBR. They showed lesser energy band gaps (2.024-2.157 eV) as compared to the NBR reference (2.147 eV). The tailored molecules also demonstrated bathochromic shifts in the chloroform (671.087-717.164 nm) and gas phases (623.251-653.404 nm) as compared to NBR compound (674.189 and 626.178 nm, respectively). From the photovoltaic perspectives, they showed promising results (2.024-2.157 V). Furthermore, the existence of intramolecular charge transfer (ICT) in the designed compounds was depicted via their DOS and TDM graphical plots. Among all the investigated molecules, NBD4 was disclosed as the excellent candidate for solar cell applications owing to its favorable properties such as the least band gap (2.024 eV), red-shifted λ max in the chloroform (717.164 nm) and gas (653.404 nm) phases as well as the minimal E b (0.126 eV). This is due to the presence of highly electronegative -NO2 unit at the terminal of electron withdrawing acceptor moiety, which leads to increased conjugation and enhanced the intramolecular charge transfer (ICT) rate. The obtained insights suggested that the designed molecules could be considered as promising materials for potential applications in the realm of OSCs.

A quantum-chemical insight into SOMO-HOMO conversion in phosphorus-boron cation radicals

Organic radicals exhibiting SOMO-HOMO conversion (SHC) electronic configurations have recently garnered increasing attention due to their exceptional stability and photophysical properties. In this study, we investigate two series of phosphorus-boron cation radicals based on 1,3,5-trimethylphenyl units substituted with P and B atoms, varying numbers of P-B moieties, and π-conjugation linkers. We perform quantum-chemical calculations to systematically assess the influence of chemical substituents on the SHC electronic structural features. Our computational results demonstrate that the SHC electronic configurations of the studied complexes are primarily determined by the number of P-B moieties, specifically, phosphorus-boron cation radicals with two P-B moieties as terminal groups in π-conjugation linkers, which efficiently arrange electrons to increase HOMO energies compared to corresponding radicals with only one P-B unit. Furthermore, spin density distributions change as the size of π-conjugation linkers increases. Natural bond orbital (NBO) and atoms-in-molecules (AIM) analyses reveal strong intramolecular charge transfer between P and B atoms along with other stabilized donor-acceptor interactions and significant covalent bonds between P and B atoms. Moreover, synergistic effects resulting from 1,3,5-trimethylphenyl substitutions and enlarged π-conjugation linkers containing P-B units confer excellent photophysical properties upon these studied radicals, making them potential stable radicals in optoelectronic applications.

Synthesis, characterization and NLO properties of 1,4-phenylenediamine-based Schiff bases: a combined theoretical and experimental approach

In the current study, three novel 1,4-phenylenediamine-based chromophores (3a-3c) were synthesized and characterized and then their nonlinear optical (NLO) characteristics were explored theoretically. The characterization was done by spectroscopic analysis, i.e. FT-IR, UV-Visible, and NMR spectroscopy, and elemental analysis. Notably, these chromophores exhibited UV-Visible absorption within the range of 378.635-384.757 nm in acetonitrile solvent. Additionally, the FMO findings for 3a-3c revealed the narrowest band gap (4.129 eV) for 3c. The GRPs for these chromophores were derived from HOMO-LUMO energy values, which showed correspondence with FMO results by depicting a minimum hardness (2.065 eV) for 3c. Among these compounds, 3c displayed the highest nonlinear behavior with maximum μtot, βtot and γtot values of 4.79 D, 8.00 × 10-30 and 8.13 × 10-34 a.u., respectively. Our findings disclosed that the synthesized 1,4-phenylenediamine chromophores may be considered promising candidates for nonlinear optical materials, showing potential applications in the realm of optoelectronic devices.

Experimental and Computational studies on Intramolecular charge transfer, Terahertz and Two photon absorption of 3-[(4-Nitrophenyl Azo)]-9H-Carbazole-9-Ethanol (NPACE) from their Vibrational spectra for Optical limiting and NLO applications

Non-linear optical (NLO) features of 3-[(4-Nitrophenyl Azo)]-9H-Carbazole-9-Ethanol (NPACE) chromophore were investigated by FT-IR, FT-Raman, and UV-visible spectra aided by Density Functional Theory (DFT) using the B3LYP/6-311++G(d,p) basis set of Gaussian 16 W package. It is observed from the DFT calculation that the slight increase in the endocyclic angle of C13 -C14 -C15 and the reduction in exocyclic angle of N40 -N39 -C14 and C15 -C14 -N39 ascertained by experimental XRD values indicating the intramolecular charge-transfer interaction between the carbazole and nitrophenyl group through the diazo bridge. The vibrational contribution to the linear electro-optic effect is 15% of the total hyperpolarizability being calculated at B3LYP/6-311++G (d, p) for the NPACE molecule. It is also observed that the 8a, 19a, and 19b modes of the carbazole ring and the 8a, 8b, and 19b modes of the phenyl ring are found to be simultaneously and intensely active in IR and Raman spectra explaining the charge transfer interactions throughout the molecule. The low value of the HOMO- LUMO energy gap (2.5843 eV) and the deviation between the measured absorption wavelength (3.36 eV) from the computed (3.87 eV), both these facts substantiate the intramolecular charge transfer. The polarizability and first-order hyperpolarizability were calculated as 6.48 × 10-24 and 3.8 × 10-29 esu, respectively. The second harmonic generation (SHG) measurement experiment of NPACE was carried out using the powder method. The SHG efficiency is measured in comparison with the urea standard. The calculated torsional mode at 20 cm-1 is in excellent quantitative agreement with the experimentally determined terahertz absorption peak. The two-photon absorption coefficient of NPACE was estimated to be 0.9 × 10-11 mW-1, which is mainly due to the D-π-A type of molecular structure, and the optical limiting threshold for NPACE was estimated to be 1.52 × 1013 Wm-2 enabling this material as a potential candidate for optical limiting applications.

Exploration of linear and third-order nonlinear optical properties for donor-π-linker-acceptor chromophores derived from ATT-2 based non-fullerene molecule

In the current study, seven non-fullerene compounds abbreviated as ATTD2-ATTD8 were designed through structural tailoring and their nonlinear optical (NLO) properties were reported. The objective of this study was to explore the potential for newly configured D-π-A type non-fullerene-based compounds. Quantum chemical methods were adopted and revealed the molecules as highly efficient materials with favorable NLO characteristics for use in optoelectronic devices. The M06 functional along with the 6-311G(d,p) basis set in chloroform solvent were utilized for the natural bonding orbital (NBO) analysis, absorption spectra and computational assessments of frontier molecular orbitals (FMOs), global reactivity descriptors (GRPs), transition density matrix (TDM) and nonlinear optical properties (NLO) for ATTR1 and ATTD2-ATTD8. The HOMO-LUMO energy gap was significantly reduced in all the designed moieties compared to the reference compound in the following decreasing order: ATTR1 > ATTD8 > ATTD4 > ATTD5 > ATTD2 > ATTD7 > ATTD6 > ATTD3. All of the designed molecules (ATTD2-ATTD8) showed good NLO response. Global reactivity parameters were found to be closely associated with the band gap between the HOMO and LUMO orbitals, and the compound with the smallest energy gap, ATTD3, exhibited a lower hardness value of 1.754 eV and higher softness value of 0.570 eV with outstanding NLO response. For the reference compound and ATTD2-ATTD8 derivatives, attributes like dipole moment (μtot), average polarizability 〈α〉, first hyperpolarizability (βtot), and second hyperpolarizability γtot were calculated. Out of all the derivatives, ATTD3 revealed the highest amplitude with a βtot of 8.23 × 10-27 esu, which was consistent with the reduced band gap (1.754 eV) and suggested it was the best possibility for NLO materials in the future.

Facile Synthesis and DFT Analysis of Novel Thiazole-Based Hydrazones: An Experimental and Theoretical Perspective

Hydrazone compounds with remarkable nonlinear optical (NLO) properties were found with vast applications due to their cost-effective synthesis and greater stability. Therefore, we synthesized hydrazone scaffolds (TCAH1-TCAH8) by condensation reaction, and their structural confirmation was accomplished with spectroscopic methods (1H-, 13C-NMR, and HRMS). Quantum chemical calculations were also performed at B3PW91/6-311G(d,p) functional of DFT to explore electronic, structural, and chemical properties. To understand the NLO responses of afore-said chromophores, various kinds of analyses such as natural bonding orbitals (NBOs), frontier molecular orbitals (FMOs), UV-vis analysis, and density of states (DOS) were performed. Findings showed that the HOMO-LUMO energy gap in TCAH8 (3.595 eV) was found to be lower than the TCAH1-TCAH7 (4.123-3.932 eV) with a large red shift which leads to a substantial NLO response. Furthermore, strong intramolecular interactions showed the highest stabilization energy (24.1 kcal mol-1) for TCAH8 in the NBO transitions, combined with the least binding energy. The significant NLO response of TCAH4 was explored with ⟨α⟩, βtot, and ⟨γ⟩ values as 5.157 × 10-23, and 2.185 × 10-29, and 2.753 × 10-34 esu, respectively, among the entitled compounds. The recent findings may inspire scientists to develop extremely effective NLO materials for forthcoming hi-tech applications.

Efficient Synthesis, Spectroscopic Characterization, and Nonlinear Optical Properties of Novel Salicylaldehyde-Based Thiosemicarbazones: Experimental and Theoretical Studies

Currently, we reported the synthesis of six novel salicylaldehyde-based thiosemicarbazones (BHCT1-HBCT6) via condensation of salicylaldehyde with respective thiosemicarbazide. Through various spectroscopic methods, UV-visible and NMR, the chemical structures of BHCT1-HBCT6 compounds were determined. Along with synthesis, a computational study was also performed at the M06/6-31G(d,p) functional. Various analyses such as natural bond orbital (NBO) analysis, natural population analysis, frontier molecular orbital (FMO) analysis, and molecular electrostatic potential surfaces were carried out to understand the nonlinear optical (NLO) characteristics of the synthesized compounds. Additionally, a comparative study was carried out between DFT and experimental results (UV-vis study), and a good agreement was observed in the results. The energy gap calculated through FMOs was found to be in decreasing order as 4.505 (FHCT2) > 4.499 (HBCT6) > 4.497 (BHCT1) = 4.497(HMCT5) > 4.386 (CHCT3) > 4.241(AHCT4) in eV. The global reactivity parameters (GRPs) were attained through E _HOMO and E _LUMO, which described the stability and hardness of novel compounds. The NBO approach confirmed the charge delocalization and stability of the molecules. Among all the investigated compounds, a larger value (557.085 a.u.) of first hyperpolarizability (β_tot) was possessed by CHCT3. The NLO response (β_tot) of BHCT1-HBCT6 was found to be 9.145, 9.33, 13.33, 5.43, 5.68, and 10.13 a.u. times larger than that of the standard para-nitroaniline molecule. These findings ascertained the potential of entitled ligands as best NLO materials for a variety of applications in modern technology.

Enhancing the Photovoltaic Properties via Incorporation of Selenophene Units in Organic Chromophores with A2-π2-A1-π1-A2 Configuration: A DFT-Based Exploration

Currently, polymer organic solar cells (POSCs) are widely utilized due to their significant application, such as low-cost power conversion efficiencies (PCEs). Therefore, we designed a series of photovoltaic materials (D1, D2, D3, D5 and D7) by the incorporation of selenophene units (n = 1-7) as π₁-spacers by considering the importance of POSCs. Density functional theory (DFT) calculations were accomplished at MPW1PW91/6-311G (d, p) functional to explore the impact of additional selenophene units on the photovoltaic behavior of the above-mentioned compounds. A comparative analysis was conducted for designed compounds and reference compounds (D1). Reduction in energy gaps (∆E = 2.399 - 2.064 eV) with broader absorption wavelength (λ_max = 655.480 - 728.376 nm) in chloroform along with larger charge transference rate was studied with the addition of selenophene units as compared to D1. A significantly higher exciton dissociation rate was studied as lower values of binding energy (E_b = 0.508 - 0.362 eV) were noted in derivatives than in the reference (E_b = 0.526 eV). Moreover, transition density matrix (TDM) and density of state (DOS) data also supported the efficient charge transition origination from HOMOs to LUMOs. Open circuit voltage (V_oc) was also calculated for all the aforesaid compounds to check the efficiency, and significant results were seen (1.633-1.549 V). All the analyses supported our compounds as efficient POSCs materials with significant efficacy. These compounds might encourage the experimental researchers to synthesize them due to proficient photovoltaic materials.

Role of donors in triggering second order non-linear optical properties of non-fullerene FCO-2FR1 based derivatives: A theoretical perspective

The organic compounds are known as an emerging class in the field of nonlinear optical (NLO) materials. In this paper, D-π-A configured oxygen containing organic chromophores (FD2-FD6) were designed by incorporating various donors in the chemical structure of FCO-2FR1. This work is also inspired by the feasibility of FCO-2FR1 as an efficient solar cell. Theoretical approach involving DFT functional i.e., B3LYP/6-311G(d,p) was utilized to achieve useful information regarding their electronic, structural, chemical and photonic properties. The structural modifications revealed significant electronic contribution in designing HOMOs and LUMOs for the derivatives with lowered energy gaps. The lowest HOMO-LUMO band gap obtained was 1.223 eV for FD2 compound in comparison to the reference molecule (FCO-2FR1) i.e., 2.053 eV. Moreover, the DFT findings revealed that the end-capped substituents play a key role in enhancing the NLO response of these push-pull chromophores. The UV-Vis spectra of tailored molecules revealed larger λ _max values than the reference compound. Furthermore, strong intramolecular interactions showed the highest stabilization energy (28.40 kcal mol^-1) for FD2 in the natural bond orbitals (NBOs) transitions, combined with the least binding energy (-0.432 eV). Successfully, the NLO results were favorable for the same chromophore (FD2) which showed the highest value for dipole moment (μ _tot = 20.049 D) and first hyper-polarizability (β _tot = 11.22 × 10^-27 esu). Similarly, the largest value for linear polarizability ⟨α⟩ was obtained as 2.936 × 10^-22 esu for FD3 compound. Overall, the designed compounds were calculated with greater NLO values as compared to FCO-2FR1. The current study may provoke the researchers towards designing of highly efficient NLO materials via using the suitable organic linking species.

Theoretical designing of non-fullerene derived organic heterocyclic compounds with enhanced nonlinear optical amplitude: a DFT based prediction

In current era, non-fullerene (NF) chromophores have been reported as significant NLO materials due to promising optoelectronic properties. Therefore, a series of NF based chromophores abbreviated as TPBD2-TPBD6 with D–π–A architecture was designed from the reference compound (TPBR1) by its structural tailoring with an efficient donor and various acceptor groups for the first time. First, the structures of said compounds were optimized at M06-2X/6-311G (d,p) level. Further, the optimized structures were utilized to execute frontier molecular orbitals (FMOs), UV–Visible (UV–Vis) absorption, density of states (DOS) and transition density matrix (TDM) analyses at the same level to understand the non-linear (NLO) response of TPBR1 and TPBD2-TPBD6. Promising NLO results were achieved for all derivatives i.e., the highest amplitude of linear polarizability ⟨α⟩, first (βtotal) and second ($$\gamma$$ γ total) hyperpolarizabilities than their parent molecule. The compound TPBD3 was noted with the most significant NLO properties as compared to the standard molecule. The structural modeling approach by utilizing the acceptor molecules has played a prominent role in attaining favorable NLO responses in the molecules. Thus, our study has tempted the experimentalists to synthesize the proposed NLO materials for the modern optoelectronic high-tech applications.

A Comprehensive Study of N-Butyl-1H-Benzimidazole

Imidazole derivatives have found wide application in organic and medicinal chemistry. In particular, benzimidazoles have proven biological activity as antiviral, antimicrobial, and antitumor agents. In this work, we experimentally and theoretically investigated N-Butyl-1H-benzimidazole. It has been shown that the presence of a butyl substituent in the N position does not significantly affect the conjugation and structural organization of benzimidazole. The optimized molecular parameters were performed by the DFT/B3LYP method with 6-311++G(d,p) basis set. This level of theory shows excellent concurrence with the experimental data. The non-covalent interactions that existed within our compound N-Butyl-1H-benzimidazole were also analyzed by the AIM, RDG, ELF, and LOL topological methods. The color shades of the ELF and LOL maps confirm the presence of bonding and non-bonding electrons in N-Butyl-1H-benzimidazole. From DFT calculations, various methods such as molecular electrostatic potential (MEP), Fukui functions, Mulliken atomic charges, and frontier molecular orbital (HOMO-LUMO) were characterized. Furthermore, UV-Vis absorption and natural bond orbital (NBO) analysis were calculated. It is shown that the experimental and theoretical spectra of N-Butyl-1H-benzimidazole have a peak at 248 nm; in addition, the experimental spectrum has a peak near 295 nm. The NBO method shows that the delocalization of the aσ-electron from σ (C1-C2) is distributed into antibonding σ* (C1-C6), σ* (C1-N26), and σ* (C6-H11), which leads to stabilization energies of 4.63, 0.86, and 2.42 KJ/mol, respectively. Spectroscopic investigations of N-Butyl-1H-benzimidazole were carried out experimentally and theoretically to find FTIR vibrational spectra.

Exploration of Nonlinear Optical Properties for the First Theoretical Framework of Non-Fullerene DTS(FBTTh2)2-Based Derivatives

Organic compounds having significant nonlinear optical (NLO) applications are being employed in the optoelectronics field. In the current work, a series of non-fullerene acceptor (NFA) based compounds are designed by modifying the acceptors with different substituents using DTS(FBTTh ₂ ) ₂ R1 as a reference compound. To study the NLO responses to the tuning of various acceptors, DFT and TD-DFT based parameters were calculated at the M06 level along with the 6-31G(d,p) basis set. The designed compounds (MSTD2-MSTD7) showed smaller values of the energy gap in comparison to the reference compound. The energy gaps of the title compounds were linked to global reactivity insights; MSTD7 provided a lower band gap, with smaller and larger quantities for hardness and softness characteristics, respectively. Further, UV-vis analyses were performed for all of the designed compounds, displaying wavelengths red-shifted from that of DTS(FBTTh ₂ ) ₂ R1 _. The intraelectron transfer (ICT) process and stability of the title compounds were explored via frontier molecular orbital (FMO) and natural bond orbital (NBO) studies, respectively. Out of all the designed compounds, the highest value of linear polarizability ⟨α⟩ of 3.485 × 10^-22 esu, first hyperpolarizability (β_total) of 13.44 × 10^-27 esu and second-order hyperpolarizability ⟨γ⟩ of 3.66 × 10^-31 esu were exhibited by MSTD7. In short, all of the designed compounds exhibited promising NLO properties because of their low charge transport resistance. These NLO properties may be useful for experimental researchers to uncover NLO materials for modern applications.

de la Torre A, Khan MU, Raza AR, Kamal GM, Rehman MF, Alam MM, Imran M, Braga AA, Pertino MW. Facile Synthesis of Diversely Functionalized Peptoids, Spectroscopic Characterization, and DFT-Based Nonlinear Optical Exploration

Compounds having nonlinear optical (NLO) characteristics have been proved to have a significant role in many academic and industrial areas; particularly, their leading role in surface interfaces, solid physics, materials, medicine, chemical dynamics, nuclear science, and biophysics is worth mentioning. In the present study, novel peptoids (1-4) were prepared in good yields via Ugi four-component reaction (Ugi-4CR). In addition to synthetic studies, computational calculations were executed to estimate the molecular electrostatic potential, natural bond orbital (NBO), frontier molecular orbital analysis, and NLO properties. The NBO analysis confirmed the stability of studied systems owing to containing intramolecular hydrogen bonding and hyperconjugative interactions. NLO analysis showed that investigated molecules hold noteworthy NLO response as compared to standard compounds that show potential for technology-related applications.

Ultrasound-assisted theophylline polymorphic transformation: Selective polymorph nucleation, molecular mechanism and kinetics analysis

In this paper, the ultrasound-assisted solvent-mediated polymorphic transformation of theophylline was explored in detail. The induction time and reconstruction time were significantly decreased by ultrasound, thereby decreasing the total transformation time and promoting the transformation process. The ultrasound-promoted efficiency of nucleation was different in three alcoholic solvents, which was difficult to explain by traditional kinetic effects. To resolve the above confusion, binding energies calculated by Density Functional Theory were applied to explore the relationship between the ultrasound-promoted efficiency of nucleation and solute-solvent interactions. Then, a possible molecular self-assembly nucleation pathway affected by ultrasound was proposed: the ultrasound could change and magnify the crucial effect of the specific sites of solute-solvent interactions in the nucleation process. Finally, the transformation kinetics with different effective ultrasonic energies was quantitatively analyzed by Avrami-Erofeev model, indicating that the dissolution element in the rate-limiting step was gradually eliminated by higher ultrasonic energy. Fortunately, the elusive crystal form V could be easily obtained by the ultrasound-assisted polymorph transformation. This proved to be a robust method to produce high purity form V of theophylline. The outcome of this study demonstrated that the proper ultrasonic irradiation had the potential to produce specific polymorphs selectively.

Nanometer CeO2 doped high silica ZSM-5 heterogeneous catalytic ozonation of sulfamethoxazole in water

A novel CeO₂ doped high silica ZSM-5(CeO₂@HSZSM-5) composite was originally fabricated via ammonia precipitation for the catalytic ozonation of sulfamethoxazole (SMX). Physicochemical properties have been investigated through electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, etc. The prepared nanometer CeO₂@HSZSM-5 had a much higher specific surface (348-395 m²/g), a finer crystallite size (8.2-33.5 nm) and superior stability. Temperature-programmed desorption and reduction analysis revealed that the formed CeO₂ nanoparticles on the surface of CeO₂@HSZSM-5 could improve the reducibility of surface-capping oxygen, induce more oxygen vacancies and promote oxygen migration. CeO₂@HSZSM-5 exhibited excellent catalytic performance for SMX mineralization in the pH range of environmental waters. The great enhancement of CeO₂@HSZSM-5 catalytic activity was ascribed to the conversion of O₃ into active oxygen involved in SMX mineralization, including ^.OH, O₂^.- and ¹O₂. This work provides a reference for the removal of pollutants by zeolite supported Ce catalytic ozonation process in water.

Exploration of CH⋯F & CF⋯H mediated supramolecular arrangements into fluorinated terphenyls and theoretical prediction of their third-order nonlinear optical response

In the present study, three novel fluorinated terphenyl compounds i.e., 2′,4,4′′,5′-tetrafluoro-1,1':4′,1′′-terphenyl (1), 2′,5′-difluoro-1,1':4′,1′′-terphenyl (2) and 2′,5′-difluro-4,4′′-diphenoxy-1,1:4′,1′′-terphenyl (3) have been synthesized by Suzuki Miyaura method. Single crystal XRD study reveals ð-ð stacking stabilization in molecular packing along with F⋯H and F⋯C interactions. This computational quantum chemical exploration was also done by using density functional theory (DFT) methods. The comparison of experimental (SC-XRD) and theoretical (DFT) investigations on structural parameters have been reported which shows reasonable agreements. Hirshfeld surface analysis explores the strength of intermolecular interactions present in the synthesized compounds. A substantial computational analysis of synthesized compounds is done for their optoelectronic and third-order nonlinear optical properties. The third-order NLO study was performed at M06/6-311G* level of theory. A comparative analysis of third-order polarizability of studied compounds is done with that of para-nitroaniline (p-NA) molecule which is often considered as a prototype NLO molecule. The third-order NLO analysis results suggest that all investigated compounds 1, 2 and 3 have significant potential as efficient third-order NLO molecules as compared to p-NA. The studied compounds 1, 2 and 3 possess about 13.7 times, 5.2 times and 5.17 times larger third-order polarizability amplitudes than that of p-NA (25.45 × 10⁻³⁶ esu) as calculated at same M06/6-311G* levels of theory. Time-dependent density functional theory (TD-DFT) calculations are performed for electronic excitation energies and their oscillator strengths. The studies of frontier molecular orbitals (FMO) analysis, total and partial density of states (DOS) were performed to investigate the intramolecular charge transfer (ICT) process in the entitled compounds.

Three novel fluorinated terphenyls were synthesized by a Suzuki Miyaura method. DFT and TDDFT were performed to explore FMO, DOS analysis and third-order NLO properties. This may provide new ways to utilise fluorinated terphenyl compounds as advanced functional materials.