The synthesized Zn(II) complex of 3-/6-methylpicolinic acid (3-/6-MepicH) was structurally characterized by mass spectrometry (MS) as well as H-1 and C-13 NMR spectroscopy. The spectral features were investigated by the FTIR and UV-Vis spectra. To elucidate third-order nonlinear optical (NLO) characteristic, Z-scan study was fulfilled. Theoretical characterizations were carried out using different featured DFT methods. Moreover, the values of external electric field (E), polarization (P), and electric displacement (D) for the Zn(II) complex were computed employing DFT/M06-L, CAM-B3LYP, and HSEh1PBE functionals. Similarly, the linear optical (LO) susceptibility and polarization parameters chi((1))/P-(1) as well as the second- and third-order nonlinear optical (NLO) tensors chi((2))/P-(2) and chi((3))/P-(3) were derived at the same computational levels. Furthermore, the refractive index (n) and optical band gap were determined within the UV-Vis spectrum. Subsequently, the Zn(II) complex's static and dynamic LO and NLO properties were examined at the DFT/M06-L, CAM-B3LYP, and HSEh1PBE levels. The electronic band gap (E-g), dipole moment and polarizability values were obtained at 4.37 eV (experimental) and 4.777 eV (DFT/M06-L), 8.009 D (DFT/M06-L), 43.134 x 10(-24) esu and 38.954 x 10(-24) esu, respectively. From the Z-scan experiments, the complex exhibited a third-order nonlinear optical susceptibility (chi((3))) of 62.5068 x 10(-4) and a second-order molecular hyperpolarizability (gamma) of -6532.41 x 10(-28) esu. Using the DFT/M06-L method, the values of / and third-order nonlinear optical susceptibilities of the complex in ethanol were determined as 70.427 x 10(-36), 94.085 x 10(-36) and 2599.27 x 10(-36) esu, respectively. The significant nonlinear optical responses from Z-scan measurements and DFT-based calculations reveal that the compound exhibits promising characteristics for advanced optical sensing applications, including intensity-dependent detectors and environmentally responsive phase-modulating sensors.

The structure of the newly synthesized Cd(II) complex of 6-chloropyridine-2-carboxylic acid (6-ClPCA) was determined by the XRD method. The molecular structure was confirmed via single-crystal X-ray diffraction, while vibrational and electronic properties were investigated through FT-IR, UV–Vis spectroscopy, and DFT-based quantum chemical calculations. Five different DFT functionals were employed to optimize the molecular geometry and predict vibrational spectra, with statistical fitting parameters (MAD, RMS, MPD

This study reports the synthesis, crystal structure, spectroscopic, electronic, thermal and nonlinear optical properties of a novel Cu(II) complex of 6-fluoro-pyridine-2-carboxylic acid (6Fpca) ligand. The [Cu (6Fpca)2 center dot(H2O)] complex was crystallized in the orthorhombic Pbca space group with a distorted tetragonal pyramidal coordination sphere around the central Cu(II) ion. The coordination sphere around the central Cu(II) ion was also proved by FT-IR and theoretical IR spectra. UV-Vis spectra for the Cu(II) complex revealed that the tc -> tc*, n -> tc* and ligand-metal charge transfer interactions occur in the Cu(II) complex. The first-order hyperpolarizability beta(-w;w,0) value for the [Cu(6Fpca)2 center dot(H2O)] complex was 22.265 x 10-30 esu at 0.0856252 au, exhibiting a decrease to 11.823 x 10-30 esu at 0.0428126 au. Similarly, the second-order hyperpolarizability gamma (-w; w,0,0) value was 111.07 x 10-30 esu at 0.0856252 au and decreased to 38.352 x 10-30 esu at 0.0428126 au. These results showed that the Cu(II) complex demonstrated a high degree of nonlinear optical (NLO) activity at 0.0856252 au.

Ongoing exploration focuses on synthesizing and characterizing coordination compounds to improve the design of nonlinear optical (NLO)-based materials. In this regard, to examine spectral and static/frequency-dependent linear/NLO parameters, the new Zn (II) complex {[Zn(6-MePyAld)(2)(Cl)]; 6-MePyAld: 6-methylpyridine-2-carboxaldehyde} was synthesized and characterized by using H-1 and C-13 NMR, mass (LC-HRMS), powder XRD, and FTIR spectra. The electronic features of synthesized complex were investigated by considering the TD-CAM-B3LYP/ and TD-M06L/6-311G(d,p)//LanL2DZ levels of time-dependent density functional theory (TD-DFT). Moreover, the theoretical linear optical (LO), second-, and third-order NLO susceptibility tensors/polarization (chi((1))/P-(1), chi((2))/P-(2), chi((3))/P-(3)) parameters for the Zn (II) complex were computed using the DFT/M06L and DFT/CAM-B3LYP levels. The external electric field (E), polarization (P), and electric displacement (D) values of the Zn (II) complex were also calculated using the same DFT levels. To investigate microscopic LO (isotropic polarizability /, and anisotropic polarizability (triangle alpha (0;0)/triangle alpha (-omega;omega)) and second-/third-order NLO (/// and ) parameters for the Zn (II) complex, the DFT/M06L and DFT/CAM-B3LYP levels in the gas phase were used. The triangle alpha (0;0), triangle alpha (-omega;omega), , , and for Zn (II) complex were computed at 17.288 x 10(-24), 21.782 x 10(-24), 14.692 x 10(-30), 466.80 x 10(-30), and 210.79 x 10(-30) esu, respectively, by using the DFT/CAM-B3LYP level. Moreover, the / and in the gas phase computed at the DFT/CAM-B3LYP level for Zn (II) complex were obtained at 129.74 x 10(-36), 3997.6 x 10(-36), and -886.60 x 10(-36) esu, in turn. According to the CAM-B3LYP level, the value is 8.65 and 18.53 times higher than the values of para-nitroaniline (pNA) and urea, respectively. The obtained static/dynamic beta and gamma values of Zn (II) complex are greater than those of urea and pNA. Zn (II) complex exhibited remarkably microscopic second-order and particularly third-order NLO features. It is predicted that our study will shed light on NLO materials that might be used in telecommunication and optoelectronics.

In this study, the theoretical calculations on 2-[2-(2,4-dimethoxy-phenyl)-vinyl]-1-ethyl-pyridinium iodide (DMPI), which was previously synthesized and experimentally examined, were performed and compared with the corresponding experimental results. The optimized geometrical parameters, vibrational frequencies, 1H and 13C-NMR chemical shifts, HOMO-LUMO and the optical band gap energies of DMPI compound were obtained theoretically by using B3LYP and HSEh1PBE methods with LANL2DZ basis set. The other important optical properties such as refractive index, extinction coefficient, conductivity, dielectric constant, VELF and SELF were investigated using experimental and theoretical spectra. The dipole moment, the mean polarizability, the third-order susceptibility, first and second-order hyperpolarizabilities and nonlinear refractive index parameters were also computed at HSEh1PBE/LANL2DZ and B3LYP/LANL2DZ levels respectively. According to the values of theoretical NLO parameters, DMPI compound indicates high NLO efficiency, as expressed in the experimental study. Hence DMPI appears to be a promising candidate for electro-optic, photonic and NLO applications.

In order to enhance nonlinear optics (NLO)-based technologies, current research focuses on the design and synthesis of coordination materials. In this context, to investigate spectral and theoretical linear optical (LO)/nonlinear optical (NLO) behaviors, novel metal complexes including azide {[Mn (L-1)(2)(N-3)(2)], (9), [Ni(L-1)(2)(N-3)], (10), [Co-2(L-1)(2)(N-3)(2)]& sdot;2H(2)O, (11); L-1: N-(pyridin-2-ylmethylene)methanamine} were synthesized. The vibrational and electronic spectral features of complexes 9-11 were investigated by UV-Vis and FT-IR spectra. Depending on the central metal ion and coordination geometries of complexes, the microscopic static nonlinear behaviors were examined by using the CAM-B3LYP/and omega B97XD/6-311 + G (d,p)//LanL2DZ levels of density functional theory (DFT). Furthermore, the vibrational and electronic properties of complexes 9-11 based on the same levels of time-dependent/density functional theory (TD-DFT/DFT) were surveyed. Additionally, the theoretical chi((1)), chi((2)), and chi((3)) parameters, known as linear optical, second-, and third-order nonlinear optical susceptibility tensors, as well as linear, second-, and third-order polarization parameters (P-(1), P-(2), and P-(3)) for complexes 9-11 were examined. The greatest value for complex 10 found to be 262.55 x 10(-30) esu using CAM-B3LYP level is 820.5 and 2019.6 times higher than the urea findings (0.32 x 10(-30) esu and 0.130 x 10(-30) esu). The results indicate that complex 9 having the highest value obtained at 2216.40 x 10(-36) esu using CAM-B3LYP level is 47.76 and 316.63 times greater than those of pNA (15 x 10(-36) esu) and urea (7 x 10(-36) esu), respectively. Complexes 10 and 9 demonstrated promising microscopic second-order and third-order NLO features, respectively. Our research is anticipated to provide insight into NLO materials that may have applications in optoelectronics and telecommunication field.

Aim: The goal of this study is to synthesize new metal complexes containing N-methyl-1-(pyridin-2-yl)methanimine and azide ligands as alpha-glucosidase inhibitors for Type 2 diabetes. Materials & methods: The target complexes (12-16) were synthesized by reacting N-methyl-1-(pyridin-2-yl)methanimine (L-1) with sodium azide in the presence of corresponding metal salts. The investigation of target protein interactions, vibrational, electronic and nonlinear optical properties for these complexes was performed by molecular docking and density functional theory studies. Results: Among these complexes, complex 13 (IC50 = 0.2802 +/- 0.62 mu M) containing Hg ion showed the highest alpha-glucosidase inhibitory property. On the other hand, significant results were detected for complexes containing Cu and Ag ions. Conclusion: Complex 13 may be an alternate anti-diabetic inhibitor according to in vitro/docking results.

To investigate the optical parameters, novel metal complexes of N-(pyridin-2-ylmethylene)methanamine (L1), obtained as Schiff base by the condensation reaction of 2-pyridinecarboxaldehyde with methylamine, and isothiocyanate [Mn(L1)2(NCS)2], (1), [Co(L1)2(NCS)2], (2), [Ni(L1)2(NCS)2], (3) were synthesized. FT–IR and UV–Vis spectra were applied to examine the spectral features for complexes 1,2/3 characterized by XRD/LC-HRMS. Hirshfeld surface analysis was performed to describe intermolecular interactions for complexes 1 and 2. Moreover, the CAM-B3LYP and ωB97XD/6–311 + G(d,p)//LanL2DZ levels of DFT/TD-DFT methods were used to survey optimal complex structures, spectral and nonlinear optical parameters, as well as remarkable contributions in the electronic transitions for synthesized complexes 1–3. In the mid-IR region, the mean refractive index/polarizability parameters for 1–3 were found to be 1.63/5.87 × 10–24 esu, 1.46/4.80 × 10–24 esu, and 1.50/4.48 × 10–24 esu, respectively. By considering the UV–Vis absorption parameters, the experimental refractive index, optical band gap, polarizability, optical conductivity, and third-order nonlinear optical susceptibility parameters for complexes 1–3 in methanol were examined. The maximum third-order NLO susceptibility values in the photon energies of 4.68, 4.21, and 5.25 eV were obtained at 51.65 × 10–13, 51.42 × 10–13, and 51.42 × 10–13 esu, respectively. In short, detailed experimental and corresponding theoretical spectral and optical parameters for the synthesized complexes were investigated in terms of structure–property. The NLO results display that complex 1 may be a candidate for NLO material using in data storage, telecommunications, laser technology, etc. sectors in the future.

Diabetes is one of the fastest growing global health crises of the 21st century. One of the current therapeutic approaches used in the treatment of diabetes involves the suppression of carbohydrate hydrolyzing enzymes such as α‐glucosidase. In this context, α‐glucosidase inhibitors are important in the treatment and prevention of diabetes. For this reason, new Schiff base complexes including isothiocyanate {[Cd(L1)2(NCS)2], (1), [Zn(L1)2(NCS)2], (2), [Cu(L1)2(NCS)2], (3), [Ag(L1)(NCS)2], (4), [Hg(L1)2(NCS)Cl], (5); L1: N‐(pyridin‐2‐ylmethylene)methanamine} were synthesized to investigate α‐glucosidase inhibitor potentials. The IC50 values of complexes 1–5 were found at 0.2376 ± 0.82 and 251.403 ± 2.54‐μM range. Among these complexes, complex 5 has the highest α‐glucosidase inhibitor property. The spectral investigations for the complexes 1/2–5 characterized by XRD/LC‐HRMS were performed by UV–Vis and FT–IR spectra. Furthermore, the TD‐DFT/DFT calculations were fulfilled by using CAM‐B3LYP and ωB97XD/6–311+G(d,p)//LanL2DZ levels to obtain optimum complex structures, spectral, linear and nonlinear optical properties for 1–5. According to obtained theoretical nonlinear optical results, complex 3 is a strong indicator in terms of microscopic nonlinear optical (NLO) properties. The docking studies of these complexes were examined to display the target protein interactions with these complexes.

Herein we report the synthesis, DFT calculations, and molecular docking studies of a pyrazole derivative, (E)-N'-benzylidene-5-methyl-1H-pyrazole-3-carbohydrazide (E-BMPC) as alpha-glucosidase and alpha-amylase inhibitor. Molecular structure of E-BMPC has been confirmed by single crystal X-ray diffraction (XRD), FTIR, H-1, and C-13 NMR spectra. In addition, density functional theory (DFT) calculations on E-BMPC were carried out to obtain frontier molecular orbital energies and first-order static hyperpolarizability (beta). The alpha-amylase and alpha-glucosidase enzyme inhibitory of E-BMPC was also tested. E-BMPC displayed moderate inhibitory activity with IC50 values 310.57 +/- 2.67 and 182.19 +/- 3.20 against alpha-glucosidase and alpha-amylase enzymes, respectively. Molecular docking analysis provided the inhibition constant of E-BMPC molecule for alpha-amylase enzyme as 33.60 mM. Both in vitro and in silico enzyme inhibition studies showed that E-BMPC molecule is a better inhibitor for alpha-amylase than alpha-glucosidase. The beta parameter for the molecule under investigation was also calculated as 4.2 x 10(-30) esu.

Novel transition metal-based complexes that may be of value as biological agents and/or nonlinear optical materials, Zn (II) and Cu (II) transition metal complexes of 6-chloropyridine-2-carboxylic acid (LH), were successfully synthesized. The chemical structure of each complex was characterized using X-ray diffraction (XRD) method and FT-IR spectroscopy. XRD and FT-IR demonstrated that L ligand coordinate to central metal ions through the donor N and O atoms. By coordinating two H2O ligand to Zn (II) ion, a distorted octahedral complex geometry was constructed for 1. As for 2, a distorted trigonal bipyramidal coordination geometry was obtained by a H2O ligand coordination to Cu (II) ion. Theoretical studies using B3LYP/6-311++G(d,p)-LanL2DZ were performed to further validate the proposed structures. The molecular docking of 1 to SARS-CoV-2 main protease (PDB: 6LU7) gives a binding energy of −5.24 kcal/mol and inhibition constant of 144.6 μM, demonstrating that 1 is a more promising candidate to biologically active complexes than 2. The first-order hyperpolarizability (β) parameter for 1 and 2 was calculated as 0.88 × 10−30 and 10.40 × 10−30 esu, respectively. These β values also demonstrated that 2 exhibits more effective NLO character than 1 due to the electronic configuration and coordination geometry. © 2022 John Wiley & Sons, Ltd.

A new crystal, i.e, (E)-5-methyl-N'-(pyridin-2-ylmethylene)-1H-pyrazole-3-carbohydrazide (E-MPPC) has been synthesized and characterized by using FT-IR, UV-Vis, H-1-NMR, C-13-NMR, ESI-MS and single-crystal X-ray diffraction. In addition, a density functional theory study for the title compound was carried out. The theoretical geometry of the ground state and the electronic structure of the title compound were optimized by the DFT/B3LYP method in conjunction with 6-311++G(d,p) basis set. E-MPPC was evaluated in vitro for their alpha-glucosidase enzyme inhibition. The title compound displayed moderate inhibitory activity with IC50 value of 714.25 +/- 8.33 mu M against alpha-glucosidase enzyme. In addition, molecular docking study was performed to investigate how E-MPPC interacts with the protein structure of alpha-glucosidase enzyme. Final intermolecular energy and estimated inhibition constant for this docking study were obtained as -5.50 kcal/mol and 173.57 mu M, respectively. The first order static hyperpolarizability (beta) parameter for E-MPPC was also calculated as 11.2 x 10(-30) esu. Natural bond orbital analysis was also executed to investigate intramolecular charge transfer interactions in the title compound. (C) 2021 Elsevier B.V. All rights reserved.

Diabetes mellitus (DM) is a common degenerative disease and characterized by high blood glucose levels. Since the effective antidiabetic treatments attempt to decrease blood glucose levels, keeping glucose under control is very important. Recent studies have demonstrated that α-glucosidase inhibitor improves postprandial hyperglycemia and then reduces the risk of developing type 2 diabetes in patients. Therefore, the design and synthesis of high affinity glucosidase inhibitors are of great importance. In this regard, novel series of mixed-ligand M(II) complexes containing 2,2′-bipyridyl {[Hg(6-mpa)2(bpy)(OAc)]·2H2O, (1), [Co(6-mpa)2(bpy)2], (2), [Cu(6-mpa)(bpy)(NO3)]·3H2O, (3), [Mn(6-mpa)(bpy)(H2O)2], (4), [Ni(6-mpa)(bpy)(H2O)2]·H2O, (5), [Fe(6-mpa)(bpy)(H2O)2]·2H2O, (6), [Fe(3-mpa)(bpy)(H2O)2]·H2O, (7)} were synthesized as potential α-glucosidase inhibitors. Their effects on α-glucosidase activity were evaluated. All synthesized complexes displayed α-glucosidase inhibitory activity with IC50 values ranging from 0.184 ± 0.015 to > 600 μM. The experimental spectral analyses were carried out using FT–IR and UV–Vis spectroscopic techniques for these complexes characterized by XRD and LC–MS/MS. Moreover, the calculations at density functional theory approximation were used to obtain optimal molecular geometries, vibrational wavenumbers, electronic spectral behaviors, and major contributions to the electronic transitions for the complexes 1–7. Finally, to display interactions between the synthesized complexes and target protein (the template structure Saccharomyces cerevisiae isomaltase), the molecular docking study was carried out.

A novel Zn(II) complex of 6-ClpicH and picH was synthesized and its structure was determined by XRD technique. The detailed experimental optical susceptibility and band gap, refractive index, linear polarizability, optical and electrical conductivity parameters in various concentrations were investigated by means of the UV-Vis spectroscopic data. The optical band gap, refractive index (n), linear optical susceptibility (chi((1))), third-order nonlinear optical susceptibility (chi((3))), second- and third-order nonlinear optical (beta and gamma) parameters were examined by using DFT/M06-L and omega B97XD/6-311++G(d,p) levels. The IC50 value of Zn(II) complex against alpha-glucosidase was also obtained at 0.44 mM. The experimental band gap of the Zn(II) complex at 13, 33, 44 and 94 mu M concentrations in ethanol were found to be 4.38, 4.37, 4.35 and 4.28 eV, respectively. The third-order NLO susceptibility chi((3)) parameter at 94 mu M concentration corresponding to the photon energies of 4.6 and 5.7 eV in the UV-Vis region were observed at 206.6 x 10(-13) and 294.3 x 10(-13) esu, respectively. Besides, the theoretical chi((3)) values were obtained at 50.58 x 10(-13) and 20.37 x 10(-13) esu by using M06-L level. These results indicate that Zn(II) complex could be an effective third-order NLO candidate material. In brief, the detailed theoretical and experimental structural, spectral and optical properties of the Zn(II) complex were presented comparatively. (C) 2021 Elsevier B.V. All rights reserved.

The Mn(II) and Zn(II) complexes of 6‐bromopicolinic acid (6‐BrpicH) were synthesized for the first time, and their molecular structures were determined by X‐ray diffraction (XRD) technique. The detailed experimental spectral studies were executed by Fourier‐transform infrared (FT‐IR) and UV–Vis spectra. The experimental optical properties, such as refractive index, linear polarizability, optical susceptibility, optical band gap, extinction coefficient, dielectric constant, and volume energy loss function (VELF) and surface energy loss function (SELF) parameters obtained from the transmission spectra with solution technique in ethanol solvent of these complexes, were investigated. Additionally, the refractive index (n), optical band gap, χ(1) (linear optical susceptibility), χ(3) (third‐order nonlinear optical susceptibility), and first‐ and second‐hyperpolarizability (β and γ) parameters were surveyed by using density functional theory (DFT)/HSEh1PBE/6‐311G(d,p)/LanL2DZ level. The experimental and theoretical optical band gap energies of complex 2 were obtained at 4.26 and 4.67 eV. The experimental and theoretical n values of complex 1 in the mid‐IR region were found to be 1.581 and 1.58 (in gas phase). The experimental linear optical and χ(1) parameters were calculated at 31.73 × 10−24 and 14.58 × 10−2 esu for complex 1 in the mid‐IR region; the corresponding theoretical parameters for complex 1 in the gas phase were obtained at 36.07 × 10−24 and 18.35 × 10−2 esu. The second‐order nonlinear optical (NLO) results exhibit that complex 1 is a promising candidate to materials with the high second‐order hyperpolarizability values obtained as 540.71 × 10−36 and 56.83 × 10−36 esu in ethanol solvent and gas phase. Moreover, the intermolecular and intramolecular bonding and the definition of coordination geometries around the central metal ions, as well as the electronic charge transfer interactions in the Mn(II) and Zn(II) complexes, were confirmed by natural bond orbital (NBO) analysis. To sum up, the detailed experimental and theoretical structural, spectroscopic, electronic, and optical properties of the synthesized complexes were comparatively presented.