Orthorhombic Space Group Research Articles

Synthesis and structural characterization of new perovskite phases, Ba2Bi0.572TeO6± δ and SrLa2NiFeNbO9

Ba2Bi0.572TeO6± δ and SrLa2NiFeNbO9 ceramics were prepared in polycrystalline form by conventional solid-state reaction techniques in air. The crystal structures of the title compounds were determined at room temperature from X-ray powder diffraction (XRPD) data using the Rietveld method. The Ba2Bi0.572TeO6± δ structure crystallizes in a triclinic space group I–1 with unit-cell parameters a = 6.0272(2) Å, b = 6.0367(1) Å, c = 8.5273(3) Å, α = 90.007(7)°, β = 90.061(2)°, and γ = 90.015(4)°. The tilt system of the BiO6 and TeO6 octahedra corresponds to the notation a–b–c–. The crystal structure of the SrLa2NiFeNbO9 compound adopts an orthorhombic Pbnm space group with lattice parameters a = 5.6038(5) Å, b = 5.5988(4) Å, and c = 7.9124(6) Å. The BO6 octahedra (B = Ni/Fe/Nb) sharing the corners in 3D. Along the c-axis, the octahedra are connected by O(1) atoms of (x,y,1/4) positions; while in the ab-plane, they are linked by O(2) atoms of (x,y,z) positions. The bond angle of B–O1–B is 168.7° and that of B–O2–B is 156.3°. The octahedral lattice corresponds to the tilt pattern a–a–c+; it indicates that the octahedra tilt out-of-phase along the a,b-axes and in phase along the c-axis.

RE(HSeO3)(SeO3)(H2O)·(H2O) (RE = Y, Gd): Two Rare-Earth Selenite Nonlinear Optical Crystals with Wide Band Gaps.

The band gap is one of the significant parameters for nonlinear optical (NLO) materials, which is the key factor in their application band in laser technology. This study reports the synthesis of two rare-earth selenite NLO crystals, namely, RE(HSeO3)(SeO3)(H2O)·(H2O) (RE = Y, Gd), utilizing the hydrothermal technique. The two compounds are isostructural, and both belong to the orthorhombic chiral space group of P212121 and possess three-dimensional structures consisting of two-dimensional rare-earth selenite layers connected by hydrogen bonds (O-H··O). These two compounds exhibit a moderate second harmonic generation intensity of 0.5/0.8 × KDP and wide energy band gaps reaching 4.8 eV. Comprehensive density functional theory analyses based on first-principles were carried out to unravel the relationship between the structural and corresponding properties. This work provides an approach for band gap enlargement in rare-earth selenite systems and is beneficial to the design of future NLO materials.

Single-crystal structure, Hirshfeld surface and DFT analyses of chrysomycin A, a marine microbe-derived promising agent for anticancer and antimicrobial therapy

Chrysomycin A (CA) is an important Streptomyces-derived aromatic polyketide with therapeutic potential for treatment of cancer and bacterial infections. In order to prepare highly pure CA for new drug development, a simple and effective strategy to crystallize CA was firstly developed by the liquid phase diffusion method in this work. The single-crystal structure of CA and its Hirshfeld surface property analyses showed that the asymmetric unit of CA crystal consists of one CA molecule and a water in the orthorhombic space group P212121 and it has π-π interactions between benzene rings. CA crystal stacking is consolidated by three intermolecular hydrogen bonds including carbonyl/keto-C-O···H(water), naphthalene-C-O···H(water) and glycoside-O-H···O(water) and van der Waals forces. Furthermore, the HOMO-LUMO energy gap, UV-vis spectral parameters, electrostatic potential, mullliken charge and nonlinear optical properties analyzed in DFT calculations. These results pave a fundamental way for the production of CA using the feasible crystallization approach and the study of molecular mechanisms of action (MoA).

Structural, spectral characterization and dielectric properties of azidopentamminecobalt(III) complex salts containing SiF62‒ and IO3‒ anions

In the present work, two new cobalt(III) complex salts [Co(NH3)5N3]SiF6∙2H2O (1) and [Co(NH3)5N3]IO3.Cl.H2O (2) were synthesised. The crystals were grown by the slow evaporation solution technique at room temperature, and their structure was determined by means of single crystal X-ray diffraction studies. Complex salt (1) crystalizes in orthorhombic P212121 space group, with cell parameters a = 8.8969(9) (Å), b = 10.0689(10) (Å), and c = 14.1254(14) (Å). Complex salt (2) crystalizes in triclinic P-1 space group with cell parameters a = 6.8220(9) (Å), b = 7.1709(9) (Å), and c = 12.8742(15) (Å). The band gap values for (1) and (2) have been calculated using Tauc's method, yielding values of 1.72 eV for (1) and 2.51eV for (2). Furthermore, the dielectric constant properties of [Co(NH3)5N3]SiF6∙2H2O (1) and [Co(NH3)5N3]IO3.Cl.H2O (2) have also been studied, and results indicate the high conduction nature of [Co(NH3)5N3]SiF6∙2H2O (1) .

Synthesis, Structural, Spectroscopic (NMR, FT-IR and UV-vis), NLO, in silico (ADMET and Molecular Docking) and DFT Investigations of a Flavonol Derivative 2-(4-chlorophenyl)-7-fluoro-3-hydroxy-4H-chromen-4-one

The geometric, spectroscopic and electronic features of the newly synthesized 3-Hydroxy-2-(4-chlorophenyl)-7-fluoro-4H-chromen-4-one have been analyzed using a combination of single crystal XRD, FT-IR, NMR shifts, and UV-Vis. spectroscopic methods both experimentally and theoretically. The molecule has crystallized in orthorhombic space group Pca21 and it has stabilized with C-H···O, O-H···O intra-molecular and O-H···O inter-molecular interactions. The geometric parameters (bond lengths and bond angles), vibrational wavenumbers, 1H and 13C NMR chemical shifts, UV-Vis. electronic transitions, the HOMO (highest occupied molecular orbital) and the LUMO (lowest unoccupied molecular orbital) analyses, NLO (non-linear optical properties) and the MEP (molecular electrostatic potential) surface have been computed by using the DFT/B3LYP quantum chemical method with 6-311++G(d,p) level of theory to compare with the experimental findings. Absorption bands of the molecule have computed around 300 and 360 nm, while observed at 244, 312 and 344 nm in the experimental UV-Vis. spectrum. Moreover, the mean polarizability value of the compound has been calculated 6.47 times greater than urea. The objective of the in silico investigation was to ascertain the biological effect profile of the title compound. The ADMETlab 2.0 web service has been employed to analyze the physicochemical, medicinal chemistry, metabolism, distribution, absorption, excretion and toxicity features of the compound. Its protein kinase CK2 inhibitory activity for the target macromolecule 5M4U has been investigated by means of a molecular docking study to investigate the anti-cancer activity of our flavonol derivative compound.

Synthesis and Characterization of Air‐Stable Palladium(II) and Copper(I) Ph‐Garphos Complexes and their Applications to Asymmetric Catalysis

AbstractAir‐stable palladium(II) and copper(I) complexes containing the 4,4′,6,6′‐tetramethoxybiphenyl‐2,2′‐diyl)bis(diphenylphosphine) ligands, (R)‐Ph‐Garphos ((R)‐L1) and ((S)‐Ph‐Garphos ((S)‐L1), were synthesized and characterized by 1H‐, 13C‐, and 31P{1H} NMR spectroscopy and elemental analyses. The PdCl2((R)‐Ph‐Garphos) ((R)‐1) and PdCl2((S)‐Ph‐Garphos) ((S)‐1) complexes were assessed for the Suzuki‐Miyaura cross‐coupling of aryl halides with phenylboronic acid under ambient conditions, or naphthyl substrates under reflux. X‐ray crystal structures of the copper complexes revealed that [Cu((R)‐Ph‐Garphos)I] ((R)‐2) crystallized as a three‐coordinate monomer in the orthorhombic space group P212121 whereas [Cu((S)‐Ph‐Garphos)I] ((S)‐2) crystallized as a tetrahedral (μ‐I) dimer in the same crystal system. The synthesis of the analogous [Cu((R)‐Ph‐Garphos)OAc] ((R)‐3) is also described. Complexes (R)‐2 and (R)‐3 were evaluated for the asymmetric hydrosilylation of ketones wherein enantioselectivities of up to 83 % ee were achieved.

Tuning structural modulation and magnetic properties in metal-organic coordination polymers [CH3NH3]CoxNi1-x(HCOO)3.

Three solid solutions of [CH3NH3]CoxNi1-x(HCOO)3, with x = 0.25 (1), x = 0.50 (2) and x = 0.75 (3), were synthesized and their nuclear structures and magnetic properties were characterized using single-crystal neutron diffraction and magnetization measurements. At room temperature, all three compounds crystallize in the Pnma orthorhombic space group, akin to the cobalt and nickel end series members. On cooling, each compound undergoes a distinct series of structural transitions to modulated structures. Compound 1 exhibits a phase transition to a modulated structure analogous to the pure Ni compound [Cañadillas-Delgado, L., Mazzuca, L., Fabelo, O., Rodríguez-Carvajal, J. & Petricek, V. (2020). Inorg. Chem. 59, 17896-17905], whereas compound 3 maintains the behaviour observed in the pure Co compound reported previously [Canadillas-Delgado, L., Mazzuca, L., Fabelo, O., Rodriguez-Velamazan, J. A. & Rodriguez-Carvajal, J. (2019). IUCrJ, 6, 105-115], although in both cases the temperatures at which the phase transitions occur differ slightly from the pure phases. Monochromatic neutron diffraction measurements showed that the structural evolution of 2 diverges from that of either parent compound, with competing hydrogen bond interactions that drive the modulation throughout the series, producing a unique sequence of phases. It involves two modulated phases below 96 (3) and 59 (3) K, with different q vectors, similar to the pure Co compound (with modulated phases below 128 and 96 K); however, it maintains the modulated phase below magnetic order [at 22.5 (7) K], resembling the pure Ni compound (which presents magnetic order below 34 K), resulting in an improper modulated magnetic structure. Despite these large-scale structural changes, magnetometry data reveal that the bulk magnetic properties of these solid solutions form a linear continuum between the end members. Notably, doping of the metal site in these solid solutions allows for tuning of bulk magnetic properties, including magnetic ordering temperature, transition temperatures and the nature of nuclear phase transitions, through adjustment of metal ratios.

Potassium- and Lithium-Ammonia Intercalation into Excitonic Insulator Candidate Ta2NiSe5.

Two new reduced phases derived from the topical excitonic insulator candidate Ta2NiSe5 have been synthesized via the intercalation of lithium and potassium from solutions of the metals in liquid ammonia. Li(NH3)Ta2NiSe5 and KTa2NiSe5 both crystallize in orthorhombic space group Pmnb with the following lattice parameters: a = 3.5175(1) Å, b = 18.7828(7) Å, and c = 15.7520(3) Å and a = 3.50247(3) Å, b = 13.4053(4) Å, and c = 15.7396(2) Å, respectively. They have increased unit cell volumes of 48% and 31%, respectively, relative to that of Ta2NiSe5. Significant rearrangement of the transition metal selenide layers is observed in both intercalates compared to the parent phase. In Li(NH3)Ta2NiSe5, neutron diffraction experiments confirm the location of the light Li, N, and H atoms, and solid-state nuclear magnetic resonance (NMR) experiments show that H, N, and Li each occupy a single environment at ambient temperature on the NMR time scale. Magnetometry data show that both intercalates have increased magnetic susceptibilities relative to that of Ta2NiSe5, consistent with the injection of electrons during intercalation and an enhancement of the Pauli paramagnetism.

Protein expression, purification, crystallization and crystallographic studies of BPSL0741 from Burkholderia pseudomallei.

Burkholderia pseudomallei is the causative agent of the lethal disease melioidosis. This bacterium infects animals and humans and is increasingly resistant to multiple antibiotics. Recently, genes associated with survival of the bacterium in the infected host have been identified. One of these genes, bpsl0741, is annotated as a hypothetical protein of 185 amino acids. Here, recombinant BPSL0741 (rBPSL0741) protein was expressed, purified, verified by mass spectrometry, crystallized and analyzed by X-ray diffraction. rBPSL0741 was crystallized by vapor diffusion using a reservoir solution consisting of 0.2 M ammonium acetate, 0.1 M sodium acetate trihydrate pH 4.6, 30% PEG 4000. The crystals diffracted to 2.1 Å resolution using an in-house X-ray diffractometer and belonged to an orthorhombic space group, with unit-cell parameters a = 62.92, b = 64.57, c=89.16 Å. The Matthews coefficient (VM) was calculated to be 2.18 Å3 Da-1, suggesting the presence of two molecules per asymmetric unit and an estimated solvent content of 43.5%. The crystal was deemed to be suitable for further structural studies, which are currently ongoing.

Crystal structures and properties of derivatives of the alkaloid matrine: salts and hydrate forms.

We report the crystal structures of three matrine derivatives, namely, the salts (1R,2R,9S,17S)-6-oxo-7,13-diazatetracyclo[7.7.1.02,7.013,17]heptadecan-13-ium (2E)-3-(3,4-dihydroxyphenyl)prop-2-enoate (matrine caffeinate) sesquihydrate, C15H25N2O+·C9H7O4-·1.5H2O (Matrine-CA), and the 2-hydroxybenzoate (salicylate) monohydrate, C15H25N2O+·C7H5O3-·H2O (Matrine-SA), as well as the 1.75-hydrate form, (1R,2R,9S,17S)-7,13-diazatetracyclo[7.7.1.02,7.013,17]heptadecan-6-one 1.75-hydrate, C15H24N2O·1.75H2O (Matrine-H). Each derivative exhibited a consistent molecular conformation for the matrine core, which is notably distinct from that of the anhydrous form. Notably, both salts crystallized in the orthorhombic space group P212121, with an asymmetric unit featuring one cation and one anion. Within the two salt structures, intermolecular proton transfer between matrine and the acid is observed, culminating in the formation of a matrine cation protonated at the tertiary amine N site. The Matrine-CA crystal packing is manifested as a three-dimensional (3D) network arising from one-dimensional (1D) supramolecular helical chains, stabilized by N-H...O and O-H...O hydrogen bonds. In the case of Matrine-SA, the matrine cation is interconnected via hydrogen bonds with salicylate anions and water molecules, also forming a 1D helical motif. The structure of the hydrate form, Matrine-H, is reported again with the disordered solvent molecules accurately located. To further elucidate the structural attributes, Hirshfeld surface analysis and fingerprint plots are employed, offering a nuanced perspective on the intermolecular contacts and interactions within these crystalline forms.

Er3+ doped BZBO single crystal: Growth and electro-elastic property characterization

Large-sized and high-quality Er: Bi2ZnB2O7 (Er: BZBO) single crystal has been grown using the Kyropoulos method. The crystal structure is refined by the Rietveld method, Er: BZBO belongs to the orthorhombic system and space group Pba2, lattice parameters: a = 10.811(1) Å, b = 11.006(1) Å, c = 4.8817(4) Å, which are slightly reduced after doping with Er3+. The thermal expansion anisotropy is studied and shows a decrease with coefficients of α11 = 7.69(1) × 10−6 K−1, α22 = 9.90(9) × 10−6 K−1, and α33 = 1.98(8) × 10−6 K−1, respectively. The relative dielectric constants are found to be εT11/ε0 = 32.8(1), εT22/ε0 = 17.2(1), and εT33/ε0 = 17.0(9), respectively. The dielectric, elastic, and piezoelectric constants for the Er: BZBO crystal are determined by the impedance method, with the piezoelectric coefficients d15, d24, d31, d32 and d33 are measured as 1.1(9), −5.4(2), 1.8(7), −5.9(1) and 1.1(5) pC/N, respectively. Furthermore, the temperature dependence of the piezoelectric coefficients from room temperature to 500 °C is evaluated, showing good temperature stability for d24 and d32 with variations were −7 % and 13 %, respectively.

Crystal growth, characterization and sensing studies of a new metal-organic framework of Sr(II) with phenylmalonic acid

A new metal-organic framework of Sr(II) with phenylmalonic acid, {[Sr(PMA)(H2O)].H2O}n (SPMA) has been prepared by gel diffusion technique. SXRD data show that the crystal belongs to the orthorhombic space group Pbca. In the crystal structure, the phenylmalonate ligand adopts monodentate, bis-monodentate and bidentate coordination modes with the Sr(II) ions. The Sr-phenylmalonate units extend three dimensionally forming a network structure. Intermolecular hydrogen bonding further stabilizes the crystal system. The compound exhibits strong luminescence emission at 290 nm upon excitation at 240 nm. Sensing property of the title compound towards Fe3+ ion is also investigated.

Hydroflux Synthesis and Structural Phase Transition of Rare-Earth Borate Hydroxides Na2[RE(BO3)(OH)2] (RE = Y, Gd-Er).

Reacting RE2O3 and H3BO3 in an ultra-alkaline NaOH hydroflux at about 250 °C yielded pure, crystalline samples of Na2[RE(BO3)(OH)2] (RE = Y, Gd-Er). The compounds dehydrate to Na3RE(BO3)2 upon heating in air to about 500 °C. Na2[RE(BO3)(OH)2] (RE = Tb-Er) are photoluminescent under UV radiation. Their UV-Vis spectra show the typical absorptions associated with 4f-4f transitions and absorption edges in the UV (band gaps ≥ 5.7 eV). The RE3+ cation is coordinated by seven oxygen atoms, which define a distorted pentagonal bipyramid. The bipyramids share trans-edges of their base forming infinite chains. Triangular (BO3)3- groups connect the chains into layers. The crystal structure of Na2[Ho(BO3)(OH)2] was investigated at various temperatures in the range 100 K ≤ T ≤ 320 K. Above 310(2) K, the compound crystallizes in the orthorhombic space group Cmcm (β-phase), below, it undergoes a displacive phase transition of second order resulting in a monoclinic structure in space group C2/c (α-phase). The critical exponents derived from different structural parameters indicate a cooperative distortion of the borate layers, but a rather uncorrelated adaptation of the sodium cations to their local environment. The other compounds of the series also adopt the structure of the α-phase at 296 K.

Investigations of structure, thermal stability and optical properties of a new NLO crystal (C3H5N2)+(CF3COO)-

New NLO imidazolium trifluoro acetate (C3H5N2)+(CF3COO)- single crystals were synthesized by solution evaporation method, with its structure, thermal stability, absorption spectrum, photoluminescence and second order nonlinear optical (NLO) properties were systematically investigated. This crystal features 0-dimensional noncentrosymmetric structure with orthorhombic space group I212121 which consist of isolated organic imidazolium cation (C3H5N2)+ and trifluoro acetate anion (CF3CO2)-. A high thermal stability up to 125 °C, and the absorption edge at 260 nm with a wide band gap of 4.55 eV were respectively determined. In addition, the photoluminescence performance with an emission peak at 363 nm can be ascribed to the π-π* transition absorption of imidazole ring. Notably, moderate phase-matching SHG response of 0.64 times KH2PO4 was evaluated for (C3H5N2)+(CF3COO)-. All the results indicate the potential applications of (C3H5N2)+(CF3COO)- in optical field.

Emergent symmetry in TbTe3revealed by ultrafast reflectivity under anisotropic strain.

We report ultrafast reflectivity measurements of the dynamics of the order parameter of the charge density wave (CDW) in TbTe3under anisotropic strain. We observe an increase in the frequency of the amplitude mode with increasing tensile strain along thea-axis (which drives the lattice intoa > c, withaandcthe lattice constants), and similar behavior for tensile strain alongc(c > a). This suggests that both strains stabilize the corresponding CDW order and further support the near equivalence of the CDW phases oriented ina- andc-axis, in spite of the orthorhombic space group. The results were analyzed within the time-dependent Ginzburg-Landau framework, which agrees well with the reflectivity dynamics. Our study presents an ultrafast approach to assess the stability of phases and order parameter dynamics in strained systems.

Crystal structures, phase transition, and Hirshfeld surface analyses of the bromide and chloride congeners of aqua[2,4,6-tris(pyridin-4-yl)-1,3,5-triazine]zinc(II) halide.

During the course of exploring crystallization conditions in generating metal-organic frameworks (MOFs) for use in the crystalline sponge method, two discrete metal-organic complexes, namely, aqua[2,4,6-tris(pyridin-4-yl)-1,3,5-triazine]zinc(II) bromide, [Zn(C18H12N6)(H2O)]Br2, and aqua[2,4,6-tris(pyridin-4-yl)-1,3,5-triazine]zinc(II) chloride, [Zn(C18H12N6)(H2O)]Cl2, were encountered. Structures in the orthorhombic space group Pnma (No. 62) for the bromide congener at 299 K and the chloride congener at 100 K were obtained. A phase transition for the bromide congener occurred upon cooling from 299 to 100 K, yielding a crystal polymorph with four domains that exhibits monoclinic P21/m space-group symmetry (No. 11), which arises from conformational changes. The main intramolecular contacts that contribute to the crystal packing in all observed structures are H...H, Halide...H/H...Halide, C...H/H...C, and N...H/H...N. Intramolecular hydrogen bonding between the Zn-bound water and non-Zn-bound pyridyl N atoms is a prominent feature within the three-dimensional networks. Aromatic π-stacking between the non-Zn-bound pyridine rings and contacts involving the halide ligands further stabilize the crystal packing.

Pressure induced structural and electronic band transition in CsPbBr3

Cesium lead bromide (CsPbBr3) is a prominent halide perovskite with extensive optoelectronic applications. In this study, we report the pressure modulation of CsPbBr3’s crystal structure and electronic properties at room temperature up to 5 GPa. We have observed a crystal structure transition from the orthorhombic Pnma space group to a new monoclinic phase in the space group P21/c at 2.08 GPa. The structure is associated with ~8% of density jump across the transition boundary. DFT calculations have suggested that the structure transition leads to a change in the electronic band structure, and there is an emergent indirect bandgap at the Pnma-P21/c phase transition boundary at 2.08 GPa. Across the transition boundary, the electronic band gap of CsPbBr3 increased from 2.07 eV to 2.38 eV, which explains its pressure-induced color change. Our study demonstrates the importance of using in-situ crystal structure in the electronic band structure calculations in halide perovskites.

Crystal structure, optical properties, Hirshfeld surface analysis and bactericidal activity of a new organic-inorganic hybrid: 4-methyl-1-(2'-nitrobenzyl)pyridinium tetrabromocuprate(II)

In this work, an organic-inorganic hybrid crystal with excellent bactericidal activity, 4-methyl-1-(2'-nitrobenzyl)pyridinium tetrabromocuprate(II) ([4Me2NO2BzPy]2[CuBr4]), was synthesized by the crystal growth by a slow evaporation method and characterized. [4Me2NO2BzPy]2[CuBr4] crystallized in the orthorhombic space group Pna21. Hirshfeld surface analysis indicated that the H···H (28.8%), H···Br/Br···H (27.0%), and O···H/H···O (17.5%) interatomic contacts played a primary role in contributing to the stacking of the crystals. Thermogravimetric analysis showed that the material was stable up to 192.5 °C. The charge transfer interaction between anions and cations was explained by UV-Vis diffuse reflectance spectroscopy. [4Me2NO2BzPy]2[CuBr4] exhibited favorable bactericidal activity against Staphylococcus aureus and Escherichia coli.

Surface‐Modified Mesoporous V2‐xSb2xO5‐δ Ceramics for Improving the Electrostatic Chemisorption of Methylene Blue

AbstractHerein, mesoporous V2‐xSb2xO5‐δ (Sb−V−O) compounds, encompassing a compositional range of x varying between, 0.05≤x≤0.08, with orthorhombic Pmmn space group symmetry, are synthesized by high‐temperature solid‐state reaction method. Scanning electron microscopy indicated the formation of microscale rods and flakes and EDS spectra affirmed the stoichiometric precision of their composition adhering to the formulated chemical formula. Nitrogen adsorption isotherms exhibited the distinctive type IV pattern, accompanied by an H3 hysteresis loop, signifying the formation of mesoporous micro rods and flakes. Brunauer‐Emmett‐Teller measurements demonstrated an augmented surface area, ranging from 16.67–28.74 m2/g, mirroring the effect of the increase in the concentration of Sb cations. The study demonstrated complete Methylene Blue dye removal within a brief 90 minute period, highlighting its efficacy in water remediation. The adsorption kinetics was aptly described by the pseudo‐second‐order model which exhibited a high degree of fit (R2=0.99). Freundlich adsorption isotherm was used to describe the multilayer adsorption of MB dye on the Sb−V−O surface indicating an exponential increase in adsorption active sites. Enhanced cationic MB dye adsorption on negative Sb−V−O surface is attributed to the electrostatic chemisorption by the interaction of NMe2+ on the negative surface modified Sb−V−O compounds.

Analogous Chain Selenite Chlorides Ba2M(SeO3)2Cl2 (M = Cu2+, Ni2+, Co2+, Mn2+) and Pb2Cu(SeO3)2Cl2 with Tunable Spin S: Syntheses and Characterizations.

A series of analogous chain selenite chlorides Ba2M(SeO3)2Cl2 (M = Cu 1, Ni 2, Co 3, Mn 4) and Pb2Cu(SeO3)2Cl2 5 with tunable spin S from S = 1/2 to S = 5/2 have been hydrothermally synthesized and characterized. These analogues crystallized in the orthorhombic Pnnm space group (monoclinic P21/n space group for 5) all containing M2+-SeO3-M2+ spin chains, which are further separated by the Ba2+ ions (Pb2+ for 5). The magnetic susceptibility results of 1, 2, and 5 show broad maxima around 80.0, 18.9, and 78.0 K, respectively, indicating good one-dimensional (1D) magnetism. Meanwhile, no long-range order (LRO) is observed down to 2 K for both 1 and 5, while the isostructural compounds 2, 3, and 4 exhibit LRO at 3.4 K, 10.8 K, and 5.7 K, respectively, which are further confirmed by the heat capacity and electron spin resonance results, as well as the observed spin-flop transitions in the M-H curves measured at 2 K below TN. The magnetizations of 1-5 at 7 T are still far from saturation. In addition, thermal stability and FT-IR and UV-vis-NIR spectroscopy of 1-5 are reported.