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The recyclable nanomagnetic Pd-complex PAMAM G0-Pd@γ-Fe2O3 is reported for catalytic C–C cross-coupling reactions of challenging substrates.

The conformational analysis of N-formyl-D-serine-D-alanine-NH2 dipeptide was comprehensively studied using the density functional theory methods in the gas and solution phases. The all-expected 35=243 stable conformers were explored, where 91 conformers were located, and the rest of them were migrated to the more stable geometries. Migration pattern suggests the more stable dipeptide model with the serine in βL, γD, γL and the alanine in γL and γD configurations. The investigation of side-chain–backbone interactions revealed that the most stable conformer, γD–γL, is in the β − turn region of the Ramachandran map; therefore, serine-alanine dipeptide model should be adopted with a β − turn conformation. QTAM consideration of the intramolecular hydrogen bonding in β-turns disclosed the highest stable conformer as γD–γL includes the three hydrogen bonds. The computed UV-Vis spectrum alongside of NBO calculation showed and explained the five main electronic transition bands derived of n→ n* of intra-ligand alanine moiety of dipeptide structure.

Bismuth molybdate has three phases α-Bi

The interesting g-C3N4 nanosheet morphology has drawn huge attention in photocatalytic applications because of its special features. Nonetheless, the relative activity of these nanosheets is still controversial due to the low available active sites and the high recombination probability of photo-induced charge carriers. In this work, in situ sol–gel approach was applied to synthesize holey g-C3N4 nanosheets/hydroxyapatite (HAp) nanospheres with plentiful in-plane holes. Herein, the presence of Ca2+ plays a key role in the formation of holey defects on 2D g-C3N4. In-plane holes provide nanosheets with more active edges and diffusion channelsv, resulting in a tremendous enhanced mass and photo-induced charge transfer speed. Moreover, the holes make highly numbered boundaries, which lead to the prevention of aggregation. On the other hand, distributed nano-HAp spheres on these nanosheets can form effective heterojunctions having high photo-degradation ability of pollutants. Intrinsic O-vacancies inside HAp unit cells mainly affect the capture of photogenerated electrons, pollutant molecules, and O2 gas. The synergistic presence of O-vacancies and holey defects (C-vacancies) on 2D g-C3N4 plays a key role in raising the photocatalytic performance of holey g-C3N4/HAp. It can be concluded that the proposed preparation method is a promising approach for simultaneous synthesis of holey g-C3N4 and surface heterojunctions of Ca-based materials. This new structure has shown significant degradation ability of bisphenol A, a prominent pollutant, with a low amount (0.01 g) and short time.

Reactivation of BK polyomavirus (BK virus) is associated with the polyomavirusassociated nephropathy (PVAN) and hemorrhagic cystitis (HC), which induce allograft failure. Therefore, the identification of BK virus in the early stage is significantly related to the improvement of allograft function and patient survival. Herein, a facil alkoxide-based sol-gel technique was executed to prepare hydroxyapatite nanoparticles (HANPs). The structural properties of HANPs were characterized using Powder X-ray Diffractometer (PXRD), Fourier transform infrared spectroscopy (FTIR), Energy Dispersive X-ray Analysis (EDXA), and transmission electron microscopy (TEM). The results of the current study showed that the proposed biosensor could be used for detection of BK virus in the urine sample. For this goal, a probe ssDNA was immobilized on the HANPs-modified Glassy Carbon Electrode (GCE), and then the hybridization between the target and probe sequences was studied by measuring the electrochemical response of Methylene Blue (MB) using differential pulse voltammetry (DPV) method. The efficiency of this biosensor was investigated by the extracted DNA from the urine samples and the sensitivity and specificity of this biosensor were studied by synthetic sequences. The proposed biosensor indicates a linear response from 50.00 × 10 -12 to 1.00 × 10 -9 mol/L with a detection limit of 41.08 × 10 -12 mol/L.

[Ni{2-H2NC(=O)C5H4N}2(H2O)2][Ni{2,6-(O2C)2C5H3N}2]·4.67H2O, a new complex salt containing a bis(2,6-dicarboxypyridine)nickel(II) anion and a bis(2-amidopyridine)diaquanickel(II) cation, was synthesized and characterized. The crystal is stabilized by an extensive network of hydrogen bonds. Alternate layers of anions and cations/water molecules parallel to (010) can be distinguished. Computational studies of the network packing of the title compound by high-level DFT-D/B3LYP calculations indicate stabilization of the networks with conventional and non-conventional intermolecular O—H...O, N—H...O and C—H...O hydrogen bonds along with π-stacking contacts. Due to the presence of water molecules and the importance of forming hydrogen bonds with the involvement of water clusters to the stability of the crystal packing, the importance and role of these water clusters, and the quantitative stability resulting from the formation of hydrogen bonds and possibly other noncovalent bonds such as π-stacking are examined. The binding energies obtained by DFT-D calculations for these contacts indicate that hydrogen bonds, especially O—H...O and N—H...O, control the construction of the crystalline packing. Additionally, the results of Bader's theory of AIM for these interactions agree reasonably well with the calculated energies.

The catalytic esterification of free fatty acids is an important reaction pathway for chemical synthesis and biodiesel production, wherein efficient heterogeneous catalysts are sought to replace mineral acids. Herein, the esterification of oleic acid together with some familiar fatty acids is demonstrated with methanol over a heterogeneous heteropolyacid-functionalized zeolite imidazolate framework [H6–nP2W18O62n–/ZIF(HnHis.)+n]. This new heterogeneous catalyst (named as HPA/ZIF(His.) throughout the text) with an average particle size of 80 nm was prepared via condensation of histamine with zinc chloride and characterized by means of Fourier transform infrared (FT-IR), X-ray diffraction (XRD), UV–vis, energy-dispersive X-ray spectrometry, Brunauer–Emmett–Teller, thermogravimetric analysis (TGA), inductively coupled plasma - optical emission spectrometry (ICP-OES), and scanning electron microscopy. According to the performed characterizations, an HPA loading of 40.5 wt % is obtained for HPA/ZIF(His.) from ICP-OES analysis. Moreover, a typical type-IV isotherm with similar adsorption–desorption properties as seen for ZIF-8 is attained. In addition, TGA measurement confirms less stability of HPA/ZIF(His.) compared to that of pure ZIF(His.). The catalytic performance of the nanomaterial is evaluated with respect to temperature, catalyst loading, and methanol/oleic acid ratio and leads to a high yield of methyl ester (>90%) under reflux for 4 h. The preliminary kinetic studies confirm a pseudo-first-order kinetic model for the esterification of oleic acid. To explore the scope of the HPA/ZIF(His.) catalyst in methyl ester production, other free fatty acids with various chain lengths are also successfully tested. Although the nanocatalyst loses a part of its activity during reuse, however, it is stable over at least four recycles as confirmed by XRD and FT-IR. Eventually, the response surface methodology (RSM) is used as a statistical modeling approach to get the best-optimized reaction conditions compared to the performed single-variable benchmarking experiments. Therefore, the central composite design (CCD) and RSM attained a platform to determine the relationship among the reaction time, acid/methanol molar ratio, and catalyst dosage.

The novel synthetic Sol‒EPD process of a thin film including of well decorated g‒C

The new cocrystal adducts of N-phthaloyl-β-alanine and benzimidazole (1:2) with molecular formula C18H15N3O4 (1) was synthesized by slow evaporation process of the aqueous solution containing the two said moieties. The confirmation of proposed formula can be established through crystal structure as well as FTIR analysis. The crystal structure was confirmed by single X–ray crystal analysis. The experimental and theoretical studies of photophysical properties like Fourier Transform Infrared (FTIR) and ultraviolet–visible spectroscopy (UV–Vis) have been done. The cocrystal belong to monoclinic crystallographic system with space group P21/c, Z = 4. DPPH radical scavenging activity of the title cocrystal is slightly lower than coformer with lower IC50 value, respectively. One dimensional infinite chain in direction of [010] parallel to b direction. Optimized crystalline network structure of 1 shows that conventional N−H⋯O, and O H⋯N, and the non−conventional C H⋯O hydrogen bonds (HBs) gathered the monomeric components of 1 (1−mon). The reliable calculations of the dispersion corrected density functional theory (DFT−D) display that N−H⋯O and O−H⋯N HBs more share in the stabilization of the network structure. The theoretical study of UV–Vis spectra in solvents (water, acetonitrile, methanol, and n–heptanes) confirms the experimental results as seven main bands in 180–270 nm range. They could attribute to intra-ligand charge transfer (ILCT) as benzimidazole → benzimidazole and N-phthaloyl-β-alanine → N-phthaloyl-β-alanine with π → π* character.

The restricted global fear within contaminated ecosystem has been motivated the impress works to employ the photocatalytic degradation of organic pollutants and pesticides. Generally, stability and water solubility of pesticides cause high impacts on environment due to high resistance in ecosystem. Heterogeneous nano-photocatalyst can be introduced as one of the most appealing technologies bearing great remediation performance because of the high surface area and intense correlated activity. The heterogeneous catalytic nanomaterials have been operated to harvest, turn, and supply clean and renewable sunlight energy. It can be performed through entire water splitting and CO production to provide green-sustainable solar fuels alongside of wide ranges of environmental aspects. We reviewed in the presented chapter focusing on the application of effective nanomaterials in environmental remediation about industrial and agricultural effluents. For years TiO2 photocatalyst has been largely utilized but includes restricted activity just in UV spectrum due to wide band gap. Therefore, it is crucial to development of new effective visible light-sensitive photocatalysts with lower band gap that can be activated by a notable percentage of the solar irradiations. Herein, we try to discuss the basic science drives for performance improving of visible/solar light photocatalysts. First, the corresponding principles which include of thermodynamics, kinetics, and recombination rate are followed. The second section reviews the new effective reported visible-activated photocatalytic compounds considering with proposed photoexcitation mechanisms and reducing the charges recombination. Finally, the main challenges and future prospects for better handling of photocatalytic technology were briefly discussed.

Enhancing demand for environmental protection has become an urgent need more than ever. For this purpose, water the most known indispensable essences for survivorship of aboveground organisms should be specifically considered. Today, quality of water as dominant source influence of the animate systems has been endangered by various harmful contamination levels. Accordingly, rescuing approaches and cleaning compounds in safe manner demanding for improvement of the quality of potable and industrial utilizing waters are daily pursued. Different materials of bismuth having layered structures, hybridized orbitals, low band gap, and band positions can be attended because of significant ability of water remediation. At this book chapter, we reviewed the photocatalytic efficiency of Bi−compounds, the heterojunction and Z−scheme composites of them, and the synthetization method. Heterojunction or Z−scheme combinations led to obtain high separation photogenerated electrons−hole and reduction of the recombination rate. Furthermore, type II of heterojunction and Z−scheme connections with other Bi- or non-Bi compounds was applied as an effective solution to enhance photocatalytic performance. The major points are related to the activity about (1) water remediation and (2) photoelectrochemical water splitting. The presented review tries to demonstrate the high potential of Bi−compounds and Bi−composites for water remediation and hydrogen and oxygen production through redox reactions of water activated by solar light irradiation, respectively.

Theoretical conformational analysis of N–formyl–L–serine–L–alanine–NH2 dipeptide model was investigated using B3LYP/6-311+G(d,p) and M06-2X/6-311+G(d,p) calculations. In this research, 243 total possible conformations of the dipeptide model were optimized including 87 stable conformers and the other disappeared ones migrated to more stable geometries. Migration pattern suggests more stability of the dipeptide model with the serine (ser) in βL, γL, and γD and the alanine (ala) in γD and γL configurations, along with 26 of the found conformers having β-turn structures. Our calculations reveal that the most stable conformer, γL+γD, is in β-turn region of Ramachandran map; therefore, serine-alanine (ser-ala) dipeptide model should be adopted with a β-turn conformation. The atoms in molecules (AIM) topological analysis was carried out to characterize the nature of the intramolecular hydrogen bonding in β-turn structures. The γL+γD, including three hydrogen bonds, has the highest stability, while αLaγL as the most unstable β-turn conformer bears two and one hydrogen bonds at the B3LYP/6-311+G(d,p) and M06-2X/6-311+G(d,p) levels of theory, respectively.

In this study, we demonstrate the application of newly developed magnetic potassium substituted hydroxyapatite (KHA/Fe3O4) for the extraction of organophosphorus pesticides (OPPs) from water samples. Nanoparticles of KHA were synthesized through an easy alkoxide–based sol–gel technique. The structure of nanocomposite was characterized by X–ray diffraction (XRD), Fourier transform infrared (FTIR) analysis, and energy dispersive X–ray analysis (EDXA). The OPPs were analyzed by gas chromatography–flame ionization detector (GC–FID). Variables affecting the performance of both extraction steps such as pH of the water sample, the sorbent amount, the desorption conditions, and the extraction time solvent were studied and optimized. Under optimum conditions, good linearity was achieved for all analytes in the 0.1–200 ng mL−1 concentration range. The limits of detection (at an S/N ratio of 3) are between 0.03 and 0.22 ng mL−1. The intra-day (n = 5) and inter-day (n = 3) relative standard deviations (RSD%) of three replicates were each demonstrated in the range of 5.2–9.1% and 5.6–9.0%, respectively. The recoveries of OPPs from spiked real water samples and fruit juices are between 89.0 and 99.7%, with relative standard deviations between 5.5 and 10.8%.

Theoretical conformational analysis of N-formyl-L-serine-L-alanine-NH

In the present work, nano-particles of potassium-substituted hydroxyapatite with formula of (Ca2.94K2.06)(PO4)0.94(CO3)2.06(OH) (KHA) are reported showing effective adsorption of Congo red dye in the room temperature. Synthesized sol–gel-derived KHA was identified by XRD, FTIR, TGA/DTA, and EDXA analyses. Moreover, the size of nano-particles and micro-strain of the synthesized KHA were measured using Williamson–Hall (W–H) plots and TEM in amount of 65–70 nm. The capacity of equilibrium adsorption (qm) for 100 ppm of Congo red was evaluated as high as 505.19 mg g−1 under optimum conditions. The adsorption charts and kinetic results obtained at ambient conditions well fitted with the Langmuir equation and the pseudo–first–order model with correlation coefficients of 0.9939 and 0.9867, respectively. The obtained results obviously show that the new synthesized KHA can be used for industrial wastewater purification in a good manner. The title nano-material also shows excellent antibacterial activity as highly prevention of bacteria strain growth with the lowest concentration of 125 µg/mL.

In this work, for the first time, we have investigated the structural and optoelectronic properties of Erlotinib hydrochloride (C22H24N3O4+·Cl−) (1) anticancer drug using DFT calculations by the full-potential (linearized) augmented plane wave (FP(L)APW) calculations and hybrid density functional B3LYP. The monomeric ion of 1 participates in some 2-D fragments through different non-covalent interactions, including H-bonds (HBs) and π-stacking. Dispersion-corrected density functional theory calculations (DFT-D) have been used for obtaining the corrected values of the calculated binding energy of non-covalent interactions of the respective network of 1. Delocalization indices are the criterions for bond polarity by measuring the share of electron pair between two atoms. The results show that involved HBs can be classified from moderate to strong. The results show that HBs, especially non-covalent C–H···O interactions, govern the network formation along the a and c axes. Density of state results by the FP(L)APW show that this complex has a wide band gap (2.28 eV). The top of the valence band is originating mainly from Cl-, N- and O-p states and the bottom of the conduction band is composed of C- and N-p states. These states play a key role in optical transitions of C22H24N3O4+·Cl− anticancer drug. Optical results show that this molecule is birefringent.

As a continuation of our studies on the coordination chemistry of 8-aminoquinoline (8-aq) and related nitrogen-containing heterocyclic ligands, we report the synthesis and crystal structure of a new complex of formula cis-[Co(8-aq)2(NCS)2] (1) by slow evaporation of an aqueous ethanolic solution containing a mixture of 8-aq, KSCN, and Co(NO3)2⋅6H2O. As expected, the 8-aq ligand chelates to the metal with the resulting coordination sphere being distorted octahedron. Examination of the packing of 1 in the crystal together with the results of high level DFT-D/B3LYP calculations indicate the packing is stabilized by non-classical intermolecular N–H⋯S, N–H⋯C, C–H⋯N, and C–H⋯S hydrogen bonds (HBs) together with π-stacking interactions. It should be noted that dispersion corrected density functional theory (DFT-D) calculations of the binding energy of non-covalent interactions prove that N–H⋯S HBs govern the formation of the crystalline 3D network.

In the present work a novel cocrystal adduct of N –phthaloyl–β–alanine and 2,2–bipyridyl as compound 1 with molecular formula C 16 H 13 N 3 O 4 was synthesized by slow evaporation process of the ethanoic solution containing these two moieties. In followings, the crystal structure and photophysical properties of 1 was characterized by single X-ray crystal analysis, FTIR, and UV–Vis spectra. The thermal behavior was analyzed by the Thermogravimetric/Differential Thermal Analyzer (TG-DTA). The cocrystal belong to monoclinic crystallographic system with space group P 21/ n , Z = 4. DPPH radical scavenging activity of the title cocrystal is slightly higher than coformer with lower IC 50 value. Finally, using DFT calculations executed at hybrid B3LYP/6–311+G ( d , p ) level of theory the geometric and electronic structures of the crystalline network of C 16 H 13 N 3 O 4 ( 1 ), studied. Inter-molecular conventional O H⋯N as well as the non-conventional C H⋯O hydrogen bonds (HBs) and C H···π and C O···π stacking interactions gathered the monomeric structures of 1 ( 1-mon ) to create the 3D architecture of the network ( 1-net ). The dispersion corrected density functional theory (DFT-D) calculations indicate that O H⋯N and C H⋯O HBs, govern the 1-net formation. The calculated UV–Vis spectrum in vacuo has agreement with the experimental one that shows five major bands in the range of 170–271 nm that could assigned to transitions between 2,2-bipyridyl and N -phthaloyl-β-alanine parts of 1 with n → π ∗ and π → π* ligand-ligand-charge transfer (LLCT) character. The calculated electronic spectra in solvents (water, acetonitrile, methanol, and n–heptane) comparing with the vacuo one show broad bands with blue shifts.

In this work, a new nanoflake morphology for Bi2WO6 ultra–thin film was successfully coated from an aqueous electrolyte by the electrophoretic deposition method. Two SS mesh sheets were interlaced as an innovative designed substrate. The new structures of double substrates played vital role in the light harvesting because of more available catalyst surfaces and great influence in photocatalytic issues. These films were applied for photocatalytic degradation of metronidazole and amoxicillin in binary and single modes as pharmaceutical pollutant models. The observed results confirmed the remarkable photocatalytic degradation activity due to the innovative designed substrates made the new film morphology having higher light harvesting sites. Two cross interlaced sheets (double form) provided more available light trapping and harvesting surfaces due to small vacancy sites between two substrates which prevented from the light crossing comparison with the simple mesh sheet (single form). Electrochemical impedance spectroscopy and photocurrent studies suggested the higher separation of photogenerated hole/electrons for the double mode of substrates. It can be assigned to the low film thickness resulted in the short charge transfer route and enhanced photocatalytic efficiency. Catalyst surface has the low adsorption ability within the large molecules of amoxicillin; in the single mode pollutant solution; led to the low catalytic efficiency. But in the binary mixture, higher catalytic ability for amoxicillin degradation was observed. In addition, new nanoflakes retarded the charge recombination by creation of new routes made the more desired photocatalytic degradation. On can conclude, this innovative designed substrate will open the new arena filed for construction of the photocatalytic tools applicable in the large scale up of environmental pollutants.

For the first time, a new Cu(II) complex including pyrazine (pyz) and a tridentate O,N,O–donor hydrazone ligand formulated as Cu(L)(pyz)(CH3OH)]+ (1) (LH=[CF3C(OH)=CH–C(CH3)=N–NH–CO–C6H4(OH)]) (CuClC 17 H 18 F 3 N 4 O 4 ) has been investigated using density functional theory (DFT) methods. The DFT approaches have been performed by applying B3LYP/LANL2DZ/6–311 + G(d, p) and full potential linearized augmented plane wave (FP–LAPW) methods. The complex belongs to triclinic crystallographic system with space group of P1, Z = 2. Selected 1 as monomeric unit (1-mon) through a variety of non-covalent interactions containing hydrogen bonds (HBs) and π-stacking, constructs a 2-D coordination polymeric plane. The dispersion corrected density functional theory (DFT-D) calculations indicate that the conventional O–H···N and the non-conventional C–H···F HBs, govern the related network (1-net) formation. The calculated-B3LYP/LANL2DZ/6–311 + G(d, p) electronic spectrum in gas phase in good agreement with the experimental one shows five major bands in the range of 268–582 nm that could be assigned to MLCT and LLCT transitions with n → π* character. Calculated optoelectronic spectra by FP–LAPW show that Cu–3d state play key role in optical transitions and plasma wavelength of 243 nm found for this studied compound.

Structural and optoelectronic properties of NiCl2C14H26N6 complex (1) using DFT calculations by various exchange correlation potentials including PBE–Generalized Gradient Approximation (PBE–GGA) and hybrid density functional B3LYP are investigated. The complex belongs to monoclinic crystallographic system with P2(1)/n space group, Z = 4. Selected 1 as monomeric unit (1−mon) through C H···Cl hydrogen bonds (HBs) constructs a 2–D coordination polymeric plane. The dispersion corrected density functional theory (DFT−D) calculations determine the binding energies of the non−conventional C H···Cl HBs constructor of the crystalline network (1−net). The calculated−B3LYP/LANL2DZ/6–311+G(d, p) electronic spectrum in gas phase shows four major bands in the range of 200–240 nm that could assigned to MLCT and LMCT transitions with n → π∗ and π∗ → σ∗ characters. The calculated results of electronic transitions in water using PCM method include broad bands with blue shifts in comparison with the vacuo one. Density of states results by the PBE–GGA show that this complex has a wide band gap (3.0 eV). The optoelectronic properties predict that it can be efficiently used in the optoelectronic molecular devices.

In this study, an effective adsorbent calcium hydroxyapatite ( CaHA ) having high adsorption capacity about aqueous solution of Congo red dye in ambient temperature is presented. Nano particles of CaHA were prepared through a new easy alkoxide–based sol–gel technique. The structural characterization of synthesized CaHA were performed by X–ray diffraction (XRD), Fourier transform infrared (FTIR) analysis, thermal behavior (DTA), morphology and elemental analysis via scanning electron microscopy (SEM). The nano particle size and micro–strain of CaHA were measured using modified Shcerrer equation as Williamson–Hall method and transmission electron microscopy (TEM). XRD pattern shows hexagonal structure of the nano–particle CaHA with P 6 3 / m space group that the size measured through XRD and TEM methods are in good agreement as 25 nm. The equilibrium adsorption capacity ( q m ) for 100 ppm CR was measured to be 487.80 mg g −1 under optimal conditions. The adsorption isotherms and kinetic data well fitted with the Langmuir model and the pseudo–second order equation with correlation coefficients of 0.9979 and 0.9902, respectively. The calculated structures of CR and its complex including Ca 2+ and PO 4 3− ions show the electrostatic interactions of anionic CR dye and Ca 2+ site and hydrogen bonding of amine group and phosphate of CaHA surface. Thermodynamic parameters (ΔG° CaHA can be good candidate for application in the management of environmental.

The presented work studies the geometric and electronic structures of the crystalline network of a novel amide based carboxylic acid derivative, N–[(4–chlorophenyl)]–4–oxo–4–[oxy] butane amide, C10H10NO3Cl (1), constructed via hydrogen bonds (HBs) and stacking non–covalent interactions. Compound 1 was synthesized and characterized by FTIR, 1H, and 13C NMR, and UV–Vis spectra, X–ray structural, DTA–TG, and EI–MS, analyses. DFT calculations about molecular and related network of 1 were performed at hybrid B3LYP/6–311+G (d, p) level of theory to support the experimental data. The neutral monomeric structures join together via inter−molecular conventional O/N H⋯O and non−conventional C H⋯O HBs and O H···π and C O···π stacking interactions to create 2−D architecture of the network. The results of dispersion corrected density functional theory (DFT−D) calculations within the binding energy of the constructive non−covalent interactions demonstrate that HBs, especially conventional O H⋯O and N H⋯O, govern the network formation. The calculated electronic spectrum show six major bands in the range of 180–270 nm which confirm the experimental one within an intense band around 250 nm. These charge transfer bands result from shift of lone pair electron density of phenyl to chlorine or hydroxyl or phenyl functional groups that possess π → π* and π → n characters.

In this work the synthesis of a new compound formulated as C12H12N4OS, ((S)-1-(6-Phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)ethanol) (5) reported and theoretical studies of the non‒covalent interactions constructed the related crystalline network described. It has been characterized by IR, Mass, and 1H, 13C NMR spectroscopy and single crystal X‒ray diffraction analysis. The binding energy of the non‒covalent interactions constructing the network of 5 have been calculated by dispersion corrected density functional theory (DFT‒D). The optimization of the formed network using H‒bonding and π‒stacking revealed that 1‒D coordination chain has been composed of neutral monomeric compound. For this purpose, the independent smallest fragment (monomer) and subsequently the related network, including seven monomers, having all non‒covalent interactions have been optimized. The results demonstrate that hydrogen bonds, especially O H⋯N, C H⋯O, C H⋯N, and C H⋯S interactions, govern the network formation. The calculated results of electronic transition in agreement with the experiment ones show eleven major bands derived from σ → π, n → n/σ*/π* aromatic rings to hydroxyl, inter‒atomic of oxygen, and thiadiazine to phenyl ring charge transfer transitions.

[Ni{2-H

A green protocol has been developed for preparation of the wide variety of colored xanthene derivatives using a new efficient magnetic solid acid catalyst bearing polyamidoamine dendrimer moiety as a nanoscopic compound. Dendrimers, highly symmetric molecules around a core and 3D spherical morphology, show interesting traits based on their functionalized groups on the branched surface. They can be designed to provide water soluble structures or pseudo-active sites of biomolecules. The catalyst was assembled via a polyamidoamine dendrimer immobilized on the surface of γ-Fe2O3 followed by the sulfonylation of the amine groups by chlorosulfonic acid resulting in γ-Fe2O3@PAMAM-SO3H. Herein, PAMAM dendrimer with repeating amine/amide branches as catchable sites of sulfonic acid groups was introduced as transformer of homogeneous to heterogeneous acidic catalysts. The physicochemical properties of synthesized catalyst were studied using by FT-IR, FE-SEM, XRD, VSM, EDS, TGA/DTG, and TEM. Finally, the catalytic activity of γ-Fe2O3@PAMAM-SO3H was evaluated for the preparation of xanthene derivatives via a one-pot, three components reaction of aromatic aldehydes with i) β-naphthol, ii) cyclic 1,3-dicarbonyl, iii) β-naphthol and cyclic 1,3-dicarbonyl compounds, iv) 2-hydroxy-1,4-naphthoquinone, leading to the eco-riendly preparation of the target compounds in good to excellent yields. The catalyst could be easily recycled for at least five consecutive runs without significant loss in its catalytic activity.

In this work a new method of square‒wave voltammetry was performed for electrodepositing of Bi

For the first time, the structural and optoelectronic properties of a new complex formulated as CuBr2(C6H7N)2 (1) [trans-dibromidobis(3-methylpyridine-κN) copper(II)] were studied by density functional theory (DFT) calculations. They are performed using B3LYP through the Gaussian 09 program and also with full potential linearized augmented plane wave (FP-LAPW) methods within the Generalized Gradient Approximation (GGA) and Hartree-Fock (HF) theory by the Wien2k package. The neutral monomeric complex participates in a variety of non-covalent interactions, including hydrogen bonding and π stacking to create a 2D coordinate plane. The binding energy value of the non-covalent interactions responsible for the crystalline network formation of 1 were calculated using the method of dispersion corrected density functional theory (DFT-D). In this method, the independent smallest fragment (monomer) and subsequently the related network, including seven monomers bearing all non-covalent interactions were optimized. The results demonstrate that hydrogen bonds, especially non-conventional C–H···Br interactions, govern the network formation along the a and c axes. It can be mentioned because of these directed interactions, increasing of charge transfer along x and z directions results in increasement of the absorption and refractive index along y and z directions, and vice versa. The results of band structure show indirectly and directly the nature of the bandgap within GGA and HF, respectively. The bandgap value of CuBr2(C6H7N)2 is comparable to those of binary semiconductor compounds. DOSs spectra reveal that 3d Cu, 4p Br, and 2p C states play important roles in the optical transitions of the electrons. The calculated electronic absorption of the UV/Vis spectrum shows six major electron-transition bands derived from d → d (ligand field) n → n, n → π*, π → n, and σ → n MLCT and LMCT transitions. The calculated absorption spectrum of the titled complex through FP-LAPW within GGA method shows good consistency with the B3LYP/def2-TZVP/6-311+G(d,p) method. Our calculated birefringence results show that 1 has capability of nonlinear optical, which can be used in the nonlinear optoelectronic devices.

An easy alkoxide-based sol–gel method based on Ca(NO3)2·4H2O and triethyl phosphate [PO(OC2H5)3; TEP] as Ca and P precursors have been developed to synthesize nano-hydroxyapatite (HA). The structural evolution of the samples was studied using X-ray diffraction (XRD), thermal behavior, infrared analysis, and elemental analysis via scanning electron microscopy. It is noticeable that raising of the firing temperature resulted in increasing the HA content as the dominant phase at 600 and 700 °C. The phase transformation from amorphous to crystalline HA occurred at the low temperature of 400 °C, while at higher temperatures other Ca–P compounds as secondary phases transformed to HA. The crystallite size distributions and micro-strain of the HA samples produced were characterized by XRD methods with the aid of Scherrer and Williamson–Hall equations. The results of transmission electron microscopy as a complementary and reliable technique are in good agreement with those obtained from XRD. The results indicate that increasing the firing temperature caused permanent growth of mean crystallite size and a decrease in micro-strain.

The reported complexes formulated as [MnCl2(hppH)2] (1), [FeCl2(hppH)2] (2), and [NiCl2(hppH)2] (3) and a new theoretically designed example, [CuCl2(hppH)2] (4), have been used for calculations at the B3LYP/LANL2DZ/6-311G (d, p) level of density functional theory (DFT). The intramolecular hydrogen bonds (HB) N H⋯Cl could followed through their physicochemical properties such as, vibrational frequency, electronic transmission in UV–Visible spectroscopy, metal–ligand donor–acceptor interactions in NBO analysis, total energy and frontier molecular orbital energy. These properties influenced by the relationship of structure and metal–ligand electron density exchange will be discussed. The computations revealed that the stronger N H⋯Cl HB exists in complexes with longer M Cl and M Nimine bonds and shorter H⋯Cl bond, and vice versa that confirms the shortest and longest HBs in 4 and 3, respectively. These results agree with the second–order perturbation energies obtained by NBO analysis within charge transfer from the proton–acceptor chlorine to the p∗ orbital of the N atom. The calculated electronic absorption spectra by TD–DFT calculations show the larger Cl− to M2+ donation in 2 and 3 in comparison with 1 and 4 that confirms the stronger HB in 1 and 4 compared to 2 and 3. In order to find the basis set effect on the structure, vibrational frequencies, and electronic transitions, we use another basis set def2-TZVP includes polarization function for Mn element in complex 1. The obtained test results showed unremarkable differences between two basis sets LANL2DZ and def2-TZVP (cf. Figs. S2, S3 and Tables S1 and S2 in Supplementary Materials).

A new mixed ligand complex formulated as [Co(pydc)(2-apym)(H2O)2]·H2O (1) (pydcH2 = pyridine–2,6–dicarboxylic acid, 2-apym = 2-aminopyrimidine) has been used for density functional theory (DFT) calculations. The neutral monomeric complex participates in a variety of non-covalent interactions including H-bonding and π-stacking to create a 1-D coordination chain. In order to determine the binding energy of the non-covalent interactions responsible for the crystalline network formation of 1 they have been studied by dispersion corrected density functional theory (DFT-D) calculations. For this purpose, the independent smallest fragment (monomer) and subsequently the related network including seven monomers bearing all non-covalent interactions have been optimized. The results demonstrate that hydrogen bonds, especially N–H···O interactions, govern the network formation. The calculated electronic absorption spectrum agrees with experiment in which three major electron-transition bands derived from (σ, p) → π∗ and π → π∗ ligand to ligand charge transfer (LLCT), and π → n and π → π∗ pydc intra-ligand charge transfer (ILCT) transitions are seen.

Vanadium oxo-peroxo complexes are known as the best functional models of vanadium haloperoxidases (VHPOs) enzymes. Their quantity and quality structure activity and property relationship can be followed up by NMR calculations. The DFT/B3LYP/6-311+G (d,p)/LANL2DZ method has been used to calculate the geometry and electronic structures and 51V and 17O NMR chemical shifts of a series of 7 oxo-peroxo vanadium (V) complexes mimicking the active site of vanadium bromoperoxidase (VBPO) in the gas and solvent (acetonitrile) phases. They contain tetradentate tripodal amine ligands (TPALs). Compilation of NMR, electronic, and vibrational spectroscopic data and metric parameters for the studied complexes permits us to draw correlations among 51V and 17O peroxo chemical shift, the electronic charge transfer band, the O–O vibrational frequency, and the O–O bond length. A direct dependence of the magnetic shielding of the vanadium center and peroxide group on the electronic character of the ligand was observed in all cases. Studied complexes exhibit 51V and 17O NMR chemical shifts of −590 to −430 ppm and 650–740 ppm, respectively. A Ramsey-type correlation between the chemical shifts and the energy of the ligand-to-metal charge transfer (LMCT) was found that suggests the electron donating ability of the ligands and the energy gap HOMO–LUMO of the peroxo complexes are linearly correlated. Vibrational frequency and length of the O–O bond also correlate with the inverse LMCT energy. The calculated values of νO–O place above 900 cm−1 and O–O distances in the range of 1.40–1.42 A. In general, the more reactive complexes within bromide oxidation contain weakly electron donating TPALs and represent higher energy LMCT, longer O–O length, and lesser 51V and 17O chemical shifts.

WZnO-NH2@H3PW12O40 (WZnO/HPA) nanocomposite is disclosed in the photocatalytic degradation of some pharmaceutical wastes by focusing on methylene blue as a case study. The prepared nanophotocatalyst is characterized by XRD, FT-IR, FESEM, TEM, XPS, PL, UV–Vis, and EDX. Compared to pure ZnO, WO3, and H3PW12O40, the heterojunction nanocomposite of WZnO/HPA shows much better degradation efficacy for methylene blue (MB) under UV–Vis light irradiation. Surprisingly, the heterogeneous catalytic system shows very good activity under the irradiation of sun-light and > 40% degradation is achieved for MB after 90 min. In addition, a range of important polluting drugs were also conducted under the standard photocatalytic conditions. The enhanced photocatalytic degradation efficiency would be due to the reduced recombination of photogenerated electron-holes. It seems that degradation process follows a charge transfer mechanism by means of this effective heterogeneous nanocomposite. Reactive species including OH and •O2− together with h+ are expected to be involved in the photodegradation reaction of MB. The highest photocatalytic activity of WZnO/HPA may be due to the enhanced visible light absorption, electron-hole recombination blockage, lowering of the band gap, and increased number of oxygen vacancies or defects.

New thin BiVO4 film using facile water‒based electrophoretic deposition process was synthesized on the webbed stainless steel surface. This work can be considered as a green method owing to use of safe, non–flammable, and cheap media of water as solvent of electrophoretic deposition. Structural and morphological properties of the resultant film were studied by X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), Elemental and Mapping analyses (EDS), Optical Microscopy, Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy (XPS) analysis. The moderate diameter size of nanorods of the deposited BiVO4 was measured in the range of 100 to 150 nm. The prepared three layered thin film was shown permanent photocatalytic degradation rate of Amoxicillin pharmaceutical pollution as high as 97.45 % after 90 min. It can be suggested that BiVO4 nanorods have the high ability of hole–electron separation and electron transferring through the alternative routes. Indeed, the prepared thin films of BiVO4 having nanoroad morphology possess great potential for light harvesting. Moreover, webbed stainless steel with electron acceptor character leads to severe separation of photogenerated hole‒electron. The mechanistic study of the scavenging reaction introduced the hydroxyl radicals as the main specie in the photocatalytic process. It is interesting that obtained results of photocatalytic process of this BVO film within different pollutants (dyes, phenol, and drugs) demonstrated the high efficiency and mineralization rate.

The crystalline network of a stable form of Gefitinib (C22H24ClFN4O3) as a new anticancer has been theoretically studied. DFT calculations demonstrated that the packed network of Gefitinib was constructed by hydrogen bonds as the main constructor force. Hydrogen bond interactions link the molecular layers result to 2D structure formation along the bc plane of unit cell. However, network grows through π–stacking of the fragments along a direction. Dispersion corrected density functional theory calculations (DFT−D) were applied for evaluation of the binding energy value of the non–covalent forces which demonstrate N H⋯O and C H⋯O as the primary creator interactions of the intended 3D network. Moreover, the intermolecular HBs and π⋯stacking interactions were studied by Bader’s theory of AIM. Calculated/FP-LAPW visible region of optical spectra was shown that this molecule is approximately transparent in the x and z directions with greater interacting power in the z-direction than x and y ones. The maximum absorption is related to the x direction and it is low in the y and z directions because of the hydrogen bonds existence in bc plan.

A density functional theory (DFT) study of the bromide oxidation mechanism catalyzed by a series of 14 oxo-peroxo vanadium(V) complexes containing tripodal amine ligands (hereafter called TPALs) is presented. The rate-determining step is the transfer of the protonated oxygen atom of the peroxide moiety to the bromide substrate via an SN2 mechanism within the respective complex. In all cases, a direct dependence of the calculated atomic charge on vanadium with the electronic character of the ligand was observed. The TPAL is decorated with a series of substituents exhibiting different donor groups and lengths which affect the barrier energy; the substituent effects on the barrier have been examined. A significant decrease of the barrier energy (by 1–6 kcal mol−1) is observed either upon protonation of the imine functional group or third substituent elongation of the TPAL. Increasing the electron donation ability of the ligands decreases the HOMO–LUMO energy gap of the peroxo complexes and increases the ligand-to-metal charge transfer (LMCT). The use of substituents with poor electron donation ability causes an activation of the complexes. The same effect is observed using TPAL substituents that are able to form intramolecular hydrogen bonds. Compared to the gas phase, the energy barriers are in general lower if solvent effects (acetonitrile) are taken into account. Compared to the previously used V-Hheida (heida = N-(2-hydroxyethyl) iminodiacetic acid), our calculations suggest that the new oxo-peroxo vanadium(V) V-peyc (N-(2-pyridylethyl-6-carbamoyl) iminodiacetic acid), V-Haada (H3aada: 2,2′-(2-aminoacetamido) diacetic acid) and V-pyc (H2pyc: N-(2-pyridylmethyl-6-carbamoyl) iminodiacetic acid) complexes are good functional models of vanadium-dependent bromoperoxidase (VBPO).

Three new organic–inorganic hybrid materials based on two important heteropolyoxometalates namely Preyssler (=K12.5H1.5[Na(H2O)P5W30O110]·35H2O) and Wells–Dawson (=K6[P2W18O62]·10H2O) anions, namely, (Hpro)9(Hleu)3K2[Na(H2O)P5W30O110]·25H2O (1), (Hpro)4(Hasp)[HP2W18O62]·20H2O (2), and (Hpro)11K3[Na(H2O)P5W30O110]·18H2O (3) where pro, leu, and asp are proline, leucine, and asparagine, respectively, were prepared and identified by elemental analysis, infrared and proton nuclear magnetic resonance spectroscopies, and thermogravimetric analysis. The hybrid materials are made up of positively charged amino acids, [Na(H2O)P5W30O110]14− and [P2W18O62]6− anions, and H2O molecules of crystallization. These constituents’ fragments held together into a three-dimensional supermolecular network through non-covalent interactions. The protonation constants of the amino acids used, and Preyssler and Wells–Dawson species in all possible protonated forms, the equilibrium constants for binary systems of proline–asparagine and proline–leucine, and the stoichiometry and stability constants of the corresponding binary and ternary hybrids with Preyssler and Wells–Dawson heteropolyoxometalates in aqueous solution were investigated by potentiometric pH titration method. The stoichiometries of the most hybrid species in solution were compared with the corresponding hybrids in the solid phase, in detail.