A symmetry-oriented crystal structure prediction method for crystals with rigid bodies.

We have developed an efficient crystal structure prediction (CSP) method for desired chemical compositions, specifically suited for compounds featuring recurring molecules or rigid bodies. We applied this method to two metal chalcogenides: LiPSand NaGeSe, treating PSas a tetrahedral rigid body and GeSeas an ethane-like dimer rigid body. Initial trials not only identified the experimentally observed structures of these compounds but also uncovered several novel phases, including a new stannite-type LiPSstructure and a potential stable structure for NaGeSethat exhibits significantly lower energy than the observed phase, as evaluated by density functional theory calculations.

C-H amination chemistry mediated by trinuclear Cu(I) sites supported by a ligand scaffold featuring an arene platform and tetramethylguanidinyl residues.

Tripodal ligands that can encapsulate single or multiple metal sites in -symmetric geometric configurations constitute valuable targets for novel catalysts. Of particular interest in ligand development are efforts toward incorporating apical elements that exhibit little if any electron donicity, to enhance the electrophilic nature of a positioned active oxidant (, metal-oxo, -nitrene). The tripodal ligand TMGtrphen-Arene has been synthesized, featuring an arene platform 1,3,5-substituted with phenylene arms possessing tetramethylguanidinyl (TMG) residues.

Interpenetrated Lattices of Quaternary Chalcogenides Displaying Magnetic Frustration, High Na-Ion Conductivity, and Cation Redox in Na-Ion Batteries.

A series of quaternary selenides, NaGaSe ( = Mn, Fe, and mixed Zn/Fe), have been synthesized for the first time employing a high-temperature solid-state synthesis route through stochiometric or polychalcogenide flux reactions. Along with the selenides, a previously reported sulfide analogue, NaFeGaS, is also revisited with new findings. These compounds form an interpenetrated structure made up of a supertetrahedral unit.

On-Demand MXene-Coupled Pyroelectricity for Advanced Breathing Sensors and IR Data Receivers.

MXene-inspired two-dimensional (2D) materials like TiCT are widely known for their versatile properties, including surface plasmon, higher electrical conductivity, exceptional in-plane tensile strength, EMI shielding, and IR thermal properties. The MXene nanosheets coupled poly(vinylidene fluoride) (PVDF) nanofibers with ∼-26 pm V are able to capture the smaller thermal fluctuation due to a superior pyroelectric coefficient of ∼130 nC m K with an improved (∼7 times with respect to neat PVDF nanofibers) pyroelectric current figure of merit (FOM). The significant enhancement of the pyroelectric response is attributed to the confinement effect of 2D MXene (TiCT) nanosheets within PVDF nanofibers, as evidenced from polarized Fourier transform infrared (FTIR) spectroscopy and scanning probe microscopy (SPM).

A Comparative Study of Cationic Copper(I) Reagents Supported by Bipodal Tetramethylguanidinyl-Containing Ligands as Nitrene-Transfer Catalysts.

The bipodal compounds [(TMGbiphen)Cu-NCMe](PF) (R = Me, Ar (4-CFPh-)) and [(TMGbiphen)Cu-I] have been synthesized with ligands that feature a diarylmethyl- and triaryl-amine framework and superbasic tetramethylguanidinyl residues (TMG). The cationic Cu(I) sites mediate catalytic nitrene-transfer reactions between the imidoiodinane PhI = NTs (Ts = tosyl) and a panel of styrenes in MeCN, to afford aziridines, demonstrating comparable reactivity profiles. The copper reagents have been further explored to execute C-H amination reactions with a variety of aliphatic and aromatic hydrocarbons and two distinct nitrene sources PhI = NTs and PhI = NTces (Tces = 2,2,2-trichloroethylsulfamate) in benzene/HFIP (10:2 v/v).

Cationic Divalent Metal Sites (M = Mn, Fe, Co) Operating as Both Nitrene-Transfer Agents and Lewis Acids toward Mediating the Synthesis of Three- and Five-Membered -Heterocycles.

The tripodal compounds [(TMGtrphen)M-solv](PF) (M = Mn, Fe, Co; solv = MeCN, DMF) and bipodal analogues [(TMGbiphen)M(NCMe)](PF) ( = 3 for Mn, Fe; = 2 for Co) and [(TMGbiphen)MCl] have been synthesized with ligands that feature a triaryl- or diarylmethyl-amine framework and superbasic tetramethylguanidinyl residues (TMG). The dicationic M(II) sites mediate catalytic nitrene-transfer reactions between the imidoiodinane PhI═NTs (Ts = tosyl) and a panel of styrenes in MeCN to afford aziridines and low yields of imidazolines (upon MeCN insertion) with an order of productivity that favors the bipodal over the tripodal reagents and a metal preference of Fe > Co ≥ Mn. In CHCl, the more acidic Fe(II) sites favor formation of 2,4-diaryl--tosylpyrrolidines by means of an in situ (3 + 2) cycloaddition of the initially generated 2-aryl--tosylaziridine with residual styrene.

Lithium selenometallates of triel elements, LiMSe (M = Al and Ga), aliovalent doping and their ionic conductivity.

Ternary selenometallates, LiMSe (M = Al(I) and Ga(II)), have been synthesized for the first time through high temperature solid-state reactions combining elements and LiSe in stoichiometric compositions. LiMSe crystallizes in the 2/ space group, forming a pseudo-2D layer type structure with edge sharing LiSe and MSe tetrahedra along the -axis. These layers are interleaved by octahedrally coordinated Li ions located in the interlayer space.

Crystal structure, electronic structure, and optical properties of the novel LiCdGeS, a wide-bandgap quaternary sulfide with a polar structure derived from lonsdaleite.

The novel quaternary thiogermanate LiCdGeS (tetralithium cadmium digermanium heptasulfide) was discovered from a solid-state reaction at 750 °C. Single-crystal X-ray diffraction data were collected and used to solve and refine the structure. LiCdGeS is a member of the small, but growing, class of I-II-IV-VI diamond-like materials.

Is the Electrophilicity of the Metal Nitrene the Sole Predictor of Metal-Mediated Nitrene Transfer to Olefins? Secondary Contributing Factors as Revealed by a Library of High-Spin Co(II) Reagents.

Recent research has highlighted the key role played by the electron affinity of the active metal-nitrene/imido oxidant as the driving force in nitrene additions to olefins to afford valuable aziridines. The present work showcases a library of Co(II) reagents that, unlike the previously examined Mn(II) and Fe(II) analogues, demonstrate reactivity trends in olefin aziridinations that cannot be solely explained by the electron affinity criterion. A family of Co(II) catalysts (17 members) has been synthesized with the assistance of a trisphenylamido-amine scaffold decorated by various alkyl, aryl, and acyl groups attached to the equatorial amidos.

Discovery of an olivine-type lithium manganese thiophosphate, LiMnPS, a building block approach.

An olivine-type orthothiophospate LiMnPS has been synthesized for the first time through a building block approach by reacting preformed ternary lithium thiophospate with MnCl. Diffuse reflectance measurements show an optical band gap of 2.36 eV, which is further confirmed by DFT calculations.

Sodium-Stuffed Open-Framework Quaternary Chalcogenide Built with (CuGaS) Ribbons Cross-Linked by Unusual Linear Cu(I) Pillars.

A quaternary compound, NaCuGaS, the first member in the A-Cu-Ga-S (A = alkali metal) series, has been synthesized from a solid-state metathesis reaction between NaGaS and CuCl as well as from a combination of NaS, Ga, Cu, and S. The compound crystallizes in a monoclinic crystal system, space group 2/, and represents a unique open-framework structure with channels filled with eight crystallographically distinct Na ions. The anionic framework is built up of infinite chains of corner-shared GaS tetrahedra fused together by an edge-shared dimer of CuS tetrahedra forming one-dimensional ribbons of (CuGaS), which are cross-linked by linearly coordinated S-Cu-S linkages resulting in a three-dimensional network with tunnels filled with Na atoms.

Ternary alkali ion thiogallates, AGaS (A = Li and Na), with isolated tetrahedral building units and their ionic conductivities.

Two new ternary thiogallates in the A5GaS4 (A = Li (i) and Na (ii)) series have been synthesized for the first time employing a gas passing route using oxide precursors and a high temperature solid state route using stoichiometric combinations of elements, respectively. Li5GaS4 crystallizes in the P21/m space group and the structure is built up of layers of corner sharing tetrahedra of LiS4 and GaS4 stacked along the a-axis and the octahedrally coordinated Li ions residing in the interlayer space. Na5GaS4 crystallizes in the Pbca space group and the structure consists of isolated (GaS4)5- tetrahedra held together by charge balancing sodium ions in distorted tetrahedral and octahedral coordination geometries.

Interplay between Oxo and Fluoro in Vanadium Oxyfluorides for Centrosymmetric and Non-Centrosymmetric Structure Formation.

Herein, we report the syntheses of two lithium-vanadium oxide-fluoride compounds crystallized from the same reaction mixture through a time variation experiment. A low temperature hydrothermal route employing a viscous paste of VO, oxalic acid, LiF, and HF allowed the crystallization of one metastable phase initially, LiVO(HO)F⋅2HO (), which on prolonged heating transforms to a chemically similar yet structurally different phase, LiVOF (). Compound crystallizes in centrosymmetric space group, 2/ with = 6.

Soft chemical routes to electrochemically active iron phosphates.

New iron phosphates with related structures have been synthesized using hydrothermal and ion-exchange routes, and their electrochemical properties were investigated. First, NaFe(HPO) was synthesized employing a hydrothermal route and its structure was determined from single-crystal X-ray diffraction data. Subsequent Na and partial proton ion exchange with Li ion produced a known phase, LiFe(HPO), and complete deprotonation of LiFe(HPO) with Li by employing a solid-state ion-exchange route produced the new phase LiFe(PO).

A highly fluorinated lithium iron phosphate with interpenetrating lattices: electrochemistry and ionic conductivity.

LiFePOF, a new member of the family of alkali transition metal fluorophosphates, has been synthesized and characterized using single-crystal X-ray diffraction, Fe Mössbauer spectroscopy and magnetic susceptibility measurements. The existence of an infinite {-[PO(FeF)]-} tetrahedral network in an inter-penetrated diamond lattice, along with the presence of seven unique Li sites, presents interesting structural features of this structure-type for energy storage applications. The initial results of (de)lithiation reveal that a relatively low fraction of theoretical capacity may be utilized reversibly (0.

Magnetically Frustrated Quaternary Chalcogenides with Interpenetrating Diamond Lattices.

A series of quaternary sulfides of the composition NaMGaS (M = Mn (1), Fe (2), and Co (3)) have been synthesized in sealed quartz ampules. In these compounds, divalent transition metal and Ga occupy the same crystallographic site in the Ga-S network, forming a supertetrahedral, T2 (adamantane) unit, through the corner-sharing of four M/GaS tetrahedra. The corner sulfur atoms of the T2 clusters are further connected to similar T2 units to form an open continuous three-dimensional (3D) anionic framework of composition {[GaMS]}.

Tetragonal versus Hexagonal: Structure-Dependent Catalytic Activity of Co/Zn Bimetallic Metal-Organic Frameworks.

Tetragonal and hexagonal phases of monometallic Zn and bimetallic Co/Zn metal-organic frameworks (MOFs), with secondary building units (SBUs) containing a M3O (M = metal) cluster, were synthesized from identical constituents using a benzenetricarboxylate (BTC(3-)) linker that forms decorated 3,6- and 3,5-connected networks, respectively. There exist subtle differences between the SBUs; one of the metal atoms in the M3O cluster in the tetragonal phase has one dissociable DMF solvent molecule while that in the hexagonal phase has three. Connectivities between the SBUs form one-dimensional channels in both MOFs.

Employing Synergetic Effect of Doping and Thin Film Coating to Boost the Performance of Lithium-Ion Battery Cathode Particles.

Atomic layer deposition (ALD) has evolved as an important technique to coat conformal protective thin films on cathode and anode particles of lithium ion batteries to enhance their electrochemical performance. Coating a conformal, conductive and optimal ultrathin film on cathode particles has significantly increased the capacity retention and cycle life as demonstrated in our previous work. In this work, we have unearthed the synergetic effect of electrochemically active iron oxide films coating and partial doping of iron on LiMn1.

Metallic Ternary Telluride with Sphalerite Superstructure.

A new ternary compound with composition Cu5Sn2Te7 has been synthesized using the stoichiometric reaction of Cu, Sn, and Te. The compound crystallizes in C2 space group with unit cell parameters of a = 13.549(2) Å, b = 6.

Phosphite as Polyanion-Based Cathode for Li-Ion Battery: Synthesis, Structure, and Electrochemistry of LiFe(HPO3)2.

A new lithium containing iron(III) phosphite, LiFe(HPO3)2, has been synthesized via a solvent-free, low temperature, solid-state synthesis route. The crystal structure of this material has been determined employing single-crystal X-ray diffraction, which indicates that the compound has a three-dimensional structure formed by isolated FeO6 octahedral units joined together via bridging HPO3 pseudopyramidal moieties. This arrangement leads to the formation of channels along all the three crystallographic directions, where channels along the a- and b-axes host Li(+) ions.

Alkali-metal thiogermanates: sodium channels and variations on the La3CuSiS7 structure type.

Five new isotypic quaternary chalcogenides containing rare-earth metal atoms crystallizing in the hexagonal noncentrosymmetric space group P6(3) (No. 173) with the La(3)CuSiS(7) structure type have been synthesized by reacting the appropriate anhydrous rare-earth trichloride with sodium thiogermanate, Na(2)GeS(3). The reaction between LnCl(3) and Na(2)GeS(3) in an evacuated fused-silica ampule produced high yields of good-quality crystals of NaLn(3)GeS(7) [Ln = Ce (I), Nd (II), Sm (III), Gd (IV), and Yb (V)], while a similar reaction between EuCl(3) and Na(2)GeS(3) yielded a quinary chloride thiogermanate, Na(1.

A versatile tripodal Cu(I) reagent for C-N bond construction via nitrene-transfer chemistry: catalytic perspectives and mechanistic insights on C-H aminations/amidinations and olefin aziridinations.

A Cu(I) catalyst (1), supported by a framework of strongly basic guanidinato moieties, mediates nitrene-transfer from PhI═NR sources to a wide variety of aliphatic hydrocarbons (C-H amination or amidination in the presence of nitriles) and olefins (aziridination). Product profiles are consistent with a stepwise rather than concerted C-N bond formation. Mechanistic investigations with the aid of Hammett plots, kinetic isotope effects, labeled stereochemical probes, and radical traps and clocks allow us to conclude that carboradical intermediates play a major role and are generated by hydrogen-atom abstraction from substrate C-H bonds or initial nitrene-addition to one of the olefinic carbons.

Novel di-tertiary-butyl phenylhydrazones as dual cyclooxygenase-2/5-lipoxygenase inhibitors: synthesis, COX/LOX inhibition, molecular modeling, and insights into their cytotoxicities.

Although dual inhibition of Cyclooxygenase-2 (COX-2) and 5-Lipoxygenase (5-LOX) enzymes is highly effective than targeting COX or LOX alone, there are only a few reports of examining such compounds in case of colorectal cancers (CRC). In the present work we report that the novel di-tert-butyl phenol-based dual inhibitors DTPSAL, DTPBHZ, DTPINH, and DTPNHZ exhibit significant cytotoxicity against human CRC cell lines. Molecular docking studies revealed a good fit of these compounds in the COX-2 and 5-LOX protein cavities.

Targeting triple negative breast cancer cells by N3-substituted 9,10-phenanthrenequinone thiosemicarbazones and their metal complexes.

Novel N(3)-substituted 9,10-Phenanthrenequinone thiosemicarbazones and their copper, nickel and palladium complexes are structurally characterized and reported along with the single crystal X-ray structures of three ligands and one nickel complex. All compounds were evaluated for their antiproliferative potential against Triple Negative Breast Cancer (TNBC) cells which have poor prognosis and no effective drugs to treat with. All compounds exhibited antiproliferative activity against these cells.