Cambridge Crystallographic Data Centre Research Articles

Observation of Transition from Ferroelasticity to Ferroelectricity by Solvent Selective Effect in Anilinium Bromide.

Organic ferroelectrics are highly desirable for their light weight, mechanical flexibility and biocompatibility. However, the rational design of organic ferroelectrics has always faced great challenges. Anilinium bromide (AB) has two structures reported in the Cambridge Crystallographic Data Centre, which might be an mmmF2/m type ferroelastic (AB-1). When we studied its ferroelasticity, we were surprised to discover that there was another crystal (AB-2) in H2 O besides this one, and they were very difficult to separate. By changing the solvent, we found that AB-1 crystals could be formed in ethanol, where ferroelastic domains were visualized by polarized light microscopy, and AB-2 crystals could be obtained from various crystallization solvents of methanol, isopropanol, N-butanol, acetonitrile, dimethyl sulfoxide, and N,N-dimethylformamide, which undergo a ferroelectric phase transition with mm2Fm, showing clear ferroelectricity in two phases. To our knowledge, the regulation of ferroelasticity to ferroelectricity by solvent selective effect is unprecedented in the field of ferroelectrics. This work reveals the important role of solvent effect in organic ferroelectrics.

Observation of Transition from Ferroelasticity to Ferroelectricity by Solvent Selective Effect in Anilinium Bromide

AbstractOrganic ferroelectrics are highly desirable for their light weight, mechanical flexibility and biocompatibility. However, the rational design of organic ferroelectrics has always faced great challenges. Anilinium bromide (AB) has two structures reported in the Cambridge Crystallographic Data Centre, which might be an mmmF2/m type ferroelastic (AB‐1). When we studied its ferroelasticity, we were surprised to discover that there was another crystal (AB‐2) in H2O besides this one, and they were very difficult to separate. By changing the solvent, we found that AB‐1 crystals could be formed in ethanol, where ferroelastic domains were visualized by polarized light microscopy, and AB‐2 crystals could be obtained from various crystallization solvents of methanol, isopropanol, N‐butanol, acetonitrile, dimethyl sulfoxide, and N,N‐dimethylformamide, which undergo a ferroelectric phase transition with mm2Fm, showing clear ferroelectricity in two phases. To our knowledge, the regulation of ferroelasticity to ferroelectricity by solvent selective effect is unprecedented in the field of ferroelectrics. This work reveals the important role of solvent effect in organic ferroelectrics.

Twisted Intramolecular Charge Transfer—Aggregation-Induced Emission Fluorogen with Polymer Encapsulation-Enhanced Near-Infrared Emission for Bioimaging

Fluorescence probes with strong near-infrared (NIR) emission and water solubility are considered useful visualization tools for localization marking as well as investigating cell migration and tran...

On modelling disordered crystal structures through restraints from molecule-in-cluster computations, and distinguishing static and dynamic disorder.

Distinguishing disorder into static and dynamic based on multi-temperature X-ray or neutron diffraction experiments is the current state of the art, but is only descriptive, not predictive. Here, several disordered structures are revisited from the Cambridge Crystallographic Data Center 'drug subset', the Cambridge Structural Database and own earlier work, where experimental intensities of Bragg diffraction data were available. Using the molecule-in-cluster approach, structures with distinguishable conformations were optimized separately, as extracted from available or generated disorder models of the respective disordered crystal structures. Re-combining these 'archetype structures' by restraining positional and constraining displacement parameters for conventional least-squares refinement, based on the optimized geometries, then often achieves a superior fit to the experimental diffraction data compared with relying on experimental information alone. It also simplifies and standardizes disorder refinement. Ten example structures were analysed. It is observed that energy differences between separate disorder conformations are usually within a small energy window of RT (T = crystallization temperature). Further computations classify disorder into static or dynamic, using single experiments performed at one single temperature, and this was achieved for propionamide.

IsoStar Program Suite for Studies of Noncovalent Interactions in Crystals of Chemical Compounds

Both Cambridge Crystallographic Data Centre (CCDC) and Protein Data Bank (PDB) provide unique opportunities for finding information about the structures of chemical and biochemical compounds in the solid state. The IsoStar—a knowledge-based library of intermolecular interactions—is a very powerful tool for automatic analysis of a large amount of data from these databases. The IsoStar program suite could help chemists in understanding of probability of occurrence (frequencies) and spatial characteristics (directionalities) of noncovalent contacts (including hydrogen, halogen, and chalcogen bonds, as well as interactions involving π-systems) between pairs of chemical functional groups; this web application may also be useful for crystal engineers, crystallographers, medicinal chemists, and researchers in fields of computational chemistry and molecular modeling.

Photocatalyzed Dual-Oxidative Trifluoromethylthio-Trifluoromethylation of Alkenes with CF 3 SO 2 Na

A novel photocatalyzed trifluoromethylthio-trifluoromethylation of alkenes has been developed, using CF3SO2Na as both CF3 and SCF3 source. This photocatalyzed dual-oxidative strategy, which combine...

Transition-Metal-Free Reductive Cross-Coupling Employing Metabisulfite as a Connector: General Construction of Alkyl–Alkyl Sulfones

Transition-Metal-Free Reductive Cross-Coupling Employing Metabisulfite as a Connector: General Construction of Alkyl–Alkyl Sulfones

Light-Responsive Proton Conductor: Record High Gain of Proton Conductivity Achieved by Photoinduced Electron-Transfer Strategy

Light-Responsive Proton Conductor: Record High Gain of Proton Conductivity Achieved by Photoinduced Electron-Transfer Strategy

Синтез и строение продуктов реакции 2,2’-дипиридила с треххлористой сурьмой

Adducts have been obtained from antimony trichloride and 2,2'-bipyridyl in acetonitrile: [C10H9N2]2+[OSb2Cl6]2 (1) и [C10H9N2]+ {[(C10H8N2)SbCl3]2[Cl]} (2). The compounds have been identified by IR spectroscopy and X-ray diffraction analysis. According to the X-ray diffraction data, the pale green crystals 1 consist of two types of bipyridyl cations and binuclear anions [OSb2Cl6]2, in which two SbCl3 fragments are linked through an oxygen atom and two bridged chlorine atoms. The coordination polyhedron of the antimony atom is a square pyramid with two terminal (SbClterm 2.418(5)2.497(4) Å) and two bridged chlorine atoms (SbClbr 3.044(4)–2.849(5) Å) at the base and the oxygen atom at the fifth vertex (SbO 1.95(1) and 1.93(9) Å). The Sb–O–Sb group has been curved (119.3(5)o) so that the antimony atoms approach each other at a distance of 3.348(2) Å, which is greater than the sum of the covalent radii of these atoms (2.08 Å), but less than the sum of their van der Waals radii (4.4 Å). The antimony atom shifts from the equatorial plane [Cl4] towards the carbon atom by 0.254 Å. Along with the main product of the reaction, there are minor amounts of yellow-orange crystals 2, consisting of two types of bipyridyl cations and binuclear chlorine-containing anions {[(C10H8N2)SbCl3]2[Cl]}, in which two antimony-containing fragments (distorted octahedron) (C10H8N2)SbCl3 are linked by a chlorine bridging atom (SbClbr 2.59(8) Å). The bridging chlorine atom occupies the sixth vertex of the octahedron (SbCl 3.13(1) Å), the opposite vertex is occupied by one of the nitrogen atoms of the bipyridyl ligand, the second nitrogen atom (SbN 2.22(9) Å) of which lies in the equatorial plane with three chlorine atoms (SbCl 2.58(1), 2.61(1), 2.56(1) Å). Complete tables of atom coordinates, bond lengths and valence angles are deposited at the Cambridge Crystallographic Data Center ((№ 2041289; deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk/data_request/cif).

Синтез и строение бис(2,5-дифторбензоата) трис(2-метоксифенил)сурьмы

Tris(2-methoxyphenyl)antimony bis(2,5-difluorobenzoate) (1) has been obtained by the oxidative addition reaction between tris(2-methoxyphenyl)antimony, 2,5-difluorocarboxylic acid and tertiary butyl hydroperoxide in diethyl ether with the 72% yield. The compound has been identified by IR spectroscopy and X-ray diffraction analysis. According to the X-ray diffraction data, the crystal of compound 1 contains two types of crystallographically independent molecules a and b, the geometric parameters of which are slightly different. In molecules a and b the antimony atoms have a distorted trigonal-bipyramidal coordination with the oxygen atoms of the carboxylate ligands in the axial positions. The crystal also contains a solvate molecule of diethyl ether, disordered in two positions. The updated ratios of position contributions are 0.50/0.50. The sums of the CSbC angles in the equatorial plane of molecules 1a and 1b are 359.9(3)° and 359.8(3)°, respectively. The OSbO axial angles are 174.60(16)° (1a) and 175.51(17)° (1b). The antimony atom departs from the equatorial plane [C3] by 0.040 Å for both molecules. The conformation of the aryl ligands with respect to the equatorial plane [C3] is propeller-like. The SbC bond lengths have close values: 2.097(7)2.127(6) Å in 1a, 2.107(7)2.115(6) Å in 1b. The SbO distances (2.112(5), 2.131(5) Å in 1a, 2.107(5), 2.128(5) Å in 1b) are commensurate with the covalent SbO bond lengths. Bidentate carboxylate ligands are coordinated to the metal atom less symmetrically in molecule 1а, while the SbO(=С) intramolecular distances are 3.116(7), 3.063(7) Å in 1a, and 3.120(6) Å, 3.126(7) Å in 1b, which is less than the sum of the van der Waals radii of the Sb and O atoms. In molecules 1a and 1b short distances are observed between the oxygen atoms of the methoxy groups and the antimony atoms (3.080(6), 3.138(7), 3.164(4) Å for 1a, 3.023(6), 3.085(5), 3.194(7) Å for 1b), which increases the coordination number of the antimony atom. The structure of the crystal is presented in such a way that the solvate molecules of diethyl ether, arranged in one chain of the form (∙∙∙СH3CH2OCH2CH3∙∙∙F∙∙∙)n, are surrounded by molecules of tris(2-methoxyphenyl)antimony bis(2,5-difluorobenzoate), forming a shell of sorts for a chain of ether molecules. This interaction is due to hydrogen bonds: –ОСH(СH3)–H∙∙∙F, Et2O∙∙∙HMeO–, –ОСH2CH2–H∙∙∙F. Molecules of the a and b types contact each other through hydrogen bonds С=О∙∙∙HMeO–, F∙∙∙HMeO–, F∙∙∙HAr, and Sb–O∙∙∙HAr. Also, the СН∙∙∙π interactions and the stacking effect are observed in the packing of molecules. Complete tables of atom coordinates, bond lengths and valence angles are deposited at the Cambridge Crystallographic Data Center (No. 2077192 (1), deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk/data_request/cif).

Реакции пентафенилсурьмы и пента-пара-толилсурьмы с каликсареном [4-t-BuC6H2OH(S-2)

Pentaphenylantimony and penta-para-tolylantimony react with calixarene [4-t-BuC6H2OH(S-2)]4 (СArH) by way of arene elimination and formation of the [Ph4Sb]+[СAr]- × TolH (1), [p-Tol4Sb]+[CAr]- × H2O (2) ionic products with a yield up to 96%. The compound has been identified by IR spectroscopy and X-ray diffraction analysis. According to the X-ray diffraction data, compounds 1 and 2 are ionic complexes with solvate molecules of toluene (1) and water (2). The cation has a tetrahedral coordination of the antimony atom with aryl ligands at the polyhedron vertices; the anion is represented by the deprotonated form of p-tert-butylthiacalix[4]arene. The three tert-butyl groups, the phenyl ring and solvated toluene in the structure of compound 1, and two tert-butyl fragments in the structure of compound 2 are disordered over two positions. The tetrahedral coordination of antimony atoms in the cations of compounds 1 and 2 is slightly distorted. The CSbC angles deviate from the theoretical value and vary within 106.0(4)−117.7(4)° (1), 105.75(15)−112.84(15)° (2). The average Sb–C bond lengths are 2.101(3) and 2.106(4) Å in structures 1 and 2, respectively. The [СAr]- anion is in the cone conformation, the upper rim of which is represented by the tert-butyl groups in the para-position, while the lower one is represented by hydroxy groups, one of which is deprotonated. The СAr–O– bond length (1.318(4) (1) and 1.326(4) (2) Å) is less than the average value of the СAr–OH bond lengths (1.338(4) (1) and 1.343(4) (2) Å), which indicates increasing multiplicity of the bond and localization of a negative charge on the oxygen atom. Intramolecular hydrogen bonds with the neiboring O atom are observed. The H∙∙∙O distances are 2.16, 1.69, 1.77 Å in 1 and 1.92, 1.79, 1.76 Å in 2. Dihedral angles between opposite phenoxide rings are 60.64° and 87.07° (1) and 83.85° and 80.42° (2), which indicates somewhat less symmetric anion in structure 1 than in structure 2. The formation of the crystal spatial structure is due to the formation of hydrogen bonds between ions with participation of oxygen and sulfur atoms, as well as СН∙∙∙π–interactions, while the ions form chains in the crystal of compound 1, and layers in the crystal of compound 2. Complete tables of atom coordinates, bond lengths and valence angles are deposited at the Cambridge Crystallographic Data Center (No. 1850118 (1); No. 2013220 (2); deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk/data_request/cif).

Исследование строения дикарбоксилатов трис(4-фторфенил)сурьмы (4-FC6H4)3Sb[OC(O)R]2 (R = C6H3F2-2,3, C6H3(NO2)2-3,5, C6H4OMe-2, CF2Br, CH=CHPh, CH3, C≡CH)

The interaction of tris(4-fluorophenyl)antimony with 2,3-difluorobenzoic acid, as well as with 3,5-dinitrobenzoic, 2-methoxybenzoic, bromodifluoroacetic, cinnamic, formic, and propionic acids in the presence of tert-butyl hydroperoxide (1:2:1 mol.) in ether at ambient temperature has given tris(4-fluorophenyl)antimony dicarboxylates (4-FC6H4)3Sb[OC(O)R]2, where R = C6H3F2-2,3 (1), C6H3(NO2)2-3,5 (2), C6H4OMe-2 (3), CF2Br (4), CH=CHPh (5), CH3 (6), и C≡CH (7). The IR spectra of compounds 17, recorded on a Shimadzu IRAffinity-1S Fourier transform IR spectrometer, in a KBr pellet within the 4000–400 cm–1 interval, contain absorption bands of carbonyl groups, which are shifted to the low-frequency vibration region in comparison with the IR spectra of the initial acids. According to the X-ray diffraction data obtained on a Bruker D8 QUEST diffractometer, compound 1 has the following crystallographic parameters of the unit cell: space group P-1, a = 9.034(4), b = 11.351(8), c = 14.814(9) Å, α = 70.11(3)°, β = 88.60(2)°, γ = 87.03(2)°, V = 1426(15) Å3, ρcalc = 1.679 g/cm3, Z = 2. The antimony atom in 1 has a distorted trigonal-bipyramidal coordination with carboxylate ligands in axial positions. The OSbO axial angle is 176.95 (6)°. The lengths of the Sb−O and Sb−C bonds are equal to 2.135(2), 2.121(2) and 2.113(3)–2.116 (3) Å. The Sb•••O=C distances are 3.040(2), 2.861 (3) Å, that is, less than the sum of the van der Waals radii of antimony and oxygen (3.70 Å). The antimony atom departs from the equatorial plane [C3] by 0.038 Å. Complete tables of atom coordinates, bond lengths and valence angles are deposited at the Cambridge Crystallographic Data Center (№ 2051716; deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk/data_request/cif).

Rational Preparation of Atomically Precise Non-Alkyl Tin-Oxo Clusters with Theoretical to Experimental Insights into Electrocatalytic CO 2 Reduction Applications

Tin oxides (SnO2) have been widely utilized in electronics, nanolithography, and catalysis. As the atomically precise models of SnO2, tin-oxo clusters (TOCs) not only provide opportunities for mech...

Multiple Hydrogen Bond-Induced Structural Distortion for Broadband White-Light Emission in Two-Dimensional Perovskites

Low-dimensional hybrid lead-halide perovskites with broadband white-light emission upon near-UV excitation have attracted immense scientific interest due to their potential application for the next...

Benchmark of Generic Shapes for Macrocycles.

Macrocycles target proteins that are otherwise considered undruggable because of a lack of hydrophobic cavities and the presence of extended featureless surfaces. Increasing efforts by computational chemists have developed effective software to overcome the restrictions of torsional and conformational freedom that arise as a consequence of macrocyclization. Moloc is an efficient algorithm, with an emphasis on high interactivity, and has been constantly updated since 1986 by drug designers and crystallographers of the Roche biostructural community. In this work, we have benchmarked the shape-guided algorithm using a dataset of 208 macrocycles, carefully selected on the basis of structural complexity. We have quantified the accuracy, diversity, speed, exhaustiveness, and sampling efficiency in an automated fashion and we compared them with four commercial (Prime, MacroModel, molecular operating environment, and molecular dynamics) and four open-access (experimental-torsion distance geometry with additional “basic knowledge” alone and with Merck molecular force field minimization or universal force field minimization, Cambridge Crystallographic Data Centre conformer generator, and conformator) packages. With three-quarters of the database processed below the threshold of high ring accuracy, Moloc was identified as having the highest sampling efficiency and exhaustiveness without producing thousands of conformations, random ring splitting into two half-loops, and possibility to interactively produce globular or flat conformations with diversity similar to Prime, MacroModel, and molecular dynamics. The algorithm and the Python scripts for full automatization of these parameters are freely available for academic use.

Secondary Metal Coordination Using a Tetranuclear Complex as Ligand Leading to Hexanuclear Complexes with Enhanced Thermal Barriers for Electron Transfer

Postsynthesis of the paramagnetic square-shaped complex {[(Tp*Me)Fe(μ-CN)2(CN)][Co(dmbpy)2]}2(BPh4)2·6MeCN·H2O [1, Tp*Me = tris(3,4,5-trimethylpyrazole)-borate; dmbpy = 4,4′-dimethyl-2,2′-bipyridin...

Acidity-Driven Bidirectional Room-Temperature Spin-State Switch and Fluorescence Modulation of a Mononuclear Fe(II) Complex

Room-temperature switchable materials showing multiple responses toward external stimuli are highly desired. Herein, we report bidirectional spin-state switch and fluorescence modulation of an Fe(I...

Positive/Negative Phototropism: Controllable Molecular Actuators with Different Bending Behavior

Herein, a series of molecular actuators based on the crystals of (E)-2-(4-fluorostyryl)benzo[d]oxazole (BOAF4), (E)-2-(2,4-difluorostyryl)benzo[d]oxazole (BOAF24), (E)-2-(4-fluorostyryl)benzo[d]thi...

Chiral Cobalt(II) Complex Catalyzed Asymmetric [2,3]-Sigmatropic Rearrangement of Allylic Selenides with α-Diazo Pyrazoleamides

Organoselenium compounds, due to their high structural diversity, special function, and biological activities, have drawn attention in synthetic chemistry. Herein, a novel example of chiral N,N′-di...

Facile Synthesis of Aryl-Substituted Cycloarenes via Bismuth(III) Triflate-Catalyzed Cyclization of Vinyl Ethers

Cycloarenes are an essential class of polycyclic aromatic hydrocarbons with unique electronic structure, but their synthesis is very challenging. Herein, we report a facile synthetic strategy prima...