Ferrocenyl-based di- and trinuclear lanthanide complexes: solid state structures, (spectro)electrochemical and DFT studies

Dinuclear and trinuclear ferrocenylcarboxylato-bridged lanthanide complexes of type [Ln(μO:κ2OO'-O2CFc)(O2CFc)2(H2O)(dmf)]2·(dmf)2 (Ln = Sm (2), Eu (3), Gd (4), Tb (5); Fc = Fe(η5-C5H4)(η5-C5H5)), and novel [Bu4N][Ln3(μ-O2CFc)3(μO:κ2OO'-O2CFc)3(O2CFc)3(μ3-OH)]·[Bu4N]Cl (Ln = Gd (6), Tb (7)) were prepared by the reaction of [LnCl3·6H2O] (synthesis of 2-5) or LnCl3 (synthesis of 6, 7) with FcCO2H (1) in the ratio of 1 : 3. As evidenced by single crystal X-ray structure determination, in 2-5 the lanthanide ions are connected by symmetric FcCO2 units. In addition, two ferrocenylcarboxylato groups are μ-bridged to LnIII. Each LnIII ion is coordinated by nine oxygen donor atoms derived from one H2O, one dmf and three carboxylates. The latter are found in chelating κ2 and bridging μ,κ3 coordination modes. Complexes 6 and 7 assemble three LnIII cores around a central μ3-netting hydroxide and nine FcCO2 entities. A combination of κ2, μ,κ2 and μ,κ3 coordination modes results in an eight-fold coordination sphere for each metal, which is best described as bicapped trigonal prismatic. IR spectroscopy confirms the chelating and bridging motifs. Electrochemical studies of complexes 2-7via cyclic voltammetry (CV) and square-wave voltammetry (SWV) showed one redox event between E°' = 250 and 260 mV vs. FcH/FcH+ for 2-5 with all six FcCO2 redox events superimposed. Complexes 6 and 7 show a total of three events in the CV with the oxidations of the nine FcCO2 units occurring in close proximity. Deconvolution of individual redox events correlates well with the mononuclear complex [Bu4N][Gd(O2CFc)4]. UV-Vis/NIR spectroelectrochemical measurements of 7 did not reveal electron transfer between either Fc units, nor the coordinated lanthanides and resembled the absorption behavior of [Bu4N][Tb(O2CFc)4]. DFT (Density Functional Theory) calculations on the B3LYP def2-TZVP level of theory were carried out to assign the order of redox events in 6 showing that the spatial distance towards the most recent redox center, instead of the binding mode, is decisive.

Phosphorus-substitution effect on the phase stabilization, electrical and spectroscopic properties of LAMOX-based electrolyte for solid oxide fuel cells

A series of P5+ - doped La2Mo2O9 phases with different concentrations of P5+ were prepared using conventional solid-state reactions. The formation of phase-pure P5+-doped La2Mo2O9 has been monitored by powder X-ray diffraction, thermal analysis, conductivity measurements, Raman, and FT-IR absorption techniques. The structure and lattice parameters of La2Mo2-yPyO9-y/2 are obtained from Rietveld refinement. The effect of substituting P for Mo reveals that the phase transition which occurs in La2Mo2O9 around 560 °C disappears when y > 0.02, as demonstrated by thermal analysis. Pure P5+-doped phases with monoclinic structure (α-form, the space group P21) were observed for the concentration of optically active ions up to y = 0.02. When the concentration of P5+ ions is higher, a cubic structure (β-form, the space group P213) starts to appear. However, up to the concentration of y = 0.03 of the P5+ ion a mixture of the monoclinic and cubic phases has been observed. From infrared and Raman analysis it is confirmed that different vibration modes arise from the vibration of molybdenum-oxygen bands. Mo-O bond lengths are also found to be independent of P-doping.

On the high-temperature phase transition of a new chlorocadmate(ii) complex incorporating symmetrical Cd2Cl6 clusters: structural, optical and electrical properties

In the present investigation, a new hybrid crystal, with the formula [(C4H9)4P]2Cd2Cl6 has been synthesized by the slow evaporation method at room temperature. It was characterized by X-ray diffraction (XRD), Hirshfeld surface, differential scanning calorimetry (DSC), optical measurement and complex impedance. Single crystal X-ray diffraction structural analysis revealed that the title compound crystallizes in the triclinic system with space group P1̄ and cell parameters: a = 11.972 (1) Å, b = 15.418 (1) Å, c = 15.426 (2) Å, αa = 68.71 (2) °, β = 73.20 (3) ° and γ = 74.39 (2)°. The Hirshfeld surface analysis was conducted to investigate intermolecular interactions and associated 2D fingerprint plots, revealing quantitatively the relative contribution of these interactions in the crystal cohesion. DSC studies indicated one phase transition at about 348 K. Optical absorption spectra show that the band gap of [(C4H9)4P]2Cd2Cl6 is approximately 2.65 eV. The Nyquist plot showed only one semicircular arc, representing the grain effect in the electrical conduction. The thermal evolution of the conductivity of the grains presents an Arrhenius type behavior, demonstrating that charge carriers have to overcome different energy barriers while conducting and relaxing. Besides, the AC conductivity was analyzed by Jonscher's law and the conduction mechanism is well ensured by the correlated barrier hopping (CBH) model.

Crystal Chemistry, Optic and Magnetic Characterizations of a New Copper Based Material Templated by Hexahydrodiazepine

Crystals of the new organic-inorganic material (DAP-H2)[CuBr₄] (1); (DAP = hexahydrodiazepine (C₅H₁₄N₂)) were successfully synthesized by slow evaporation and characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermal analysis, UV-Vis-NIR diffuse reflectance spectroscopy, and magnetic measurements. X-ray investigation demonstrates that 1 crystallizes in the monoclinic space group C2/c. The supramolecular crystal structure of 1 is guided by several types of hydrogen bonding which connect anions and cations together into a three-dimensional network. The optical band gap was determined by diffuse reflectance spectroscopy to be 1.78 eV for a direct allowed transition, implying that it is suitable for light harvesting in solar cells. The vibrational properties of this compound were studied by infrared spectroscopy, while its thermal stability was established by simultaneous TGA-DTA from ambient temperature to 600 °C. The study of the photoresponse behavior of an optoelectronic device, based on (C₅H₁₄N₂)[CuBr₄], has shown a power conversion efficiency (PCE) of 0.0017%, with J _sc = 0.0208 mA/cm², V _oc = 313.7 mV, and FF = 25.46. Temperature dependent magnetic susceptibility measurements in the temperature range 1.8-310 K reveal weak antiferromagnetic interactions via the two-halide superexchange pathway [2J/k _B = -8.4(3) K].

Uncovering the Role of Electronic Doping in Lead-free Perovskite (CH3 NH3 )2 CuCl4-x Brx and Solar Cells Fabrication

Lead halide perovskites are attractive pigments to fabricate solar cells in the laboratory, owing to their high power conversion efficiency. However, given the presence of Pb, such materials also have a high level of toxicity and are carcinogenic for humans and aquatic life. Arguably, this hampers their acceptability for immediate commercialization. This study entails the synthesis, optoelectronic properties, and photovoltaic parameters of two-dimensional copper-based perovskites as an environmentally benign alternative to lead-based perovskites. The perovskites - (CH₃ NH₃ )₂ CuCl_4-x Br_x with x=0.3 and 0.66 - are derivatives of the stable (CH₃ NH₃ )₂ CuCl₄ . The single crystals and powders diffractograms suggest compositions with variations in Cl/Br ratio and dissimilar bromine localization in the inorganic framework. The copper mixed halide perovskite exhibits a narrow absorption with a bandgap of 2.54-2.63 eV related to the halide ratio disparity (crystal color variation). These findings demonstrate the impact of halides to optimize the stability of methylammonium copper perovskites and provide an effective pathway to design eco-friendly perovskites for optoelectronic applications.

Vibrational Spectroscopies, Global Reactivity, Molecular Docking, Thermodynamic Properties and Linear and Nonlinear Optical Parameters of Monohydrate Arsonate Salt of 4-Aminopyridine

In this work, a structural and electronic properties of a novel organic arsenate template by 4-aminopyridine, with the general formula (C₅H₇N₂)(C₅H₈N₂)[AsO₄]·H₂O ((4-APH)(4-APH₂)[AsO₄]·H₂O) have been presented. The density functional theory (DFT) along with B3LYP hybrid functional is employed. The optimized structure was found to be in well consistent with the X-ray diffraction geometry. The examination of the vibrational spectrum was correlated by DFT calculation using the unit cell parameters obtained from the experiment data. Besides, the thermodynamic functions (heat capacity, entropy, enthalpy) from spectroscopic data by statistical methods were obtained for the range of temperature 100–1000 K. In addition, the molecular orbital calculations such as Natural Bond Orbitals (NBOs), AIM approach, HOMO–LUMO energy gap, NLO characteristic and Hirshfeld surface analysis were also performed with the same level of DFT. Electronic stability of the compound arising from hyper conjugative interactions and charge delocalization were also investigated based on the natural bond orbital (NBO) analysis. Molecular docking studies were also conducted as part of this study. The theoretical results showed an excellent agreement with the experimental values.

A promising 1D Cd-based hybrid perovskite-type for white-light emission with high-color-rendering index

A one dimensional (1D) perovskite-type (C6H7NBr)3[CdBr5] (abbreviated 4-BAPC) was synthesized by slow evaporation at room temperature (RT). 4-BAPC crystalizes in the monoclinic system with the space group P21/c. The 1D inorganic chains are formed by corner sharing CdBr6 octahedra. Thermal measurement shows that 4-BAPC is stable up to 190 °C. Optical characterization demonstrates that the grown crystal is an indirect bandgap material with a bandgap value of 3.93 eV, which is consistent with theoretical calculations. The electronic structure, calculated using density functional theory, reveals that the valence band originates from a combination of Br-4p orbitals and Cd-4d orbitals, whereas the conduction band originates from the Cd-5s orbitals. The photoluminescence spectroscopy shows that the obtained material exhibits a broad-band white light emission with extra-high CRI of 98 under λ exc = 380 nm. This emission is mainly resulting from the self-trapped exciton recombinations within the inorganic CdBr6 octahedron, and the fluorescence within the organic conjugated ammonium salt.

Attenuation of ovalbumin-induced inflammation and lung oxidative injury in asthmatic rats by Zingiber officinale extract: combined in silico and in vivo study on antioxidant potential, STAT6 and TNF-α pathways

In the present study we focused on the anti-asthmatic and antioxidant effects of Zingiber officinalis roscoe L. (ZO) aqueous extract. This study includes 20 adult male rats, which were grouped into four; Group I: control group; Group II: asthmatic group (Ovalbumin sensitized/challenge model, Oval group); Group III: received ovalbumin sensitized/challenge associated a dose of 207 mg/kg body weight (BW) of ZO (Oval + D1 group); Group IV: received ovalbumin sensitized/challenge associated a dose of 414 mg/k BW of ZO (Oval + D2 group). After 21 days, blood and lung samples were collected for biochemical, hematological, and histopathological analyses. The ameliorative effect of ZO phytochemical compounds was also assessed by in silico approach on transducer and activator of transcription 6 (STAT6) and tumor necrosis factor-α (TNF-α) receptors. The oxidative/antioxidative status was evaluated in the lung tissues. Our results show that ZO extract alleviated the ovalbumin-induced hematological and biochemical disruptions associated oxidative injury. In fact, white and red blood cells (WBC and RBC, respectively), aspartate aminotransaminase (ASAT), malondialdehyde (MDA), glutathione (GSH), and glutathione peroxidase (GPx) were significantly disrupted (p < 0.05) in Oval group and alleviated following ZO treatment. Besides, several histopathological features were outlined in lung tissues of Oval group. Interestingly, ZO was found to exert ameliorative effects on tissue level. In silico analyses, particularly the binding affinities, the number of H-bonds, the embedding distance and the molecular interactions of ZO phytochemical compounds with either STAT6 or TNF-α supported the in vivo results. These findings confirm the potential ethno-pharmacological effects of ZO against asthma and its associated complications.

Kidney injury and oxidative damage alleviation by Zingiber officinale: pharmacokinetics and protective approach in a combined murine model of osteoporosis

Ginger (Zingiber officinale) is considered as a nutraceutical spice, which possesses several health promotion and benefits. This study was carried out to investigate the phyto-chemical composition, the antioxidant capacities, the drug-likeness, and pharmacokinetic properties of ginger extract on kidney injury-associated osteoporosis in rats. Phenolic and flavonoid contents were assessed by standard chemical analysis methods and HPLC. In vivo protective effect was based on the use of female rats to evaluate the effect on renal injury as a result of combined osteoporosis using biochemical markers, oxidative status, and histological analyses. Results showed that ZO contained appreciable amounts of phenolics and flavonoids and it exhibited high scavenging activity. Ovariectomy-associated corticotherapy induced severe renal injury marked by altered biochemical markers (creatinine, urea, and uric acid), reduced GFR, significative oxidative damage signs, and disrupted antioxidant status in the combined osteoporotic rats. The histopathological examination revealed structural modifications of kidney tissues. However, all these changes were reversed following the use of ZO. These results confirm the renoprotective and antioxidant potential of ginger against renal injuries in osteoporotic rats.

Organically tuned white-light emission from two zero-dimensional Cd-based hybrids

In this work, we report two zero-dimensional Cd-based hybrid compounds, denoted CdACP and CdODA, where the Cd atoms adopt tetrahedral geometry. The optical analysis reveals that these materials are classified as wide-gap semi-conductors which makes them suitable for optoelectronic applications. The photoluminescence analysis proves the wavelength dependent white-light emission behavior of the investigated materials. The structural-optical property studies show that, thanks to the heavy halide effect, the CdACP exhibits both fluorescence and room temperature phosphorescence through harvesting triplet states. Meanwhile, in contrast to CdACP, the white light emission from CdODA is purely fluorescence in nature. In fact, within CdODA, both C-H⋯π and N-H⋯N interactions facilitate the intramolecular proton transfer (ESIPT) between the different cations which leads to ultra-fast fluorescence through excited state ESIPT. Under sub-gap excitations, the inorganic sub-lattice is responsible for the blue-green emission through the STE mechanism, while the organic cations contribute by an intense red emission.

Excitation dependent white and red-NIR emission of MnII-based complex

Nowadays, the organic and organic-inorganic supramolecular crystals are potential candidates for lighting applications. In this work, a new molecular crystal (C5H8N3)2[MnCl4(C5H7N3)2] abbreviated (AmpH)2[MnCl4(Amp)2], (C5H7N3 = Amp = 2-amino-4-methylpyrimidine), containing octahedral...

"Shake 'n Bake" Route to Functionalized Zr-UiO-66 Metal-Organic Frameworks

We report a novel synthetic procedure for the high-yield synthesis of metal-organic frameworks (MOFs) with fcu topology with a UiO-66-like structure starting from a range of commercial ZrIV precursors and various substituted dicarboxylic linkers. The syntheses are carried out by grinding in a ball mill the starting reagents, namely, Zr salts and the dicarboxylic linkers, in the presence of a small amount of acetic acid and water (1 mL total volume for 1 mmol of each reagent), followed by incubation at either room temperature or 120 °C. Such a simple "shake 'n bake" procedure, inspired by the solid-state reaction of inorganic materials, such as oxides, avoids the use of large amounts of solvents generally used for the syntheses of Zr-MOF. Acidity of the linkers and the amount of water are found to be crucial factors in affording materials of quality comparable to that of products obtained under solvo- or hydrothermal conditions.

A novel sulfate-bridged binuclear copper(ii) complex: structure, optical, ADMET and in vivo approach in a murine model of bone metastasis

A novel complex, formulated as [Cu₂(μ₃-SO₄)₂(C₄H₆N₂)₄], showed significant ameliorative effects on tumor osteolytic lesions in malignant Walker 256/B breast cancer-induced bone metastases.

Tunable broad-band white-light emission in two-dimensional (110)-oriented lead bromide perovskite (C3H8N6)[PbBr4]: optical, electronic and luminescence properties

The 2D-perovskite (C3H8N6)[PbBr4] shows white-light emission with room-temperature phosphorescence based on the strategy of heavy-atom-participated anion–π+ interactions.

Antiproliferative Homoleptic and Heteroleptic Phosphino Silver(I) Complexes: Effect of Ligand Combination on Their Biological Mechanism of Action

A series of neutral mixed-ligand [HB(pz)₃]Ag(PR₃) silver(I) complexes (PR₃ = tertiary phosphine, [HB(pz)₃]⁻ = tris(pyrazolyl)borate anion), and the corresponding homoleptic [Ag(PR₃)₄]BF₄ compounds have been synthesized and fully characterized. Silver compounds were screened for their antiproliferative activities against a wide panel of human cancer cells derived from solid tumors and endowed with different platinum drug sensitivity. Mixed-ligand complexes were generally more effective than the corresponding homoleptic derivatives, but the most active compounds were [HB(pz)₃]Ag(PPh₃) (5) and [Ag(PPh₃)₄]BF₄ (10), both comprising the lipophilic PPh₃ phosphine ligand. Detailed mechanistic studies revealed that both homoleptic and heteroleptic silver complexes strongly and selectively inhibit the selenoenzyme thioredoxin reductase both as isolated enzyme and in human ovarian cancer cells (half inhibition concentration values in the nanomolar range) causing the disruption of cellular thiol-redox homeostasis, and leading to apoptotic cell death. Moreover, for heteroleptic Ag(I) derivatives, an additional ability to damage nuclear DNA has been detected. These results confirm the importance of the type of silver ion coordinating ligands in affecting the biological behavior of the overall corresponding silver complexes, besides in terms of hydrophilic–lipophilic balance, also in terms of biological mechanism of action, such as interaction with DNA and/or thioredoxin reductase.

Synthesis, intermolecular interactions and biological activities of two new organic-inorganic hybrids C6H10N2,2Br and C6H10N2,2Cl·H2O

A slow evaporation method has permitted the crystallization of two novel crystals of (2-aminomethyl)pyridindiumdihalide C₆H₁₀N₂,2Br (1) and C₆H₁₀N₂,2Cl·H₂O (2). The structures of the prepared compounds (1) and (2) were elucidated by single-crystal X-ray diffraction which revealed that they crystallize, respectively, with triclinic and monoclinic symmetries. Their crystal packing was stabilized by non-covalent interactions, including N–H⋯Br, C–H⋯Br, N–H⋯Cl, O–H⋯Cl and N–H⋯O hydrogen bonds. 3-D Hirshfeld surface analysis followed by 2-D fingerprint schemes gives insights into the intermolecular interactions in the crystalline structure. Furthermore, the FT-IR spectroscopy of these two compounds was carried out. The synthesized products were also screened for in vitro antioxidant and antimicrobial activities, which reveals their favourable antioxidant activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) as well as the discolouration of β-carotene.

A slow evaporation method has permitted the crystallization of two novel crystals of (2-aminomethyl)pyridindiumdihalide C₆H₁₀N₂,2Br (1) and C₆H₁₀N₂,2Cl·H₂O (2).

Synthesis, structural determination and antimicrobial evaluation of two novel CoII and ZnII halogenometallates as efficient catalysts for the acetalization reaction of aldehydes

Background

Complexes of imidazole derivatives with transition metal ions have attracted much attention because of their biological and pharmacological activities, such as antimicrobial, antifungal, antiallergic, antitumoural and antimetastatic properties. In addition, imidazoles occupy an important place owing to their meaningful catalytic activity in several processes, such as in hydroamination, hydrosilylation, Heck reaction and Henry reaction. In this work, we describe the crystallization of two halogenometallate based on 2-methylimidazole. Their IR, thermal analysis, catalytic properties and antibacterial activities have also been investigated.

Results

Two new isostructural organic-inorganic hybrid materials, based on 2-methyl-1H-imidazole, 1 and 2, were synthesized and fully structurally characterized. The analysis of their crystal packing reveals non-covalent interactions, including C/N–H···Cl hydrogen bonds and π···π stacking interactions, to be the main factor governing the supramolecular assembly of the crystalline complexes. The thermal decomposition of the complexes is a mono-stage process, confirmed by the three-dimensional representation of the powder diffraction patterns (TDXD). The catalytic structure exhibited promising activity using MeOH as solvent and as the unique source of acetalization. Moreover, the antimicrobial results suggested that metal-complexes exhibit significant antimicrobial activity.

Conclusion

This study highlights again the structural and the biological diversities within the field of inorganic–organic hybrids.

Chiral and achiral copper(ii) complexes: structure, bonding and biological activities

A route to noncentrosymmetric hybrid materials is discussed through three noncentrosymmetric materials. These compounds crystallize in either a chiral polar or achiral polar space group, and exhibit high antioxidant and anti-hypertensive activities.

Inorganic layered structures in hybrid double sulfates: related phases and thermal reactivity

The crystal structures of hybrid sulfate salts show a lamellar aspect with interlayer spacings of 12 and 13 Å.

2-Methyl-benzene-1,3-di-ammonium dinitrate

In the crystal structure of the title salt, C7H12N2 (2+)·2NO3 (-), the nitrate ions are located in the vicinity of the protonated amine groups, accepting strong N-H⋯O hydrogen bonds. Each ammonium group is involved in a total of three such inter-actions with neighbouring nitrate ions, generating a three-dimensional network. In addition, there are π-π inter-actions between the aromatic rings of centrosymmetrically related di-ammonium moieties, with a centroid-centroid distance of 3.682 (1) Å.