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.

Computational Investigation of Near-Infrared-Absorbing Indeno[1,2-b]indole Analogues as Acceptors in Organic Photovoltaic Devices.

Organic solar cells (OSCs) with fullerene-free acceptors have recently been in high demand in the solar cell market because OSCs are less expensive, more flexible, long-lasting, eco-friendly, and, most importantly, have better photovoltaic performance with a higher PCE. We used INTIC as our reference R molecule and designed five new molecules DF1-DF5 from this R molecule. We attempted to test the power conversion efficiencies of five designed novel molecules, DF1-DF5. Therefore, we compared the PCE values of DF1-DF5 with that of R. We used a variety of computational techniques on these molecules to achieve this goal. Among the designed molecules, DF5 proved to be the best due to its lowest H-L bandgap energy E g (1.82 eV), the highest value of λmax (844.58 nm) within dichloromethane, the lowest excitation energy (1.47 eV), and the lowest oscillator strength value. The newly designed molecule DF2 exhibited the highest dipole moment (21.98 D), while DF3 displayed the minimum binding energy (0.34 eV) and the highest V oc value (1.37 V) with HOMOdonor-LUMOacceptor. According to the partial density of states (PDOS) and transition density matrix (TDM) analysis, DF2 and DF5 exhibited the best results. Charge-transfer (CT) analysis of the blend DF5 and PTB7-Th confirmed the accepting nature of the DF5 molecule. These findings show that by modifying the end-capped units, we can create customized molecules with improved photovoltaic properties. These findings also show that when compared with R, all of the designed molecules DF1-DF5 have improved optoelectronic properties. As a result, it is strongly advised to employ these conceptualized molecules in the practical synthesis of organic solar cells (OSCs).

Key Electronic, Linear and Nonlinear Optical Properties of Designed Disubstituted Quinoline with Carbazole Compounds.

Organic materials development, especially in terms of nonlinear optical (NLO) performance, has become progressively more significant owing to their rising and promising applications in potential photonic devices. Organic moieties such as carbazole and quinoline play a vital role in charge transfer applications in optoelectronics. This study reports and characterizes the donor-acceptor-donor-π-acceptor (D-A-D-π-A) configured novel designed compounds, namely, Q3D1-Q3D3, Q4D1-Q1D2, and Q5D1. We further analyze the structure-property relationship between the quinoline-carbazole compounds for which density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were performed at the B3LYP/6-311G(d,p) level to obtain the optimized geometries, natural bonding orbital (NBO), NLO analysis, electronic properties, and absorption spectra of all mentioned compounds. The computed values of λmax, 364, 360, and 361 nm for Q3, Q4, and Q5 show good agreement of their experimental values: 349, 347, and 323 nm, respectively. The designed compounds (Q3D1-Q5D1) exhibited a smaller energy gap with a maximum redshift than the reference molecules (Q3-Q5), which govern their promising NLO behavior. The NBO evaluation revealed that the extended hyperconjugation stabilizes these systems and caused a promising NLO response. The dipole polarizabilities and hyperpolarizability (ß) values of Q3D1-Q3D3, Q4D1-Q1D2, and Q5D1 exceed those of the reference Q3, Q4, and Q5 molecules. These data suggest that the NLO active compounds, Q3D1-Q3D3, Q4D1-Q1D2, and Q5D1, may find their place in future hi-tech optical devices.

Synthesis, Structure Study, First-Principles Investigations and Luminescence Properties of Europium and Terbium Complexes.

The synthesis of 1-benzyl-2-((2-Aminoethyl) amino)-5-oxopyrrolidine-3,4-diyl diacetate (boad), an oxopyrrolidine type ligand; designed to coordinate lanthanides (Eu3+ and Tb3+) to get luminescent material. The target complexes showed good photoluminescence properties, which indicate that this type of compound can be used as sensitizers having luminescence for the green (Tb3+) and red (Eu3+) emission. The obtained results revealed that sensitizer efficiency can be improved by adding ligands like acac (Eu(acac)3, which has also enhanced the luminescence quantum output and period for Eu3+ ions. The ground state geometries were developed by using density functional theory at B3LYP/6-31G** level. The charge transfer analysis and electronic properties were performed. The Europium and Terbium complexes formation with boad ligand was explored based on molecular electrostatic potential, MDC-q charges, and frontier molecular orbitals (FMOs) analysis.

Electron Donor and Acceptor Influence on the Nonlinear Optical Response of Diacetylene-Functionalized Organic Materials (DFOMs): Density Functional Theory Calculations.

Herein, we report the quantum chemical results based on density functional theory for the polarizability (α) and first hyperpolarizability (ß) values of diacetylene-functionalized organic molecules (DFOM) containing an electron acceptor (A) unit in the form of nitro group and electron donor (D) unit in the form of amino group. Six DFOM 1-6 have been designed by structural tailoring of the synthesized chromophore 4,4'-(buta-1,3-diyne-1,4-diyl) dianiline (R) and the influence of the D and A moieties on α and ß was explored. Ground state geometries, HOMO-LUMO energies, and natural bond orbital (NBO) analysis of all DFOM (R and 1-6) were explored through B3LYP level of DFT and 6-31G(d,p) basis set. The polarizability (α), first hyperpolarizability (ß) values were computed using B3LYP (gas phase), CAM-B3LYP (gas phase), CAM-B3LYP (solvent DMSO) methods and 6-31G(d,p) basis set combination. UV-Visible analysis was performed at CAM-B3LYP/6-31G(d,p) level of theory. Results illustrated that much reduced energy gap in the range of 2.212-2.809 eV was observed in designed DFOM 1-6 as compared to parent molecule R (4.405 eV). Designed DFOM (except for 2 and 4) were found red shifted compared to parent molecule R. An absorption at longer wavelength was observed for 6 with 371.46 nm. NBO analysis confirmed the involvement of extended conjugation and as well as charge transfer character towards the promising NLO response and red shift of molecules under study. Overall, compound 6 displayed large α and ßtot, computed to be 333.40 (a.u) (B3LYP gas), 302.38 (a.u.) (CAM-B3LYP gas), 380.46 (a.u.) (CAM-B3LYP solvent) and 24708.79 (a.u), 11841.93 (a.u.), 25053.32 (a.u) measured from B3LYP (gas), CAM-B3LYP (gas) and CAM-B3LYP (DMSO) methods respectively. This investigation provides a theoretical framework for conversion of centrosymmetric molecules into non-centrosymmetric architectures to discover NLO candidates for modern hi-tech applications.

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.

Functionalization of protected tyrosine via Sonogashira reaction: synthesis of 3-(1,2,3-triazolyl)-tyrosine.

1,2,3-Triazol tyrosines were synthesized from tyrosine alkynes that were in turn prepared via Sonogashira cross-coupling reaction. The tyrosine alkynes were subjected to click-chemistry reaction conditions leading to the corresponding 3-(1,2,3-triazolyl)-tyrosines in yields ranging from moderate to good.

Crystal structure of 1-benzyl-2-hy-droxy-5-oxopyrrolidin-3-yl acetate.

In the title compound, C13H15NO4, the oxopyrrolidin-3-yl ring has an envelope conformation, with the C atom bearing the acetate group being the flap. The acetate and phenyl groups are inclined with respect to the central ring, forming dihedral angles of 50.20 (12) and 87.40 (9)°, respectively, with the least-squares plane through the ring. The dihedral angle between the acetate group and the phenyl ring is 63.22 (8)°, indicating a twisted conformation in the mol-ecule. In the crystal, supra-molecular chains along the b axis are formed by (hy-droxy)O-H⋯O(ring carbon-yl) hydrogen bonds. The chains are consolidated into the three-dimensional architecture by C-H⋯O inter-actions.

Pakistamide C, a new sphingolipid from Abutilon pakistanicum

The Abutilon genus from the Malvaceae family is of medicinal importance, and members of this genus are distributed in the tropical and subtropical regions of Asia and other parts of the world. Abutilon pakistanicum Jafri & Ali is mainly found in Pakistan. It has been used by different systems of traditional medicines to treat different diseases. Pakistamide C, a new sphingolipid, has been isolated from the ethyl acetate soluble fraction of the methanolic extract of A. pakistanicum. Different spectroscopic techniques such as NMR (1H, 13C, COSY, NOESY, HSQC, HMBC) and Mass spectrometry (EI-MS, and FAB-MS experiments) were used to elucidate the structure of pakistamide C.

Tunable porous organic crystals: structural scope and adsorption properties of nanoporous steroidal ureas.

Previous work has shown that certain steroidal bis-(N-phenyl)ureas, derived from cholic acid, form crystals in the P6(1) space group with unusually wide unidimensional pores. A key feature of the nanoporous steroidal urea (NPSU) structure is that groups at either end of the steroid are directed into the channels and may in principle be altered without disturbing the crystal packing. Herein we report an expanded study of this system, which increases the structural variety of NPSUs and also examines their inclusion properties. Nineteen new NPSU crystal structures are described, to add to the six which were previously reported. The materials show wide variations in channel size, shape, and chemical nature. Minimum pore diameters vary from ~0 up to 13.1 Å, while some of the interior surfaces are markedly corrugated. Several variants possess functional groups positioned in the channels with potential to interact with guest molecules. Inclusion studies were performed using a relatively accessible tris-(N-phenyl)urea. Solvent removal was possible without crystal degradation, and gas adsorption could be demonstrated. Organic molecules ranging from simple aromatics (e.g., aniline and chlorobenzene) to the much larger squalene (M(w) = 411) could be adsorbed from the liquid state, while several dyes were taken up from solutions in ether. Some dyes gave dichroic complexes, implying alignment of the chromophores in the NPSU channels. Notably, these complexes were formed by direct adsorption rather than cocrystallization, emphasizing the unusually robust nature of these organic molecular hosts.

Thymofolinoates A and B, new cinnamic acid derivatives from Euphorbia thymifolia.

Two new cinnamic acid derivatives, thymofolinoates A (1) and B (2) have been isolated from the chloroform soluble fraction of Euphorbia thymifolia and their structures assigned from 1H and 13C NMR spectra, DEPT and by 2 D COSY, HMQCand H MBC experiments. In addition, p-hydroxy cinnamic acid(3), 5-hydroxy-6,7,8,4'-tetramethoxy flavone (4), and 5-hydroxy-3',4',6,7,8-pentamethoxy flavone (5) have also been isolated for the first time from this species.

Spiraeamide, new sphingolipid from Spiraea brahuica.

Spiraeamide, a new sphingolipid, has been isolated from the ethyl acetate-soluble fraction of the methanolic extract of the whole plant of Spiraea brahuica, along with marrubiin, 19-acetylmarrubenol, and 6-acetylmarruenol. Their structures were elucidated by ¹H and ¹³C NMR spectra, and COSY, NOESY, HMQC, HMBC, EI-MS, and FAB-MS experiments.

Vicarin, a new isoflavone from Eremostachys vicaryi.

Vicarin (1), a new isoflavone, has been isolated from the ethyl acetate-soluble fraction of the ethanolic extract of Eremostachys vicaryi, along with soforanarin B (2), luteolin 7-O-ß-D-glucopyranoside (3), and hamighriprasin (4). Their structures were elucidated on the basis of their spectral data including MS and 2D NMR.

A secondary metabolite amberin from Amberboa ramosa.

Amberin (1), a new sesquiterpene lactone, has been isolated from the ethyl acetate soluble fraction of Amberboa ramosa together with apigenin (2), jaseocidine (3), crysoeriol (4), and 3ß, 8α-dihydroxy-11α-methyl-1αH, 5αH, 6ßH, 7αH, 11ßH-guai-10(14), 4 (15)-dien-6, 12-olide (5). The structures of the isolated compounds have been elucidated by 1D and 2D NMR spectroscopy.

Structural determination of abutilins A and B, new flavonoids from Abutilon pakistanicum, by 1D and 2D NMR spectroscopy.

Two new flavonoids, abutilin A and B, were isolated from the chloroform soluble fraction of Abutilon pakistanicum and their structures assigned from (1)H and (13)C NMR spectra, DEPT and by 2D COSY, HMQC and HMBC experiments. Ferulic acid (3), (E)-cinnamic acid (4), 5-hydroxy-4',6,7,8-tetramethoxyflavone (5), kaempferol (6), luteolin (7) and luteolin 7-O-beta-D-glucopyranoside (8) have also been reported from this species.