Mechanochemical preparation of molecular and supramolecular organometallic materials and coordination networks

Abstract

This Dalton Perspective deals with solvent-free reactions taking place within solids or between solids or involving a solid and a vapour. The focus is on reactions involving organometallic and coordination compounds and occurring via reassembling of non-covalent bonding, e.g. hydrogen bonds, and/or formation of ligand-metal coordination bonds. It is argued that reactions activated by mechanical mixing of solid reactants as well as those obtained by exposing a crystalline solid to a vapour can be exploited to "make crystals", which is the quintessence of crystal engineering. It is demonstrated through a number of examples that solvent-free methods, such as co-grinding, kneading, milling of molecular solids, or reactions of solid with vapours represent viable alternative, when not unique, routes for the preparation of novel molecular and supramolecular solids as well as for the preparation of polymorphic or solvate modifications of a same species. The structural characterization of the products requires the preparation of single crystals suitable for X-ray diffraction, a goal often achieved by seeding.

Solid-State Transformations of Sulfathiazole Polymorphs: The Effects of Milling and Humidity

“…This has been successfully used in the preparation of a drug in a pure form and it is an environmentally friendly procedure [33][34][35]. The role of solvent is that of a crystallization catalyst and it is believed to function as a lubricant for molecular diffusion [36]. To the best of our knowledge, no study has reported the application of SDM to sulfathiazole.…”

Clean and Efficient Synthesis Using Mechanochemistry: Coordination Polymers, Metal-Organic Frameworks and Metallodrugs

“…20 Although the detailed mechanisms 17 underlying LAG cocrystallization, and especially control of polymorphism 21 and templating of open molecular framework, 18 are not known, simple explanations for the efficiency and speed of LAG have recently been proposed. In particular, it was proposed by several research groups 22,23 that the speed of reactions conducted by…”

Controlling Solvate Formation of a Schiff Base by Combining Mechano-chemistry with Solution Synthesis

“…Among these preparatory procedures, mechanochemical methods such as liquid-assisted grinding (LAG) 40,41 or ion-and liquid-assisted grinding (ILAG) 42,43 have shown a great potential as efficient methods for supramolecular and covalent synthesis of new materials. [44][45][46][47] Our group has recently reported mechanochemical synthesis of a Schiff base derived from 2-hydroxy-1-naphthaldehyde and 2-aminobenzonitrile 48 and described simultaneous covalent solvent-free synthesis and polymorphism control using neat grinding and seeding-assisted grinding (SEAG), i.e. neat grinding in the presence of seed crystals of the desired product.…”