Exploiting Reaction-Diffusion Conditions to Trigger Pathway Complexity in the Growth of a MOF.

Coordination polymers (CPs), including metal–organic frameworks (MOFs), are crystalline materials with promising applications in electronics, magnetism, catalysis, and gas storage/separation. However, the mechanisms and pathways underlying their formation remain largely undisclosed. Herein, we demonstrate that diffusion-controlled mixing of reagents at the very early stages of the crystallization process (i.e., within ≈40 ms), achieved by using continuous-flow microfluidic devices, can be used to enable novel crystallization pathways of a prototypical spin-crossover MOF towards its thermodynamic product. In particular, two distinct and unprecedented nucleation-growth pathways were experimen…

A Stereochemically Driven Supramolecular Polymerisation

Anthracyclines self-assemble in water into dimers. In the presence of sufficiently high salt (NaCl) concentrations, solutions of the antibiotic doxorubicin, but not those of the closely related molecules daunomycin and epirubicin, turn into gels barely compatible with the presence of small oligomers. The use of spectroscopic, scattering, imaging and computational techniques, allowed light to be shed on the self-assembly process that triggered doxorubicin gelification. A complex picture emerged, with doxorubicin molecules assembled into long, highly chiral, supramolecular aggregates made of hundreds of units, showing redshifted fluorescence spectra, very short fluorescence lifetimes and smal…

The self-association equilibria of doxorubicin at high concentration and ionic strength characterized by fluorescence spectroscopy and molecular dynamics simulations

Abstract The self-association equilibria of doxorubicin hydrochloride (DX), at high drug and NaCl concentrations, are studied by temperature scan fluorescence spectroscopy, with the support of molecular dynamics (MD) calculations. Even though all anthracyclines show dimerization equilibria, DX only can further associate into long polymeric chains according to DXmon ⇄ DXdim ⇄ DXpol. This is reflected not only in the mechanical properties of DXpol solutions (behaving as thixotropic gels) but also in their spectroscopic behaviour. Fluorescence, in particular, is the technique of election to study this complex set of equilibria. Upon increasing the temperature, DXpol melts into DXdim, which in …

Inside Cover: Exploiting Reaction‐Diffusion Conditions to Trigger Pathway Complexity in the Growth of a MOF (Angew. Chem. Int. Ed. 29/2021)

Innentitelbild: Exploiting Reaction‐Diffusion Conditions to Trigger Pathway Complexity in the Growth of a MOF (Angew. Chem. 29/2021)

Inside Cover: Exploiting Reaction-Diffusion Conditions to Trigger Pathway Complexity in the Growth of a MOF

How do you unveil pathway complexity in a crystallization process? In their Research Article on page 15920, Alessandro Sorrenti, Marco D′Abramo, Guillermo Mínguez Espallargas, Josep Puigmartí-Luis, and co-workers show that harnessing a reaction-diffusion (RD) process within a continuous flow microfluidic device, and on a millisecond timescale, is key to enable two unprecedented nucleation-growth pathways during a MOF synthesis.