Ionothermal syntheses and crystal structures of two cobalt(II)–carboxylate compounds with different topology

Metal-organic frameworks of linear trinuclear cluster secondary building units: structures and applications

Secondary building units (SBUs) in metal-organic frameworks (MOFs) are essential from both a structural and performance perspective. While a variety of SBUs, such as paddlewheel CuII2, triangular CrIII3, tetrahedral ZnII4, and octahedral ZrIV6 have been extensively studied, the linear trinuclear SBUs (herein denoted as M₃), though frequently encountered, are rarely discussed as a class. A literature survey reveals that M₃ clusters are ubiquitous in discrete molecular entities as well as in MOFs. Unlike most other cluster types, however, they have an unprecedented metal diversity and ligand tolerance. The single-crystals of some M₃-based MOFs are also sufficiently robust upon guest removal and exchange or multi-step post-modifications to enable catalytic mechanism elucidation. Some of these M₃-based SBUs endow MOFs with stability under demanding conditions necessary, for example, in flue gas separation. Herein we review MOFs sustained by this common but under-appreciated class of SBUs and discuss applications of the resulting MOF motifs.

Structure-directing effects of ionic liquids in the ionothermal synthesis of metal-organic frameworks

Traditional synthesis of metal-organic frameworks (MOFs) involves the reaction of a metal-containing precursor with an organic linker in an organic solvent at an elevated temperature, in what is termed a 'solvothermal' reaction. More recently, many examples have been reported of MOF synthesis in ionic liquids (ILs), rather than an organic solvent, in 'ionothermal' reactions. The high concentration of both cations and anions in an ionic liquid allows for the formation of new MOF structures in which the IL cation or anion or both are incorporated into the MOF. Most commonly, the IL cation is included in the open cavities of the MOF, countering the anionic charge of the MOF framework itself and acting as a template around which the MOF structure forms. Ionic liquids can also serve other structure-directing roles, for example, when an IL containing a single enantiomer of a chiral anion leads to a homochiral MOF, even though the IL anion is not itself incorporated into the MOF. A comprehensive review of ionothermal syntheses of MOFs, and the structure-directing effects of the ILs, is given.

Cluster- and chain-based magnetic MOFs derived from 3d metal ions and 1,3,5-benzenetricarboxylate

Three H₃BTC-supported 3D MOFs with triangular M₃ (M = Co, Ni) clusters and rod-shaped sinusoidal-like Mn-chains as building units have been successfully obtained under solvothermal conditions, and complexes 1–3 exhibit antiferromagnetic behaviours.

Ionic liquids for energy, materials, and medicine

As highlighted by the recent ChemComm web themed issue on ionic liquids, this field continues to develop beyond the concept of interesting new solvents for application in the greening of the chemical industry. Here some current research trends in the field will be discussed which show that ionic liquids research is still aimed squarely at solving major societal issues by taking advantage of new fundamental understanding of the nature of these salts in their low temperature liquid state. This article discusses current research trends in applications of ionic liquids to energy, materials, and medicines to provide some insight into the directions, motivations, challenges, and successes being achieved with ionic liquids today.