Total Synthesis of Enlicitide Decanoate.

We report the total synthesis of enlicitide decanoate, an orally bioavailable inhibitor of proprotein convertase subtilisin/kexin type 9 that is being developed for the treatment of atherosclerotic cardiovascular disease. It is a highly complex macrocyclic peptide with a significant number of nonpeptide structural elements that presents a daunting synthetic chemistry challenge. We describe the development of a convergent, efficient, and robust manufacturing process that enables the large-scale production of enlicitide.

Revisiting the solid-state landscape of creatine citric acid: A salt or a cocrystal?

Creatine, a widely used sports supplement, has been formulated in several different ways due to its poor solubility profile. Among these, coformulations of creatine and citric acid have been extensively studied, leading to reports of both salt and cocrystal formations. However, the zwitterionic nature of creatine has presented challenges in determining the favored formation and the influencing factors leading to the observation of salt or cocrystal.

Transient Catenation in a Zirconium-Based Metal-Organic Framework and Its Effect on Mechanical Stability and Sorption Properties.

Interpenetration of two or more sublattices is common among many metal-organic frameworks (MOFs). Herein, we study the evolution of one zirconium cluster-based, 3,8-connected MOF from its non-interpenetrated (NU-1200) to interpenetrated (STA-26) isomer. We observe this transient catenation process indirectly using ensemble methods, such as nitrogen porosimetry and X-ray diffraction, and directly, using high-resolution transmission electron microscopy.

The state of the field: from inception to commercialization of metal-organic frameworks.

As chemists and materials scientists, it is our duty to synthesize and utilize materials for a multitude of applications that promote the development of society and the well-being of its citizens. Since the inception of metal-organic frameworks (MOFs), researchers have proposed a variety of design strategies to rationally synthesize new MOF materials, studied their porosity and gas sorption performances, and integrated MOFs onto supports and into devices. Efforts have explored the relevance of MOFs for applications including, but not limited to, heterogeneous catalysis, guest delivery, water capture, destruction of nerve agents, gas storage, and separation.

Insights into the Structure and Dynamics of Metal-Organic Frameworks via Transmission Electron Microscopy.

Metal-organic frameworks (MOFs) are hybrid materials composed of metal ions and organic linkers featuring high porosity, crystallinity, and chemical tunability at multiple length scales. A recent advancement in transmission electron microscopy (TEM) and its direct application to MOF structure-property relationships have changed how we consider rational MOF design and development. Herein, we provide a perspective on TEM studies of MOFs and highlight the utilization of state-of-the-art TEM technologies to explore dynamic MOF processes and host-guest interactions.

Maximizing Magnetic Resonance Contrast in Gd(III) Nanoconjugates: Investigation of Proton Relaxation in Zirconium Metal-Organic Frameworks.

Gadolinium(III) nanoconjugate contrast agents (CAs) provide significant advantages over small-molecule complexes for magnetic resonance imaging (MRI), namely increased Gd(III) payload and enhanced proton relaxation efficiency (relaxivity, ). Previous research has demonstrated that both the structure and surface chemistry of the nanomaterial substantially influence contrast. We hypothesized that inserting Gd(III) complexes in the pores of a metal-organic framework (MOF) might offer a unique strategy to further explore the parameters of nanomaterial structure and composition, which influence relaxivity.

Balancing volumetric and gravimetric uptake in highly porous materials for clean energy.

A huge challenge facing scientists is the development of adsorbent materials that exhibit ultrahigh porosity but maintain balance between gravimetric and volumetric surface areas for the onboard storage of hydrogen and methane gas-alternatives to conventional fossil fuels. Here we report the simulation-motivated synthesis of ultraporous metal-organic frameworks (MOFs) based on metal trinuclear clusters, namely, NU-1501-M (M = Al or Fe). Relative to other ultraporous MOFs, NU-1501-Al exhibits concurrently a high gravimetric Brunauer-Emmett-Teller (BET) area of 7310 m g and a volumetric BET area of 2060 m cm while satisfying the four BET consistency criteria.

Ligand-Directed Reticular Synthesis of Catalytically Active Missing Zirconium-Based Metal-Organic Frameworks.

Zirconium-based metal-organic frameworks (Zr-MOFs) based on nets such as , , , , and with diverse potential applications have been widely reported. Zr-MOFs based on the highly connected 6,12-connected net, however, remain absent on account of synthetic challenges. Herein we report the ligand-directed reticular syntheses and isoreticular expansion of a series of Zr-MOFs with the edge-transitive net from 12-connected hexagonal-prismatic Zr nodes and 6-connected trigonal-prismatic linkers, i.

A Bismuth Metal-Organic Framework as a Contrast Agent for X-ray Computed Tomography.

A new bismuth metal-organic framework (MOF), bismuth-NU-901 (Bi-NU-901), featuring the topology and a pore with a diameter of ∼11 Å, was solvothermally synthesized, and its use as an X-ray computed tomography (CT) contrast agent was tested. X-ray CT is a common diagnostic method used in the medical field. Inside the body, contrast media enhance the distinction between tissues and organs of similar density.

Porosity Dependence of Compression and Lattice Rigidity in Metal-Organic Framework Series.

Porous materials, including metal-organic frameworks (MOFs), are known to undergo structural changes when subjected to applied hydrostatic pressures that are both fundamentally interesting and practically relevant. With the rich structural diversity of MOFs, the development of design rules to better understand and enhance the mechanical stability of MOFs is of paramount importance. In this work, the compressibilities of seven MOFs belonging to two topological families (representing the most comprehensive study of this type to date) were evaluated using in situ synchrotron X-ray powder diffraction of samples within a diamond anvil cell.

Oxygen-Assisted Cathodic Deposition of Zeolitic Imidazolate Frameworks with Controlled Thickness.

Processing metal-organic frameworks (MOFs) as films with controllable thickness on a substrate is increasingly crucial for many applications to realize function integration and performance optimization. Herein, we report a facile cathodic deposition process that enables the large-area preparation of uniform films of zeolitic imidazolate frameworks (ZIF-8, ZIF-71, and ZIF-67) with highly tunable thickness ranging from approximately 24 nm to hundreds of nanometers. Importantly, this oxygen-reduction-triggered cathodic deposition does not lead to the plating of reduced metals (Zn and Co).