Metal-organic frameworks (MOFs) are microporous materials with huge potential for chemical processes, including retention or separation of guest molecules. Structural collapse at high-pressure, and transitions to liquid states at high temperature, have recently been observed in this family. Here, we show that the effect of simultaneous high pressure and temperature application on ZIF-62 and ZIF-4 results in complex behaviour, with distinct high-and low-density amorphous phases occurring over different regions of the pressure-temperature phase diagram. In-situ powder X-ray diffraction, Raman spectroscopy and optical microscopy reveal that the stability of the liquid MOF-state expands significantly towards lower temperatures at intermediate, industrially achievable pressures. Furthermore, the MOF-glass formed by melt quenching the high temperature liquid is shown to demonstrate permanent, accessible porosity. Our results thus imply a novel route to the synthesis of functional MOF glasses at low temperatures, avoiding decomposition upon heating at ambient pressure.

Herein, we report that UiO-type (UiO = University of Oslo) metal-organic frameworks (MOFs) can be transformed into self-propelled micromotors by employing several different metal-based propulsion systems. Incorporation of a bipyridine ligand into the UiO-67 lattice transforms the crystallites, upon metalation, into single-site, metal-based catalytic "engines" to power the micromotors with chemical fuel. The "engine performance" (i.e., propulsion) of the single-site powered micromotors has been tuned by the choice of the metal ion utilized. In addition, a chemical "braking" system was achieved by adding chelating agents capable of sequestering the metal ion engines and thereby suppressing the catalytic activity, with different chelators displaying different deceleration capacities. These results demonstrate that MOFs can be powered by various engines and halted by different brakes, resulting in a high degree of motion design and control at the nanoscale.

A photocatalytic Ru complex was incorporated into a Zr(iv)-based metal-organic framework (MOF) via postsynthetic methods. The resulting UiO-67-Ru(bpy)3 shows efficient and recyclable catalytic activity for the aerobic oxidation of arylboronic acids under near-UV and visible light irradiation.

Indole prenyltransferases AnaPT, CdpC3PT, and CdpNPT are known to catalyze the formation of prenylated pyrroloindoline diketopiperazines from tryptophan-containing cyclic dipeptides in one-step reactions. In this study, we investigated the different stereoselectivities of these enzymes toward all the stereoisomers of cyclo-Trp-Ala and cyclo-Trp-Pro. The stereoselectivities of AnaPT and CdpC3PT mainly depend on the configuration of the tryptophanyl moiety in the substrates, and they usually introduce the prenyl moiety from the opposite sides. CdpNPT showed lower stereoselectivity, and the structure of the second amino acid moiety in the substrates is important for the stereospecificity in its enzyme catalysis. Moreover, we determined the crystal structure of AnaPT in complex with thiolodiphosphate and compared it with the known structures of CdpNPT. Our results clearly revealed the presence of an indole binding mode that has so far not been characterized.

Background: Known indole prenyltransferases catalyzed regioselective prenylations at N-1, C-2, C-3, C-4, C-6, and C-7 of the indole ring. Results: Recombinant 5-DMATS was assayed with tryptophan and derivatives in the presence of DMAPP. Conclusion: 5-DMATS prenylated indole derivatives at C-5. Significance: 5-DMATS fills the last prenylation gap of indole derivatives and could be used as a potential catalyst for chemoenzymatic synthesis.

Nature synthesizes many strained natural products that have diverse biological activities. Uncovering these biosynthetic pathways may lead to biomimetic strategies for organic synthesis of such compounds. In this work, we elucidated the concise biosynthetic pathway of herquline A, a highly strained and reduced fungal piperazine alkaloid. The pathway builds on a nonribosomal peptide synthetase derived di-tyrosine piperazine intermediate. Following enzymatic reduction of the P450-crosslinked di-cyclohexadienone, N-methylation of the piperazine serves as a trigger that leads to a cascade of stereoselective and nonenzymatic transformations. Computational analysis of key steps in the pathway rationalizes the observed reactivities.

We show flux melting by using a liquid MOF as a solvent for a secondary, non-melting MOF component.

Metal–organic frameworks (MOFs) have attracted increasing attention for applications in heterogeneous photocatalysis.