Single Crystal XRD Data Research Articles

Mongrel synthesis of tin (IV) based 3-aminopyridine with hydrogen halides: Structural, optical, thermal analysis, DFT, Hirshfeld surface analysis and antibacterial investigations

The novel organic-inorganic hybrid materials (C5H7N4)2 [SnCl6] 2- (1) and (C5H7N4)2 [SnBr6]2-(2) have been synthesized and characterized by single-crystal X-ray diffraction at room temperature. Both compounds demonstrate the crystal system was triclinic with Pī space group. Hirshfeld surface analysis investigate the intermolecular interactions and crystal packing derived by single-crystal XRD data reveals the closer contacts associated with strong interactions. Infrared spectrum of both compounds shows the NH stretching band at 3396 cm−1 which indicates a protonated amine group. The product crystals optical characteristics were inspected using UV–visible and photoluminescence spectroscopy. The thermal characteristics were evaluated simultaneously using thermogravimetric (TG) and differential thermal analysis. Tin formal oxidation state was determined as +4 through bond valence sum calculations and CSM shows the ideal octahedral geometry of the anions. DFT calculations utilizing the B3LYP method with the LanL2DZ basis set provide optimized geometries and molecular electrostatic potential maps. We explored the energy difference between (HOMO) and (LUMO) orbitals to understand molecular electrical transport capabilities. The biological activity of the investigated compounds are examined against pathogens which indicates efficacy against bacterial strains.

A New Mineral Calcioveatchite, SrCaB11O16(OH)5·H2O, and the Veatchite–Calcioveatchite Isomorphous Series

The new mineral calcioveatchite, ideally SrCaB11O16(OH)5·H2O, is a Ca-Sr-ordered analogue of veatchite. It was found at the Nepskoe potassium salt deposit, Irkutsk Oblast, Siberia, Russia in halite-sylvite and sylvite-carnallite rocks, with boracite, hilgardite, kurgantaite, hydroboracite, volkovskite, veatchite, anhydrite, magnesite, and quartz. Calcioveatchite forms prismatic or tabular crystals up to 1 × 1.5 × 3 mm3 and crystal clusters up to 3 mm across. It is transparent and colourless with vitreous lustre. Calcioveatchite is brittle, cleavage is perfect on {010}, the Mohs’ hardness is ca 2, Dmeas is 2.58(1), and Dcalc is 2.567 g cm−3. Calcioveatchite is optically biaxial (+), α = 1.543(2), β = 1.550(5), γ = 1.626(2), 2Vmeas = 30(10)°, and 2Vcalc = 35°. The average chemical composition (wt.%, electron microprobe, H2O calculated by stoichiometry) is: CaO 7.05, SrO 20.70, B2O3 61.96, H2O 10.22, and total 99.93. The empirical formula, calculated based on 22 O apfu = O16(OH)5(H2O) pfu, is Sr1.23Ca0.78B10.99O16(OH)5·H2O. Calcioveatchite is monoclinic, space group P21, a = 6.7030(3), b = 20.6438(9), c = 6.6056(3) Å, β = 119.153(7)°, V = 798.26(8) Å3, and Z = 2. Polytype: 1M. The strongest reflections of the powder XRD pattern [d,Å(I,%)(hkl)] are: 10.35(100)(020), 5.633(12)(110), 5.092(10)(120), 3.447(14)(060), 3.362(13)(101, 051), 3.309(38)(–102), 2.862(10)(012), and 2.585(19)(080). The crystal structure was solved based on single-crystal XRD data, R1 = 0.0420. Calcioveatchite (calcioveatchite-1M) is an isostructural analogue of veatchite-1M with the 11-fold cation polyhedron occupied mainly by Sr [Sr0.902(8)Ca0.098(8)] whereas the 10-fold polyhedron is Ca dominant [Ca0.686(7)Sr0.314(7)]. The chemical composition of veatchite from five localities in Russia (Nepskoe), Kazakhstan (Shoktybay and Chelkar in the North Caspian Region), and the USA (Tick Canyon and Billie Mine in California) was studied, and it is shown to exist in nature as a continuous, almost complete isomorphous series which extends from Ca-free veatchite, Sr2B11O16(OH)5·H2O, to calcioveatchite with the composition Sr1.14Ca0.87B10.99O16(OH)5·H2O.

Benzothiazole-based Schiff base for sensing Ca2+ ions: Synthesis, DFT studies, toxicity evaluation in zebrafish embryo and in silico analysis of MMP-9 inhibition

A new heterocyclic Schiff base, 2-(2-benzo(d)thiazol-2yl)hydrazono)methyl)phenol (BTAZ) synthesized from 2-hydrazinobenzothaizole and salicyclaldehyde was characterized by spectral, mass and single crystal XRD data and subjected to sense Ca2+ ions in methanol–water mixture (1:1, v/v) using UV–visible absorption and fluorescence emission spectral studies. The probe BTAZ showed specific detection of Ca2+ ions in a solution containing various metal ions with a detection limit as low as 5.1 × 10−6 M via photo-induced electron transfer (PET) pathway. The binding stoichiometry between BTAZ and Ca2+ was determined to be 2:1 by Job’s plot method. The stoichiometry and optical properties of both BTAZ and BTAZ-Ca2+ complex showed good correlation with theoretical results based on DFT and TD-DFT calculations. The pharmacological evaluation of the probe BTAZ against bacterial and fungal stains also demonstrated its notable efficacy to control their growth in vitro along with anti-oxidant capabilities. Further, toxicity assay of the probe BTAZ against zebrafish embryo did demonstrate that it is non-toxic to the test model in vivo. Ability of the probe BTAZ to inhibit matrix metalloproteinase-9 (MMP-9) enzyme was analyzed in detail using in silico experiments.

The cubic and trigonal polymorphs of NaMn1/2Sn1/2S2 (Na2MnSnS4)

RT-NaMn1/2Sn1/2S2 was prepared by mechanochemical synthesis from a mixture of Na2S, MnS, and SnS2. The crystal structure was determined from X-ray powder diffraction data. The chemical composition was confirmed by energy dispersive X-ray spectroscopy, and the electrical conductivity was measured using electrochemical impedance spectroscopy. The RT-NaMn1/2Sn1/2S2 sample crystallizes with rock salt-type structure, space group Fm3‾m, a = 5.4368(2) Å, V = 160.71(2) Å3, and Z = 2. This sample exhibits an irreversible phase transition. It transforms into a high temperature phase, HT-NaMn1/2Sn1/2S2 which crystallizes with α-NaFeO2-type structure, space group R3‾m, a = 3.7523 (4) Å, c = 19.883 (2) Å, V = 242.44 (4) Å3, and Z = 3. The structure was determined from single crystal XRD data. The electrical conductivities of the RT- and HT-forms are 2.5 × 10−8 S cm−1 (Ea = 0.58 eV) and 3.3 × 10−7 S cm−1 (Ea = 0.42 eV) at 25 °C, respectively.

Specific features of Copper(II) chloride complexes with Caffeine: Synthesis, Structure, DFT calculations

The present article is devoted to the consideration of the interconversions of copper(II) chloride complexes with caffeine (caf) ([CuII2(μ2-Cl)2(caf)2(H2O)2] (1),[CuII3(μ-Cl)6(caf)(H2O)]n (1a), [Cu4(μ2-Cl)6(μ4-O)(caf)4](1b), 2[CuII(caf)Cl2].0.25THF (1c), [CuII(caf)2Cl2] (2)), depending on the synthesis conditions, and to studies on the four-nuclear copper(II) bromide complex with acetamide (AcAm) ([Cu4(μ2-Br)6(μ4-O)(AcAm)4](3)). The results obtained have been confirmed by different methods (powder XRD, single crystal XRD analysis, IR-, ESI-MS-, EPR-spectroscopy, and magnetic properties studies). Two bromide ions in (3) are non-equivalent to the other four and this fact may result in the modification of the exchange integral between bonded copper ions. Single crystal XRD data have been compared with the results of DFT calculations. It has been found that the thermodynamic stability of the complexes grows with an increase in the number of copper atoms and bridging chloride ions and a decrease in the number of water molecules in the formula unit of the compound. The calculation results for complexes with acetamide are in a good correlation with those of caffeine and experimental data.

High-Temperature Crystal Chemistry of Meta-Autunite Group Minerals: Metatorbernite, Cu(UO2)2(PO4)2(H2O)8 and Metazeunerite, Cu(UO2)2(AsO4)2(H2O)8

Thermal expansion of metatorbernite, Cu(UO2)2(PO4)2(H2O)8 (1), and metazeunerite, Cu(UO2)2(AsO4)2(H2O)8 (2), has been investigated using single-crystal and powder X-ray diffraction. Both minerals are prone to dehydration, which proceeds already at ambient conditions. According to the single-crystal XRD data, 1 is stable up to 300(50) K, while 2 is stable up to 250(50) K. Powder XRD studies at various temperatures suggest that 1 dehydrates in three stages at ca. 353, 373, and 483 K, while 2 in two stages at ca. 283 and 543 K. Calculation of the main coefficients of thermal expansion reveals strong anisotropy. The expansion is maximal in the direction normal to the autunite-type layers. This correlates with the anisotropy in thermal evolution of Cu–O bond lengths and differences in the thermal behavior of PO4 and AsO4 tetrahedra.

Synthesis, Structure, and Hirshfeld Surface Analysis of tetrakis(N,N’-diethylthiourea)bis(isothiocyanato)nickel

The complex compound tetrakis(N,N’-diethylthiourea)bis(isothiocyanato)nickel or [Ni(detu)4(NCS)2] (denoted as UMCC-1) has been synthesized by reflux method in two different solvents namely acetone and methanol. This study aims to synthesize, characterize, and analyze the Hirshfeld Surface complex UMCC-1, which was obtained using the reflux method with the mole ratio of NiCl2: detu: KSCN is 1:2:4. Single crystals UMCC-1 in acetone and methanol are dark green in color with melting points of 135-137°C and conductivity of 66.4-84.4 µS. The FTIR absorption band analysis of the two crystals is very similar, ν(C S) detu 590 cm−1 and ν(C≡N) isothiocyanate 2119 cm−1. The refinement of the crystal structure from the single crystal XRD data shows that the two dark green crystals are a molecular type that has a distorted octahedral geometry with the same crystal lattice, monoclinic crystal lattice, P21/c1 space group (no.14), crystal lattice parameter a= 11.112(3) Å, b= 17.249(5) Å, c= 9.647(3) Å, and β= 100.785(10). However, the complex produced in acetone solvent has better refinement quality than methanol concerning %R= 3.27 and %R = 4.55, respectively. The UMCC-1 crystal shows intermolecular hydrogen bonds N-H---S(isothiocyanato) and intramolecular hydrogen bonds N-H---S(detu) with Hirshfeld Surface analysis showing a significant contribution of H---H (69.5%) on crystal packing.

Brassisterol A, a new ergosterol from co-cultivation of fungi attenuates neuroinflammation via targeting NLRP3/caspase-1/GSDMD pathway

Three new ergosterol derivatives brassisterol A–C (1–3) and two new epimeric bicycle-lactones brassictones A and B (4 and 5), were isolated from the co-cultivation of Alternaria brassicicola and Penicillium granulatum. The absolute configurations of these isolates were confirmed by extensive NMR spectra, TD-DFT ECD calculation, and the single crystal XRD data analysis. Amongst the metabolites, compound 1 exhibited potential anti-Parkinson’s disease activity in both MPTP-induced zebrafish and MPP+-induced SH-SY5Y cells. Molecular mechanism studies in vitro showed that 1 attenuated the increase of α-synuclein, NLRP3, ASC, caspase-1, IL-1β, IL-18, and GSDMD expression in the MPP+ induced PD model. Molecular docking in silico simulations exhibited that 1 was well accommodated to one of the binding pockets of NLRP3 8ETR in an appropriate conformation via forming typical hydrogen bonds as well as possessing a high negative binding affinity (-8.97 kcal/mol). Thus, our work suggested that 1 protected dopaminergic cell from neuroinflammation via targeting NLRP3/caspase-1/GSDMD signaling pathway.

Atypical Metal‐Center Coordination in Two Cyanide‐Based Coordination Polymers

AbstractThis contribution reports the crystal structure, solved and refined from single crystal XRD data, of two cyanide‐based coordination polymers, with K[Cu2(CN)3] ⋅ H2O (1) and [Cd(H2O)]2Cd(H2O)2[Cu(CN)3Cu(CN)2]2 ⋅ 8H2O (2) as formula units. These coordination polymers are characterized by metal‐metal bonds between copper atoms. In 1, the framework is formed by Cu−Cu(CN)3 pseudo tetrahedral blocks linked by planar Cu2(CN)3 units. In this material, a defined Cu−Cu bond was identified, which is congruent with the corresponding Raman spectrum. The K atom and water molecule occupy the framework cavities. In 2, the Cu−Cu bond is observed in Cu2(CN)6 blocks which remain linked to Cd(NC)2(H2O)4 and Cd(NC)4(H2O)2 units occupying their axial and equatorial coordination positions, respectively. The solid framework is completed by the −N=C−Cu−C=N− chains linked to Cd(NC)4(H2O)2 moieties. The crystal structure for 2 contains two different sites for the metal centers. The structural study was complemented by recording IR, Raman, and UV/Vis spectra. These two coordination polymers behave as semiconductor materials with a band gap of 2.79 and 3.43 eV, respectively, as derived from the Tauc plot of the corresponding UV/Vis spectrum. Band structure calculations properly supported these values. 1 is a material of an indirect band gap, while 2 has a direct band gap.

Some morpholine tethered novel aurones: Design, synthesis, biological, kinetic and molecular docking studies

Enzymes are the biological macromolecules that have emerged as an important drug target as their upregulation/imbalance leads to various pathological conditions, such as inflammation, parasitic infection, Alzheimer’s, cancer, and many others. Here, we designed and synthesized some morpholine tethered novel aurones and evaluated them as potential inhibitors for CTSB, α-amylase, lipase and activator for trypsin. All the newly synthesized compounds were fully characterized by various spectroscopic techniques (1H NMR, 13C NMR, HRMS) and the Z-configuration to them was assigned based on single crystal XRD data and 1H NMR chemical shift values. Further, the hybrids were evaluated for their intracellular (cathepsin B) and extracellular (trypsin, lipase, amylase) enzyme inhibition potencies. The in-vitro inhibition screening against cathepsin B revealed that most of the synthesized compounds are good competitive inhibitors (% inhibition = 22.91–75.04), with 6q (% inhibition = 75.04) and 6r (% inhibition = 71.13) as the eminent inhibitors of the series. At the same time, they exhibited weak to moderate inhibition towards amylase (% inhibition = 7.22–22.48) and lipase (% inhibition = 16.29–54.83). A significant trypsin activation (% activation = 107.42–196.47) was observed even at the micromolar concentration of the compounds. Furthermore, the drug-modeling studies showed a good correlation between the in-vitro experimental results and the calculated binding affinity of the screened compounds with all the tested enzymes. These findings are expected to provide a new lead in drug development for different pathological disorders wherever these enzymes are involved.

Creating Conjugated C-C Bonds between Commercial Carbon Electrode and Molecular Catalyst for Oxygen Reduction to Hydrogen Peroxide.

Immobilizing molecular catalysts on electrodes is vital for electrochemical applications. However, creating robust electrode-catalyst interactions while maintaining good catalytic performance and rapid electron transfer is challenging. Here, without introducing any foreign elements, we show a bottom-up synthetic approach of constructing the conjugated C-C bond between the commercial Vulcan carbon electrode and an organometallic catalyst. Characterization results from FTIR, XPS, aberration-corrected TEM and EPR confirmed the successful and uniform heterogenization of the complex. The synthesized Vulcan-LN4 -Co catalyst is highly active and selective in the oxygen reduction reaction in neutral media, showing an 80 % hydrogen peroxide selectivity and a 0.72 V (vs. RHE) onset potential which significantly outperformed the homogenous counterpart. Based on single-crystal XRD and NMR data, we built a model for density functional theory calculations which showed a nearly optimal binding energy for the *OOH intermediate. Our results show that the direct conjugated C-C bonding is an effective approach for heterogenizing molecular catalysts on carbon, opening new opportunities for employing molecular catalysts in electrochemical applications.

Y4O2(CN2)3Cl2, Its Relation to the Metal-Rich Y2Cl3, and the Photoluminescence of Y4O2(CN2)3Cl2:Ce

AbstractY4O2(CN2)3Cl2 and some isotypic rare earth (RE) carbodiimides RE4O2(CN2)3Cl2 (RE = Sm, Gd, Tb) were prepared by solid-state metathesis reaction between RECl3, REOCl and Li2CN2. The crystal structure of Y4O2(CN2)3Cl2 was solved and refined from single-crystal XRD data with the monocline space group C2/m. Homologous compounds with RE = Sm, Gd, Tb were assigned isotypically by means of XRD powder diffraction. The structure of Y4O2(CN2)3Cl2 is characterized by one-dimensional cluster chains which are showing a striking resemblance to the trans-edge bridging RE6-octahedra in the structures of Y2Cl3, β-Y2Cl3N, and RE2N(CN2)Cl, despite different numbers of cluster electrons. Crystals of RE4O2(CN2)3Cl2 appear as transparent rods. The presence of (NCN)2− ions is confirmed by infrared spectroscopy. Y4O2(CN2)3Cl2, doped with Ce3+ is a photoluminescent material that is showing an emission band in the orange region (λ = 550 nm) of the visible spectrum.

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XX. Evseevite, Na2Mg(AsO4)F, the first natural arsenate with an antiperovskite structure

AbstractThe new mineral evseevite was found in the Arsenatnaya fumarole, Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. Evseevite is represented by two chemical varieties. The variety close to the end-member Na2Mg(AsO4)F (holotype) is associated with sanidine, hematite, tenorite, aegirine, cassiterite, sylvite, halite, johillerite, badalovite, calciojohillerite, hatertite, arsmirandite, yurmarinite, axelite, polyarsite, aphthitalite, potassic-magnesio-fluoro-arfvedsonite, litidionite, ferrisanidine and tridymite. The P- and S-enriched variety (cotype) is associated with hematite, fluorophlogopite, svabite, fluorapatite, tilasite, calciojohillerite, forsterite, cassiterite, belomarinaite and aphthitalite. Evseevite occurs as prismatic, acicular or hair-like crystals up to 0.7 mm long combined in clusters up to 0.5 mm, brushes or crusts up to 2 × 2 mm. It is transparent, colourless or pale pinkish, with vitreous lustre. Dcalc is 3.377 g cm–3 for the holotype and 3.226 g cm–3 for the cotype. Evseevite is optically uniaxial (+), α = 1.545(2), β = 1.546(2), γ = 1.549(2) and 2Vmeas = 40(10)°. The empirical formulae calculated based on O+F = 5 apfu are (Na1.99Ca0.03K0.01)Σ2.03(Mg0.98Fe3+0.01Zn0.01Cu0.01)Σ1.01[(As0.98Si0.01)Σ1.01O4](F0.97O0.03) for the holotype and Na2.02(Mg1.00Fe3+0.03)Σ1.03[(As0.69P0.25S0.07)Σ1.01O4](F0.78O0.22) for the cotype. Evseevite is orthorhombic, Pbcn, a = 5.3224(1), b = 14.1255(3), c = 12.0047(3) Å, V = 902.53(4) Å3 and Z = 8. Strong reflections of the powder XRD pattern [d,Å(I)(hkl)] are: 4.001(100)(121), 3.479(56)(023), 3.041(45)(042), 2.657(44)(200), 2.642(68)(142) and 2.613(36)(104). The crystal structure was solved from single-crystal XRD data and refined on powder data by the Rietveld method, Rwp = 0.0068, Rp= 0.0047 and Robs = 0.0435. Evseevite is isostructural to moraskoite Na2Mg(PO4)F. The structure of evseevite can be described in terms of anion-centred polyhedra. F-centred octahedra [FNa4Mg2]7+ share faces to form chains [FNa2Mg]3+ and AsO4 tetrahedra are located between the chains. Evseevite belongs to a small set of minerals with antiperovskite structures and is the first natural arsenate with antiperovskite units. The mineral is named in honour of the Russian mineralogist Aleksandr Andreevich Evseev (born 1949).

N'-(3,4-dimethoxybenzylidene)-4-methylbenzenesulfonohydrazide derivatives: Synthesis, quantum chemical method, in silico ADMET, molecular docking and molecular dynamic simulations

A new N'-(3,4-dimethoxybenzylidene)-4-methylbenzenesulfonohydrazide derivatives were prepared from a condensation reaction between 4-methylbenzenesulfonohydrazide and 3,4-dimethoxybenzaldehyde. The structure of DMSH was elucidated using various spectral techniques including FT-IR, 1HNMR and 13CNMR. The structure of DMSH bond parameters also confirmed by single crystal XRD analysis of related derivatives and optimized bond parameters are calculated by density functional theory (DFT) method at B3LYP/6–311 G (d, p) level of theory. The optimized geometrical parameters obtained by DFT calculation are in good agreement with single crystal XRD data. The experimentally observed FT-IR bands were assigned to different normal modes of the molecule. The results show a good agreement with each other when these computed bond parameters are compared to XRD values of related compounds. The stability, chemical reactivity and charge transfer within the molecule was explained by frontier molecular orbital calculations. Atomic charges on the various atoms of DMSH obtained by Mulliken population analysis. Potential reactive sites of the DMSH compound have been identified by MEP which is mapped to the electron density surfaces. The reported molecule is used as a potential NLO material since it has a high μβ0 value. The theoretical UV–vis spectrum of the compound is used to study the visible absorption maxima (λ max). The molecular docking mechanism between DMSH ligand and COVID-19/6WCF and COVID-19/6Y84 receptors were studied to investigate the binding modes of this compound at the active sites. Molecular docking outcomes have shown that the DMSH molecule can be considered as a potential agent against COVID-19/6WCF-6Y84 receptors. In addition, the theoretical parameters of the bioactive molecules were calculated to establish their drug-likeness qualities and ADME/T analysis was carried out to examine the drug properties of the synthesized compound. Molecular dynamics simulation was performed for COVID-19 main protease (Mpro: 6WCF/6Y84) to understand the elements governing the inhibitory effect and the stability of interaction under dynamic conditions. The resultant complex structures were subjected to 100 ns simulation run to estimate their binding stabilities using GROMACS. The molecular dynamics simulation studies provided essential evidence that the systems were stable during the progression of 100 ns simulation run.

Synthesis, crystal structure, Hirshfeld surface, biological evaluation, DFT and molecular docking studies of unsymmetrical 3-allyl-5-ethyl-1,4-dihydro-2,6-dimethyl-4-phenyl pyridine-3,5-dicarboxylate derivatives

By employing ceric ammonium nitrate as an effective catalyst in the one-pot four-component Hantzsch reaction, a new series of unsymmetrical 1, 4-dihydropyridines were synthesised. The synthesised compounds were identified using spectral methods and the structure of the compound 3-allyl-5-ethyl-4(3-fluorophenyl)-1,4-dihydro-2,6-dimethyl-4-phenylpyridine-3,5-dicarboxylate (5f) was confirmed by single crystal XRD analysis. Optimised bond parameters were calculated using DFT /B3LYP/6-311++(d,p) basis set and also compared with single crystal XRD data. The calculated hyperpolarisability may be attractive for further studies on the material's NLO properties. NBO analysis was used to examine the stability of the molecule resulting from the hyper conjugative interaction and charge delocalisation. The eventual charge transfer interactions that occur within the molecule are explained by HOMO–LUMO analysis. MEP reveals the electrophilic and nucleophilic reactive sites of the molecule. According to the Hirshfeld surface analysis, the intermolecular stabilisation in the crystal is mostly caused by hydrogen bond interactions between H … H, C–H … C, C–H … N, and particularly C–H–O. It was discovered that the chemicals 5d and 5i were effective antimicrobials activity. Molecular docking studies were employed to identify the primary binding site of piperidine to receptors. These results indicate that the target molecules may be considered for further drug design endeavours. Research highlights Compound synthesised by the one-pot four component Hantzsch method. Single crystal of 3-allyl-5-ethyl-4(3-fluorophenyl)−1,4-dihydro-2,6-dimethyl-4-phenylpyridine-3,5-dicarboxylate(5f) was obtained by slow evaporation method. Hirshfeld analysis and fingerprint plots were performed to confirm the intermolecular interactions in the crystal structure. The stability and reactivities of 5f was achieved from DFT calculation. The antimicrobial studies showed that compounds have promising antimicrobial properties. Molecular docking studies were employed to identify the primary binding site of piperidine to receptors.

CaPt4P6, first calcium-containing representative of the ternary pyrite-derived pnictides of the BaPt4As6 type: Synthesis, crystal, and electronic structure

Mixed calcium-platinum phosphide CaPt4P6 was synthesized using flux-assisted high-temperature ampoule technique. According to single-crystal XRD data it crystallizes in the monoclinic space group C2/c with Z ​= ​4 (a ​= ​8.1361(3) Å, b ​= ​7.9489(3) Å, c ​= ​11.3803(5) Å, β ​= ​90.860(2)o, R1 ​= ​0.0240, wR2 ​= ​0.0618) and belongs to the BaPt4As6 structure type, the structure of which is derived from pyrite structure where one atom of alkaline earth metal per formula unit occupies P2-unit position. DFT calculations predict all known representatives of the BaPt4As6 structure type to be narrow-gap semiconductors (calculated bandgap values are: 0.43 ​eV (CaPt4P6), 0.57 ​eV (SrPt4P6), 0.27 ​eV (SrPt4As6) and 0.40 ​eV (BaPt4As6)). Bonding analysis establishes that all these compounds are based on the 3D framework of the Pt-Pn and Pn-Pn interactions, with AE cations occupying the voids with varying degree of the distortion of the AE coordination.

Synthesis, structural characterization, Hirshfeld surface and theoretical studies of 2-bromopyridinium picrate

Single-crystal X-ray diffraction analysis was used to determine the crystal structure of 2-bromopyridinium picrate (2BPP), which was formed using a slow evaporation solution growth approach. It belongs to a triclinic system with the centrosymmetric space group Pī. Supramolecular assembly is constructed by N-H•••O and π•••π stacking interaction. By employing FT-IR analysis to identify the functional groups that are present in the molecule, the band gap energy was calculated by using the Kubelka-Munk algorithm. A study of the intermolecular interactions and crystal packing using Hirshfeld surface analysis, derived by single crystal XRD data, reveals the close contacts associated with strong interactions. Theoretical calculations were done by the density functional theory (DFT) method.

Protonation of Imino Moiety in Aminoguanidine by Heterolytic O–H Bond Cleavage on Phthalic Acid: Theoretical, Experimental and DNA Binding Studies

Aqueous neutralization reaction between aminoguanidine hydrogencarbonate and phthalic acid yielded the crystals of aminoguanidine hydrogenphthalate monohydrate (AHPMH). The crystal quality is further improved by repeated recrystallization and single crystals were obtained. The single crystal XRD data reveals that the compound crystallizes in the monoclinic crystal system with the Cc space group. The unit cell consists of four molecules (z = 4) and in the crystal lattice they are linked by O–H···O and N–H···O intermolecular hydrogen bonding. Geometrical and vibrational analyses were performed by B3LYP/6311G(d,p) basis set and compared with the single crystal XRD values. The Mulliken charge and molecular electrostatic potential (MEP) analyses have been used to predict the reaction behaviour and bond cleavage fashion during the reaction. The heterolytic O-H bonding electrons are shifted towards the oxygen atom (-0.6112 e) and it possesses high electronegative which influenced the formation of strong hydrogen bond. The binding constant (Kb) of the AHPMH indicates that strong interactions are developed between the title compound and CT-DNA.

Nishanbaevite, KAl2O(AsO4)(SO4), a new As/S-ordered arsenate-sulfate mineral of fumarolic origin

The new mineral nishanbaevite, ideally KAl2O(AsO4)(SO4), was found in sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with euchlorine, alumoklyuchevskite, langbeinite, urusovite, lammerite, lammerite-β, ericlaxmanite, kozyrevskite, and hematite. Nishanbaevite occurs as long-prismatic or lamellar crystals up to 0.03 mm typically combined in brush-like aggregates and crusts up to 1.5 mm across. It is transparent, colourless, with vitreous lustre. Dcalc = 3.012 g cm− 3. Nishanbaevite is optically biaxial (–), α = 1.552, β ≈ γ = 1.567. The chemical composition (average of seven analyses) is: Na2O 3.79, K2O 8.01, CaO 0.10, CuO 0.21, Al2O3 30.08, Fe2O3 0.50, SiO2 1.62, P2O5 0.66, As2O5 32.23, SO3 22.59, total 99.79 wt%. The empirical formula calculated based on 9 O apfu is: (K0.57Na0.41Ca0.01)Σ0.99(Al1.99Fe3+0.02Cu0.01)Σ2.02(As0.95S0.95Si0.09P0.03)Σ2.02O9. Nishanbaevite is orthorhombic, Pbcm, a = 15.487(3), b = 7.2582(16), c = 6.6014(17) Å, V = 742.1(3) Å3 and Z = 4. The strongest reflections of the powder XRD pattern [d,Å(I)(hkl)] are: 15.49(100)(100), 6.56(30)(110), 4.653(29)(111), 3.881(54)(400), 3.298(52)(002), 3.113(29)(121), and 3.038(51)(202, 411). The crystal structure, solved from single-crystal XRD data (R = 7.58%), is unique. It is based on the complex heteropolyhedral sheets formed by zig-zag chains of Al-centred polyhedra (alternating trigonal bipyramids AlO5 and octahedra AlO6 sharing edges) and isolated tetrahedra AsO4 and SO4. Adjacent chains of Al polyhedra are connected via AsO4 tetrahedra to form a heteropolyhedral double-layer. Its topological peculiarity is considered and compared with those in structurally related compounds. The (K,Na) site is located in the interlayer space between SO4 tetrahedra. The position of nishanbaevite among the arsenate-sulfates and their specific structural features are discussed. The mineral is named in honour of the Russian mineralogist Tursun Prnazorovich Nishanbaev (1955–2017).

Antimony(III) dithiocarbamates: Structural studies and exploration of the rare Sb···Sb interaction

• Synthesis and characterization of antimony(III) dithiocarbamates. • Crystal structures and supramolecular features of the metal complexes. • Exploration of the rare antimony-antimony interaction. • DFT studies. Herein, we report synthesis and spectroscopic characterization of a new piperidine-based homoleptic antimony(III) dithiocarbamate complex Sb[S 2 CN(CH 2 ) 4 CH(Bn)] 3 ) (1) and solid state crystal structure of a piperazine - based complex Sb[S 2 CN(CH 2 ) 4 N(Bn)] 3 (2) . This study identifies molecular and supramolecular features of the two compounds based on single crystal XRD data. Interestingly, complex 1 features an Sb ··· Sb (stibophilic) linkage, a rarely observed interaction in this class of compounds. To investigate the rarity of this stibophilic linkage CSD retrieved structures have been scrutinized and DFT studies conducted. XRD data unveiled that the linkage materializes in two possible ways: firstly, when monomers carrying pentagonal pyramidal coordination geometry adopt usual orientations (antiparallel alignment of the monomers attached through four-membered [Sb—S ··· ] 2 ring) and characteristically organized neighboring “anchoring molecules” influence them to substantiate the linkage, and secondly when monomers align in unusual patterns (this is observed in both usual geometries, pentagonal pyramidal and trigonal antiprismatic). Interestingly, trigonal antiprismatic geometry with usual pattern of dimeric aggregation is deprived of the Sb ··· Sb linkage. Furthermore, DFT data are well consistent with the findings, and convincingly explains the rarity of the linkage.