Advances in Solid-State Transformations of Coordination Bonds: From the Ball Mill to the Aging Chamber

Abstract

Controlling the formation of coordination bonds is pivotal to the development of a plethora of functional metal-organic materials, ranging from coordination polymers, metal-organic frameworks (MOFs) to metallodrugs. The interest in and commercialization of such materials has created a need for more efficient, environmentally-friendly routes for making coordination bonds. Solid-state coordination chemistry is a versatile greener alternative to conventional synthesis, offering quantitative yields, enhanced stoichiometric and topological selectivity, access to a wider range of precursors, as well as to molecules and materials not readily accessible in solution or solvothermally. With a focus on mechanochemical, thermochemical and “accelerated aging” approaches to coordination polymers, including pharmaceutically-relevant materials and microporous MOFs, this review highlights the recent advances in solid-state coordination chemistry and techniques for understanding the underlying reaction mechanisms.

Mechanoenzymatic Breakdown of Chitinous Material to N‐Acetylglucosamine: The Benefits of a Solventless Environment

“…[31][32][33] Mechanochemistry,t hat is, reactions induced or sustained by mechanicalm illing or shear,h as recently emerged as aw ay to conductc hemical transformationsi ne ither the complete absence of solvents or,i nt he case of liquid-assistedg rinding (LAG), [34][35][36] in the presence of as mall amount of al iquid that can enhancea nd direct reactivity while avoiding solubility limitations. It was recently shown that enzymes can retain activity under mechanochemicalconditions, [37][38][39][40][41][42] and our group has reported that efficient mechanoenzymatic hydrolysis of cellulose can be achieved by repeating cycles of millinga nd aging (static incubation) [43][44][45] of physical mixtures of the solid substrate, lyophilized cellulase enzymes,a nd as mall amount of water.T his process, termed reactive aging (RAging), led to significantly higher glucosec oncentrationst han previously reported methods and, importantly,w ithoutt he need for biomass pretreatment or the use of harsh chemicals. [46] Because the amount of water in RAging is orders of magnitude lower than in conventional solution processes and stoichiometrically comparable to that of the substrate, we speculated that RAging should provide am ore suitable environmentf or chitinase activity compared with conventionalb iocatalysis.…”

Nitrogen‐Doped Biomass‐Derived Carbon Formed by Mechanochemical Synthesis for Lithium–Sulfur Batteries

“…The second issue can be addressed by the concept of mechanochemistry. Mechanochemistry has been applied repeatedly as a sustainable and cost‐effective alternative to conventional synthesis concepts in the fields of pharmaceutical, organic, and inorganic chemistry, especially in the field of metal–organic frameworks (MOFs) . Mechanochemical syntheses rely on the input of mechanical energy to initiate chemical reactions, for instance by grinding solids in high‐energy ball mills.…”

“…The second issue can be addressed by the concept of mechanochemistry.M echanochemistryh as been appliedr epeatedly as as ustainable and cost-effective alternative to conventional synthesis concepts in the fields of pharmaceutical, [43,44] organic, [45][46][47] and inorganic chemistry,e specially in the field of metal-organic frameworks (MOFs). [48][49][50][51][52] Mechanochemicals yntheses rely on the input of mechanicale nergy to initiate chemical reactions, for instanceb yg rinding solids in high-energy ball mills. In contrastt om any conventionals yntheses, mechanochemical pathwaysa llow the production of materials without the use of any solvent, [53,54] with high yields, [55,56] short reaction times, [12,57] and easy scalability.…”

3D‐Superstructured Networks Comprising Fe‐MIL‐88A Metal‐Organic Frameworks Under Mechanochemical Conditions

“…Mechanochemical reactions are of great interest because of their synthetic advantages such as scalable production, zero reaction waste, reduced reaction times, enhanced selectivity and different reactivities compared with reactions performed in solution . Recently, mechanochemical syntheses of MOFs have been demonstrated via mortar grinding, ball milling, microwave, and twin‐screw extrusion . Although there are reports of MOFs being synthesized by mechanochemical reactions, the preparation of morphology controlled hierarchical MOFs superstructures is still challenge.…”