P1 Space Group Research Articles

Cationic iridium (III) complexes bearing fluorinated Ar-BIAN ligands: Synthesis, structure, electronic, and electrochemical properties

Three cationic iridium (III) complexes, [(ppy)2Ir(4-FPhBIAN)]PF6 (Ir1), [(ppy)2Ir(3,4-F,FPhBIAN)]PF6 (Ir2), [(ppy)2Ir(4-CF3PhBIAN)]PF6 (Ir3) were synthesized from 2-phenylpyridine (Hppy) as cyclometalating ligand and N,N′-bis(aryl)acenaphthene as ancillary ligand. All the complexes were characterized by FT-IR, 1H, 13C and 19F NMR spectroscopies, and elemental analysis. The molecular structures of the complexes were determined by X-ray crystallography. These complexes were crystalized as greenish-black needles in the triclinic P1 space group for complexes Ir1 and Ir3, while Ir2 was crystalized in the orthorhombic P212121 space group. Electrochemical properties were studied by cyclic voltammetry analysis. All the complexes showed quasi-reversible oxidation and reduction peaks, and reversibility increased by scan rate. Electronic properties were studied by UV-visible spectroscopy, and intense absorption band below 300 nm was obtained compared to intense absorption bands between 300 ~ 530 nm. Density functional theory (DFT) calculations were employed to get better understanding of electrochemical properties.

FT-IR spectroscopic analyses of complex formation process phosphorylated betaines with metal ions

The interaction of alkaline, alkaline earth, transition metals and rare earth elements with alkyl{[benzyl(dialkyl)ammonio]methyl}phosphonates L1 and L2 was studied by Fourier Transform Infrared (FT-IR) spectroscopy. The changes in the nitro group stretching bands, phosphoryl stretching bands were monitored. The main centers of coordination of the ligands have been established.The structure of ethyl{[benzyl(dipropylammonio]methyl}phosphonate characterized by routine X-ray spectroscopy. Single crystal X-ray diffraction analysis showed that the compound crystallizes as a zwitterion in P212121 space group and stabilized by hydrogen O–H•••O bonds.

Synthesis, characterization, electrochemical behavior, molecular simulation studies and in vitro toxicity assessment of new metal Schiff base complexes derived from 3‑methoxy-2‑hydroxy-benzaldehyde and allylamine

In this research, a series of new Schiff base complexes of CoL3 (1) and NiL2 (2) were derived from 3‑methoxy-2‑hydroxy-benzaldehyde with 3-amino‑prop-1-ene (allylamine). The functional groups were elaborately demonstrated using elemental analyses, Mass spectra, Fourier transform infrared (FT-IR), UV–Vis spectroscopy and single-crystal X-ray diffraction technique. X-ray diffraction results revealed that both complexes crystallized in the triclinic system with a space group of P1¯. The structural studies exhibited octahedral and square planar geometry for (1) and (2) around the central metal ion. Moreover, the redox behavior of the complexes was evaluated in methanol by cyclic voltammetry (CV) technique. The electrochemical behavior of the complexes showed the electronic effects of the groups on redox potential for both complexes. The synthesized allyl-based metal complexes were tested for anticancer activity in the human colorectal (SW-480) cancer cell line. In vitro cell proliferation was studied by microculture tetrazolium technique (MTT colorimetric assay) which indicated that all treatment groups are capable of decreasing the proliferation rate of SW-480 cells. The cytotoxic measurements showed strong inhibitory activity against cancer cells for all ligands and complexes in a concentration-dependent manner. Pharmacophore of novel colorectal cancer compounds was also explored. Molecular docking studies of our Schiff bases complexes was carried out to bind to B-DNA .

Ternary Zinc Antimonides Unlocked Using Hydride Synthesis

Three new sodium zinc antimonides Na11Zn2Sb5, Na4Zn9Sb9, and NaZn3Sb3 were synthesized utilizing sodium hydride NaH as a reactive sodium source. In comparison to the synthesis using sodium metal, salt-like NaH can be ball-milled, leading to the easy and uniform mixing of precursors in the desired stoichiometric ratios. Such comprehensive compositional control enables a fast screening of the Na-Zn-Sb system and identification of new compounds, followed by their preparation in bulk with high purity. Na11Zn2Sb5 crystallizes in the triclinic P1 space group (No. 2, Z = 2, a = 8.8739(6) Å, b = 10.6407(7) Å, c = 11.4282(8) Å, α = 103.453(2)°, β = 96.997(2)°, γ = 107.517(2)°) and features polyanionic [Zn2Sb5]11- clusters with unusual 3-coordinated Zn atoms. Both Na4Zn9Sb9 (Z = 4, a = 28.4794(4) Å, b = 4.47189(5) Å, c = 17.2704(2) Å, β = 98.3363(6)°) and NaZn3Sb3 (Z = 8, a = 32.1790(1) Å, b = 4.51549(1) Å, c = 9.64569(2) Å, β = 98.4618(1)°) crystallize in the monoclinic C2/m space group (No. 12) and have complex new structure types. For both compounds, their frameworks are built from ZnSb4 distorted tetrahedra, which are linked via edge-, vertex-sharing, or both, while Na cations fill in the framework channels. Due to the complex structures, Na4Zn9Sb9 and NaZn3Sb3 compounds exhibit low thermal conductivities (0.97-1.26 W·m-1 K-1) at room temperature, positive Seebeck coefficients (19-32 μV/K) suggestive of holes as charge carriers, and semimetallic electrical resistivities (∼1.0-2.3 × 10-4 Ω·m). Na4Zn9Sb9 and NaZn3Sb3 decompose into the equiatomic NaZnSb above ∼800 K, as determined by in situ synchrotron powder X-ray diffraction. The discovery of multiple ternary compounds highlights the importance of judicious choice of the synthetic method.

High-throughput macromolecular polymorph screening via an NMR and X-ray powder diffraction synergistic approach: the case of human insulin co-crystallized with resorcinol derivatives

Regular injections of insulin provide life-saving benefits to millions of diabetics. Apart from native insulin and insulin analogue formulations, microcrystalline insulin suspensions are also commercially available. The onset of action of the currently available basal insulins relies on the slow dissociation of insulin hexamers in the subcutaneous space due to the strong binding of small organic ligands. With the aim of identifying insulin–ligand complexes with enhanced pharmacokinetic and pharmacodynamic profiles, the binding affinity of two resorcinol-based molecules (4-chlororesorcinol and 4-bromoresorcinol) and the structural characteristics of insulin upon co-crystallization with them were investigated in the present study. `In solution' measurements were performed via saturation transfer difference (STD) NMR. Co-crystallization upon pH variation resulted in the production of polycrystalline precipitates, whose structural characteristics (i.e. unit-cell symmetry and dimension) were assessed. In both cases, different polymorphs (four and three, respectively) of monoclinic symmetry (P21 and C2 space groups) were identified via X-ray powder diffraction. The results demonstrate the efficiency of a new approach that combines spectroscopy and diffraction techniques and provides an innovative alternative for high-throughput examination of insulin and other therapeutic proteins.

Synthesis, crystal growth, physico-chemical and quantum chemical investigations on 2A5NPTCA single crystal: A promising candidate for NLO and optical limiting applications

• The high NLO active 2A5NPTCA single crystals have been grown by SEST. • The SXRD study evidences the centrosymmetric structure of the title crystal. • The LDT and χ (3) were found to be 3.1 GW/cm 2 and 4.2×10 −6 esu, respectively. • The DFT approach has been used to study the structural and electronic properties. • The intermolecular interaction has been evaluated by Hirshfeld surface analysis. A potentially useful third-order NLO single crystals of 2-amino-5-nitropyridinium trichloroacetate (2A5NPTCA) have been successfully grown by conventional SEST. X-ray diffraction analyses have been carried out to determine the crystal structure of the grown crystals. The obtained result shows that grown crystals can be classified into monoclinic crystal system with space group of P2 1 /n. The multiple functional groups in the 2A5NPTCA single crystal were confirmed by the FTIR spectroscopy analysis. The obtained UV–Vis NIR result discloses that the grown crystal possesses more than 60% of transmittance in the wavelength region between 405 and 1100 nm. The recorded TG and DTA spectra unveil that the thermal stability of the grown crystal of about 150°C. The large LDT (3.1 GW/cm 2 ) against Nd: YAG laser represents the utility of the 2A5NPTCA crystals for high-power laser devices. The third-order NLO parameters such as n 2 , β and χ (3) and OL threshold were evaluated using solid-state laser of wavelength 532 nm and the values were found to be 7.24×10 −8 cm 2 /W, 0.09×10 −4 cm/W, 4.2×10 −8 esu and 6.7 mW/cm 2 , respectively. The quantum-chemical calculations have been carried out to determine the various parameters of the title molecule such as β tot , FMOs and MEP by DFT approach. The impact of various intermolecular interactions in the 2A5NPTCA molecular crystal has been determined using Hirshfeld surface analysis.

Structural characterization and Kemp eliminase activity of the Mycobacterium smegmatis Ketosteroid Isomerase

The Kemp elimination reaction, involving the ring-opening of benzoxazole and its derivatives under the action of natural enzymes or chemical catalysts, has been of interest to researchers since its discovery. Because this reaction does not exist in all currently known metabolic pathways, the computational design of Kemp eliminases has provided valuable insights into principles of enzymatic catalysis. However, it was discovered that the naturally occurring promiscuous enzymes ydbC, xapA and ketosteroid isomerase also can catalyze Kemp elimination. Here, we report the crystal structure of ketosteroid isomerase (KSI) from Mycobacterium smegmatis MC2 155. MsKSI crystallizes in the P212121 space group with two molecules in an asymmetric unit, and ultracentrifugation data confirms that it forms a stable dimer in solution, consistent with the 1.9 Å-resolution structure. Our assays confirm that MsKSI accelerates the Kemp elimination of 5-nitrobenzoxazole (5NBI) with an optimal pH of 5.5. A 2.35 Å resolution crystal structure of the MsKSI-5NBI complex reveals that the substrate 5NBI is bound in the active pocket of the enzyme composed of hydrophobic residues. In addition, the Glu127 residue is proposed to play an important role as a general base in proton transfer and breaking weak O–N bonds to open the five-membered ring. This work provides a starting point for exploring the artificial modification of MsKSI using the natural enzyme as the backbone.

The Extended Eighth-Shell method for periodic boundary conditions with rotational symmetry.

The Eighth-Shell method for parallelization of molecular dynamics simulations has previously been shown to be the most optimal for efficiency at large process counts. However, in its current formulation only the P1 space group is supported for periodic boundary conditions (PBC) and thus reflection and/or rotational crystal symmetries are not supported. In this work, we outline the development and implementation of the Extended Eighth-Shell (EES) method that allows rotational symmetry by using an extended import region compared to the ES method. It simulates only the asymmetric unit and communicates coordinates and forces with images that correspond to P21 PBC. The P21 PBC has application in lipid bilayer simulations as it can be used to allow lipids to switch leaftlets, thus rapidly balancing the chemical potential difference between the two layers. Our results show that the EES method scales efficiently over large number of processes and can be used for simulations with P21 symmetry in an orthorhombic crystal.

Qualitative and Quantitative Study of Intermolecular Interactions in Imidazo[2,1‐b] [1,3,4] Thiadiazoles

AbstractThe crystal structures of three Imidazo [2, 1‐b] [1, 3, 4] thiadiazole derivatives were determined by single crystal x‐ray diffraction method. All compounds are crystallized under monoclinic crystal system, P21 space group. In solid‐state, the crystal structures are primarily stabilized by C−H…O hydrogen bonds. The chloro and bromo substituted structures exhibits sigma hole involved S…O and S…N non‐bonding interactions. A detailed analysis of crystal packing with the evaluation of interaction energies of molecular pairs extracted from both PIXEL and quantum chemical methods were presented in detail. In addition, Hirshfeld 2D fingerprint plots are used to estimate intermoleular interactions quantitatively. The iso‐structurality present in the crystal packing was investigated using XPAC analysis. The molecular electrostatic potential (MEP) was mapped to identify the reaction sites of the molecules. Further nonlinear optical properties are calculated using Density functional theory.

Synthesis of dihydrotestosterone derivatives modified in the A-ring with (hetero)arylidene, pyrazolo[1,5-a]pyrimidine and triazolo[1,5-a]pyrimidine moieties and their targeting of the androgen receptor in prostate cancer

One of the main directions of steroid research is the preparation of modified derivatives in which, in addition to changes in physicochemical properties, receptor binding is significantly altered, thus a bioactivity different from that of the parent compound predominates. In the frame of this work, 2-arylidene derivatives were first synthesized by regioselective modification of the A-ring of natural sex hormone, 5α-dihydrotestosterone (DHT). After Claisen-Schmidt condensations of DHT with (hetero)aromatic aldehydes in alkaline EtOH, heterocyclizations of the α,β-enones were performed with 3-amino-1,2,4-triazole, 3-aminopyrazole and 3-amino-5-methylpyrazole in the presence of t-BuOK in DMF to afford 7′-epimeric mixtures of A-ring-fused azolo-dihydropyrimidines, respectively. Depending on the electronic demand of the substituents of the arylidene moiety, spontaneous or 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ)-induced oxidation of the heteroring led to triazolo[1,5-a]pyrimidines and pyrazolo[1,5-a]pyrimidines in good yields, while, using the Jones reagent as a strong oxidant, 17-oxidation also occurred. The crystal structures of an arylidene and a triazolopyrimidine product have been determined by single crystal X-ray diffraction and both were found to crystallize in the monoclinic crystal system at P21 space group. Most derivatives were found to diminish the transcriptional activity of androgen receptor (AR) in reporter cell line. The candidate compound (17β-hydroxy-2-(4-chloro)benzylidene-5α-androstan-3-one, 2f) showed to suppress androgen-mediated AR transactivation in a dose-dependent manner. We confirmed the cellular interaction of 2f with AR, described the binding in AR-binding cavity by the flexible docking and showed the ability of the compound to suppress the expression of AR-regulated genes in two prostate cancer cell lines.

Enhanced luminescence properties and Judd-Ofelt analysis of novel red emitting Sr2LiScB4O10: Eu3+ phosphors for WLED applications

In this work, a new series of red emitting Eu 3+ ions activated Sr 2 LiScB 4 O 10 phosphors were synthesized by a traditional high temperature solid-state reaction technique and their structural and luminescence behavior were studied through analyzing X-ray diffraction, Scanning electron microscopy, Fourier transform infrared spectroscopy, optical absorption, photoluminescence as well as decay spectral measurements, respectively. XRD pattern showed that the prepared Sr 2 LiScB 4 O 10 :Eu 3+ phosphors crystallized into monoclinic system with the space group of P2 1 /n. FTIR study revealed the presence of different stretching and bending vibrational bands of borate group. Bonding parameter values which obtained from the band positions of the absorption spectra revealed the covalent character which existing between the Eu 3+ ions and its surrounding ligands. Under 395 nm excitation source, the studied phosphors exhibit intense red emissions in the 617 nm wavelength region corresponding to the 5 D 0 → 7 F 2 transition of Eu 3+ ions. Judd-Ofelt (JO) intensity parameters were evaluated from the PL emission spectra in order to facilitate a study of the nature of site symmetry. From the CIE color chromaticity analysis it is evident that the prepared phosphors are found to emit an intense red light with the reasonable color coordinate and color purity under the excitation of blue light and the same may be suggested as an appropriate red component for developing white LEDs. The important radiative parameters were obtained for the emission transitions using JO intensity parameters in order to ensure the suitability of prepared phosphors for display devices and laser applications. • Eu 3+ : Sr 2 LiScB 4 O 10 phosphors were fabricated by solid state reaction method for display device applications. • Eu 3+ activated Sr 2 LiScB 4 O 10 phosphors exhibited red luminescence which was confirmed by CIE chromaticity diagram. • Higher and increasing Ω 2 values contribute to the higher degree of covalency between Eu–O bond. • Bright red light with color purity of 94% was attained in the prepared phosphors excited by 395 nm. • 0.6EuSLSB phosphor exhibit appreciable radiative properties suitable for red laser and white LEDs.

X-ray powder diffraction data for N,N-dimethyl-1H-benzo[d]imidazol-2-amine, C9H11N3

X-ray powder diffraction data, unit-cell parameters, and space group for N,N-dimethyl-1H-benzo[d]imidazol-2-amine, C9H11N3, are reported [a = 11.379(3) Å, b = 10.227(5) Å, c = 7.151(1) Å, α = 90°, β = 90°, γ = 90°, unit-cell volume V = 832.318 Å3, Z = 4, ρcal = 1.286 g cm−3, and space group P21212]. All measured lines were indexed and were consistent with the P21212 space group. No detectable impurities were observed.

Synthesis, growth, physio‐chemical and Hirshfeld surface analysis of guanidinium l-glutamate single crystal

In the present work, a novel Guanidinium l-glutamate (GLG) optically transparent single crystal has been synthesized and grown by slow solvent evaporation method for the first time is reported. Single crystal X-ray diffraction demonstrates that the GLG crystallizes in non-centrosymmetric monoclinic crystal with P21 space group. The different functional groups present in the grown crystal were found by Fourier transform infrared analysis. The optical properties of the grown crystal such as absorbance, laser damage threshold have been studied. The bandgap energy of the crystal was found to be 4.66 eV. Thermal properties of GLG crystalline samples were analyzed using Thermogravimetry/Differential Thermal Analysis. Further, the material is characterized by Hirshfeld surface analysis to analyze and interrupt the intermolecular interactions of GLG. Scanning Electron Microscope (SEM) studies were carried out to study the surface morphology of the grown crystal. By using Kurtz-Perry powder technique second harmonic generation and particle size dependency was carried out for the title compound.

Crystal structures of inhibitor complexes of M-PMV protease with visible flap loops.

Mason‐Pfizer monkey virus protease (PR) was crystallized in complex with two pepstatin‐based inhibitors in P1 space group. In both crystal structures, the extended flap loops that lock the inhibitor/substrate over the active site, are visible in the electron density either completely or with only small gaps, providing the first observation of the conformation of the flap loops in dimeric complex form of this retropepsin. The H‐bond network in the active site (with D26N mutation) differs from that reported for the P21 crystal structures and is similar to a rarely occurring system in HIV‐1 PR.

Experimental and Theoretical Investigations on a Hydrous Organic salt of 2,4,6-triaminopyrimidine-1,3-diium L-tartrate monohydrate (TTM)

A hydrous organic salt of 2,4,6-triaminopyrimidine-1,3-diium L-tartrate monohydrate (TTM) has been synthesized. The structural investigations revealed the acentric crystalline packing (monoclinic system with P21 space group) of TTM crystal. The carboxylate (O5__C8__O6) group of L-tartrate anion linked to the nitrogen atoms (N3 and N4) of cation via a pair of N__H…O hydrogen bonds (N(3)__H(4)…O(6) (-x,+y-1/2,-z+1) and N(4)__H(5)…O(5) (-x,+y-1/2,-z+1)) and formed a R22(8)ring motif. Hirshfeld surface and finger print analysis were carried out to investigate the contribution of N__H…O and O__H…O and C__H…O intermolecular interactions to the structural stabilization of TTM crystal. FTIR and FT-Raman vibrational studies were effectively performed to investigate the vibrational modes of various functional groups in TTM crystal. Second order NLO property of title crystal was confirmed by modified Kurtz-Perry second harmonic generation technique. The relationship between the molecular structure and properties were investigated for TTM molecule by systematic quantum chemical calculations using density functional theory (DFT).

Enhanced Mechanical, Thermal, Photoluminescence, NLO and Antifungal Activities of Magnesium Doped Ninhydrin Crystals

A normal way of slow evaporation method had been used to preparing pure ninhydrin (PN) and magnesium doped ninhydrin (M1N) single crystals. The research describes the various characterizations of the developed PN and M1N crystals. Monoclinic crystal structure with non centrosymmetric P21 space group were marked in the developed crystals. Additionally, to find out the various functional groups of the grown PN and M1N crystals Fourier’s transformation infra-red studies had been used for this research. Vicker’s microhardness tester had been used to identify the strength of the developed crystals. In energy dispersive x-ray analysis the presence of carbon, oxygen and magnesium into the crystal lattice was observed. In connection with this by using thermal analysis the decomposition point of the developed crystals were marked. The photoluminescence study was used to identify the excitation and emission peaks of the grown samples. Conclusively, by powder Kurtz-Perry method the second harmonic generation efficiency had been verified in a greater aspect of this research. The antifungal activity of the PN and M1N crystals was observed against two fungi such as Aspergillus flavus, Aspergillus niger.

Cis and trans isomers of 1-(5-bromothiophen-2-yl)-3-(10-chloroanthracen-9-yl)prop-2-en-1-one: Synthesis and characterization

Chalcone derivatives are simple chemical scaffold found in natural products and have been extensively used as an effective template in medicinal chemistry for drug discovery. Two new geometrical isomers of 1-(5-bromothiophen-2-yl)-3-(10-chloroanthracen-9-yl)prop-2-en-1-one were synthesized, isolated and characterized by various spectroscopic techniques (FT-IR, NMR, LC-MS and UV-visible). Two different shaped (cis and trans) yellow colored single crystals were obtained by slow evaporation method and the molecular structures were confirmed by X-ray diffraction studies. The cis configuration crystallizes in the monoclinic P21/c space group, whereas, trans configuration crystallizes in the orthorhombic P212121 space group. The conformational changes lead to variations in molecular packing arrangement. In cis, 2-D layer-like architecture is constructed by C-H…O and S…S contacts, whereas, in trans 3-D zig-zag pattern is generated by C-H…O, C-H…Cl and Br…π interactions. The unique supramolecular topology of the isomers established by diverse intra and intermolecular interactions was analysed by Hirshfeld surfaces, 2D fingerprint plots, 3D energy framework and NCI index model. The Frontier molecular orbitals explored HOMO-LUMO energy gap and associated electronic properties were calculated. The molecular electrostatic potential (MEP) was plotted to identify the reactive sites in the molecule.

Structure, thermal stability and electrical properties of cellulose‐6‐phosphate: development of a novel fast Na‐ionic conductor

AbstractIn this study, alkali cellulose‐6‐phosphate (A‐CP) was prepared by the treatment of cellulose‐6‐phosphate (CP) with an aqueous solution of sodium hydroxide. X‐ray diffraction and Fourier transform infrared, 13C NMR, 31P NMR and 23Na NMR spectroscopies were used to characterize the studied polymers. CP and A‐CP crystallize in the monoclinic system of the P21 space group (cellulose Iβ). CP and A‐CP, with relative densities of 70% and 77%, respectively, were shaped into cylindrical pellets by uniaxial pressing and sintering at 423 K of A‐CP. Electrical conductivity measurements of CP and A‐CP were carried out using complex impedance spectroscopy between 298 and 433 K in the frequency range 5 Hz to 13 MHz. The influence of aqueous NaOH on the structure, thermal stability and electrical conductivity of cellulose phosphate was observed. In contrast to CP, A‐CP was stable up to temperatures exceeding 433 K and showed fast ionic conductivity σ393K = 2.03 × 10−6 S cm−1 with an activation energy of 0.73 eV. © 2021 Society of Chemical Industry

Purification and Crystallographic Analysis of a Novel Cold-Active Esterase (HaEst1) from Halocynthiibacter arcticus

This report deals with the purification, characterization, and a preliminary crystallographic study of a novel cold-active esterase (HaEst1) from Halocynthiibacter arcticus. Primary sequence analysis reveals that HaEst1 has a catalytic serine in G-x-S-x-G motif. The recombinant HaEst1 was cloned, expressed, and purified. SDS-PAGE and zymographic analysis were carried out to characterize the properties of HaEst1. A single crystal of HaEst1 was obtained in a solution containing 10% (w/v) PEG 8000/8% ethylene glycol, 0.1 M Hepes-NaOH, pH 7.5. Diffraction data were collected to 2.10 Å resolution with P21 space group. The final Rmerge and Rp.i.m values were 7.6% and 3.5% for 50–2.10 Å resolution. The unit cell parameters were a = 35.69 Å, b = 91.21 Å, c = 79.15 Å, and β = 96.9°.

Substituent-Mediated Transformation of Polynuclear Gold(I)-Sulfido Complexes—From Pentanuclear to Octadecanuclear Cluster-to-Cluster Transformation

Substituent-Mediated Transformation of Polynuclear Gold(I)-Sulfido Complexes—From Pentanuclear to Octadecanuclear Cluster-to-Cluster Transformation