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Porous liquids (PLs) are attractive materials because of their capability to combine the intrinsic porosity of microporous solids and the processability of liquids. Most of the studies focus on the synthesis of PLs with not only high porosity but also low viscosity by considering their transportation in industrial plants. However, a gap exists between PLs and solid adsorbents for some practical cases, where the liquid characteristics and mechanical stability without leakage are simultaneously required. Here, we fill in this gap by demonstrating a new concept of pore-networked gels, in which the solvent phase is trapped by molecular networks with accessible porosity. To achieve this, we fabricate a linked metal–organic polyhedra (MOPs) gel, followed by exchanging the solvent phase with a bulky liquid such as ionic liquids (ILs); the dimethylformamide solvent trapped inside the as-synthesized gel is replaced by the target IL, 1-butyl-3-methylimidazolium tetrafluoroborate, which in turn cannot enter MOP pores due to their larger molecular size. The remaining volatile solvents in the MOP cavities can then be removed by thermal activation, endowing the obtained IL gel (Gel_IL) with accessible microporosity. The CO2capacities of the gels are greatly enhanced compared to the neat IL. The exchange with the IL also exerts a positive influence on the final gel performances such as mechanical properties and low volatility. Besides ILs, various functional liquids are shown to be amenable to this strategy to fabricate pore-networked gels with accessible porosity, demonstrating their potential use in the field of gas adsorption or separation.

A new, readily tractable route to determining short-range order models for materials exhibiting occupational disorder and diffuse scattering using first-principles solid-state quantum mechanical calculations is presented and illustrated with application to the disordered, layered molecular material phloroglucinol dihydrate.

Structure–porosity relationships for metal–organic polyhedra (MOPs) are hardly investigated because they tend to be amorphized after activation, which inhibits crystallographic characterization. Here, we show a mixed-ligand strategy to statistically distribute two distinct carbazole-type ligands within rhodium-based octahedral MOPs, leading to systematic tuning of the microporosity in the resulting amorphous solids.

In coordination-based supramolecular materials such as metallogels, simultaneous temporal and spatial control of their assembly remains challenging. Here, we demonstrate that the combination of light with acids as stimuli allows for the spatiotemporal control over the architectures, mechanical properties, and shape of porous soft materials based on metal–organic polyhedra (MOPs). First, we show that the formation of a colloidal gel network from a preformed kinetically trapped MOP solution can be triggered upon addition of trifluoroacetic acid (TFA) and that acid concentration determines the reaction kinetics. As determined by time-resolved dynamic light scattering, UV–vis absorption, and 1H NMR spectroscopies and rheology measurements, the consequences of the increase in acid concentration are (i) an increase in the cross-linking between MOPs; (ii) a growth in the size of the colloidal particles forming the gel network; (iii) an increase in the density of the colloidal network; and (iv) a decrease in the ductility and stiffness of the resulting gel. We then demonstrate that irradiation of a dispersed photoacid generator, pyranine, allows the spatiotemporal control of the gel formation by locally triggering the self-assembly process. Using this methodology, we show that the gel can be patterned into a desired shape. Such precise positioning of the assembled structures, combined with the stable and permanent porosity of MOPs, could allow their integration into devices for applications such as sensing, separation, catalysis, or drug release.

Reticular framework materials thrive on designability, but unexpected reaction outcomes are crucial in exploring new structures and functionalities. By combining "incompatible" building blocks, we employed geometric frustration in reticular materials leading to emergent structural features. The combination of a pseudo-C5-symmetrical organic building unit based on a pyrrole core with a C4-symmetrical copper paddlewheel synthon led to three distinct frameworks by tuning the synthetic conditions. The frameworks show structural features typical for geometric frustration: self-limiting assembly, internally stressed equilibrium structures, and topological defects in the equilibrium structure, which manifested in formation of a hydrogen-bonded framework, distorted and broken secondary building units, and dangling functional groups, respectively. The influence of geometric frustration on the CO2sorption behavior and the discovery of a new secondary building unit shows geometric frustration can serve as a strategy to obtain highly complex porous frameworks.

The chelating ligand 1,3-bis(tris(hydroxymethyl)methylamino)propane (H6L) has been used to synthesize a family of octanuclear heterometallic complexes with the formula (NMe4)3[Mn4Ln4(H2L)3(H3L)(NO3)12] (Ln = La (1), Ce (2), Pr (3), Nd (4)). Encapsulation by the ligand causes the Mn(III) centers to lie in an unusually distorted (∼C2v) environment, which is shown by density functional theory and complete active space self-consistent field calculations to impact on the magnetic anisotropy of the Mn(III) ion. The theoretical study also supports the experimental observation of a ferromagnetic superexchange interaction between the Mn(III) ions in 1, despite the ions being separated by the diamagnetic La(III) ion. The optical properties of the compounds show that the distortion of the Mn(III) ions leads to three broad absorption bands originating from the transition metal ion, while the Nd(III) containing complex also displays some weak sharp features arising from the lanthanide f–f transitions.

Two flexible, branched, and sterically constrained di- and tripodal side arms around a phenol backbone were utilized in ligands H3L1 and H5L2 to isolate {Mn6} and {Mn3} coordination aggregates. 2,6-Bis{(1-hydroxy-2-methylpropan-2-ylimino)methyl}-4-methylphenol (H3L1) gave trinuclear complex [Mn3(μ-H2L1)2(μ1,3-O2CCH3)4(CH3OH)2](ClO4)2·4CH3OH (1), whereas 2,6-bis[{1-hydroxy-2-(hydroxymethyl)butan-2-ylimino}methyl]-4-methylphenol (H5L2) provided hexanuclear complex [Mn6(μ4-H2L2)2(μ-HL3)2(μ3-OH)2(μ1,3-O2CC2H5)4](ClO4)2·2H2O (2). Binding of acetates and coordination of {H2L1}−provided a linear MnIIIMnIIMnIIIarrangement in 1. A MnIII6fused diadamantane-type assembly was obtained in 2from propionate bridges, coordination of {H2L2}3–, and in situ generated {HL3}2–. The magnetic characterization of 1and 2revealed the properties dominated by intramolecular anti-ferromagnetic exchange interactions, and this was confirmed using density functional theory calculations. Complex 1exhibited field-induced slow magnetic relaxation at 2 K due to the axial anisotropy of MnIIIcenters. Both the complexes show effective solvent-dependent catechol oxidation toward 3,5-di-tert-butylcatechol in air. The catechol oxidation abilities are comparable from two complexes of different nuclearity and structure.

Four different carboxylato bridges have been efficiently utilized for growth of three tetranuclear nickel(II) complexes [Ni4(μ3-H2L)2(μ3-OH)2(μ1,3-CH3CO2)2](ClO4)2(1), [Ni4(μ3-H2L)2(μ3-OH)2(μ1,3-C2H5CO2)2](ClO4)2·1/2H2O (2), and [Ni4(μ3-H2L)2(μ3-OH)2(μ1,3-O2C-C6H4-pNO2)2](ClO4)(p-NO2-C6H4-CO2)·DMF·5H2O (3) and one dinuclear nickel(II)-based chain complex {[Ni2(μ-H2L)(μ1,3-O2CCH2Ph)2(H2O)](ClO4)·1/2(CH3OH)}n(4). These were obtained via the reaction of Ni(ClO4)2·6H2O with H3L [2,6-bis((2-(2-hydroxyethylamino)ethylimino)methyl)-4-methylphenol] and RCO2Na (R = CH3,C2H5, p-NO2C6H4, and PhCH2). This family of complexes is developed from {Ni2(μ-H2L)}3+fragments following self-aggregation. The complexes were characterized by X-ray crystallography and magnetic measurements. The changes from acetate, propionate, and p-nitrobenzoate to phenylacetate groups resulted in two different types of coordination aggregation. These compounds are new examples of [Ni4] and [Ni2]ncomplexes where organization of the building motifs are guided by the type of the carboxylate groups responsible for in-situ generation and utilization of HO–bridges with alteration in the aggregation process within the same ligand environment. Studies on the magnetic behavior of the compounds reveal that the exchange coupling within 1–4is predominantly antiferromagnetic in nature.

Heterogenization of molecular catalysts via their immobilization within extended structures often results in a lowering of their catalytic properties due to a change in their coordination sphere. Metal–organic polyhedra (MOP) are an emerging class of well-defined hybrid compounds with a high number of accessible metal sites organized around an inner cavity, making them appealing candidates for catalytic applications. Here, we demonstrate a design strategy that enhances the catalytic properties of dirhodium paddlewheels heterogenized within MOP (Rh-MOP) and their three-dimensional assembled supramolecular structures, which proved to be very efficient catalysts for the selective photochemical reduction of carbon dioxide to formic acid. Surprisingly, the catalytic activity per Rh atom is higher in the supramolecular structures than in its molecular sub-unit Rh-MOP or in the Rh-metal–organic framework (Rh-MOF) and yields turnover frequencies of up to 60 h–1and production rates of approx. 76 mmole formic acid per gram of the catalyst per hour, unprecedented in heterogeneous photocatalysis. The enhanced catalytic activity is investigated by X-ray photoelectron spectroscopy and electrochemical characterization, showing that self-assembly into supramolecular polymers increases the electron density on the active site, making the overall reaction thermodynamically more favorable. The catalyst can be recycled without loss of activity and with no change of its molecular structure as shown by pair distribution function analysis. These results demonstrate the high potential of MOP as catalysts for the photoreduction of CO2and open a new perspective for the electronic design of discrete molecular architectures with accessible metal sites for the production of solar fuels.

Rational design versus serendipity: The first two high‐nuclearity MnII/IIIclusters with a novel extended bis(phenylpyrazolyl)pyridyl ligand (see graphic) are described in a promising route for the preparation of new magnetic coordination aggregates, differing from conventional methods involving small bridging ligands.

A novel bispyrazolylpyridine ligand incorporating lateral phenol groups, H4L, has led to an FeIIspin‐crossover (SCO) complex, [Fe(H4L)2][ClO4]2⋅H2O⋅2 (CH3)2CO (1), with an intricate network of intermolecular interactions. It exhibits a 40 K wide hysteresis of magnetization as a result of the spin transition (with T0.5of 133 and 173 K) and features an unsymmetrical and very rich structure. The latter is a consequence of the coupling between the SCO and the crystallographic transformations. The high‐spin state may also be thermally trapped, exhibiting a very large TTIESST(≈104 K). The structure of 1has been determined at various temperatures after submitting the crystal to different processes to recreate the key points of the hysteresis cycle and thermal trapping; 200 K, cooled to 150 K and trapped at 100 K (high spin, HS), slowly cooled to 100 K and warmed to 150 K (low spin, LS). In the HS state, the system always exhibits disorder for some components (one ClO4−and two acetone molecules) whereas the LS phases show a relative ≈9 % reduction in the FeN bond lengths and anisotropic contraction of the unit cell. Most importantly, in the LS state all the species are always found to be ordered. Therefore, the bistability of crystallographic order–disorder coupled to SCO is demonstrated here experimentally for the first time. The variation in the cell parameters in 1also exhibits hysteresis. The structural and magnetic thermal variations in this compound are paralleled by changes in the heat capacity as measured by differential scanning calorimetry. Attempts to simulate the asymmetric SCO behaviour of 1by using an Ising‐like model underscore the paramount role of dynamics in the coupling between the SCO and the crystallographic transitions.

Within spin‐crossover solids…︁…︁ strong intermolecular interactions afford a means for the propagation of molecular‐scale changes and coupling with crystallographic phase transitions, which leads to intricate cooperative phenomena. In their Full Paper on page 3120 ff., J. S. Costa, O. Roubeau, G. Aromí et al. report on a novel spin‐crossover FeIIcomplex that features a dense network of intermolecular interactions. This results in a large unsymmetrical hysteresis of the spin state, which correlates with a crystallographic order–disorder transition.