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Herein, a series of N-pentylhydrazinylthiazole based compounds (EP1–EP7) were synthesized via three step synthetic strategy. The intermediates (TH1–TH7) were prepared with Hantzsch's approach followed by N-pentylation through substitution reaction to obtain targeted N-pentylhydrazinylthiazoles (EP1–EP7). The proposed structures were established with different spectroscopic methods like FTIR, 1H-, 13C-NMR, and HRMS. Further, the non-linear optical (NLO) effect of established structures was explored via quantum chemical investigations. NLO, ultraviolet–visible (UV–Vis), natural population analysis (NPA), global reactivity parameters (GRPs), and natural bond orbital (NBO) investigations were executed at M06/6-311G(d,p) level of density functional theory (DFT). UV–Vis analysis revealed that the yielded systems (EP1–EP7) exhibited absorption wavelength in UV–Vis spectrum in the range of 328.61–389.58 nm. EP1 exhibited the highest λmax value (389.58 nm) among all examined compounds due to its minimal Egap of 4.028 eV. The widening of the energy gap was observed from EP1 to EP7 (4.028–4.492 eV) as elucidated by Frontier molecular orbital (FMO) investigation. The GRPs were correlated with the results of energy gap. As EP1 depicted the minimum band gap (4.028 eV), so it exhibited the highest value of softness (0.248 eV−1) along with lower-most value of hardness (2.014 eV). NBO analysis revealed valuable insights into the charge delocalization and stability of the compounds (EP1–EP7). The dipole moment ( μ tot ) , average linear polarizability <α>, first and second order hyperpolarizabilities ( β to t and γ tot ) were also executed for EP1–EP7 at the above-mentioned level. Consequently, the maximum β tot (2.10 × 10−29 esu) and γ tot (9.31 × 10−35 esu) values were depicted by EP1 and EP3, respectively. Thus, all these outcomes unveiled that EP1 depicted robust response and proved to be the best NLO candidate for various hi-tech applications such as signal processing, fiber optics and data storage. [ABSTRACT FROM AUTHOR]

In small‐molecule organic solar cells (SM‐OSCs), it remains a big challenge to obtain favorable bulk heterojunction morphology by acceptor material design. In this report, efforts are being made to design efficient acceptor molecules for the active layer of the organic solar cell. Donor bridge modifications have been made by using effective donor units, and thus, four new molecules (KSD1–KSD4) have been designed and examined theoretically. Density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT) have been employed for the calculation of various geometric and structural parameters. Transition density matrix, open‐circuit voltage, reorganizational energy of hole and electron, and photovoltaic characteristics of newly designed molecules have been examined through quantum chemical techniques. Additionally, the frontier molecular orbital analysis along with excitation and binding energies has been performed for these molecules. A narrow bandgap with a redshift in absorption spectrum is observed for KSD1–KSD4 molecules. Results of different analyses have recommended that the designed molecules are effective contributors for organic solar cell applications. [ABSTRACT FROM AUTHOR]

Hole transport materials (HTMs) play a dominant role in enhancing the photovoltaic and optoelectronic properties of solar cells. These materials efficiently transport the hole, which significantly boosts the power conversion efficiencies of solar cells. In order to obtain better photovoltaic materials with efficient optoelectronic characteristics, we theoretically designed five new hole transport materials (Y3D1–Y3D5) after end-capped donor modifications of the recently synthesized highly efficient hole transport material Y3N (R). The relationships among photovoltaic, photophysical, optoelectronic and structural properties of these newly designed molecular models were studied at 6-31G(d,p) basis set and MPW1PW91 functional levels. Time‐Dependent Density Functional Theory (TDDFT) and density functional theory (DFT) proved to be excellent approaches for the studied systems. Geometrical parameters, molecular orbitals (MOs), open-circuit voltage (V oc), energy of binding and density of states were calculated. Low reorganization energy (RE) was noted; compared with the parent molecule (Reference/ R), the designed molecular models possess high mobility. Molecular electrostatic potential (MEP) also supports our conclusion. Last but not least, the Y3D3:PC 61 BM complex was also studied to comprehend the role of charge distribution. These analyses showed that our modelled molecules are more efficient than the Y3N molecule. Thus, recommendations are made for experimentalists to develop extremely efficient solar cells in the near future. Our results indicate that the designed and reported molecules are superior to the Y3N molecule; thus, we recommend these molecules to experimentalists for future development of highly efficient solar cells. [ABSTRACT FROM AUTHOR]

Non‐fused ring electron acceptors with different end‐capped substituents were designed to construct efficient organic solar cells (OSCs). End‐capped modification of acceptor materials is an efficient approach for developing high performance OSCs. In this report, five new S‐shaped fullerene‐free acceptor molecules (3P1 to 3P5) have been designed and examined through density function and time‐dependent density functional theories (TD‐DFTs). Designed molecules have twisted backbone with different out‐of‐plane rings that cause high solubility in dilute solvent. Different optoelectronic and photovoltaic properties of newly designed S‐shape molecules have been examined and explored through DFT tools. Orientation of frontier molecular orbitals (FMOs), light absorption range, exciton binding energy (Eb), oscillating strength (f), open circuit voltage (Voc), and transition density matrix (TDM) analysis have been performed for 3P1 to 3P5 molecules. Further, electron and hole reorganization energies are also estimated with excitation energy. Results of different computed parameters have recommended that these designed molecules are effective contributors for possible applications in the field of OSCs. [ABSTRACT FROM AUTHOR]

The sulfonamides class of drugs is known due to superb biological and notable nonlinear optical (NLO) applications. The current study reports detailed computational and spectroscopic studies of 16 novel benzene sulfonamides compounds. Computational studies on these compounds (1–16) have been performed with the aid of density functional theory (DFT) at B3LYP/6‐31G (d,p) basis set. B3LYP with the conjunction of 6‐31G(d,p) has been used to gain optimized geometries of these compounds. Different key parameters have been performed to analyze the structural‐property relationship, stability, reactivity, charge transferability, and NLO response of these novel compounds. Electronic properties including frontier molecular orbitals (FMOs) alignment, natural bond orbital (NBO) analysis, spectroscopic fourier‐transform infrared spectroscopy (FT‐IR), and NLO properties were calculated using B3LYP/6‐31G(d,p) and M06‐2X/6‐31G(d,p) basis sets. Natural bonding orbital analysis confirmed the successful electron transferability between donor moiety and acceptor moiety. The molecular electrostatic potential analysis unveils the intramolecular hydrogen bonding along with different reactive sites in these compounds 1–16. Global indices of reactivity were analyzed using energies of frontier molecular orbitals of compounds 1–16, which suggested that these compounds are chemically hard and stable compounds. Absorption maxima of all compounds were estimated with aid of time‐dependent DFT at B3LYP/6‐31G(d,p) basis set which disclosed the best agreement between experimental and DFT‐based recorded spectra. FT‐IR analysis (at B3LYP/6‐31G(d,p)) confirmed different modes of vibration in all the title compounds and also exhibit a concrete relation with experimentally recorded IR spectrums. Moreover, all the compounds (1–16) show good NLO response. NLO responses of 1–16 compounds were computed at the same level of B3LYP/6‐31G (d,p), which is found to be greater than the standard molecule. All these analyses suggest that 1–16 benzene sulfonamides compounds are found to be suitable candidates for biological and NLO applications. [ABSTRACT FROM AUTHOR]

The structural, electronic, dielectric and vibrational properties of zinc-blende (ZB) InAs were studied within the framework of density functional theory (DFT) by employing local density approximation and norm-conserving pseudopotentials. The optimal lattice parameter, direct band gap, static dielectric constant, phonon frequencies and Born effective charges calculated by treating In-4d electrons as valence states are in satisfactory agreement with other reported theoretical and experimental findings. The calculated band gap is reasonably accurate and improved in comparison to other findings. This work will be useful for more computational studies related to semiconductor devices. [ABSTRACT FROM AUTHOR]

The design and synthesis of a new triazolyl‐DPA (TAZDPA) based Zn2+ fluorescent sensor is reported. The structural architect of TAZDPA contains 2,2'‐dipicolylamine (DPA) and 1,2,3‐triazolyl moiety as chelators, which synergistically coordinate with Zn2+, resulting in dramatic fluorescent emission enhancement and a notable bathochromic shift due to the inhibition of photoinduced electron transfer (PET) process. Solution state structural characterization and molecular modeling of TAZDPA suggest that N3 of 1,2,3‐triazolyl moiety and DPA coordinate with Zn2+ to afford five‐membered coordination ring. The binding behavior and stoichiometry of the TAZDPA/Zn2+complex was studied by Job's plot, which suggested 1 : 1 stoichiometry. The nature of binding behavior of TAZDPA with Zn2+ was validated by 1H‐NMR that revealed a distinct downfield shift of DPA and triazolyl protons. Under physiological condition, TAZDPA displayed high selectivity for Zn2+ over a wide range of competing common cations, exhibiting ultra‐sensitivity with a limit of detection (LOD) of 8.3×101 nM. This implies that TAZDPA can detect chronic Zn2+ concentration for freshwater (>1.84 μM) denoted by the U.S. Environmental Protection Agency (EPA). [ABSTRACT FROM AUTHOR]

The ethyl 2-(4-methyl-(2-benzylidenehydrazinyl))thiazole-4-carboxylate ( 1) was synthesized via reaction of 4-methyl-(1-benzylidenehydrazinyl)-2-carbothioamide with ethyl bromopyruvate. The compound is characterized by FTIR and NMR before being analyzed by X-ray diffraction method. These properties of the structure are further investigated by DFT quantum chemical methods. The molecular geometry of the compound (1) was optimized using density functional theory (DFT/B3LYP) method with the cc-pVTZ basis sets in ground state. The MEP map exhibits the negative potential sites are on electronegative atoms and the positive potential sites around the hydrogen atoms. The MEP and Mulliken population analysis confirm the hydrogen bonding sites in the molecule. We have also calculated geometric parameters (bond lengths, bond angles, torsion angles), vibrational assignments and chemical shifts of the compound (1) theoretically and compared with the experimental data, these values are found in good agreement with each other. Although theoretical calculations were carried out in gas phase, however no significant differences were found in these values. [ABSTRACT FROM AUTHOR]

• NMR was employed to study the conformational aspects of MMPU. • DFT calculations were conducted to predict the electronic and structural properties. • Anti-MMPU is stabilized by intramolecular H-bonding. • Ag@SiO2 nanocomposite was synthesized and characterized. • SERS-based trace detection protocol for MMPU was developed. Phenylurea-based herbicides have been widely used to control the plant growth. Due to their toxicity, strict regulations to limit their usage have been applied. Developing trace detection protocols of substituted phenylureas has attracted more attention, especially with the availability of a wide range of spectroscopic and analytical techniques. In this study, the conformational and structural properties of 1-methoxy-1-methyl-3-phenylurea (MMPU) which belongs to the family of phenylurea-based herbicides have been characterized. The anti -configuration, facilitated by the intramolecular hydrogen bonding between the oxygen atom of the methoxy moiety and the acidic amide proton, was observed using the nuclear magnetic resonance (NMR) spectroscopy through the Selective Nuclear Overhauser Effect (SelNOE) approach. The density functional theory (DFT) calculations suggested that the anti form is at least 9 kcal/mol more stable than the corresponding syn structure. Possible degradation pathways of such a class of herbicides can be explored when a firm understanding of their electronic and conformational behaviors is established. The detection of trace MMPU has been successfully developed using the surface-enhanced Raman scattering (SERS) spectroscopic tool. The most enhanced peak associated with the carbonyl group stretching vibration which appears nearly at 1600 cm−1 has presented a Raman enhancement factor of 3.24 × 105 and a micrommolar limit of detection. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT calculation and NMR spectroscopy have been applied for conformational analysis of linuron. • The anti form of linuron is found to be significantly more stable than the syn form. • The intensities of four Raman lines were successfully enhanced and compared. • Both ring-Au 4 and HN-Au 4 interactions best represent the nature of SERS interaction. Linuron is a commonly used organic herbicide which is used in plant growth control. Due to its potential health concerns, the characterization and monitoring of linuron have been a subject of several studies. In this work, we employed nuclear magnetic resonance (NMR) and Raman spectroscopic techniques supported with the density functional theory (DFT) to investigate the conformational behavior and electronic aspects of linuron. The selective nuclear Overhauser effect (SelNOE) spectra confirmed that linuron exists predominantly in the anti configuration and is facilitated with a weak intramolecular hydrogen bonding between the acidic amide proton and oxygen of methoxy moiety. Quantum chemical results showed that the corresponding syn form of the molecule is 8.5 kcal/mol less stable. Further, the surface enhanced Raman scattering (SERS) technique using gold nanoparticles (AuNPs) was implemented as a potential spectroscopic protocol for the concentration monitoring of trace linuron. The Raman responses of four vibrational modes, namely C C stretching, C N stretching, N-H rocking and ring deformation, were successfully enhanced with an excellent linear concentration-intensity dependency. The aromatic C C stretching vibration at 1595 cm−1 in the Raman spectra has demonstrated the highest enhancement factor (6.5 × 104) and the lowest limit of detection (10-7 M). The interaction of linuron with the gold nanocluster was simulated by establishing a simple DFT model which predicted that the most pronounced binding with the gold atom takes place at the benzene ring. [ABSTRACT FROM AUTHOR]

• Sensing of procaine was investigated using SERS with Au nanoparticles. • The assignment of vibrational modes was performed by density functional theory. • SERS establishes a wider linear dynamic range and better detection limits over reported methods. • Modes prediction of interactions between procaine and gold resulting in signal enhancement. Surface-enhanced Raman scattering (SERS) spectroscopic technique was implemented for the determination of procaine in aqueous media by utilizing gold nanoparticle as substrates. A reduction technique was used to prepare the gold nanoparticles which were characterized by infrared and Raman methods. SERS spectra of procaine were recorded at a wide range of concentrations, and the Raman peaks along with their spectroscopic shifts have been identified and assigned. A Density Function Theory (DFT) calculation method was developed to understand possible interaction modes between gold atoms and procaine molecules. The intensity enhancement obtained for a number of Raman peaks were employed to develop a reliable quantitative determination approach for procaine in aqueous solutions. Such an approach exhibited high sensitivity and reproducibility with a reasonably wide linear dynamic range. The limit of detection of procaine achieved was up to 1 × 10–10 M, which is considered competitive compared to other previously reported analytical methods. [ABSTRACT FROM AUTHOR]

• Synthesis of donor-acceptor configurated nicotinaldehyde for NLO materials. • Structure confirmation through various spectroscopic technique. • Study of key electronic properties at M06/6–311 G (d,p) functional. • Utilization of TD-DFT approach for FMOs and UV–Vis analyses. In the current study, 6-methyl nicotinaldehyde derivatives (MNP - BTMP) were synthesized by using the Suzuki- cross-coupling method which involved deformylation approach. The FTIR, UV–Visible, 1HNMR and 13CNMR spectroscopic analyses were performed to validate the structures of newly synthesized derivatives. Additionally, the density functional theory (DFT) approach at M06/6–311G(d,p) level was utilized in order to calculate their optoelectronic and nonlinear optical (NLO) properties. Consequently, their HOMO-LUMO band gaps (E gap) were obtained in the range of 4.77–5.55 eV. A significant charge transfer from HOMO towards LUMO was investigated which was further supported by DOS. Moreover, they exhibited the maximum absorption wavelengths (λ max) in the UV- Vis region as 269.989–303.496 nm. Among the derivatives, BTMP was found with the least energy gap (4.77 eV) and the red-shifted absorption spectra (λ max =303.496 nm) as compared to other derivatives. Owing to these unique properties, BTMP was also found with significant linear polarizability ⟨ α ⟩ and hyperpolarizability (β tot and γ tot) values i.e., 2.816×10−23, 1.855 × 10−30 and 4.553 × 10−35 esu. , respectively among the titled compounds. These findings indicated the potential use of these organic derivatives in the NLO applications. [ABSTRACT FROM AUTHOR]

• Synthesis of hydrazinylthiazol-4(5 H)-one derivatives (EHT1-EHT5) is done by condensation reaction. • Structures were analyzed through different spectroscopic techniques. • The experimental results show good agreement with theoretical results. • NLO and electronic properties were also studied. Organic chromophores are desirable as efficient nonlinear optical (NLO) substances because of their structural tunability, easy synthesis and promising NLO response. Herein, we synthesized series of organic compounds (EHT1-EHT5) containing hydrazinylthiazol-4(5 H)-one (HT) as a base and explored their nonlinear optical (NLO) properties through quantum chemical investigations. Novel hydrazinylthiazol-4(5 H)-ones were synthesized via two step synthetic approach. The synthesized structures were initially solved by different spectroscopic techniques. The authentication of the prepared structures was achieved with high resolution mass spectrometry (HRMS). Density functional theory (DFT) studies were executed at M06/6–311 G (d,p) functional. The optimized structures were used to perform further analysis including frontier molecular orbitals (FMOs), UV- Visible (UV–Vis), natural bond orbitals (NBOs), density of states (DOS), transition density matrix (TDM) along with nonlinear optical (NLO) characteristics. The quantum chemical insights led towards minimum E gap (4.797 eV) for EHT3 among all the compounds. Additionally, the outcomes of FMOs analysis were also supported by density of state (DOS) which further elucidated the proficient charge transference between HOMO and LUMO. The NBOs analysis revealed that all compounds had promising push-pull process through the existence of electron-accepting as well as donating groups. UV–Vis analysis indicated that all the investigated compounds (EHT1-EHT5) showed absorption wavelengths in the UV–Vis region, ranging from 290.1 to 303.7 nm. Among all these examined compounds (EHT1-EHT5), EHT3 displayed the highest value of λ max (303.717 nm) owing to its minimum band gap (4.028 eV). Furthermore, maximum values of first and second-order hyperpolarizabilities (β t o t and γ t o t ) were achieved for EHT3 as 7.756, 3.029 × 10−23 and 6.984 × 10−35 esu, respectively. In summary, our investigation provides new insights for the potential use of HT- based organic compounds (EHT1-EHT5) in future NLO applications. [ABSTRACT FROM AUTHOR]

• Synthesis of novel triazole-based compounds for NLO materials. • Utilization of various spectroscopic techniques for structure elucidation. • Study of electronic and NLO properties at M06/6–311 G (d,p) functional. • Utilization of TD-DFT approach for FMOs and UV–Vis analyses. In current study, a novel series of 1,2,4-triazole based compounds (7a - 7d) was synthesized and their structure confirmation was accomplished through different spectroscopic (UV–Visible, FTIR, NMR and HRMS), elemental analysis and physio-chemical methods. Besides, the electronic properties were investigated through the DFT/TD-DFT approaches at M06/6–311G(d,p) functional. All the synthesized compounds showed simulated band gap in the range of 4.931–5.489 eV with absorption spectrain the range of 295–302 nm calculated experimentally. A significant charge transfer was observed with in molecules as supported by TDM and FMOs investigations. Compound 7a showed good NLO characteristics (β tot =1.338 × 10−29 and <γ>= 7.547 × 10−53 esu) among all the synthesized compounds owing to the lowest value of HOMO–LUMO band gap (4.931 eV). Hence it can be utilized as reasonable optoelectronic material for NLO devices. [ABSTRACT FROM AUTHOR]

The role of hexamolybdate (Lindqvist)/molybdate on the nonlinear optical response (NLO) has been systematically examined by means of density functional theory (DFT) method. It shows that the unaccompanied Lindqvist anion has zero value of nonlinear optical response because of the centrosymmetric nature. According to the guidelines of nonlinear optics, centrosymmetric compounds do not exhibit nonlinear optical response. The hexamolybdate/molybdate accompanied with phenyl rings exhibits prominent NLO response which is much higher than those of phenyl rings without Lindqvist anion/molybdate. The system 3 ([Mo 6 O 18 C 14 H 10 N 2 O 2 ] 2− ) possesses a large NLO response computed to be 460.68 × 10 −30 esu. Here, the robust synergistic effect of Lindqvist anion linked to organic rings qualifies it a good candidate for NLO applications. The introduction of two phenyl rings in Lindqvist anion significantly increases the first hyperpolarizability as compared to the Lindqvist anion (system 1) or two phenyl rings (system 2) independently. The present study offers an important understanding into the NLO properties of hexamolybdate/molybdate derivatives. [ABSTRACT FROM AUTHOR]