Recent advances in organic chemistry and materials chemistry have enabled the porosity of new materials to be accurately controlled on the nanometer scale. In this context, metal–organic frameworks (MOFs) have rapidly become one of the most attractive classes of solid supports currently under investigation in heterogeneous catalysis. Their unprecedented degree of tunability gives MOFs the chance to succeed where others have failed. The past decade has witnessed an exponential growth in the complexity of new structures. MOFs with a variety of topologies and pore sizes show excellent stability across wide ranges of pH and temperature. Even the controlled insertion of defects, to alter the MOF’s properties in a predictable manner, has become commonplace. However, research on catalysis with MOFs has been sluggish in catching up with modern trends in organic chemistry. Relevant issues such as enantioselective processes, C–H activation, or olefin metathesis are still rarely discussed. In this Perspective, we highlight meritorious examples that tackle important issues from contemporary organic synthesis, and that provide a fair comparison with existing catalysts. Some of these MOF catalysts already outcompete state-of-the-art homogeneous solutions. For others, improvements may still be required, but they have merit in aiming for the bigger challenge. Furthermore, we also identify some important areas where MOFs are likely to make a difference, by addressing currently unmet needs in catalysis instead of trying to outcompete homogeneous catalysts in areas where they excel. Finally, we strongly advocate for rational design of MOF catalysts, founded on a deep mechanistic understanding of the events taking place inside the pore.

Efficient use of energy for cooling applications is a very important and challenging field in science. Ultra-low temperature actuated ( T driving < 80 °C) adsorption-driven chillers (ADCs) with water as the cooling agent are one environmentally benign option. The nanoscale metal-organic framework [Al(OH)(C 6 H 2 O 4 S)] denoted CAU-23 was discovered that possess favorable properties, including water adsorption capacity of 0.37 g H2O / g sorbent around p / p 0 = 0.3 and cycling stability of at least 5000 cycles. Most importantly the material has a driving temperature down to 60 °C, which allows for the exploitation of yet mostly unused temperature sources and a more efficient use of energy. These exceptional properties are due to its unique crystal structure, which was unequivocally elucidated by single crystal electron diffraction. Monte Carlo simulations were performed to reveal the water adsorption mechanism at the atomic level. With its green synthesis, CAU-23 is an ideal material to realize ultra-low temperature driven ADC devices.

A bismuth-based metal-organic framework (MOF), [Bi(BTC)(H2O)]·2H2O·MeOH denoted CAU-17, was synthesized and found to have an exceptionally complicated structure with helical Bi-O rods cross-linked by 1,3,5-benzenetricarboxylate (BTC(3-)) ligands. Five crystallographically independent 1D channels including two hexagonal channels, two rectangular channels, and one triangular channel have accessible diameters of 9.6, 9.6, 3.6, 3.6, and 3.4 Å, respectively. The structure is further complicated by twinning. Rod-incorporated MOF structures typically have underlying nets with only one unique node and three or four unique edges. In contrast, topological analysis of CAU-17 revealed unprecedented complexity for a MOF structure with 54 unique nodes and 135 edges. The complexity originates from the rod packing and the rods themselves, which are related to aperiodic helices.

A series of Ru-bda water oxidation catalysts [Ru(bda)L2] (H2bda = 2,2'-bipyridine-6,6'-dicarboxylic acid; L = [HNEt3][3-SO3-pyridine], 1; 4-(EtOOC)-pyridine, 2; 4-bromopyridine, 3; pyridine, 4; 4-methoxypyridine, 5; 4-(Me2N)-pyridine, 6; 4-[Ph(CH2)3]-pyridine, 7) were synthesized with electron-donating/-withdrawing groups and hydrophilic/hydrophobic groups in the axial ligands. These complexes were characterized by (1)H NMR spectroscopy, high-resolution mass spectrometry, elemental analysis, and electrochemistry. In addition, complexes 1 and 6 were further identified by single crystal X-ray crystallography, revealing a highly distorted octahedral configuration of the Ru coordination sphere. All of these complexes are highly active toward Ce(IV)-driven (Ce(IV) = Ce(NH4)2(NO3)6) water oxidation with oxygen evolution rates up to 119 mols of O2 per mole of catalyst per second. Their structure-activity relationship was investigated. Electron-withdrawing and noncovalent interactions (attraction) exhibit positive effect on the catalytic activity of Ru-bda catalysts.