Realizing the effect of s-block metals on a charge transfer crystal of indol-2-one for enhanced NLO responses with efficient energetic offsets.

CONTEXT: Due to their unique photophysical properties, organic charge transfer crystals are becoming promising materials for next-generation optoelectronic devices. This research paper explores the impact of s-block metals on a charge transfer crystal of indol-2-one for enhanced nonlinear optical (NLO) responses with efficient energetic offsets. The study reveals that alkali metals can enhance NLO performance due to their free electrons. METHOD: The Perdew-Burke-Ernzerhof functional of DFT with dispersion correction (D3) was used, and the λmax values ranged between 596 and 669 nm, with the highest value for dichloromethane (DCM). Leveraging the unique properties of metals allowed for the development of nonlinear optical materials with improved performance and versatility. Softness (σ) values provide insight into electron density changes, with higher values indicating a greater tendency for changes and lower values indicating the opposite. The NLO results for the chromophores MMI1-MMI6 show varying linear polarizability (< α0 >) along with their first (ß0) and second (γ0) hyperpolarizabilities. Chromophore MMI4 stands out with the highest NLO performance, having two potassium (K) atoms. Its < α0 > , ß0, and γ0 values of 4.19, 7.09, and 17.43 (× 10-24 e.s.u), respectively, indicate a significant enhancement in NLO response compared to the other chromophores. The transitions involving (O20)LP → (C3-N5)π* and (O19)LP → (N12-C13)π* exhibit the highest level of stabilization, followed by (O23)π → (C10-C11)π*, while (C6-N12)π → (C6-C7)π* shows the lowest level of stabilization for chromophore MMI4. The present research work is facile in its nature, and it can be helpful for synthetic scientist to design the new materials for uniting crystal properties with metal doping for efficient NLO devices.

Structure-based screening of sp2 hybridized small donor bridges as donor: acceptor switches for optical and photovoltaic applications: DFT way.

CONTEXT: This research aims to investigate the potential of pyrazine-based small donor moieties as donor-acceptor switches for optical and photovoltaic applications. The designed organic dyes have a high light harvesting efficiency (LHE) and can potentially generate significant electrical energy. METHODS: The study focuses on understanding the structural and electronic properties of these dyes through the analysis of dihedral angles, bond lengths, and energies of frontier molecular orbitals The UV-Vis spectroscopy parameters of the designed organic dyes revealed their absorption characteristics, including transition energies, wavelengths (λmax), and oscillator strengths (f). The photovoltaic properties of the developed organic dyes show a range of values: a range of 0.95-0.99 for LHE and a range of 1.77-33.02 W for maximum power output (Pmax) with the highest value for dye DDP5. For their stabilization energies, their natural bond orbitals had values ranging from 0.56 to 128.48 kcal/mol, their E(j)E(i) values from 0.22 to 1.29 a.u, and their Fi,j values from 0.024 to 0.213 kcal/mol. Out of all dyes, the DDP5 produced highest push-pull effect and can be good choice for further studies. The design of these novel organic materials for effective and economical solar energy conversion will be aided by evaluating the potential of 5,10-diphenyl-5,10-dihydrophenazine as a donor moiety and determining the structure-property correlations controlling the photovoltaic performance of the compounds.

Design and Exploration of Benzene Like Azobis Triazoles for Long-range Push-Pull Photo-Switching Attributes.

This research paper presents a comprehensive study on the design and photovoltaic parameters of azobenzene type 24 photo switches (PSs) of triazole by density functional theory (DFT). The focus was on investigating how to create a long-range push-pull effect of different substituents on the PS properties for their application in photovoltaics by further substituent decoration. Their range of values for the maximum wavelength (λmax) ranged 315-556 nm while their HOMO-LUMO energies (Egaps) were 0.57-6.35eV. The stability of the PS was evaluated by measuring hardness (η) and softness (σ) values. Additionally, photovoltaic parameters such as open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and maximum power (Pmax) were calculated to assess the performance of the PS as photovoltaic materials. The results revealed that PSs 6 exhibited promising photovoltaic parameters to include Voc values ranging from 0.4-1.63eV, FF values ranging from 0.5438-0.929, Jsc values ranging from 19.27-50.75 mA/cm2, and Pmax values ranging from 14.72-75.91W. This indicates its potential as an efficient light-harvesting material for photovoltaic applications. Moreover, this study presents a pioneering investigation on the correlation between rotational velocity (R) and Mayer bond index (MBI) for the first time. The findings revealed a significant correlation between R and MBI, providing valuable insights into the structural dynamics of the PS. This novel finding opens up new avenues for understanding the structural dynamics of PS and their potential applications in various fields, including photovoltaics. The study provides valuable insights into the structure-property relationships of azobenzene-based PS and their suitability for photovoltaic devices. Further investigations are warranted to optimize the design of the PS, enhance their photovoltaic performance, and explore the underlying mechanisms of the correlation between R and MBIs.

Synthesis, Spectroscopic and Nonlinear Optical Properties, and Antimicrobial Activity of Cu(II), Co(II), and Ni(II) Complexes: Experimental and Theoretical Studies.

Currently, we report the preparation of transition metal complexes Co(II), Ni(II), and Cu(II) of hydrazone Schiff base ligands, which are obtained by the condensation reaction of substituted salicylaldehyde and hydrazines. The synthesized hydrazone ligands and their metal complexes were characterized by spectroscopic methods such as Fourier transform infrared (FT-IR), UV-vis, nuclear magnetic resonance (1H NMR and C13 NMR), and mass spectrometry analyses. All of the quantum chemistry calculations were performed using DFT executed in the Gaussian 09 software package. The geometry was optimized by using the density functional theory (DFT) approximation at the B3LYP level with a basis set of 6-31G (d, p). There was excellent agreement between the FT-IR values obtained experimentally and those obtained theoretically for the test compounds. It is worth noting that none of the optimized geometries for any of the Schiff base and metal complexes had any eigenvalues that were negative, indicating that these geometries represent the true minimum feasible energy surfaces. We also analyzed the electrostatic potential of the molecule and NBO calculation at the same level of theory. Gauss View 6 was utilized for the file organization of the input data. Gauss View 6.0, Avogadro, and Chemcraft were used to determine the data. Additionally, synthesized compounds were screened for antimicrobial activity against Gram-negative bacteria (Salmonella typhi, Escherichia coli) and Gram-positive bacteria (Bacillus halodurans, Micrococcus luteus) and two fungal strains (Aspergillus flavus, Aspergillus niger). These research findings have established the potential of ligands and their metal complexes as antimicrobial agents. Additionally, the compounds demonstrated promising nonlinear optical (NLO) properties, with potential applications across a wide range of contemporary technologies.

DFT-guided structural modeling of end-group acceptors at Y123 core for sensitizers as high-performance organic solar dyes and NLO responses.

CONTEXT: The organic solar cells (OSCs) are being developed with the goal of improving their photovoltaic capabilities. Here, utilizing computational methods, six new nonfullerene acceptors (NFA) comprising dyes (A1-A6) have been created by end-group alterations of the Y123 framework as a standard (R). METHODS: The DFT-based investigations at B3LYP/6-31G + (d,p) level were applied to evaluate their properties. The planar geometries associated with these structures, which lead to improved conjugation, were validated by the estimation of molecular geometries. Dyes A1-A6 have shorter Egap than R, according to a frontier molecular orbital (FMO) investigation, which encourages charge transfer in them. The dyes with their maximum absorption range were shown by optical properties to be 692-711 nm, which is significantly better than R with its 684 nm range. Their electrostatic and Mulliken charge patterns provided additional evidence of the significant separation of charges within these structures. All the dyes A1-A6 had improved light harvesting efficiency (LHE) values as compared to Y123, highlighting their improved capacity to generate charge carriers by light absorption. With the exception of dye A4, all newly developed dyes might have a superior rate of charge carrier mobility than R, according to reorganization energies λre. Dyes A3 and A4 had the greatest open-circuit voltage (Voc). Dye A3 exhibited improvement in all of its examined properties, making it a promising choice in DSSC applications.

Enhancing NLO performance by utilizing tyrian purple dye as donor moiety in organic DSSCs with end capped acceptors: A theoretical study.

A series of new organic dyes (T1-T6) with nonfullerene acceptors have been theoretically designed around the chemical structure of tyrian purple (T) natural dye. For their ground state energy parameters, all the molecular geometries of those dyes were optimized by density functional theory (DFT) at its Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level of theory with 6-31G+(d,p) basis sets. When benchmarking against several long range and range separated levels of theory, the Coulomb attenuated B3LYP (CAM-B3LYP) produced most accurate absorption maxima (λmax) value to that of T so it was further employed for further Time dependent DFT (TD-DFT) calculations. Frontier molecular orbitals (FMOs) with natural bond orbital (NBO) studies were used to study their intra molecular charge transfer (ICT). All of the dyes had their energy gaps (Eg) values between their FMOs to range around 0.96-3.39 eV, whereas the starting reference dye had an Eg of 1.30 eV. Their ionization potential (IP) values were ranged to be 3.07-7.25 eV which indicated their nature to loss electrons. The λ max in chloroform was marginally red-shifted with a value 600-625 from T (580 nm). The dye T6 showed its highest linear polarizability (<α>), and first and second order hyperpolarizabilities (ß and γ). The synthetic experts can find the present research to design finest NLO materials for current and future uses.

Molecular modeling of mordant black dye for future applications as visible light harvesting materials with anchors: design and excited state dynamics.

CONTEXT: In this study, new visible light harvesting dyes (MBR1-MBR5) have been designed as efficient materials with silyl based anchoring abilities on semiconducting units for future dye-solar cells applications. Their unique molecular structures of novel D-π-ASemiconductor type were evaluated thoroughly by density functional theory (DFT) calculations. To enhance the optical performance in visible region, a novel dye structure (MBR) was derived from the chemical structure of mordant black (MB) dye with electron acceptor semiconducting units (MBR1-MBR5). METHODS: The Coulomb-attenuating Becke, 3-parameter, Lee-Yang-Parr (CAM-B3LYP) functional, which had a hybrid and long-range correlation with 6-31G + (d,p), generated a [Formula: see text] (683 nm) that was very comparable to its experimental value (672 nm). The energies of highest occupied molecular orbitals (HOMO), lowest unoccupied molecular orbitals (LUMO), and their HOMO-LUMO energy gaps (HLG) were calculated. Their ionization potentials (IP) varied from 5.616 to 8.320 eV, demonstrating their good electron donating trend. The [Formula: see text] values of dyes displayed a significant red shift from MBR (682 nm) value with range 565-807 nm except MBR1 which was slightly blue shifted. The dye MBR4, which had the smallest HLG (0.23 eV) had the greatest second order nonlinear optical (NLO) response of 144,234 Debye-Angstrom-1. The DFT calculated results provided insight into the creation of new silyl anchoring groups for future DSSCs material designs with increased stability and effectiveness. The goal of the current study is to forecast the development of novel NLO materials with a D-π-ASemiconductor design that use semiconductors as anchoring groups to adhere to a surface.

A DFT Study on New Photovoltaic Dyes to Investigate their NLO Tuning at Near Infrared Region (NIR) as Pull-push Effect by End Capped Acceptors.

Throughout the opto-electronic devices industry, organic materials with considerable nonlinear optical (NLO) capabilities are being used. By employing 4,6-di(thiophen-2-yl)pyrimidine as a standard molecule, a series for new dyes (DMBMB1-DMBMB6) are created in the present paper by altering their functionalization with various electron acceptor (A) functional groups. The density functional fheory (DFT) and time dependent DFT (TD-DFT) based calculations have been performed to explore NLO responses by adjustment of different A units. The energy gap (Egap) of their highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) was ranged between 0.22-2.43 eV which was also used to calculate their global chemical parameters (GRPs). All the new dyes were subjected to UV-Vis studies revealing their frequencies being red shifted from starting dye (DMBMB). The theoretical investigations like frontier molecular orbital (FMO) and natural bond orbital (NBO) analysis was used to investigate their intramolecular charge transfer (ICT). The dye DMBMB6 had the greatest linear polarizability, first hyperpolarizability (αtotal), and second order hyperpolarizability (ßtotal) for all the developed dyes. In conclusion, due of their low ICT, all the dyes showed potential NLO features. Scientific researchers would be able to harness these NLO features to discover NLO materials for current and future uses.

Efficient and tunable enhancement of NLO performance for indaceno-based donor moiety in A-π-D-π-D-π-A type first DSSC design by end-capped acceptors.

BACKGROUND: The organic dyes with non-fullerene acceptors (NFAs) have aided in the creation of competitive organic solar cells (OSCs) with long-term sustainability. A series of NFA dyes (IDIC-R1-IDIC-R9) have been designed by varying the end-capped fluorinated moieties (PD1-PD6) at indaceno (IDIC) core. METHODS: All the calculations were performed by density functional theory (DFT) and time-dependent DFT (TD-DFT)-based approaches. All the geometries were optimized at B3LYP/6-31G + (d,p) of DFT level at their ground state energies. Out of several density functionals, the CAM-B3LYP with 6-31G + (d,p) basis sets was selected after a benchmark study to carry out further calculations. All the dyes had their bandgaps in 0.11-3.12 eV while their starting reference dye had a bandgap value of 2.01 eV. RESULTS: Their ionization potential (IP) implied that these dyes have strong tendency to lose electrons. The λmax of the dyes was slightly redshifted from the IDIC (476 nm) and IDIC-R (479 nm) when changing solvent polarity from methanol to DCM and then chloroforms. The natural bond orbital (NBO) analysis showed the (S63)LP → (C61-C62)π* with highest stabilization energy. Their electron injection analysis showed that these dyes can be a good anode material against the aluminum and gold electrodes. The intramolecular charge transfer (ICT) process and stability of the dyes were investigated using frontier molecular orbital (FMO) and natural bond orbital (NBO) analysis. CONCLUSION: Among all dyes, IDIC-R8 has the highest linear polarizability and second-order hyperpolarizability (ßtotal). All the dyes demonstrated promising non-linear optical (NLO) properties due to their low charge transfer barriers. Scientists would be able to exploit these properties to identify the best NLO materials for existing applications.

Exploration of Pull-Push Effect for Novel Photovoltaic Dyes with A-π-D Design: A DFT/TD-DFT Investigation.

The π-rich versus π-poor units in 4,6-di(thiophen-2-yl)pyrimidine (DTB) alternating the π-backbone of solar cells dyes have been extended with a push-pull technique to lower their HOMO-LUMO energy gap and to increase Intramolecular Charge Transfer (ICT). Density functional theory was used to optimize the ground state molecular geometries of newly designed dyes (DTB1-DTB6). Time Dependent DFT (TD-DFT) was used to simulate the Uv-vis spectral values at the maximum absorbance values ranging between 481-535 nm. These values were red shifted from DTB value of experimental (333 nm) and theoretical (346 nm). however, their computed absorbance and fluorescence spectra revealed a bathochromic shift of them upon an increasing the solvent polarity. Different DFT functionals such as (B3LYP, CAM-B3LYP, B97XD, and APFD) were employed to choose their proper use Uv-visible analysis to reveal an unexpected coherence at the B3LYP level with experimental values. As a result, the B3LYP with most diffused basis sets of 6-31G + (d,p) were used for further calculations. The parameters of Global Chemical reactivities revealed that all the dyes had a softer nature with their softness value range of 0.27-0.41. their Ionization Potentials (IP) ranged between 6.21-8.10 eV to comply that the new dyes had good electron donating potentials. With a good electron injection potential of -1.47-1.74 eV, aluminum can be the best electrode, while Au is excellent towards a hole injection operation which had the potential range of 1.79-3.68 eV. For Natural Bond Orbital (NBO) assessment, (N14)LP → (F16-F28)π* with stabilization energy of 42.55 kcal/mol was noted for DTB4. Their Second order hyperpolarizability [Formula: see text] values as their Nonlinear Optical (NLO) response ranged between 59.16-232.11 debye-angstrom-1 which were almost 6 times higher than the reference DTB (8.47D). The NLO attributes has also shown that a dyes with its small bandgap was related with higher hyperpolarizability values. Because of the decreased reorganization frequencies, newly discovered derivatives with electron transfer qualities might be comparable to or equivalent to those of commonly used electron transmission materials.

Correlating the charge transfer efficiency of metallic sulfa-isatins to design efficient NLO materials with better drug designs.

The present study presents synthesis, characterization and first principle studies on metal chelates, (1-12), of sulfonamide-isatin reacted ligands (S1-S3). All the products were evaluated by various physical and spectral (UV, IR, NMR, MS) means. The octahedral geometry for Co+2, Ni+2 and Zn+2, while square planner geometry for Cu+2 chelates were confirmed by their spectroscopic and magnetic data. Their physical chemistry investigation show the ability of aromatic rings to stabilize sulfonamide rings across NH-π interactions at their optimized geometries. The nonlinear optical response for all the compounds disclosed that the z-axis has the most contributions. An efficient electron injection and hole studies for Au and Al electrodes having the energies of - 0.1-3.1 and 0.0-11.8 eV respectively were noted. Their bioactive character was shown by global reactivity calculated from FMO energy gaps. The enzyme inhibitory results were found to be 45-61% and IC50 = 102-122 µL, for compound (4), (10), (8), (5) and (12) against the amylase, protease, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) respectively The antibacterial findings showed significant action having 11-17 mm for (2), (7) and (10) for bacterial species, Escherichia coli and Micrococcus luteus. The DPPH and ferric reducing power assay was used to evaluate the antioxidant capacity with 49.0 ± 0.09-66.2 ± 0.08% and IC50 = 102.3-122.4 µL range. In comparison to ligands, the results showed that all metal chelates had higher bioactivity. The chelation was the primary cause of their increased bioactivity. These findings suggested that such metal-based compounds might be used as antimicrobial, and antioxidant options in future to cope drug resistance.

Aminothiazole-Linked Metal Chelates: Synthesis, Density Functional Theory, and Antimicrobial Studies with Antioxidant Correlations.

During the current study, the new aminothiazole Schiff base ligands (S1 ) and (S2 ) were designed by reacting 1,3-thiazol-2-amine and 6-ethoxy-1,3-benzothiazole-2-amine separately with 3-methoxy-2-hydroxybenzaldehyde in good yields (68-73%). The ligands were characterized through various analytical, physical, and spectroscopic (FT-IR, UV-Vis, 1H and 13C NMR, and MS) methods. The ligands were exploited in lieu of chelation with bivalent metal (cobalt, nickel, copper, and zinc) chlorides in a 1:2 (M:L) ratio. The spectral (UV-Vis, FT-IR, and MS), as well as magnetic, results suggested their octahedral geometry. The theoretically optimized geometrical structures were examined using the M06/6-311G+(d,p) function of density function theory. Their bioactive nature was designated by global reactivity parameters containing a high hardness (η) value of 1.34 eV and a lower softness (σ) value of 0.37 eV. Different microbial species were verified for their potency (in vitro), revealing a strong action. The Gram-positive Micrococcus luteus and Gram-negative Escherichia coli gave the highest activities of 20 and 21 mm for compounds (8) and (7), respectively. The antifungal activity against the Aspergillus niger and Aspergillus terreus species gave the highest activities of 20 and 18 mm for compounds (7) and (6), respectively. The antioxidant activity, evaluated as DPPH and ferric reducing power, gave the highest inhibition (%) as 72.0 ± 0.11% (IC50 = 144 ± 0.11 µL) and 66.3% (IC50 = 132 ± 0.11 µL) for compounds (3) and (8), respectively. All metal complexes were found to be more biocompatible than free ligands due to their chelation phenomenon. The energies of LUMOs had a link with their activities.

Facile synthesis, spectroscopic evaluation and antimicrobial screening of metal endowed triazole compounds.

The scientific interest in developing new complexes as inhibitors of bacterial biofilm related infections is constantly rising. The present work describes the chemical synthesis, structural and biological scrutiny of a triazole Schiff base ligand and its corresponding complexes. Triazole Schiff base, (2-methoxy-4-[(1H-1,2,4-triazol-3-ylimino)methyl]phenol) was synthesized from the condensation reaction of 3-amino-1,2,4-triazole and 4-hydroxy-3-methoxybenzaldehyde in an equimolar ratio. The triazole ligand (H2L) was characterized by physical (solubility, color, melting point), spectroscopic [UV-visible (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H-NMR) and mass spectra (MS)] and micro analysis to evaluate their elemental composition. The bidentate ligand was complexed with transition metal [VO(IV), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] in 1:2 molar ratio. The complexes were characterized by physical (color, solubility, decomposition temperature, conductance and magnetic moment), FT-IR, UV-Vis and elemental analysis. Thermal stability and fluorescence properties of the compounds were also determined. Density functional theory based theoretical calculations were accomplished to gain more insight into spectroscopic properties. The frontier molecular orbital analysis revealed that the ligand was less reactive with reduced electron donating capability and more kinetic stability than complexes. The as-synthesized compounds were scrutinized for anti-bacterial and anti-fungal activity against selected strains. Cobalt complex exhibited highest antibacterial activity against Escherichia coli and nickel complex has shown highest antifungal activity against Aspergillus niger. All the compounds also showed good antioxidant activity. The theoretical results reflect consistency with the experimental findings signifying that such compounds could be the promising chemical scaffolds in the near future against microbial infectious.

A review: Pharmacological aspects of metal based 1,2,4-triazole derived Schiff bases.

Clinical reports have highlighted the radical increase of antibiotic resistance. As a result, multidrug resistance has emerged as a serious threat to human health. Many organic compounds commonly used as drugs in the past, no longer have pure organic mode of action rather need bio-transformation or more activation. Bulk of research has shown that they need trace amount of metal ions incorporated within the chemistry of bioactive molecules for enhancement of their potentiality to fight aggressively against resistance. The deficiency of some metal ions can also be responsible for many diseases like growth retardation, pernicious anemia and heart diseases in infants. To overcome these problems, there is a need to introduce novel strategies which have new mechanism of action along with significant spectrum of biological activity, enhanced safety and efficacy. Bioinorganic compounds have played imperative role in developing the new strategy in the form of "Metal Based Drugs". In current years there have been momentous rise of interest in the application of metal based Schiff base compounds to treat various diseases which are difficult to be treated with conventional methodologies. The unique properties of metal chelates acting as an intermediate between conventional organic and inorganic compounds provided innovative opportunities in the field of pharmaceutical chemistry. In this review, we have exclusively focused on the search of metal based 1,2,4-triazole derived Schiff base compounds (synthesized, reported and reviewed in the past ten years) that possess various biological activities such as antifungal, antibacterial, antioxidant, antidiabetic, anthelmintic, anticancer, antiproliferative, cytotoxic and DNA-intercalation activity.

Coumaronochromone as antibacterial and carbonic anhydrase inhibitors from Aerva persica (Burm.f.) Merr.: experimental and first-principles approaches.

The Aerva plants are exceptionally rich in phytochemicals and possess therapeutics potential. Phytochemical screening shows that Aerva persica (Burm.f.) Merr. contains highest contents i.e., total phenolics, flavonoids, flavonols, tannins, alkaloids, carbohydrates, anthraquinones and glycosides. In-vitro antibacterial and enzymatic (carbonic anhydrase) inhibition studies on methanol extracts of A. persica indicated the presence of biological active constituents within chloroform soluble portions. Investigation in the pure constituents on the chloroform portions of A. persica accomplished by column chromatography, NMR and MS analysis. The bioguided isolation yields four chemical constituents of coumaronochromone family, namely aervin (1-4). These pure chemical entities (1-4) showed significant antibacterial activity in the range of 60.05-79.21 µg/ml against various bacterial strains using ampicillin and ciprofloxacin as standard drugs. The compounds 1-4 showed promising carbonic anhydrase inhibition with IC50 values of 19.01, 18.24, 18.65 and 12.92 µM, respectively, using standard inhibitor acetazolamide. First-principles calculations revealed comprehensive intramolecular charge transfer in the studied compounds 1-4. The spatial distribution of highest occupied and lowest unoccupied molecular orbitals, ionization potential, molecular electrostatic potential and Hirshfeld analysis revealed that these coumaronochromone compounds would be proficient biological active compounds. These pure constituents may be used as a new pharmacophore to treat leaukomia, epilepsy, glaucoma and cystic fibrosis.

Synthesis, spectral characterization and computed optical analysis of potent triazole based compounds.

Biologically active triazole Schiff base ligand (L) and metal complexes [Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] are reported herein. The ligand acted as tridentate and coordinated towards metallic ions via azomethine-N, triazolic-N moiety and deprotonated-O of phenyl substituents in an octahedral manner. These compounds were characterized by physical, spectral and analytical analysis. The synthesized ligand and metal complexes were screened for antibacterial pathogens against Chromohalobacter salexigens, Chromohalobacter israelensi, Halomonas halofila and Halomonas salina, antifungal bioassay against Aspergillus niger and Aspergellus flavin, antioxidant (DPPH, phosphomolybdate) and also for enzyme inhibition [butyrylcholinesterase (BChE) and acetylcholinesterase (AChE)] studies. The results of these activities indicated the ligand to possess potential activity which significantly increased upon chelation. Moreover, vibrational bands, frontier molecular orbitals (FMOs) and natural bond analysis (NBO) of ligand (1) were carried out through density functional theory (DFT) with B3lYP/6-311++G (d,p) approach. While, UV-Vis analysis was performed by time dependent TD-DFT with B3lYP/6-311++G (d,p) method. NBO analysis revealed that investigated compound (L) contains enormous molecular stability owing to hyper conjugative interactions. Theoretical spectroscopic findings showed good agreement to experimental spectroscopic data. Global reactivity descriptors were calculated using the energies of FMOs which indicated compound (L) might be bioactive. These parameters confirmed the charge transfer phenomenon and reasonable correspondence with experimental bioactivity results.

Metal-based ethanolamine-derived compounds: a note on their synthesis, characterization and bioactivity.

Metal-based ethanolamines, (L1)-(L4) coordinated with Co(II), Cu(II), Ni(II) and Zn(II) metals in 1:2 (metal:ligand) molar ratio to produce new compounds have been reported. These compounds were screened for their bactericidal/fungicidal activity against a number of bacterial (Escherichia coli, Shigella flexneri, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus and Bacillus subtilis) and fungal strains (Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata) alongside against a shrimp species known as Artemia salina. The screening results indicated that metal complexes have significantly higher activity than uncomplexed ligands against one or more bacterial/fungal species due to chelation. The ligand (L4) displayed good bacterial and fungal activity as compared to other ligands. The antibacterial results revealed that the Zn(II) complex (16) of (L4) was found to be the most active complex and Co(II) complex (14) of the same ligand (L4), demonstrated the highest antifungal activity.

Metal based drugs: design, synthesis and in-vitro antimicrobial screening of Co(II), Ni(II), Cu(II) and Zn(II) complexes with some new carboxamide derived compounds: crystal structures of N-[ethyl(propan-2-yl)carbamothioyl]thiophene-2-carboxamide and its copper(II) complex.

A new series of compounds derived from thiophene-2-carboxamide were synthesized and characterized by IR, (1)H-NMR and (13)C-NMR, mass spectrometry and elemental analysis. These compounds were further used to prepare their Co(II), Ni(II), Cu(II) and Zn(II) metal complexes. All metal(II) complexes were air and moisture stable. Physical, spectral and analytical data have shown the Ni(II) and Cu(II) complexes to exhibit distorted square-planar and Co(II) and Zn(II) complexes tetrahedral geometries. The ligand (L(1)) and its Cu(II) complex were characterized by the single-crystal X-ray diffraction method. All the ligands and their metal(II) complexes were screened for their in-vitro antimicrobial activity. The antibacterial and antifungal bioactivity data showed that the metal(II) complexes were found to be more potent than the parent ligands against one or more bacterial and fungal strains.

Design, synthesis and in vitro bactericidal/fungicidal screening of some vanadyl(IV)complexes with mono- and di-substituted ONS donor triazoles.

A new series of anti-bacterial and anti-fungal mono- and di-substituted triazoles (L(1))-(L(6)) have been synthesized and characterized on the basis of their physical, spectral and analytical data. The ligands (L(1))-(L(6)) on reaction with vanadyl(IV) sulphate led to the formation of vanadyl(IV) metal complexes (1)-(4). The structure of the complexes has been established on the basis of their physical, spectral and elemental analyses data. The synthesized ligands and their vanadyl(IV) complexes have been screened in vitro for anti-bacterial activity against six bacterial species such as, Escherichia coli (ATCC 25922), Shigella flexneri (ATCC 12022), Pseudomonas aeruginosa (ATCC 27853), Salmonella typhi (ATCC 14028), Staphylococcus aureus (ATCC 25923) and Bacillus subtilis (ATCC 6051) and for in vitro anti-fungal activity against six fungal strains, Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata. The screening results showed the vanadyl complexes to be more bactericidal/fungicidal against one or more bacterial/fungal species. The synthesized compounds were also subjected to brine shrimp bioassay for scrutinizing their cytotoxicity.

In vitro antibacterial, antifungal and cytotoxic activities of some triazole Schiff bases and their oxovanadium(IV) complexes.

The condensation reaction of 3,5-diamino-1,2,4-triazole with methoxy-, chloro-, bromo-, iodo- and nitro-substituted 2-hydroxybenzaldehydes formed triazole Schiff bases (L(1))-(L(6)). The synthesized ligands have been characterized through physical, spectral and analytical data. Furthermore, the reaction of synthesized Schiff bases with the oxovanadium(IV) sulphate in (1:2) (metal:ligand) molar ratio afforded the oxovanadium(IV) complexes (1)-(6). All the complexes were non-electrolytic and showed a square-pyramidal geometry. The synthesized compounds have been screened for in-vitro antibacterial, antifungal and brine shrimp bioassay. The bioactivity data showed the complexes to be more active than the original Schiff bases.