Acta Crystallographica Section C Structural Chemistry最新文献

In this study, we report the results of continuous rotation electron diffraction studies of single DyPO₄·nH₂O (rhabdophane) nanocrystals. The diffraction patterns can be fit to a trigonal lattice (P3₁21) with lattice parameters a = 7.019 (5) and c = 6.417 (5) Å. However, there is also a set of diffuse background scattering features present that are associated with a disordered superstructure that is double these lattice parameters and fits with an arrangement of water molecules present in the structure pore. Pair distribution function (PDF) maps based on the diffuse background allowed the extent of the water correlation to be estimated, with 2-3 nm correlation along the c axis and ∼5 nm along the a/b axis.

Research concerning coordination polymers has been intense due to their significant variability and structural stability. With this in mind, an ionic neodymium coordination polymer was synthesized, composed of an anionic one-dimensional polymer interconnected to a cationic three-dimensional porous polymer, poly[dodecaaquabis(μ-pyridine-4-carbohydrazide-κ²N:O)bis(μ₂-4-sulfobenzoato-κ²O:O')bis(μ₃-4-sulfobenzoato-κ³O:O':O'')trineodymium(III)] catena-poly[aquabis(μ-pyridine-4-carbohydrazide-κ²N:O)bis(μ₂-4-sulfobenzoato-κ²O:O')neodymium(III)] 4.33-hydrate, {[Nd₃(C₇H₄O₅S)₄(C₆H₇N₃O)₂(H₂O)₁₂][Nd(C₇H₄O₅S)₂(C₆H₇N₃O)₂(H₂O)]·4.33H₂O}_n. The ligands used were 4-sulfobenzoate (PSB) and pyridine-4-carbohydrazide, popularly known as isoniazid (INH), an antibiotic drug. The compound crystallizes in the monoclinic space group C2/c, with Z = 4. Solid-state calculations suggest that the crystal structure is mainly stabilized by hydrogen bonds, i.e. O-H...O and N-H...O interactions among the polymers, and by van der Waals interactions involving the organic side chains. This net is tetragonal, 2-nodal 3,4-connected, and can be described as the dmd (sqc 528) type.

We report the crystal structures of three matrine derivatives, namely, the salts (1R,2R,9S,17S)-6-oxo-7,13-diazatetracyclo[7.7.1.0^2,7.0^13,17]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[7.7.1.0^2,7.0^13,17]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.

Over the last three decades, the technology that makes it possible to follow chemical processes in the solid state in real time has grown enormously. These studies have important implications for the design of new functional materials for applications in optoelectronics and sensors. Light-matter interactions are of particular importance, and photocrystallography has proved to be an important tool for studying these interactions. In this technique, the three-dimensional structures of light-activated molecules, in their excited states, are determined using single-crystal X-ray crystallography. With advances in the design of high-power lasers, pulsed LEDs and time-gated X-ray detectors, the increased availability of synchrotron facilities, and most recently, the development of XFELs, it is now possible to determine the structures of molecules with lifetimes ranging from minutes down to picoseconds, within a single crystal, using the photocrystallographic technique. This review discusses the procedures for conducting successful photocrystallographic studies and outlines the different methodologies that have been developed to study structures with specific lifetime ranges. The complexity of the methods required increases considerably as the lifetime of the excited state shortens. The discussion is supported by examples of successful photocrystallographic studies across a range of timescales and emphasises the importance of the use of complementary analytical techniques in order to understand the solid-state processes fully.

The crystal structure of the salt calcium (2R,3R)-tartrate tetrahydrate {systematic name: poly[[diaqua[μ₄-(2R,3R)-2,3-dihydroxybutanedioato]calcium(II)] dihydrate]}, {[Ca(C₄H₈O₈)(H₂O)₂]·2H₂O}_n, is reported. The absolute configuration of the crystal was established unambiguously using anomalous dispersion effects in the diffraction patterns. High-quality data also allowed the location and free refinement of all the H atoms, and therefore to a careful analysis of the hydrogen-bond interactions.

The crystal structures of 16 boron subphthalocyanines (BsubPcs) with structurally diverse axial groups were analyzed and compared to elucidate the impact of the axial group on the intermolecular π-π interactions, axial-group interactions, axial bond length and BsubPc bowl depth. π-π interactions between the isoindole units of adjacent BsubPc molecules most often involve concave-concave packing, whereas axial-group interactions with adjacent BsubPc molecules tend to favour the convex side of the BsubPc bowl. Furthermore, axial groups that contain O and/or F atoms tend to have significant hydrogen-bonding interactions, while axial groups containing arene site(s) can participate in π-π interactions with the BsubPc bowl, both of which can strongly influence the crystal packing. Bulky axial groups did tend to disrupt the π-π interactions and/or axial-group interactions, preventing some of the close packing that is seen in BsubPcs with less bulky axial groups. The atomic radius of the heteroatom bonded to boron directly influences the axial bond length, whereas the axial group has minimal impact on the BsubPc bowl depth. Finally, the crystal growth method did not generally appear to have a significant impact on the solid-state arrangement, with the exception of water occasionally being incorporated into crystal structures when hygroscopic solvents were used. These insights can help with the design and fine-tuning of the solid-state structures of BsubPcs as they continue to be developed as functional materials in organic electronics.

Two new two-dimensional (2D) coordination polymers (CPs), namely, poly[diaqua[μ₄-2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetato-κ⁴O:O':O'':O''']cadmium(II)], [Cd(C₁₄H₆N₂O₈)(H₂O)₂]_n (1), and poly[[tetraaqua[μ₄-2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetato-κ⁴O:O':O'':O'''][μ₂-2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetato-κ²O:O']dizinc(II)] dihydrate], {[Zn(C₁₄H₆N₂O₈(H₂O)₂]·H₂O}_n (2), have been synthesized by the microwave-irradiated reaction of Cd(CH₃COO)₂·2H₂O and Zn(CH₃COO)₂·2H₂O, respectively, with N,N'-bis(glycinyl)pyromellitic diimide {BGPD, namely, 2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetic acid, H₂L}. In the crystal structure of 1, the Cd^II ion is six-coordinated by four carboxylate O atoms from four symmetry-related L^2- dianions and two coordinated water molecules, furnishing an octahedral coordination geometry. The bridging L^2- dianion links four symmetry-related Cd^II cations into a 2D layer-like structure with a 3,4-connected bex topology. In the crystal structure of 2, the Zn^II ion is five-coordinated by three carboxylate O atoms from three different L^2- dianions and two coordination water molecules, furnishing a trigonal bipyramidal coordination geometry. Two crystallographically independent ligands serve as μ₄- and μ₂-bridges, respectively, to connect the Zn^II ions, thereby forming a 2D layer with a 3,3-connected hcb topology. Crystal structure analysis reveals the presence of n→π* interactions between two carbonyl groups of the pyromellitic diimide moieties in 1 and 2. CP 1 exhibits an enhanced fluorescence emission compared with free H₂L. The framework of 2 decomposes from 720 K, indicating its high thermal stability. A comparative analysis of a series of structures based on the BGPD ligand indicates that the metal-ion size has a great influence on the connection modes of the metal ions due to different steric effects, which, in turn, affects the structures of the SBUs (secondary building units) and frameworks.

A new three-dimensional (3D) coordination polymer, namely, poly[diaqua[μ₅-2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetato]barium(II)], [Ba(C₁₄H₆N₂O₈)(H₂O)₂]_n, (I), has been synthesized by the microwave-irradiated reaction of Ba(NO₃)₂ with N,N'-bis(glycinyl)pyromellitic diimide {BGPD, namely, 2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetatic acid, H₂L}. The title compound was structurally characterized by single-crystal X-ray diffraction analysis and powder X-ray diffraction analysis, as well as IR spectroscopy. In the crystal structure of (I), the Ba^II ion is nine-coordinated by six carboxylate O atoms from five symmetry-related L^2- dianions and one imide O atom, as well as two water O atoms. The coordination geometry of the central Ba^II ion can be described as a spherical capped square antiprism. One carboxylate group of the ligand serves as a μ₃-bridge linking the Ba^II cations into a one-dimensional polynuclear secondary building unit (SBU). Another carboxylate group of the ligand acts as a μ₂-bridge connecting the 1D SBUs, thereby forming a two-dimensional (2D) SBU. The resulting 2D SBUs are extended into a 3D framework via the pyromellitic diimide moiety of the ligand as a spacer. The 3D Ba framework can be simplified as a 5-connected hexagonal boron nitride net (bnn) topology. The intermolecular interactions in the 3D framework were further investigated by Hirshfeld surface analysis and the results show that the prominent interactions are H...O (45.1%), Ba...O (11.1%) and C...H (11.1%), as well as H...H (11.1%) contacts. The thermal stability, photoluminescence properties and UV-Vis absorption spectra of (I) were also investigated. The coordination polymer exhibits a fluorescence emission with a quantum yield of 0.071 and high thermal stability.

Historically, knowledge of the molecular packing within the crystal structures of organic semiconductors has been instrumental in understanding their solid-state electronic properties. Nowadays, crystal structures are thus becoming increasingly important for enabling engineering properties, understanding polymorphism in bulk and in thin films, exploring dynamics and elucidating phase-transition mechanisms. This review article introduces the most salient and recent results of the field.