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All-proportional solid solutions of the metal-free perovskite (H2dabco1−y, H2hmtay)(NH4)(BF4)3 ((d,h)-BF4) were crystallized via a mechanochemical method. Their molecular dynamics depend on the ratio y with a compositional boundary at y = 0.43, where H2dabco2+ was deduced to be at a dynamic disorder state, even below phase transition temperature to a plastic crystalline phase seen at y = 0. [ABSTRACT FROM AUTHOR]

Flexible crystalline solids exhibit unique properties in response to external stimuli like heat and light. However, challenges exist in developing crystalline solids that have similar degrees of flexibility as in solution. Herein, we report the preparation of the new flexible crystalline metal complex [Cd(CF3SO3)2(4‐spy)4] (4‐spy=4‐styrylpyridine), which contains photoreactive 4‐spy ligand. Unlike traditional solids, this metal complex displays solution state‐like [2+2] photocycloaddition reactivity. Specifically, UV irradiation of the crystalline material leads to formation of the same diverse array of dimers and cis isomer that are generated by photoreaction in the solution state. In addition, the photoresponsive flexibility of the solid leads to a photosalient effect and photo‐induced formation of pores. The origin of the solution state‐like photoreactivity of the solid is related to properties of the Cd(II) cation and fluorinated CF3SO3 anion, and the multi‐orientational arrangement of the 4‐spy ligands. [ABSTRACT FROM AUTHOR]

1,4-Diazabicyclo[2.2.2]octane (dabco) forms one-dimensional chains through intermolecular N–H+⋯N hydrogen bonds and exhibits ferroelectricity originating from proton transfer. The size of the polarized domain differs depending on the size, symmetry, and polarizability of the counter anions. Herein, two binary halide solid solutions of dabcoHBr mixed with dabcoHCl (ClBr) and dabcoHI (BrI) were prepared, and the temperature dependence of the single crystal structure and the phase transition behaviour were investigated. The solid solution of ClBr contained 3% Cl− in dabcoHBr; thus, the lattice length, space group, and volume were similar to those of dabcHBr. The phase transition temperature from the hydrogen-bonded structure to the ion-pair structure decreased from 458 to 440 K upon mixing with Cl−. In contrast, solid solution BrI was formed with all proportional solid solutions, and the crystallographic parameters characterised by single-crystal X-ray diffraction (XRD) analysis obeyed Vegard's law. Phase transition behaviours were investigated for single crystals of Br : I = 8 : 2 (Br0.80I0.20) via temperature-variable single crystal XRD analysis. A new structural range was observed between 251–373 K. Within this range, the intermolecular N–H+⋯N hydrogen bonds were weakened. This was also a ferroelectric phase similar to that of the original dabcoHBr. In the high-temperature range, a phase transition from the hydrogen-bonded phase to the ion-pair phase was observed at 435 K, which was lower than the 458 K of dabcoHBr. [ABSTRACT FROM AUTHOR]

A highly condensed packing structure with π-molecules is important to achieve high carrier transport properties. To realize condensed π-molecular arrangements, we focused on electrostatic crystal lattices consisting of cation–anion pairs and further designed an anionic N,N′-bis(ethyl sulfonate)-naphthalenediimide (ESNDI2−), which introduces structural flexibility at two –C2H4SO3− side arms. The size of the counter cation (M+) was varied from Na+, K+, Rb+, and Cs+ to design a precise crystal lattice of (M+)2(ESNDI2−)·(H2O)n salts, which is divided into hydrated salts (M+ = Na+ and K+) and anhydrous salts (M+ = K+, Rb+, and Cs+). Salt for M+ = K+ is a boundary between hydrated and anhydrous crystals, and exhibited reversible H2O adsorption–desorption behavior at 298 K. In addition, the K+ salts showed transient conductivity (φΣμ) switching behavior associated with the H2O adsorption–desorption cycle. The anhydrous salts for M+ = K+, Rb+, and Cs+ had isomorphous crystal structures, with the appearance of a two-dimensional (2D) herringbone arrangement in ESNDI2−. The condensed packing arrangement and highest φΣμ value were observed in (Rb+)2(ESNDI2−) salt. In these anhydrous salts, crystalline domains were easily formed using the simple casting method on the substrate surface. The temperature- and frequency-dependence of the dielectric constant indicated the presence of thermally induced structural fluctuations in these ionic crystal lattices. In hydrated crystals, thermal motions of Na+, K+, and H2O were dominant, whereas thermal fluctuations in the rigid M+⋯−O3S– Coulomb lattice were observed in anhydrous crystals as Debye-type relaxation. Precise structural control of the electrostatic crystal lattice determines the optimization conditions for achieving condensed π-molecular arrangement. [ABSTRACT FROM AUTHOR]

Materials exhibiting irreversible phase transitions, leading to changes in their properties, have a potential for novel application in electronic components such as a non‐rewritable high‐security memory. Here, we focused on the two salts, [(9‐triptycylammonium)([18]crown‐6)][Ni(dmit)2] (1) and [(9‐triptycylammonium)([15]crown‐5)][Ni(dmit)2] (2), which featured 2D sheet structures with alternately stacked cation and anion layers. Both salts exhibit similar cation arrangements, however, their anion arrangements differ significantly. The temperature‐dependent magnetic susceptibilities of 1 and 2 were well reproduced by the alternating chain model (JAC1/kB=−306(8), JAC2/kB=−239(3) K) and the Curie‐Weiss model (θ=−3.9(1) K), respectively. 1 experience a reversible phase transition around 40–60 K, causing anomalies in magnetic behavior. Moreover, an irreversible single‐crystal‐to‐single‐crystal phase transition to 1′ undergo at ~381 K, inducing a rearrangement of [Ni(dmit)2]− anions and a resistivity decrease from 6.5×106 to 6.5×102 Ω cm. The susceptibility curve of 1′ was reproduced by a combination of the Curie‐Weiss and dimer models (Jdimer/kB=−407(5), θ=−26.7(5) K). The irreversible transition of 1 is the first example for such supramolecule and [Ni(dmit)2]− system to our knowledge, in opening potential new‐type materials. [ABSTRACT FROM AUTHOR]

X-ray analysis of I p i -xylene- B 1 b (1:1) revealed that, perpendicular to an alternating donor-acceptor columnar stack, a ribbon network of B 1 b had formed via ChBs through S•••N C contacts ( I D i SB 1 sb : 3.22 Å, I i SB 1 sb : 137.2°, I i SB 1 sb : 112.2°; I D i SB 2 sb : 3.24 Å, I i SB 2 sb : 142.8°, I i SB 2 sb : 111.1°, respectively, for two sets of S•••N C contacts). Despite the strong ChB in Se analogues, further studies on the exploitation of ChB-related functions have been mainly conducted using BTDA ( B 1 b ), based on the higher solubility and stronger electron-accepting properties of B 1 b than of B 2 b and B 3 b ( I E i SB 1 sb SP I red i sp : -0.50 V and -0.63 V vs Fc/Fc SP + sp in MeCN, respectively). [74] The absence of S•••N C contacts in the crystal of TSeT- B 1 b can be rationalized by considering that the stronger ChBs involving Se atoms overwhelm the ChBs through S•••N C contacts in B 1 b . Keywords: supramolecular chemistry; host-guest systems; heterocycles; electron transfer; chalcogen bond; charge-transfer complex; overcrowded ethylene; crystal structure EN supramolecular chemistry host-guest systems heterocycles electron transfer chalcogen bond charge-transfer complex overcrowded ethylene crystal structure 1978 1990 13 10/09/23 20231024 NES 231024 Graph 1 Introduction Secondary bonding interactions (SBIs) have recently attracted a great deal of attention. [Extracted from the article]

Crystal structures of a tetrahedral Fe4 cluster (NH4@Fe4 ≡ 1) were investigated using a set of crystals prepared by changing the halomethane (CCl4, CHCl3, CHBr3, CH2Cl2, CH2Br2) used as the crystalline solvent. X-ray diffraction studies using single crystals clarified the structural distortion of 1 from the regular tetrahedron in pristine 1·15.88H2O. We revealed that central ammonium stabilizes the distorted structure by forming an intramolecular hydrogen bond with a ligand. By impedance measurements of the crystals, Debye-type dipole relaxations of the guest molecule were observed around 100 K. [ABSTRACT FROM AUTHOR]