•The cobalt-doped aluminophosphate molecular sieve, CoAPO-34 (with the chabazite-type topology) was prepared under ionothermal conditions using 1-ethyl-3-methylimidazolium bromide (EMIMBr) ionic liquid in presence of 1,6-hexanediamine (HDA).•The HDA is not incorporated in CoAPO-34, but is required to mediate the availability of Co2+ during the synthesis.•The material was characterized using powder X-ray diffraction (pXRD), thermogravimetric analysis (TGA) and solid-state NMR spectroscopy.•Wideline 31P NMR spectroscopy showed broad signals (∼5000–10000 ppm wide), confirming that paramagnetic cobalt ions are successfully incorporated within the framework of the materials.The cobalt-doped aluminophosphate molecular sieve, CoAPO-34 (with the chabazite-type topology) was prepared under ionothermal conditions using 1-ethyl-3-methylimidazolium bromide (EMIMBr) ionic liquid in presence of 1,6-hexanediamine (HDA). The HDA is not incorporated in CoAPO-34, but is required to mediate the availability of Co2+ during the synthesis. The material was characterized using powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and solid-state NMR spectroscopy. Wideline 31P NMR spectroscopy showed broad signals (∼5000–10000 ppm wide), confirming that paramagnetic cobalt ions are successfully incorporated within the framework of the materials.

Metal–organic frameworks (MOFs) are some of the most exciting materials in current science. Their utility and diversity of applications depends on a combination of their chemistry, their framework topology and the spatial dimensions of their pores. In this review we concentrate on the chemistry of MOFs. Specifically we bring together many aspects of MOFs that underpin their stability, reactivity and dynamic behaviour within a common theme related to (changes in) metal–ligand bonding. In each area we provide examples to illustrate the behaviour and discuss it in the context of metal lability and coordination changes. Starting with flexible behaviour in which metal–linker bonds undergo deformation rather than cleavage, we then consider coordination changes that lead to open metal sites, changes in framework topology, framework dimensionality or degree of network interpenetration. We show how these changes are linked to development of new properties, including changes in magnetic behaviour, gas adsorption characteristics, construction of composite MOFs and amorphous MOFs, as well as providing new synthetic routes for MOF preparation. We discuss how the lability of the species that make up the MOFs can affect aspects from their synthesis to the possibility of metal and linker exchange reactions that may lead to defects and disorder. The final section reviews hemilability in MOFs, where regions of different chemical behaviour within MOFs can lead to unusual properties, such as self-accelerating and ultraselective adsorption.

Copper-exchanged and acidic zeolites are shown to produce nitric oxide (NO) from a nitrite source in biologically active (nanomolar) concentrations. Four zeolites were studied; mordenite, ferrierite, ZSM-5 and SSZ-13, which had varying pore size, channel systems and Si/Al ratios. ZSM-5 and SSZ-13 produced the highest amounts of NO in both the copper and acid form. The high activity and regeneration of the copper active sites makes them good candidates for long-term NO production. Initial cytotoxicity tests have shown at least one of the copper zeolites (Cu-SSZ-13) to be biocompatible, highlighting the potential usage within biomedical applications.

Copper-exchanged and acidic zeolites are shown to produce nitric oxide (NO) from a nitrite source in biologically active (nanomolar) concentrations. Four zeolites were studied; mordenite, ferrierite, ZSM-5 and SSZ-13, which had varying pore size, channel systems and Si/Al ratios. ZSM-5 and SSZ-13 produced the highest amounts of NO in both the copper and acid form. The high activity and regeneration of the copper active sites makes them good candidates for long-term NO production. Initial cytotoxicity tests have shown at least one of the copper zeolites (Cu-SSZ-13) to be biocompatible, highlighting the potential usage within biomedical applications.

Porous organic–inorganic materials with tunable textural characteristics were synthesized using the top-down process by intercalating silsesquioxanes and polyhedral oligomeric siloxanes of different types between crystalline zeolite-derived layers. The influence of key parameters such as (i) linker nature (pure hydrocarbon, S-, N-containing); (ii) chain length in alkyl- and aryl bis(trialkoxysilyl) derivatives; (iii) denticity of the organic precursor molecules; (iv) nature and size of side chain in mono(trialkoxysilyl) substrates; (v) rigidity of the chain (saturated vs. unsaturated, aliphatic vs. aromatic); (vi) nature and size of leaving group on the structural and textural properties of formed hybrids was carefully addressed. It was established, that the optimal silsesquioxane appropriate for the formation of zeolite-derived hybrids with high textural characteristics should possess short alkyl or long aryl chains, relatively small leaving groups and denticity larger than 3. Addition of polydentate low-molecular binder improved the structural and textural characteristics of hybrids, especially when using bulky or hydrophilic linkers.

•The first example of a non-polymeric Mg-H2dhtp complex is reported.•Obtained by one-pot reflux at lower pH than leads to a known MOF, CPO-27-Mg•Hydrogen bonding interactions construct a complex 3D network.A mononuclear complex of composition Mg(H2dhtp)(H2O)5·H2O has been prepared and characterised crystallographically.A new mononuclear Mg-dhtp compound with ligand 2,5-dihydroxyterephathilic acid (dhtp) was prepared and its crystal structure was determined.

•Crystals of two salts of the chlorhexidine dication have been prepared.•The protonation sites on the chlorhexidine cation are different between the two salts.•The cation and anion packing is very similar for both salts.•Different hydrogen-bonding interactions occur between the CO32− and SO42− salts.Two salts of the chlorhexidine di-cation (H2CHx2+) – (H2CHx)(SO4)·3H2O and (H2CHx)(CO3)·4H2O – have been synthesised and characterised crystallographically.

A novel methodology, called ADOR (assembly–disassembly–organisation–reassembly), for the synthesis of zeolites is reviewed here in detail. The ADOR mechanism stems from the fact that certain chemical weakness against a stimulus may be present in a zeolite framework, which can then be utilized for the preparation of new solids through successive manipulation of the material. In this review, we discuss the critical factors of germanosilicate zeolites required for application of the ADOR protocol and describe the mechanism of hydrolysis, organisation and condensation to form new zeolites starting from zeolite UTL. Last but not least, we discuss the potential of this methodology to form other zeolites and the prospects for future investigations.

Solvothermal reaction of Zn(OAc)2 and 5-methoxy isophthalic acid (H2MeOip) in aqueous alcohols ROH (R = H, Me, Et, or iPr) affords four different novel coordination polymers. Zn2(HMeOip)(MeOip)(OAc) (1) forms as a 1D ‘ribbon of rings’ polymer. Zn6(MeOip)4.5(HMeOip)(OH)2(H2O)2·5.5H2O (2) crystallises as a complex 3D framework. Zn(MeOip)(H2O)2 H2O (3) is a 1D coordination polymer that contains almost planar strips of Zn(MeOip). compound 4, Zn5(MeOip)4(OH)2(H2O)4·H2O, obtained from aqueous iPrOH, crystallises as a 2D polymer containing two crystallographically distinct Zn5(OH)2 clusters. Preliminary nitric oxide release experiments have been conducted.

This work demonstrates synthetic strategies for the incorporation of an anticancer drug, cisplatin, and a Pt(IV) cisplatin prodrug into two zirconium-based metal–organic-frameworks (MOFs): UiO66 and UiO66-NH2. Cisplatin was chosen due to its reported high potency in killing ca. 95% of different cancers. Two approaches for its incorporation were investigated: conjugation and encapsulation. In the conjugation route, a Pt(IV) cisplatin prodrug was incorporated into UiO66-NH2 utilising its amine group in an amide-coupling reaction. In the second case, cisplatin was encapsulated into the large cavities of both MOFs. The presence of platinum was confirmed by energy-dispersive X-ray spectroscopy and microwave plasma-atomic emission spectroscopy. The cytotoxicity of the formulations was assessed on the A549 lung cancer cell line. The results show that the system in which cisplatin is conjugated to UiO66-NH2 is more efficient in inducing cell death than the materials where cisplatin is encapsulated into the pores of the MOFs. This is consistent with the higher drug loading achieved with the conjugation technique. One disadvantage of cisplatin therapy is that it may lead to thrombosis and, as a consequence, to heart attack and cardiac arrest. To ameliorate this potential side effect, we investigated the incorporation of NO (which has been widely researched for its antithrombotic properties) into the drug-loaded MOFs. All the cisplatin or pro-drug loaded MOFs are able to entrap and then release NO. Furthermore, the amount of NO released from these formulations is much greater than from the pure MOFs. As a result, the drug delivery systems developed in this work have potentially potent double functionality.

We present an ionothermal-based method for the simple and low-cost enrichment in 17O of oxide materials. This is demonstrated for the case of SIZ-4, an ionothermally-prepared aluminophosphate framework with the CHA topology. A preliminary study of unenriched samples of SIZ-4 highlights the importance of the careful choice of template in order to obtain an ordered structure. We then show how an ionothermal synthesis procedure incorporating microlitre quantities of 17O-enriched H2O enables as-prepared and calcined samples of SIZ-4 to be obtained with 17O enrichment levels that are sufficient to enable the recording of high-quality 17O solid-state NMR spectra. While second-order quadrupolar-broadened resonances are unresolved in 17O MAS NMR spectra, 17O double-rotation (DOR) and multiple-quantum (MQ)MAS NMR spectra reveal distinct resonances that are partially assigned by comparison with NMR parameters derived using first-principles calculations. The calculations also enable an investigation of the dependence of 17O NMR parameters on the local structural environment. We find that both the 17O isotropic chemical shift and quadrupolar coupling constant show clear dependencies on Al–O–P bond lengths, and angles and will therefore provide a sensitive probe of structure and geometry in aluminophosphate frameworks in future studies.

Hydrogen sulfide is an extremely toxic gas that is also of great interest for biological applications when delivered in the correct amount and at the desired rate. Here we show that the highly porous metal–organic frameworks with the CPO-27 structure can bind the hydrogen sulfide relatively strongly, allowing the storage of the gas for at least several months. Delivered gas is biologically active in preliminary vasodilation studies of porcine arteries, and the structure of the hydrogen sulfide molecules inside the framework has been elucidated using a combination of powder X-ray diffraction and pair distribution function analysis.

An exploratory study of the synthesis of vanadium (oxy)fluorides (VOFs) using ionic liquids (ILs) and deep eutectic mixtures (DESs) as a solvent yielded 10 different materials. The previously reported chain type: (NH4)2VF5 (1), (NH4)2VOF4 (2), NH4VO3 (3) and (H2NH2(CH2)2NH2)VF5 (9) have been successfully produced for the first time using ILs as the reaction media. The monomeric (HNH2CH3)2VOF4(H2O) (4), the dimer (HNH2CH3)4V2O2F8 (5) and the 1D chains (HNH2CH3)2VF5 (6), (H2O)2VF3 (7), α-(H2NH2(CH2)2NH2)VOF4 (8) and β-(H2NH2(CH2)2NH2)VOF4 (10) are novel materials. Template control has also been achieved by the selective choice of ILs or the appropriate deep eutectic mixture, where the expected template is delivered to the reaction by the partial breakdown of the urea derivative portion of the DES.

Four zinc imidazolate materials has been synthesized under ionothermal conditions using ionic liquids; [Zn(C2O4)(C3N2H4)], P21/a (1); [Zn(CH3COO)(C3N2H3)], Ima2 (2); [Zn4(C3N2H4)(C3N2H3)8], P (3) and [Zn(C3N2H3)2], I41 (4). Compounds 1 and 4 have already known structures, but have been synthesised for the first time using ionothermal methods. Compounds 2 and 3 are novel and have been synthesized for the first time in this work. The syntheses of 3 and 4 take place under almost exactly the same conditions, except that a lower synthesis temperature leads to a proportion of terminal imidazolate units in the structure of 3 while a slightly higher temperature leads to all bridging imidazolate units in 4.

Three new isostructural materials Ln(TMA)(DMU)2 (Ln(C9O6H3)((CH3NH)2CO)2; Ln: La 1, Nd 2, Eu 3; TMA: trimesate, DMU: dimethylurea) have been synthesised ionothermally using a choline chloride/dimethylurea deep eutectic mixture as the solvent. Normally in ionothermal synthesis the urea portion of the deep eutectic solvent is unstable, breaking down to release ammonium cations that act as templates. In the case of 1–3, however, the dimethylurea remains intact and is incorporated into the final structure.

It seems that, looking with a historical perspective, there is a major step change advance in porous materials science about once every decade. Usually, these advances take the form a new type of solid and depend on the expertise of synthetic chemists to develop new materials. So the question is what will be the next great leap forward in this area. Here I will offer several examples of very recent results that suggest challenges that remain in zeolite and porous materials science. They range from control over chirality and location of catalytic sites inside pores, to the preparation of ultrathin films and coatings of zeolite materials.

Copper containing MCM-41 materials can be used to both store gaseous nitric oxide and to catalytically produce nitric oxide from nitrite. The active species for the reaction is copper (I). Addition of cysteine to the solution in contact with the material has different effects depending on how much Cu(I) is present. This is a new method of extending the lifetime of gas delivery from a gas storage material.

β-NH4AlF4 has been synthesised ionothermally using 1-ethyl-3-methylimidazolium hexafluorophosphate as solvent and template provider. β-NH4AlF4 crystals were produced which were suitable for single crystal X-ray diffraction analysis. A phase transition occurs between room temperature (298 K) and low temperature (93 K) data collections. At 298 K the space group=I4/mcm (no. 140), α=11.642(5), c=12.661(5) Å, Z=2 (10NH4AlF4), wR(F2)=0.1278, R(F)=0.0453. At 93 K the space group=P42/ncm (no. 138), α=11.616(3), c=12.677(3) Å, Z=2 (10NH4AlF4), wR(F2)=0.1387, R(F)=0.0443. The single crystal X-ray diffraction study of β-NH4AlF4 shows the presence of two different polymorphs at low and room temperature, indicative of a phase transition. The [AlF4/2F2]− layers are undisturbed except for a small tilting of the AlF6 octahedra in the c-axis direction.Ionothermal synthesis, the use of an ionic liquid as the solvent in materials preparation, has been used to prepare β-NH4AlF4, and structural characterisation indicates that there are two versions of the structure, a low temperature primitive phase at 93 K and a high temperature body-centered phase at 298 K.

A novel aluminophosphate chain structure, Al(H2PO4)2F, has been synthesised ionothermally using the hydrophobic ionic liquid 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide as the solvent.

Variable temperature high resolution 29Si magic angle spinning NMR spectroscopy has been used to study the thermal behaviour of the aluminosilicate zeolite ferrierite. Three samples of have been prepared with varying quantities of framework aluminium using a fluoride based synthesis. Spectra collected between 293 and 500 K have shown that aluminosilicate ferrierite shows a displacive phase transition between the low temperature and high temperature phases of the material. A comparison of the spectra for the three samples shows that the quantity of framework aluminium has a significant effect on the phase transition temperature.

A layered aluminofluorophosphate and a cobalt–aluminophosphate material have been prepared using the azamacrocycle meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (Tet-A) as a structure-directing agent (SDA). Both were synthesised using hydrothermal techniques and their structures solved using microcrystal X-ray diffraction. The first material, [F, Tet-A]-AlPO-1, has the molecular formula Al10P10O40F2C16N4H38 and crystallises in the orthorhombic space group Pca21. Its inorganic layered structure is related to the AlPO-41 (AFO) zeolite structure type. The second material, [Co, Tet-A]-AlPO-2, has the formula Al4(PO4)4(HPO4)2·[Co(C16N4H36)]·C16N4H38·2H2O and crystallises in the triclinic space group P. This material contains a cobalt–Tet-A complex that is covalently bound to the inorganic framework and an uncoordinated Tet-A molecule that is hydrogen bonded to the framework.

Hydrosilylation reactions have been used to functionalise the exterior surfaces of octavinyloctasilsesquioxane molecules to provide routes to octaaldehyde molecules. These have been characterised by NMR and MALDI (matrix assisted laser desorption/ionisation)-TOF mass spectroscopy. Further reactions of the molecules to produce carboxylic acid and Schiff base functionalised species are also reported. The effect of temperature and catalyst on the regioselectivity of the reaction is discussed.

A family of four aluminium benzylphosphonate phases has been synthesised using hydrothermal methods. The effect of changing the synthetic conditions (starting pH, starting Al∶P ratio, aluminium source etc.) has been studied and full structural characterisation of two of the phases by NMR, TGA and X-ray diffraction methods has been completed; Al(OH)(O3PCH2C6H5)·H2O, monoclinic P21/c, a = 14.985(9), b = 7.066(5), c = 9.613(9) Å, β = 113.9(3)°, and Al3H(PO3CH2C6H5)5·H2O, monoclinic P21/c, a = 17.2497(13), b = 25.7851(18), c = 9.4339(7) Å, β = 103.567(1)°.

Porous organic–inorganic materials with tunable textural characteristics were synthesized using the top-down process by intercalating silsesquioxanes and polyhedral oligomeric siloxanes of different types between crystalline zeolite-derived layers. The influence of key parameters such as (i) linker nature (pure hydrocarbon, S-, N-containing); (ii) chain length in alkyl- and aryl bis(trialkoxysilyl) derivatives; (iii) denticity of the organic precursor molecules; (iv) nature and size of side chain in mono(trialkoxysilyl) substrates; (v) rigidity of the chain (saturated vs. unsaturated, aliphatic vs. aromatic); (vi) nature and size of leaving group on the structural and textural properties of formed hybrids was carefully addressed. It was established, that the optimal silsesquioxane appropriate for the formation of zeolite-derived hybrids with high textural characteristics should possess short alkyl or long aryl chains, relatively small leaving groups and denticity larger than 3. Addition of polydentate low-molecular binder improved the structural and textural characteristics of hybrids, especially when using bulky or hydrophilic linkers.

A novel methodology, called ADOR (assembly–disassembly–organisation–reassembly), for the synthesis of zeolites is reviewed here in detail. The ADOR mechanism stems from the fact that certain chemical weakness against a stimulus may be present in a zeolite framework, which can then be utilized for the preparation of new solids through successive manipulation of the material. In this review, we discuss the critical factors of germanosilicate zeolites required for application of the ADOR protocol and describe the mechanism of hydrolysis, organisation and condensation to form new zeolites starting from zeolite UTL. Last but not least, we discuss the potential of this methodology to form other zeolites and the prospects for future investigations.

Copper-exchanged and acidic zeolites are shown to produce nitric oxide (NO) from a nitrite source in biologically active (nanomolar) concentrations. Four zeolites were studied; mordenite, ferrierite, ZSM-5 and SSZ-13, which had varying pore size, channel systems and Si/Al ratios. ZSM-5 and SSZ-13 produced the highest amounts of NO in both the copper and acid form. The high activity and regeneration of the copper active sites makes them good candidates for long-term NO production. Initial cytotoxicity tests have shown at least one of the copper zeolites (Cu-SSZ-13) to be biocompatible, highlighting the potential usage within biomedical applications.

An exploratory study of the synthesis of vanadium (oxy)fluorides (VOFs) using ionic liquids (ILs) and deep eutectic mixtures (DESs) as a solvent yielded 10 different materials. The previously reported chain type: (NH4)2VF5 (1), (NH4)2VOF4 (2), NH4VO3 (3) and (H2NH2(CH2)2NH2)VF5 (9) have been successfully produced for the first time using ILs as the reaction media. The monomeric (HNH2CH3)2VOF4(H2O) (4), the dimer (HNH2CH3)4V2O2F8 (5) and the 1D chains (HNH2CH3)2VF5 (6), (H2O)2VF3 (7), α-(H2NH2(CH2)2NH2)VOF4 (8) and β-(H2NH2(CH2)2NH2)VOF4 (10) are novel materials. Template control has also been achieved by the selective choice of ILs or the appropriate deep eutectic mixture, where the expected template is delivered to the reaction by the partial breakdown of the urea derivative portion of the DES.

Hydrogen sulfide is an extremely toxic gas that is also of great interest for biological applications when delivered in the correct amount and at the desired rate. Here we show that the highly porous metal–organic frameworks with the CPO-27 structure can bind the hydrogen sulfide relatively strongly, allowing the storage of the gas for at least several months. Delivered gas is biologically active in preliminary vasodilation studies of porcine arteries, and the structure of the hydrogen sulfide molecules inside the framework has been elucidated using a combination of powder X-ray diffraction and pair distribution function analysis.

We present an ionothermal-based method for the simple and low-cost enrichment in 17O of oxide materials. This is demonstrated for the case of SIZ-4, an ionothermally-prepared aluminophosphate framework with the CHA topology. A preliminary study of unenriched samples of SIZ-4 highlights the importance of the careful choice of template in order to obtain an ordered structure. We then show how an ionothermal synthesis procedure incorporating microlitre quantities of 17O-enriched H2O enables as-prepared and calcined samples of SIZ-4 to be obtained with 17O enrichment levels that are sufficient to enable the recording of high-quality 17O solid-state NMR spectra. While second-order quadrupolar-broadened resonances are unresolved in 17O MAS NMR spectra, 17O double-rotation (DOR) and multiple-quantum (MQ)MAS NMR spectra reveal distinct resonances that are partially assigned by comparison with NMR parameters derived using first-principles calculations. The calculations also enable an investigation of the dependence of 17O NMR parameters on the local structural environment. We find that both the 17O isotropic chemical shift and quadrupolar coupling constant show clear dependencies on Al–O–P bond lengths, and angles and will therefore provide a sensitive probe of structure and geometry in aluminophosphate frameworks in future studies.

Four zinc imidazolate materials has been synthesized under ionothermal conditions using ionic liquids; [Zn(C2O4)(C3N2H4)], P21/a (1); [Zn(CH3COO)(C3N2H3)], Ima2 (2); [Zn4(C3N2H4)(C3N2H3)8], P (3) and [Zn(C3N2H3)2], I41 (4). Compounds 1 and 4 have already known structures, but have been synthesised for the first time using ionothermal methods. Compounds 2 and 3 are novel and have been synthesized for the first time in this work. The syntheses of 3 and 4 take place under almost exactly the same conditions, except that a lower synthesis temperature leads to a proportion of terminal imidazolate units in the structure of 3 while a slightly higher temperature leads to all bridging imidazolate units in 4.

Solvothermal reaction of Zn(OAc)2 and 5-methoxy isophthalic acid (H2MeOip) in aqueous alcohols ROH (R = H, Me, Et, or iPr) affords four different novel coordination polymers. Zn2(HMeOip)(MeOip)(OAc) (1) forms as a 1D ‘ribbon of rings’ polymer. Zn6(MeOip)4.5(HMeOip)(OH)2(H2O)2·5.5H2O (2) crystallises as a complex 3D framework. Zn(MeOip)(H2O)2 H2O (3) is a 1D coordination polymer that contains almost planar strips of Zn(MeOip). compound 4, Zn5(MeOip)4(OH)2(H2O)4·H2O, obtained from aqueous iPrOH, crystallises as a 2D polymer containing two crystallographically distinct Zn5(OH)2 clusters. Preliminary nitric oxide release experiments have been conducted.

Copper-exchanged and acidic zeolites are shown to produce nitric oxide (NO) from a nitrite source in biologically active (nanomolar) concentrations. Four zeolites were studied; mordenite, ferrierite, ZSM-5 and SSZ-13, which had varying pore size, channel systems and Si/Al ratios. ZSM-5 and SSZ-13 produced the highest amounts of NO in both the copper and acid form. The high activity and regeneration of the copper active sites makes them good candidates for long-term NO production. Initial cytotoxicity tests have shown at least one of the copper zeolites (Cu-SSZ-13) to be biocompatible, highlighting the potential usage within biomedical applications.