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The combination of 4-hydroxybenzoic acid (H2hba) with Li+, Mg2+ and Cu2+ yields coordination polymers in which metal centres are bridged by an anion of the acid, either Hhba− or hba2−. In the case of Li+, a 3D network of composition Li2(hba)DMF was isolated in which parallel channels are occupied by coordinated DMF molecules. Mg2+ combines with H2hba to form a 2D square grid network with the formula Mg(Hhba)2(H2O)2. The alignment of parallel sheets results in the formation of channels filled with 1,4-dioxane molecules that hydrogen bond to coordinated water molecules. The compound Cu3(hba)2(OH)2(1,4-dioxane)1.5·0.5(1,4-dioxane) is a complex 3D network formed from the combination of Cu2+ with H2hba under basic conditions. The crystal structure determination reveals bridging 1,4-dioxane molecules. A reversible phase change occurs in the temperature range 200–220 K. The investigation highlights the key role of the solvent molecules in the structures of this series of compounds. [ABSTRACT FROM AUTHOR]

Reaction of the chloranilate dianion with Y(NO3)3 in the presence of Et4N+ in the appropriate proportions results in the formation of (Et4N)[Y(can)2], which consists of anionic square‐grid coordination polymer sheets with interleaved layers of counter‐cations. These counter‐cations, which serve as squat pillars between [Y(can)2] sheets, lead to alignment of the square grid sheets and the subsequent generation of square channels running perpendicular to the sheets. The crystals are found to be porous and retain crystallinity following cycles of adsorption and desorption. This compound exhibits a high affinity for volatile guest molecules, which could be identified within the framework by crystallographic methods. In situ neutron powder diffraction indicates a size‐shape complementarity leading to a strong interaction between host and guest for CO2 and CH4. Single‐crystal X‐ray diffraction experiments indicate significant interactions between the host framework and discrete I2 or Br2 molecules. A series of isostructural compounds (cat)[MIII(X‐an)2] with M=Sc, Gd, Tb, Dy, Ho, Er, Yb, Lu, Bi or In, cat=Et4N, Me4N and X‐an=chloranilate, bromanilate or cyanochloranilate bridging ligands have been generated. The magnetic properties of representative examples (Et4N)[Gd(can)2] and (Et4N)[Dy(can)2] are reported with normal DC susceptibility but unusual AC susceptibility data noted for (Et4N)[Gd(can)2]. An extensive family of square grid anionic coordination polymers is formed by the combination of 8‐coordinate trivalent metal ions with bridging chloranilate ligands. Alignment of the square grid networks produces channels that are able to accommodate a variety species. The location of guest molecules within the channels has been determined using both X‐ray and neutron diffraction. [ABSTRACT FROM AUTHOR]

The uptake of inhalation anesthetics by three topologically identical frameworks is described. The 3D network materials, which possess square channels of different dimensions, are formed from the relatively simple combination of ZnII centres and dianionic ligands that contain a phenolate and a carboxylate group at opposite ends. All three framework materials are able to adsorb N2O, Xe and isoflurane. Whereas the framework with the widest channels is able to adsorb large quantities of the various guests from the gas phase, the frameworks with the narrower channels have superior binding enthalpies and exhibit higher levels of retention. The use of ligands in which substituents are bound to the aromatic rings of the bridging ligands offers great scope for tuning the adsorption properties of the framework materials. [ABSTRACT FROM AUTHOR]

The structure of Li(inox) ⋅2/3 DMF (inox−=the N-oxide of the isonicotinate anion) consists of a 3D framework with solvent-filled, square cross-section channels of approximate dimensions 5.5×5.5 Å. Unfortunately, the Li(inox) framework is unstable upon removal of DMF from the channels. When the structurally related 4-hydroxybenzoic acid (H2hba) was used in place of Hinox, and Zn2+ in place of the Li+, a structurally similar but more robust network, Zn(hba), was obtained; the isostructural compound, Co(hba), may also be prepared. Longer ligands with phenolate and carboxylate functional groups at opposite ends, such as the dianions of 4-coumaric acid (H2cma) and 4′-hydroxy-4-biphenylcarboxylic acid (H2hbpc), in combination with Zn2+ yield Zn(cma) and Zn(hbpc) frameworks, respectively, with the same PtS topology but with larger channels. The coordination polymers remain intact after desolvation and exhibit microporosity, showing the ability to sorb significant quantities of CO2, CH4, and H2. [ABSTRACT FROM AUTHOR]

The monoanion of 1,3-bis(carboxymethyl)imidazolium (H2imdc+) combines with Cu(ii) to produce an undulating 2D coordination polymer of composition [Cu2(imdc)2(CH3OH)2](BF4)2·(CH3OH)(H2O) (1) in which copper acetate-like dimers, linked by imdc− ligands, act as 4-connecting centres. Cationic sheets stack on top of each other in an A, B, A, B… fashion and produce a structure that contains channels running parallel to the plane of network. Tetrafluoroborate anions are located in channels between sheets. Upon removal of coordinated and non-coordinated solvent molecules a single crystal-to-single crystal transformation occurs to yield a similar compound but with BF4− anions now coordinated. CO2 isotherms measured at 258 and 273 K show only modest uptake of CO2 but provide an indication that the sheets move apart at elevated pressures in order to accommodate the guest molecules. A compound of composition [Cu3(OH)2(imdc)2]·SiF6·2H2O·2MeOH (3), which possesses a 3D network, is formed by the combination of copper(ii) acetate, copper(ii) hexafluorosilicate and Himdc. In this structure infinite parallel Cu3(OH)2 chains are linked by bridging imdc− ligands to form channels that have an approximately triangular cross-section. These channels are occupied by SiF62− anions in addition to solvent molecules. When copper(ii) acetate is combined with Himdc in the appropriate ratio, a 1D coordination polymer of composition Cu(imdc)2 (4) is formed in which pairs of imdc− anions bridge Cu(ii) centres. When the reaction is performed in the presence of NaBF4 a minor crystalline product with tetragonal symmetry is isolated in addition to the 1D coordination polymer. This compound of composition Cu2(imdc)4NaBF4·7H2O (5) consists of 2D Cu(imdc)2 networks and features an unusual mode of interpenetration. [ABSTRACT FROM AUTHOR]