High-Throughput Small-Molecule Crystallography at the ‘Belok’ Beamline of the Kurchatov Synchrotron Radiation Source: Transition Metal Complexes with Azomethine Ligands as a Case Study

Multiresponsive luminescent metal-organic framework for cooking oil adulteration detection and gallium(III) sensing

A new 3D metal-organic framework {[Cd16(tr2btd)10(dcdps)16(H2O)3(EtOH)]∙15DMF}n (MOF 1, tr2btd = 4,7-di(1,2,4-triazol-1-yl)benzo-2,1,3-thiadiazole, H2dcdps = 4,4'-sulfonyldibenzoic acid) was obtained and its luminescent properties were studied. MOF 1 exhibited bright blue-green luminescence with a high quantum yield of 74 % and luminescence quenching response to a toxic natural polyphenol gossypol and luminescence enhancement response to some trivalent metal cations (Fe3+, Cr3+, Al3+ and Ga3+). The limit of gossypol detection was 0.20 µM and the determination was not interfered by the components of the cottonseed oil. The limit of detection of gallium(III) was 1.1 µM. It was demonstrated that MOF 1 may be used for distinguishing between the genuine sunflower oil and oil adulterated by crude cottonseed oil through qualitative luminescent and quantitative visual gossypol determination.

Novel binuclear copper(II) complexes with sulfanylpyrazole ligands: synthesis, crystal structure, fungicidal, cytostatic, and cytotoxic activity

New binuclear copper(II) [Cu(II)] tetraligand complexes (six examples) with sulfanylpyrazole ligands were synthesized. Electron spin resonance (ESR) studies have shown that in solution the complexes are transformed to the mononuclear one. Fungicidal properties against Candida albicans were found for the Cu complexes with benzyl and phenyl substituents. An in vitro evaluation of the cytotoxic properties of Cu chelates against HEK293, Jurkat, MCF-7, and THP-1 cells identified the Cu complex with the cyclohexylsulfanyl substituent in the pyrazole core as the lead compound, whereas the Cu complex without a sulfur atom in the pyrazole ligand had virtually no cytotoxic or fungicidal activity. The lead Cu(II) complex was more active than cisplatin. Effect of the S-containing Cu complex on apoptosis and cell cycle distribution has been investigated as well.

Improving sensitivity of XANES structural fit to the bridged metal-metal coordination

Hard X-ray absorption spectroscopy is a valuable in situ probe for non-destructive diagnostics of metal sites. The low-energy interval of a spectrum (XANES) contains information about the metal oxidation state, ligand type, symmetry and distances in the first coordination shell but shows almost no dependency on the bridged metal-metal bond length. The higher-energy interval (EXAFS), on the contrary, is more sensitive to the coordination numbers and can decouple the contribution from distances in different coordination shells. Supervised machine-learning methods can combine information from different intervals of a spectrum; however, computational approaches for the near-edge region of the spectrum and higher energies are different. This work aims to keep all benefits of XANES and extend its sensitivity towards the interatomic distances in the first and second coordination shells. Using a binuclear bridged copper complex as a case study and cross-validation analysis as a quantitative tool it is shown that the first 170 eV above the edge are already sufficient to balance the contributions of Cu-O/N scattering and Cu-Cu scattering. As a more general outcome this work highlights the trivial but often overlooked importance of using `longer' energy intervals of XANES for structural refinement and machine-learning predictions. The first 200 eV above the absorption edge still do not require parametrization of Debye-Waller damping and can be calculated within full multiple scattering or finite difference approximations with only moderately increased computational costs.

Preparation, X-ray Characterization, and Reactivity of the Rod-like and Angular Germanium- and Titanium(IV)-Capped Iron(II) Bis-Clathrochelates and Their Mono- and Bis-Capped (Semi)clathrochelate Precursors

Transmetalation of the bis{triethylantimony(V)}-capped iron(II) tris-α-dioximate with n-butylboronic acid afforded the mixed antimony, boron cross-linked clathrochelate with single reactive antimony(V)-based apical fragment. This macrobicyclic precursor easily underwent the transmetalation reactions with germanium and titanium(IV) alkoxides to give the rod-like and angular FeII2MIV-trinuclear bis-clathrochelates. Those of the aforementioned diantimony(V)-capped complex with 3- and 4-carboxyphenylboronic acids afforded the monoboron-capped iron(II) semiclathrochelates, undergoing a double-cyclization (macrobicyclization) with germanium- and titanium(IV)-based capping agents. The reactions in the low-temperature range unexpectedly gave the stable 2:1 associates, formed by the bridging of two carboxyl-terminated macrobicyclic molecules of the mixed carboxylboron, triethylantimony-capped iron(II) clathrochelate with a triethylantimony(V)-based linker fragment. The obtained complexes were characterized using elemental analysis, MALDI-TOF, 1H and 13C{1H} NMR and UV-vis spectra, and single-crystal XRD experiments. The encapsulated iron(II) ion in their 3D-molecules is situated almost in the center of its FeN6-coordination polyhedron possessing a truncated trigonal-pyramidal geometry. Fe-N distances fall in the range 1.887(7)-1.945(4) Å characteristic of the low-spin iron(II) complexes. The cross-linking titanium and germanium(IV) ions in the corresponding bis-clathrochelate molecules form the octahedral MIVO6-coordination polyhedra, the MIV-O distances of which vary from 1.946(2) to 1.964(2) Å and from 1.879(7) to 1.907(6) Å, respectively.

Copper(II) coordination compounds based on bis-hydrazones of 2,6-diacetylpyridine: synthesis, structure, and cytotoxic activity

By reacting a series of 2,6-diacetylpyridine bis-hydrazones containing pyrimidine (H2L1), benzimidazole (H2L2) and phthalazine (H2L3) heterocyclic fragments with copper(II) chloride and bromide, a variety of pentacoordinated complexes of the composition [Cu(H2L1)X]X, [Cu(HL2)X] and [Cu(HL3)X], where X = Cl-, Br-, are formed. The properties and structure of the compounds were studied by means of NMR, IR, UV-vis, ESR, and X-ray absorption spectroscopy, cyclic voltammetry and X-Ray single crystal diffraction methods. It was shown that complexes of the cationic type [Cu(H2L1)X]X have an asymmetric structure with a distorted square-pyramidal geometry of the coordination unit. The coordination polyhedron of metal chelates [Cu(HL2)X] and [Cu(HL3)X] is an almost ideal square pyramid. Investigations of the cytotoxic activity of the obtained compounds in vitro on human hepatocellular carcinoma (HepG2) and non-tumor human lung fibroblast (MRC-5) cell lines demonstrated that complexes show higher activity compared with the well-known anticancer agent cisplatin. In addition, metal chelates [Cu(H2L1)Cl]Cl, [Cu(HL2)Cl], [Cu(HL2)Br] and [Cu(HL3)Cl] were less toxic to non-tumor cells MRC-5. A study of the binding of complexes to bovine serum albumin (BSA) protein using fluorescence spectroscopy showed that copper complexes are strongly bound to BSA. To study the mechanism of interaction of the complexes with the DNA of cancer cells, molecular dynamics simulation of the compound [Cu(HL3)Cl] was carried out. It was shown that the complex enters into π-stacking interactions predominantly with adenine and thymine bases.

Enhancement of intermolecular aggregation on solvent-influenced strong hydrogen-bonded single crystal

The intermolecular aggregation between the solvent and organic molecules is covered in the current article. 4,4'-(Buta-1,3-diyne-1,4-diyl)dibenzoic acid (DADBA) was used as an organic molecule and dimethyl sulfoxide (DMSO) as a solvent to create the target compound DADBA-DMSO. The material's hydrogen bonding and intermolecular aggregation were determined by appropriate characterization methods, including single-crystal X-ray diffraction (XRD), Fourier-transform infrared (FTIR), photoluminescence (PL), and cyclic voltammetry (CV) analysis. Each hydrogen of the carboxylic group is coordinated by oxygen from the DMSO molecule in the stiff planar layer packing that makes up the DADBA-DMSO crystal structure.

Synthesis, Structural Versatility, Magnetic Properties, and I- Adsorption in a Series of Cobalt(II) Metal-Organic Frameworks with a Charge-Neutral Aliphatic (O,O)-Donor Bridge

Four new metal-organic frameworks based on cobalt(II) salts and 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide (odabco) were obtained. Their crystallographic formulae are [Co3(odabco)2(OAc)6] (1, OAc- = acetate), [Co(H2O)2(HCOO)2]·odabco (2), [Co2(H2O)(NO3)(odabco)5](NO3)3·3.65H2O (3), and [Co2(DMF)2(odabco)4](NO3)4·3H2O (4; DMF = N,N-dimethylformamide). Crystal structures of 1-4 were determined by single-crystal X-ray crystallography. Coordination polymer 1 comprises binuclear and mononuclear metal-acetate blocks alternating within uncharged one-dimensional chains, in which odabco acts as a bridging ligand. A layered Co(II) formate 2 contains odabco only as guest molecules located in the interlayer space. Layered compound 3 and three-dimensional 4 have cationic coordination frameworks with 26% and 34% specific void volumes, respectively, unveiling high structural diversity of Co(II)-odabco MOFs based on quite a rare aliphatic moiety. Magnetization measurements were performed for 1, 3, and 4 and the obtained data were interpreted on the basis of their crystal structures. A strong (J/kB~100 K) antiferromagnetic coupling was found within binuclear metal blocks in 1. Ion exchange experiments revealed a considerable iodide uptake by 3 resulting in an up to 75% guest nitrate substitution within the voids of a coordination framework, found by capillary zone electrophoresis data and confirmed by single-crystal XRD. A preservation of 3 crystallinity during the exchange allowed for the guest I- positions within a new adduct with the formula [Co2(H2O)(NO3)(odabco)5]I2(NO3)·1.85H2O (3-I) to be successfully determined and the odabco aliphatic core to be revealed as a main adsorption center for quite large and easily polarizable iodide anions. In summary, this work presents a comprehensive study for a series of 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide-based MOFs of cobalt(II) within the framework of magnetic properties and reports the first example of anion exchange in odabco-based coordination networks, supported by direct X-ray structural data. The reported results unveil promising applications of such frameworks bearing ligands with an aliphatic core in the diverse structural design of selective adsorbents and other types of functional materials.

Abiraterone Acetate Complexes with Biometals: Synthesis, Characterization in Solid and Solution, and the Nature of Chemical Bonding

Abiraterone acetate (AbirAc) is the most used steroidal therapeutic agent for treatment of prostate cancer. The mainly hydrophobic molecular surface of AbirAc results in its poor solubility and plays an important role for retention of abiraterone in the cavity of the receptor formed by peptide chains and heme fragments. In order to evaluate the hydrolytic stability of AbirAc, to modify its solubility by formation of new solid forms and to model bonding of this medication with the heme, a series of d-metal complexes with AbirAc was obtained. AbirAc remains stable in water, acetonitrile, tetrahydrofuran, and ethanol, and readily interacts with dications as a terminal ligand to create discrete complexes, including [FePC(AbirAc)2] and [ZnTPP(AbirAc)] (H2PC = phthalocyanine and H2TPP = 5,10,15,20-tetraphenylporphyrine) models for ligand-receptor bonding. In reactions with silver(I) nitrate, AbirAc acts as a bridge ligand. Energies of chemical bonding between AbirAc and these cations vary from 97 to 235 kJ mol-1 and exceed those between metal atoms and water molecules. This can be indicative of the ability of abiraterone to replace solvent molecules in the coordination sphere of biometals in living cells, although the model [ZnTPP] complex remains stable in CDCl3, CD2Cl2, and 1,1,2,2-tetrachloroethane-d2 solvents and decomposes in polar dimethylsulfoxide-d6 and methanol-d4 solvents, as follows from the 1H DOSY spectra. Dynamics of its behavior in 1,1,2,2-tetrachloroethane-d2 were studied by ROESY and NMR spectra.

N-N(+) Bond-Forming Intramolecular Cyclization of O-Tosyloxy β-Aminopropioamidoximes and Ion Exchange Reaction for the Synthesis of 2-Aminospiropyrazolilammonium Chlorides and Hexafluorophosphates

Our research area is related to the spiropyrazolinium-containingcompounds, which are insufficiently studied compared with pyrazoline-containing compounds. Nitrogen-containing azoniaspiromolecules have also been well studied. In drug design and other areas, they are a priori important structures, since rigid spirocyclic scaffolds with the reduced conformational entropy are able to organize a closely spaced area. Azoniaspirostructures are currently of wide practical interest as ionic liquids, current sources (membranes), structure-directing agents in organocatalysis, and in the synthesis of ordered ceramics. Our goal was the synthesis of 2-aminospiropyrazolilammonium chlorides and hexafluorophosphates. Our methodology is based on the tosylation of β-aminopropioamidoximes with six-membered N-heterocycles (piperidine, morpholine, thiomorpholine, and phenylpiperazine) at the β-position. 2-Aminospiropyrazolilammonium chlorides and hexafluorophosphates were obtained by the reaction of double ion substitution in the reaction of toluenesulfonates of 2-aminospiropyrazolinium compounds with an ethereal solution of HCl in ethanol and with ammonium hexafluorophosphate in ethanol in quantitative yields of 55-97%. The physicochemical characteristics of the synthesized compounds and their IR and NMR spectra are presented. The obtained salts were additionally characterized by the single-crystal XRD analysis. The presence of both axial and equatorial conformations of spirocations in solids was confirmed. 2-Aminospiropyrazolilammonium chlorides and hexafluorophosphates have weak in vitro antimicrobial activity on Gram-positive and Gram-negative bacterial lines.

Tuning Crystal Packing and Magnetic Properties in a Series of [Dy12] Metallocubanes Based on Azobenzene Derivatives of Salicylic Acid

A series of four new Dy₁₂ dodecanuclear clusters based on azobenzene derivative ligands of salicylic acid (L1-L4) has been synthesized and characterized in the crystalline phase using X-ray diffraction on single crystal and powder, IR spectroscopy, elemental analysis, and DSC-TGA methods. It was revealed that all obtained clusters exhibit the formation of the similar metallic cluster nodes, as vertex-sharing heterocubanes, obtained from four Dy³⁺ cations, three bridging hydroxyl groups, and O atoms from the salicylic ligands. The coordination geometry around the Dy(III) centers has been carefully analyzed. Whereas Dy₁₂-L1 and Dy₁₂-L2 with L1 and L2 containing Me and OMe groups in para positions of the phenyl rings, respectively, form similar porous 3D diamond-like molecular networks due to CH-π interactions, for Dy₁₂-L3 with L3 bearing NO₂-electron-withdrawing group, the generation of 2D molecular grids assembled by π-π staking is observed, and for Dy₁₂-L4 with L4 bearing phenyl substituent, 3D hexagonal channels have been generated. The complexes Dy₁₂-L1, Dy₁₂-L2, and Dy₁₂-L3 exhibit a zero-field slow magnetic relaxation effect. After UV irradiation of Dy₁₂-L1, a decrease of the magnetic anisotropy energy barrier displaying the possibility of control over magnetic properties by the external stimulus has been observed.

Experimental and Computational Investigation of the Oxime Bond Stereochemistry in c-Jun N-terminal Kinase 3 Inhibitors 11H-Indeno[1,2-b]quinoxalin-11-one Oxime and Tryptanthrin-6-oxime

11H-Indeno[1,2-b]quinoxalin-11-one oxime (IQ-1) and tryptanthrin-6-oxime are potent c-Jun N-terminal kinase 3 (JNK-3) inhibitors demonstrating neuroprotective, anti-inflammatory and anti-arthritic activity. However, the stereochemical configuration of the oxime carbon-nitrogen double bond (E- or Z-) in these compounds was so far unknown. In this contribution, we report the results of the determination of the double bond configuration in the solid state by single crystal X-ray diffraction and in solution by 1D and 2D NMR techniques and DFT calculations. It was found that both in the solid state and in solution, IQ-1 adopts the E-configuration stabilized by intermolecular hydrogen bonds, in contrast to previously assumed Z-configuration that could be stabilized only by an intramolecular hydrogen bond.

Multistep synthesis and X-ray structures of carboxyl-terminated hybrid iron(II) phthalocyaninatoclathrochelates and their postsynthetic transformation into polytopic carboranyl-containing derivatives

A multistep general synthetic strategy towards polytopic carboranyl-containing (semi)clathrochelate metal complexes, based on the template synthesis, transmetallation, amide condensation and 1,3-dipolar cycloaddition reactions, is developed. Their mono(semi)clathrochelate precursors with a single reactive group were obtained using a transmetallation of the triethylantimony-capped macrobicyclic precursor. The thus obtained carboxyl-terminated iron(II) semiclathrochelate underwent a macrobicyclization with zirconium(IV) phthalocyaninate to form the corresponding phthalocyaninatoclathrochelate. The direct one-pot template condensation of the suitable chelating and cross-linking ligand synthons on the Fe²⁺ ion as a matrix was also used for its preparation. Further amide condensation of the aforementioned semiclathrochelate and hybrid complexes with propargylamine in the presence of carbonyldiimidazole gave the (pseudo)cage derivatives with a terminal CC bond. Their "click" reaction with an appropriate carboranylmethyl azide afforded the ditopic carboranosemiclathrochelates and the tritopic carboranyl-containing phthalocyaninatoclathrochelates with a flexible spacer fragment between their polyhedral entities. The obtained new complexes were characterized using elemental analysis, MALDI-TOF mass spectrometry, multinuclear NMR, and UV-vis spectroscopy, and by single crystal X-ray diffraction experiments. Their FeN₆-coordination polyhedra show a truncated trigonal-pyramidal geometry, while the cross-linking heptacoordinate Zr⁴⁺ or Hf⁴⁺ cations in the hybrid compounds form the M^IVN₄O₃-coordination polyhedra with the geometry of a capped trigonal prism.

Synchrotron single-crystal XRD, IR-, Raman spectroscopy and high pressure study of synthetic krieselite

Spontaneous crystals of krieselite (Ge analogue of topaz) with the chemical formula Al₂[(Ge_0.75Si_0.25)O₄](F_1.63OH_0.37) were synthesized using a thermo-gradient hydrothermal method at a temperature of 600/650 °C and pressure of 100 MPa. The unit cell parameters are: a = 8.9732(8) Å, b = 8.4823(7) Å, c = 4.7379(5) Å, V = 360.62(6) ų, space group Pnma. The F^-/OH^- content of the samples was refined by FTIR spectroscopy method. Raman spectroscopy showed the main differences between the spectra of krieselite and topaz at the ambient conditions. The assignment of observed and calculated A_g bands (cm^-1) for non-polarized Raman spectra was carried out. Using in situ Raman spectroscopy at high pressures, the dependence of the shift in the position of the main bands of the krieselite Raman spectrum on the pressure was established, and the corresponding paths of pressure induced distortion of crystal structure was assumed. According to the data of Raman spectroscopy, it was revealed that krieselite does not undergo the phase transitions up to 30 GPa. The probable way of crystal structure distortion within the space group Pnma was proposed based on simulation of high-pressure Raman spectra.

A nitrosyl iron complex with 3.4-dichlorothiophenolyl ligands: synthesis, structures and its reactions with targets - carriers of nitrogen oxide (NO) in vivo

In this work, a new binuclear nitrosyl complex with 3.4-dichlorothiophenolyl ligands [Fe₂(SC₆H₃Cl₂)₂(NO)₄] has been synthesized. Nitrosyl iron complexes (NICs) are systems for the storage and delivery of NO in the body. There is a dynamic equilibrium between dinitrosyl iron units bound to low molecular weight ligands and high molecular weight (protein) ligands in vivo. From this point of view, the transformation of the studied complex in DMSO and buffer, as well as in biological systems, has been analyzed. In DMSO, it decomposes into mononuclear NICs, which quickly decay in buffer solutions with NO release. The high molecular weight product is formed as a result of the binding of the complex to bovine serum albumin (the Stern-Volmer constant is 2.1 × 10⁵ M^-1). In this case, the complex becomes a prolonged NO-donor. Such a long-term effect has been observed for the first time. Similarly, in a system with oxyhemoglobin, NO generation is slower; the UV-vis spectra show a gradual formation of methemoglobin. On the other hand, reduced glutathione has little effect on the NO-donor properties of the complex despite the fact that ligand substitution is observed in the system and a binuclear product is formed. Mucin binds the complex, and the decomposition mechanism is different from that for buffer solutions. Thus, these proteins and glutathione are able to participate in the transformation of the complex and modulate its properties as a potential drug.

A Series of Metal-Organic Frameworks with 2,2'-Bipyridyl Derivatives: Synthesis vs. Structure Relationships, Adsorption, and Magnetic Studies

Five new metal-organic frameworks based on Mn(II) and 2,2'-bithiophen-5,5'-dicarboxylate (btdc^2-) with various chelating N-donor ligands (2,2'-bipyridyl = bpy; 5,5'-dimethyl-2,2'-bipyridyl = 5,5'-dmbpy; 4,4'-dimethyl-2,2'-bipyridyl = 4,4'-dmbpy) [Mn₃(btdc)₃(bpy)₂]·4DMF, 1; [Mn₃(btdc)₃(5,5'-dmbpy)₂]·5DMF, 2; [Mn(btdc)(4,4;-dmbpy)], 3; [Mn₂(btdc)₂(bpy)(dmf)]·0.5DMF, 4; [Mn₂(btdc)₂(5,5'-dmbpy)(dmf)]·DMF, 5 (dmf, DMF = N,N-dimethylformamide) have been synthesized, and their crystal structure has been established using single-crystal X-ray diffraction analysis (XRD). The chemical and phase purities of Compounds 1-3 have been confirmed via powder X-ray diffraction, thermogravimetric, and chemical analyses as well as IR spectroscopy. The influence of the bulkiness of the chelating N-donor ligand on the dimensionality and structure of the coordination polymer has been analyzed, and the decrease in the framework dimensionality, as well as the secondary building unit's nuclearity and connectivity, has been observed for bulkier ligands. For three-dimensional (3D) coordination polymer 1, the textural and gas adsorption properties have been studied, revealing noticeable ideal adsorbed solution theory (IAST) CO₂/N₂ and CO₂/CO selectivity factors (31.0 at 273 K and 19.1 at 298 K and 25.7 at 273 K and 17.0 at 298 K, respectively, for the equimolar composition and the total pressure of 1 bar). Moreover, significant adsorption selectivity for binary C₂-C₁ hydrocarbons mixtures (33.4 and 24.9 for C₂H₆/CH₄, 24.8 and 17.7 for C₂H₄/CH₄, 29.3 and 19.1 for C₂H₂/CH₄ at 273 K and 298 K, respectively, for the equimolar composition and the total pressure of 1 bar) has been observed, making it possible to separate on 1 natural, shale, and associated petroleum gas into valuable individual components. The ability of Compound 1 to separate benzene and cyclohexane in a vapor phase has also been analyzed based on the adsorption isotherms of individual components measured at 298 K. The preferable adsorption of C₆H₆ over C₆H₁₂ by 1 at high vapor pressures (V_B/V_CH = 1.36) can be explained by the existence of multiple van der Waals interactions between guest benzene molecules and the metal-organic host revealed by the XRD analysis of 1 immersed in pure benzene for several days (1≅2C₆H₆). Interestingly, at low vapor pressures, an inversed behavior of 1 with preferable adsorption of C₆H₁₂ over C₆H₆ (K_CH/K_B = 6.33) was observed; this is a very rare phenomenon. Moreover, magnetic properties (the temperature-dependent molar magnetic susceptibility, χ_p(T) and effective magnetic moments, μ_eff(T), as well as the field-dependent magnetization, M(H)) have been studied for Compounds 1-3, revealing paramagnetic behavior consistent with their crystal structure.

(2-Hydroxy-3-Methoxybenzylidene)thiazolo[3,2-a]pyrimidines: Synthesis, Self-Assembly in the Crystalline Phase and Cytotoxic Activity

A series of new 2-hydroxy-3-methoxybenzylidenethiazolo[3,2-a]pyrimidines with different aryl substituents at the 5 position are synthesized and characterized by ¹H/ ¹³C NMR and IR-spectroscopy and mass-spectrometry, as well as single crystal X-ray diffraction (SCXRD). It was demonstrated that the type of hydrogen bonding can play a key role in the chiral discrimination of these compounds in the crystalline phase. The hydrogen bond of the O-H...N type leads to 1D supramolecular heterochiral chains or conglomerate crystallization in the case of the formation of homochiral chains. The hydrogen bond of O-H...O type gave racemic dimers, which are packed into 2D supramolecular layers with a parallel or angular dimers arrangement. Halogen bonding of the N...Br or O...Br type brings a new motif into supramolecular self-assembly in the crystalline phase: the formation of 1D supramolecular homochiral chains instead 2D supramolecular layers. The study of cytotoxicity against various tumor cells in vitro was carried out. It was found that 2-hydroxy-3-methoxybenzylidenethiazolo[3,2-a]pyrimidines with 3-nitrophenyl substituent at C5 carbon atom demonstrated a high efficiency against M-HeLa (cervical adenocarcinoma) and low cytotoxicity against normal liver cells.

N-Cyclohexylcyclohexanaminium {[acetyl(methyl)amino]methyl}bis [4,5-dibromobenzene-1,2-diolato]silicate(IV) 4,5-dibrobenzene-1,2-diol Ethanol Solvate

An X-ray diffraction study of a transesterification product of N-methyl-N-(trimethoxysilylmethyl)acetamide by 4,5-dibromobenzene-1,2-diol was carried out. It was established that the coordination polyhedron of the silicon atom in an anionic complex is a distorted octahedron disordered due to the superposition of the Δ and Λ optical isomers. The presence of various hydrogen donor groups in bis(cyclohexyl)ammonium cations, solvent ethanol molecules, and non-coordinated 4,5-dibromobenzene-1,2-diol caused the formation of H-bonded chains, while dibromobenzenediol also took part in stacking interactions.

Synthesis, Structure, Spectral-Luminescent Properties, and Biological Activity of Chlorine-Substituted N-[2-(Phenyliminomethyl)phenyl]-4-methylbenzenesulfamide and Their Zinc(II) Complexes

New azomethine compounds of 2-(N-tosylamino)benzaldehyde or 5-chloro-2-(N-tosylamino)benzaldehyde and the corresponding chlorine-substituted anilines, zinc(II) complexes based on them have been synthesized. The structures of azomethines and their complexes were determined by elemental analysis, IR, ¹H NMR, X-ray spectroscopy, and X-ray diffraction. It is found that all ZnL₂ complexes have a tetrahedral structure according to XAFS and X-ray diffraction data. The photoluminescent properties of azomethines and zinc complexes in methylene chloride solution and in solid form have been studied. It is shown that the photoluminescence quantum yields of solid samples of the complexes are an order of magnitude higher compared to the solutions and range from 11.34% to 48.3%. The thermal properties of Zn(II) complexes were determined by thermal gravimetric analysis (TGA) and differential scanning calorimetry. The TGA curves of all the compounds suggest their high thermal stability up to temperatures higher than 290 °C. The electrochemical properties of all complexes were investigated by the cyclic voltammetry method. The multilayered devices ITO/PEDOT:PSS/NPD/Zn complex/ TPBI/LiF/Al with wide electroluminescence (EL) color range spanning the range from bluish-green (494 nm) to green (533 nm) and the high values of brightness, current and power efficiency were fabricated. The biological activity of azomethines and zinc complexes has been studied. In the case of complexes, the protistocidal activity of the zinc complex with azomethine of 5-chloro-2-(N-tosylamino)benzaldehyde with 4-chloroaniline was two times higher than the activity of the reference drug toltrazuril.

Highly Luminescent Crystalline Sponge: Sensing Properties and Direct X-ray Visualization of the Substrates

A phenomenon of crystalline sponge is represented by guest-dependent structural fluidity of the host polymeric lattice in highly crystalline sorbents, such as metal-organic frameworks, driven by multiple weak intermolecular interactions. Such induced fitting in MOFs is a valuable property in selective adsorption, guest determination by single-crystal XRD and in-situ structural analysis under external stimuli. In this work, a porous three-dimensional metal-organic framework [Eu₂(DMF)₄(ttdc)₃]·4.45DMF (1_DMF; DMF = N,N-dimethylformamide, ttdc^2- = trans-thienothiophenedicarboxylate anion) was applied as a crystalline sponge bearing luminescent functionality to couple its sensing properties with direct structural determination of the adsorbed molecules. As a result, the paper discusses crystal structures and luminescent properties for the successfully obtained new adducts with the crystallographic formulae [Eu₂(DMSO)₄(ttdc)₃]·2.5DMSO·2.2H₂O (1_DMSO; DMSO = dimethylsulfoxide), [Eu₂(DMF)₄(ttdc)₃]·3phet (1_phet; phet = phenylethanal) and [Eu₂(DMF)_3.5(cin)_0.5(ttdc)₃]·1.64cin (1_cin; cin = trans-cinnamaldehyde). As a result of inclusion of DMSO into 1, a slight increase in the quantum yield and excited state phosphorescence lifetime was observed, while the adsorption of phet leads to a considerable (up to three times) decrease in the corresponding values. The incorporation of cinnamal results in a full quenching of QY, from 20% down to zero, and a more than order of magnitude diminishing of the excited state lifetime compared to the initial 1_DMF. The effective sensing of cinnamal was explained from the structural point of view by its direct coordination to the Eu³⁺ emitter, as well as by multiple weak intermolecular interactions with ttdc antenna ligand, both capable of enhancing the non-radiative energy dissipation.

Synthesis, Self-Assembly in Crystalline Phase and Anti-Tumor Activity of 2-(2-/4-Hydroxybenzylidene)thiazolo[3,2-a]pyrimidines

A series of new thiazolo[3,2-a]pyrimidines different by aryl substituents in 2 and 5 positions are synthesized and characterized in solution as well as in the crystalline phase using ¹H and ¹³C NMR-, IR-spectroscopies, mass-spectrometry methods, and single crystal X-ray diffraction (SCXRD). The SCXRD study revealed the role of intermolecular H-bonding in the formation of supramolecular architectures (racemic monomers, centrosymmetric racematic dimers, or homochiral 1D chains) of obtained thiazolo[3,2-a]pyrimidines derivatives depending on solvents (aprotic DMSO or protic EtOH) used upon the crystallization process. Moreover, the in vitro study of cytotoxicity toward different tumor cells showed their high or moderate efficiency with moderate cytotoxicity against normal liver cells which allows to consider the obtained thiazolo[3,2-a]pyrimidine derivatives as promising candidates for application as antitumor agents.

N-(4-Methyl-3-((4-(pyridin-3-yl)pyrimidin-2-yl)amino)phenyl)-4-((4-methylpiperazin-1-yl)methyl)benzamide

Imatinib is one of the most used therapeutic agents to treat leukemia, which specifically inhibits the activity of tyrosine kinases. This polytopic molecule has been structurally characterized only in the form of its piperazin-1-ium salt (mesylate, picrate, citrate, fumarate or malonate). Herein we present the crystal structure of the freebase Imatinib which precipitated from a 1:10 mixture with arginine. The molecule realizes an extended conformation and forms infinite H-bonded chains through its amide, amine and pyrimidine groups.

Aliphatic-Bridged Early Lanthanide Metal–Organic Frameworks: Topological Polymorphism and Excitation-Dependent Luminescence

Six new three-dimensional metal–organic frameworks based on early lanthanide(III) cations and trans-1,4-cyclohexanedicarboxylic acid (H2chdc) were obtained. Their crystal structures were determined by single-crystal X-ray diffraction analysis. The structure of [La2(H2O)4(chdc)3]·2DMF·H2O (1; DMF = N,N-dimethylformamide) contains one-dimensional infinite La(III)-carboxylate chains interconnected by cyclohexane moieties to form a highly porous polymeric lattice with 30% solvent accessible volume. Compounds [Ln2(phen)2(chdc)3]·0.75DMF (2Ln; Ln3+ = Ce3+, Pr3+, Nd3+ and Sm3+; phen = 1,10-phenanthroline) are based on binuclear carboxylate building blocks, which are decorated by chelate phenanthroline ligands and interconnected by cyclohexane moieties to form more dense isostructural coordination frameworks with primitive cubic pcu topology. Compound [Nd2(phen)2(chdc)3]·2DMF·0.67H2O (3) is based on secondary building units similar to 2Ln and contains a coordination lattice isomeric to 2Ln with a rare hexagonal helical snz topology. Thermal stability and luminescent properties were investigated. For 2Sm, a strong and nonmonotonous dependence of the luminescence color on the variation of excitation wavelength was revealed, changing its emission from pinkish red at λex = 340 nm to white at λex = 400 nm, and then to yellow at lower excitation energies. Such nonlinear behavior was rationalized in terms of the contribution of several different luminescence mechanisms. Thus, 2Sm is a rather rare example of a highly tunable monometallic lanthanide-based luminophore with possible applications in light-emitting devices and optical data processing.

Annealing-Induced Structural Behavior of Mn Dopant Ions in Calcium Orthovanadate Ca3(VO4)2 Single Crystals

The crystal and local structures of Czochralski-grown calcium orthovanadate (Ca₃(VO₄)₂) single crystals doped with over-stoichiometric 0.05 wt % Mn₂O₃ (CVO:0.05Mn) and annealed under different conditions are studied by single-crystal conventional and synchrotron X-ray diffraction, X-ray absorption spectroscopy, and electron paramagnetic resonance for the first time. Bottom (annealing in air) and top (annealing in air and in vacuum) parts of the CVO:0.05Mn crystal differ in the manganese content (higher in the bottom part), formal charge (Mn⁴⁺ and Mn^(3+δ)+, respectively), and color (orange bottom part; light orange and yellow top parts annealed in air and vacuum, respectively). Manganese ions are located in one (Ca3, distorted two-capped trigonal prism) of five crystallographic Ca sites and have octahedral coordination, which is consistent with crystal-chemical properties of transition-metal ions. The presence of vacancies in one of three V sites is revealed. Formal charge 5+ for vanadium ions is confirmed by X-ray photoelectron spectroscopy. Different colors of CVO:Mn crystals and different formal charges of manganese are explained depending on the growth and post-growth treatment conditions.

Revealing the peculiar local behavior of manganese and cobalt in diffusion-doped calcium orthovanadate Ca3(VO4)2

Laser Ca₃(VO₄)₂ single crystals (СVO; space group R3c, Z = 21) with crystallochemical formula Ca1₁₈Ca2₁₈Ca3₁₈Ca4₆(Ca5 + Са5А)₃(V1₁₈V2₁₈V3₆)O₁₆₈ grown by the Czochralski method were doped with Мn₂O₃ (CVO:Мn₂O₃) and Сo₃O₄ (CVO:Co₃O₄) by high-temperature diffusion annealing. Statistical and local structures were comprehensively studied by single-crystal and powder synchrotron X-ray diffraction and conventional single-crystal X-ray diffraction as well as by X-ray absorption spectroscopy for the first time. The presence of Mn^(2+δ)+ ions with a mixed formal charge and Co²⁺ ions in the Ca2 (monocapped trigonal prism), Ca3 (two-capped trigonal prism), and Ca4 (octahedron) sites was revealed by diffraction methods. The tetrahedral coordination and the coordination intermediate between tetrahedral and octahedral were established for Mn^(2+δ)+ and Co²⁺ ions, respectively. A fundamentally different structural behavior of dopant ions (concentration, formal charge, and coordination environment) in the CVO crystals doped with manganese in the form of Mn₂O₃ during the crystal growth or by high-temperature diffusion annealing was observed. The relationship between characteristic bands in the absorption, fluorescence, and excitation spectra of CVO:Мn₂O₃ and CVO:Co₃O₄ samples and transition metals with specific formal charges is discussed.

Crystalline State Hydrogen Bonding of 2-(2-Hydroxybenzylidene)Thiazolo[3,2-a]Pyrimidines: A Way to Non-Centrosymmetric Crystals

Thiazolopyrimidines are attractive to medical chemists as new antitumor agents due to their high inhibiting activity towards the tumor cells replication process and easy modification of their structure by varying of the number and nature of substituents. The presence of asymmetric C5 carbon atoms requires the development of racemic mixture separation procedures for these heterocycles. One of the more effective ways is the crystallization of a racemic compound as a conglomerate. A prerequisite for such separation is the formation of non-centrosymmetric crystals presenting Sohncke space groups. For the construction of chiral supramolecular ensembles in a crystalline state, hydrogen bonds were chosen as supramolecular synthons. In this context, salicylic derivatives at the C2 atom of thiazolopyrimidines were synthesized. The crystal structures of the obtained compounds were established by SCXRD. The regularities of the solvent’s influence on the crystal packaging were revealed. The conditions for the preparation of crystals with the chiral space group due to intermolecular hydrogen bonds were discovered.

Structural features of selenate based {Mo132} keplerate capsules

A new structural feature and significant stabilizing effect were found for keplerate-type nanospherical polyoxometalates.

Synthesis, supramolecular isomerism, and photoluminescence of scandium(III) complexes with tetrafluoroterephthalate ligand

Here we present a new family of seven Sc(III) complexes with tetrafluoroterephthalate ligand (tFBDC2−), having non-polymeric and polymeric 2D and 3D structures. These complexes are characterized by SC XRD, PXRD,...

Impact of flexible succinate connectors on the formation of tetrasulfonylcalix[4]arene based nano-sized polynuclear cages: structural diversity and induced chirality study

The formation of three types of supramolecular coordination cages is described. Tetrasulfonylcalixarene, combined with metallic salts (Ni, Co and Zn) and the flexible succinate ligand, led to cages. H bonded induced chirality was observed for both isomorphous cages.

The Crystal Structure Elucidation of a Tetrapeptide Analog of Somatostatin DOTA-Phe-D-Trp-Lys-Thr-OMe

Herewith, we report for the first time the crystal structure of tetrapeptide FwKT (Phe-D-Trp-Lys-Thr), which is considered to represent an epitope for biomedically relevant hormone somatostatin. The target molecule was successfully crystalized, solved and refined as a conjugate of the tetrapeptide moiety bearing a protective group DOTA at the N-terminus and methylated at the O-terminus. The combination of a hormone active site and a powerful chelator make the substance a highly prospective targeted drug delivery system, especially for peptide receptor radionuclide therapy (PRRT) applications.

Crystal Structures, Thermal and Luminescent Properties of Gadolinium(III) Trans-1,4-cyclohexanedicarboxylate Metal-Organic Frameworks

Four new gadolinium(III) metal-organic frameworks containing 2,2′-bipyridyl (bpy) or 1,10-phenanthroline (phen) chelate ligands and trans-1,4-cyclohexanedicarboxylate (chdc2−) were synthesized. Their crystal structures were determined by single-crystal X-ray diffraction analysis. All four coordination frameworks are based on the binuclear carboxylate building units. In the compounds [Gd2(bpy)2(chdc)3]·H2O (1) and [Gd2(phen)2(chdc)3]·0.5DMF (2), the six-connected {Ln2(L)2(OOCR)6} blocks form a 3D network with the primitive cubic (pcu) topology. In the compounds [Gd2(NO3)2(phen)2(chdc)2]·2DMF (3) and [Gd2Cl2(phen)2(chdc)2]·0.3DMF·2.2dioxane (4), the four-connected {Ln2(L)2(X)2OOCR)4} units (where X = NO3− for 3 or Cl− for 4) form a 2D square-grid (sql) network. The solid-state luminescent properties were investigated for the synthesized frameworks. Bpy-containing compound 1 shows no luminescence, possibly due to the paramagnetic quenching by Gd3+ cation. In contrast, the phenathroline-containing MOFs 2–4 possess yellow emission under visible excitation (λex = 460 nm) with the tuning of the characteristic wavelength by the coordination environment of the metal center.

Peculiar Spin-Crossover Behavior in the 2D Polymer K[FeIII(5Cl-thsa)2]

A potassium salt of the N₂S₂O₂-coordination Fe(III) anion K[Fe(5Cl-thsa)₂] (1) (5Cl-thsa - 5-chlorosalicylaldehyde thiosemicarbazone) is synthesized and characterized structurally and magnetically over a wide temperature range. Two polymorphs of salt 1 characterized by the common 2D polymer nature and assigned to the same orthorhombic Pbcn space group have been identified. The molecular structure of the minor polymorph of 1 was solved and refined at 100, 250, and 300 K is shown to correspond to the LS configuration. The dominant polymorph of 1 features K⁺ cations disordered over a few crystallographic sites, while the minor polymorph includes fully ordered K⁺ cations. The major polymorph exhibits a complete three-step cooperative spin-crossover transition both in the heating and cooling modes: The first step occurs in a temperature range from 2 to 50 K; the second abrupt hysteretic step occurs from 200 to 250 K with T_1/2 = 230 K and a 6 K hysteresis loop. The third gradual step occurs from 250 to 440 K. According to ⁵⁷Fe Mössbauer, XRPD, and EXAFS data, the spin-crossover transition for the dominant polymorph is quite peculiar. Indeed, the increase in the HS concentration by 57% at the second step does not result in the expected significant increase in the iron(III)-ligand bond lengths. In addition, the final step of the spin conversion (Δγ_HS = 26%) is associated with a structural phase transition with a symmetry lowering from the orthorhombic (Pbcn) to the monoclinic (P2₁/n) space group. This nontrivial phenomenon was investigated in detail by applying magnetization measurements, electron spin resonance, ⁵⁷Fe Mössbauer spectroscopy, and DFT calculations. These results provide a new platform for understanding the multistep spin-crossover character in the Fe(III) thsa-complexes and related compounds.

Cinnamal Sensing and Luminescence Color Tuning in a Series of Rare-Earth Metal-Organic Frameworks with Trans-1,4-cyclohexanedicarboxylate

Three isostructural metal-organic frameworks ([Ln2(phen)2(NO3)2(chdc)2]·2DMF (Ln3+ = Y3+ for 1, Eu3+ for 2 or Tb3+ for 3; phen = 1,10-phenanthroline; H2chdc = trans-1,4-cyclohexanedicarboxylic acid) were synthesized and characterized. The compounds are based on a binuclear block {M2(phen)2(NO3)2(OOCR)4} assembled into a two-dime nsional square-grid network containing tetragonal channels with 26% total solvent-accessible volume. Yttrium (1)-, europium (2)- and terbium (3)-based structures emit in the blue, red and green regions, respectively, representing the basic colors of the standard RGB matrix. A doping of Eu3+ and/or Tb3+ centers into the Y3+-based phase led to mixed-metal compositions with tunable emission color and high quantum yields (QY) up to 84%. The bright luminescence of a suspension of microcrystalline 3 in DMF (QY = 78%) is effectively quenched by diluted cinnamaldehyde (cinnamal) solutions at millimolar concentrations, suggesting a convenient and analytically viable sensing method for this important chemical.

Intense multi-colored luminescence in a series of rare-earth metal-organic frameworks with aliphatic linkers

Two series of highly luminescent yttrium(iii), europium(iii) and terbium(iii) metal-organic frameworks containing diimine aromatic ligands and the dicarboxylate linker trans-1,4-cyclohexanedicarboxylate (chdc^2-) which can be described by the general formulas [M₂(bpy)₂(chdc)₃], where M = Y³⁺ (1), Eu³⁺ (2), and Tb³⁺ (3) and bpy = 2,2'-bipyridyl, and [M₂(phen)₂(chdc)₃], where M = Y³⁺ (4), Eu³⁺ (5), and Tb³⁺ (6) and phen = 1,10-phenanthroline, were synthesized and characterized. All compounds are based on the same dinuclear {M₂(L)₂(OOCR)₆} building blocks and possess a similar topology of the 3D framework with narrow pores. The chelate aromatic ligands act as efficient light-harvesting antennas for subsequent energy transfer to the emitting metal center (M = Eu³⁺, Tb³⁺) or intraligand photoemission (M = Y³⁺). As a result, the reported compounds display intense emission in the red (Eu³⁺), green (Tb³⁺) or blue (Y³⁺) regions representing three basic colors (RGB) of visible light. The measured quantum yields (QYs) of the solid-state luminescence for individual compounds were found to be 63% (1), 46% (2), 59% (3), 2.3% (4), 55% (5) and 49% (6). The drastic reduction of the luminescence efficiency for 4 is explained by the strong disorder of phen ligands. The high thermal stability (up to 300 °C) and exceptional moisture resistance of the bpy-based frameworks 1-3 were confirmed by TG and PXRD measurements. Various bimetal or trimetal compositions were also prepared for the bpy-series. The luminescence properties of these mixed-metal compounds depend on both the chemical composition and excitation wavelength (λ_ex). Remarkably, pure white emission with color temperature = 6126 K was achieved for [Y_1.68Eu_0.08Tb_0.24(bpy)₂(chdc)₃] at λ_ex = 360 nm with QY = 20%. The reported results suggest that the obtained coordination framework series is a convenient platform for the design of highly efficient light emitting materials with tunable properties.

Unprecedented interplay of antiferro- and ferromagnetic exchange interactions through intermolecular hydrogen bonds in mononuclear Cu(ii) complexes

A nontrivial case of a combination of ferro- and antiferromagnetic exchange interactions in mononuclear copper(ii) complexes, determined by HB networks, is reported.