The rotational dynamics, dielectric response and phase transitions of a unique crystalline supramolecular rotor are controlled by the existence/absence of guest water molecules causing prominent ...effects on the supramolecular interactions. Such an unprecedented rotationally bistable rotor can promote the understanding of precise control of molecular rotors in crystals.
A supramolecular rotor exhibits two switchable rotational states controlled by guest water in crystals.
Using Na-encapsulated benzo18crown-6 (Na)(B18C6) as a counter cation, we successfully magnetically isolated a fluoride-bridging Dy dinuclear complex {(PW
11
O
39
)Dy(H
2
O)
2
2
F} (Dy
2
POM) with ...lacunary Keggin ligands. (Na)(B18C6) formed two types of tetramers through C-H O, π π and C-H π interactions, and each tetramer aligned in one dimension along the
c
-axis to form two types of channels. One channel was partially penetrated by a supramolecular cation from the ±
a
-axis direction, dividing the channel in the form of a "bamboo node". Dy
2
POM was spatially divided by this "bamboo node," which magnetically isolated one portion from the other. The temperature dependence of the magnetic susceptibility indicated a weak ferromagnetic interaction between the Dy ions bridged by fluoride. Dy
2
POM exhibited the magnetic relaxation characteristics of a single-molecule magnet, including the dependence of AC magnetic susceptibility on temperature and frequency. Magnetic relaxation can be described by the combination of thermally active Orbach and temperature-independent quantum tunneling processes. The application of a static magnetic field effectively suppressed the relaxation due to quantum tunneling.
(Na
+
)(benzo18crown-6) forms a bamboo-like supramolecular architecture within the crystal. Dinuclear Dy complexes with polyoxometalate ligands embedded between bamboo nodes exhibited a clear single-molecule magnet (SMM) response.
The key to designing and fabricating highly efficient mixed protonic–electronic conductors materials (MPECs) is to integrate the mixed conductive active sites into a single structure, to break ...through the shortcomings of traditional physical blending. Herein, based on the host–guest interaction, an MPEC is consisted of 2D metal–organic layers and hydrogen‐bonded inorganic layers by the assembly methods of layered intercalation. Noticeably, the 2D intercalated materials (≈1.3 nm) exhibit the proton conductivity and electron conductivity, which are 2.02 × 10−5 and 3.84 × 10−4 S cm−1 at 100 °C and 99% relative humidity, much higher than these of pure 2D metal–organic layers (>>1.0 × 10−10 and 2.01×10−8 S cm−1), respectively. Furthermore, combining accurate structural information and theoretical calculations reveals that the inserted hydrogen‐bonded inorganic layers provide the proton source and a networks of hydrogen−bonds leading to efficient proton transport, meanwhile reducing the bandgap of hybrid architecture and increasing the band electron delocalization of the metal–organic layer to greatly elevate the electron transport of intrinsic 2D metal–organic frameworks.
The guest particles of inorganic ions and/or molecules insert into the interlamination of neutral host framework 2D MOFs, manufacturing the host–guest architecture of 2D metal–organic layers and hydrogen‐bonded inorganic layers. The intercalated layer provides the proton source and reduces the bandgap of hybrid architecture, which leads to the high‐efficiency mixed protonic–electronic transport.
We present a new hybrid compound, namely (Me
2
NH
2
)KFe(CN)
5
(NO), possessing a unique nitroprusside-based inorganic host framework in 4-connected
sra
topology encapsulating organic guest cations. ...The flexible host-guest hydrogen bonds and synchronously deformed inorganic framework give rise to thermal-responsive switching behaviours on both thermal expansion and nonlinear optical properties during the phase transition at around room temperature.
A new nitroprusside-based hybrid (Me
2
NH
2
)KFe(CN)
5
(NO) exhibits thermo-responsive switching behaviours on uniaxial expansivity and SHG signal owing to flexible host-guest hydrogen bonds and the synchronously deformable inorganic framework.
Two new compounds were obtained by assembling the (2-methoxy-5-nitro-anilinium)(18-crown-6)
+
cation with non-polar PF
6
−
and polar SO
3
CF
3
−
anions, respectively. Benefiting from its polar anion, ...the SO
3
CF
3
−
compound reveals a more significant dielectric switching behaviour during phase transition, demonstrating an effective strategy to enhance the dielectric property by adding polar components.
Two new crystalline compounds containing non-polar and polar anions, respectively, reveal distinct dielectric switching responses.
Designing and synthesizing more advanced high-energetic materials for practical use via a simple synthetic route are two of the most important issues for the development of energetic materials. ...Through an elaborate design and rationally selected molecular components, two new metal-free hexagonal perovskite compounds, which are named as DAP-6 and DAP-7 with a general formula of (H2dabco)B(ClO4)3 (H2dabco2+ = 1,4-diazabicyclo2.2.2octane-1,4-diium), were fabricated via an easily scaled-up synthetic route using NH3OH+ and NH2NH3+ as B-site cations, respectively. Compared with their NH4+ analog ((H2dabco)(NH4)(ClO4)3; DAP-4), which has a cubic perovskite structure, DAP-6 and DAP-7 have higher crystal densities and enthalpies of formation, thus exhibiting higher calculated detonation performances. Specifically, DAP-7 has an ultrahigh thermal stability (decomposition temperatures (Td) = 375.3 °C), a high detonation velocity (D = 8.883 km·s−1), and a high detonation pressure (P = 35.8 GPa); therefore, it exhibits potential as a heat-resistant explosive. Similarly, DAP-6 has a high thermal stability (Td = 245.9 °C) and excellent detonation performance (D = 9.123 km·s−1, P = 38.1 GPa). Nevertheless, it also possesses a remarkably high detonation heat (Q = 6.35 kJ·g−1) and specific impulse (Isp = 265.3 s), which is superior to that of hexanitrohexaazaisowurtzitane (CL-20; Q = 6.23 kJ·g−1, Isp = 264.8 s). Thus, DAP-6 can serve as a promising high-performance energetic material for practical use.
Zero thermal expansion materials are crucial for manufacturing high-precision devices, but most of these materials discovered so far are inorganic. Organic zero thermal expansion materials are rare ...due to the need for precise control over the complex supramolecular interactions between organic groups in order to modulate their thermal expansion properties. Here, we report a novel organic crystalline supramolecular rotor, (3-chloro-1-adamantylammonium)(18-crown-6)ClO4, which exhibits planar positive–zero–negative thermal expansion along the a- and c-axes, with zero thermal expansion behavior in the range of 250–317 K. X-ray single-crystal structures, differential scanning calorimetry (DSC) measurements, and molecular dynamics simulations disclosed that such unique transition in thermal expansion results from the static–swing–rotation transition of 18-crown-6 in the crystal structure.
Although the development of artificial molecular machines has garnered considerable attention in recent years, the construction of multifunctional solid-state molecular machines still faces several ...challenges. Herein, we report a supramolecular approach as an efficient strategy for building multifunctional trigger systems. In crystals composed of Ni(dmit)2− with a spin of S = 1/2 and supramolecular structures consisting of 4-aminopyridinium+ and benzo18crown-6, supramolecular cations with dynamic degrees of freedom affect the magnetic and dielectric properties and induce negative thermal expansion (NTE). The supramolecular cations in the crystals form one-dimensional columns. Two adjacent columns form a supramolecular ladder structure via π···π interactions between the phenylene groups of benzo18crown-6 and are arranged within a two-dimensional layer. A disorder between the two sites of the phenylene ring was observed in one of the crystallographically independent benzo18crown-6. Disordered benzo18crown-6 formed polar domains within the crystal, resulting in relaxor ferroelectricity. With increasing temperature, the supramolecular ladders elongated and the translational motion of benzo18crown-6 caused the molecular ladder to move closer to each other. Consequently, the crystals shrunk in the direction perpendicular to the ladder, exhibiting uniaxial NTE, and the magnetic exchange interaction between the Ni(dmit)2− crystals was disrupted.
In Mn(5-MeOsalen)(Cl)
2
(dibenzo24crown-8), dibenzo24crown-8 formed a supramolecule
via
multi-point interactions with the Mn(5-MeOsalen)(Cl) dimer. The dimer was magnetically isolated with
S
T
= 4 ...and weak interdimer magnetic interactions. The crystal exhibited single-molecule magnet behaviour with an anisotropic barrier of 26(1) K, which is the highest among the Mn-salen series reported to date.
Neutral Mn salen-type dimer is magnetically isolated and exhibits SMM behaviour by supramolecular formation with dibenzo24crown-8 in a crystal.
In Mn(5-MeOsalen)(Cl)2(dibenzo24crown-8), dibenzo24crown-8 formed a supramolecule via multi-point interactions with the Mn(5-MeOsalen)(Cl) dimer. The dimer was magnetically isolated with ST = 4 and ...weak interdimer magnetic interactions. The crystal exhibited single-molecule magnet behaviour with an anisotropic barrier of 26(1) K, which is the highest among the Mn-salen series reported to date.
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