In recent years, the use of mechanical energy to promote chemical changes on matter has grown in popularity. As a result, the number of new mechanochemical reactions, particularly in the field of organic chemistry, has been increasing. Consequently, now there is a significant body of evidence suggesting that mechanochemistry holds promise to become a game-changer in chemical synthesis. In this second thematic issue on mechanochemistry, the Beilstein Journal of Organic Chemistry aims at providing its readership with an excellent collection or papers in the field of mechanochemistry ranging from mechanosynthesis of organic molecules, catalysis under mechanochemical conditions, mechanistic studies of mechanochemical transformations, polymer mechanochemistry, and much more.
Graphical Abstract
Figure 1: Biologically relevant molecules made, used or derivatized by mechanochemistry.
Figure 2: Isomeric diacyl-sn-glycerols (DAGs).
Scheme 1: Synthetic route to access protected DAGs; PG = protecting group.
Scheme 2: Protection of glycidol (1) with TBDMSCl in the ball mill. MM = mixer mill, PBM = planetary ball mil...
Scheme 3: Cobalt-catalyzed epoxide ring-opening in the ball mill.
Scheme 4: Mechanosynthesis of DAGs 5.
Scheme 5: Conjugation of DAG 5a with 7-hydroxycoumarin (9).
Figure 3: UV−vis spectra of DAG 6a (dotted line) and conjugated DAGs 10a and 10a’ as a mixture (10a/10a’ 72:2...
Graphical Abstract
Figure 1: A generalized overview of coordination-driven self-assembly.
Figure 2: Examples of self-assembly or self-sorting and subsequent substitution.
Figure 3: Synthesis of salen-type ligand followed by metal-complex formation in the same pot [55].
Figure 4: Otera’s solvent-free approach by which the formation of self-assembled supramolecules could be acce...
Figure 5: Synthesis of a Pd-based metalla-supramolecular assembly through mechanochemical activation for C–H-...
Figure 6: a) Schematic representation for the construction of a [2]rotaxane. b) Chiu’s ball-milling approach ...
Figure 7: Mechanochemical synthesis of the smallest [2]rotaxane.
Figure 8: Solvent-free mechanochemical synthesis of pillar[5]arene-containing [2]rotaxanes [61].
Figure 9: Mechanochemical liquid-assisted one-pot two-step synthesis of [2]rotaxanes under high-speed vibrati...
Figure 10: Mechanochemical (ball-milling) synthesis of molecular sphere-like nanostructures [63].
Figure 11: High-speed vibration milling (HSVM) synthesis of boronic ester cages of type 22 [64].
Figure 12: Mechanochemical synthesis of borasiloxane-based macrocycles.
Figure 13: Mechanochemical synthesis of 2-dimensional aromatic polyamides.
Figure 14: Nitschke’s tetrahedral Fe(II) cage 25.
Figure 15: Mechanochemical one-pot synthesis of the 22-component [Fe4(AD2)6]4− 26, 11-component [Fe2(BD2)3]2− ...
Figure 16: a) Subcomponent synthesis of catalyst and reagent and b) followed by multicomponent reaction for sy...
Figure 17: A dynamic combinatorial library (DCL) could be self-sorted to two distinct products.
Figure 18: Mechanochemical synthesis of dynamic covalent systems via thermodynamic control.
Figure 19: Preferential formation of hexamer 33 under mechanochemical shaking via non-covalent interactions of...
Figure 20: Anion templated mechanochemical synthesis of macrocycles cycHC[n] by validating the concept of dyna...
Figure 21: Hydrogen-bond-assisted [2 + 2]-cycloaddition reaction through solid-state grinding. Hydrogen-bond d...
Figure 22: Formation of the cage and encapsulation of [2.2]paracyclophane guest molecule in the cage was done ...
Figure 23: Formation of the 1:1 complex C60–tert-butylcalix[4]azulene through mortar and pestle grinding of th...
Figure 24: Formation of a 2:2 complex between the supramolecular catalyst and the reagent in the transition st...
Figure 25: Halogen-bonded co-crystals via a) I···P, b) I···As, and c) I···Sb bonds [112].
Figure 26: Transformation of contact-explosive primary amines and iodine(III) into a successful chemical react...
Figure 27: Undirected C–H functionalization by using the acidic hydrogen to control basicity of the amines [114]. a...
Graphical Abstract
Scheme 1: Fast trimethylene carbonate polymerization using a solvent-free ball-milling approach.
Figure 1: IR thermometer images showing reactor temperatures at the end of the two individual ball-milling re...
Graphical Abstract
Scheme 1: Catalyzed mechanochemical Knoevenagel condensation of fluorobenzaldehydes and malonodinitrile. The ...
Figure 1: Comparison of XRPD pattern of malonodinitrile (2) and (p-fluorobenzylidene) malonodinitrile (3a). T...
Figure 2: a) XRPD pattern of (p-fluorobenzylidene)malonodinitrile (3a) direct after the synthesis with differ...
Figure 3: Mass spectra of the different products of 3a. Red: peak off the molecular ion [M + H]+ of piperidin...
Figure 4: a) In situ XRPD pattern of the mechanochemical Knoevenagel condensation of 1a and 2 with 2 µL catal...
Figure 5: Comparison of XRPD patterns of both polymorphs of the product 3a. Red: triclinic polymorph t3a. Blu...
Figure 6: Results of multivariate data analysis of Raman spectra for 30 Hz milling experiments. Principal com...
Graphical Abstract
Figure 1: A) Porphyrin structure and labelling system. B) Substituents in the ortho-position of the group att...
Scheme 1: Steps leading to the formation of a porphyrin.
Scheme 2: Mechanochemical synthesis of tetramesitylporphyrin.
Graphical Abstract
Figure 1: A: Mechanochemical polymerization of BCMBP (4,4’-bis(chloromethyl)-1,1’-biphenyl) towards the porou...
Figure 2: A: IR spectra of the monomer BCMBP and NG-HCP showing a decrease of the C–Cl vibration after the re...
Figure 3: A: Evolution of pressure in the course of the reaction measured by the GTM system. The addition of ...
Figure 4: The correlation between the liquids’ boiling point and the SSA of the polymer. In general, a lower ...
Figure 5: Physisorption isotherms of benzene vapour at different temperatures on HCP synthesised classically ...
Figure 6: Physisorption isotherms of cyclohexane on mechanochemically synthesised HCP at temperatures 288, 29...
Graphical Abstract
Figure 1: CrI% for chitin samples, before and after milling in a jar with one ball made of SS, ZrO2, Cu, Al, ...
Figure 2: Value of CrI after milling as a function of the Vickers hardness values of the media (Jar and ball)...
Figure 3: Crystallinity index (%) after milling as a function of frequency. ZrO2 and SS jars are compared, bo...
Figure 4: Crystallinity index (%) of chitin milled with 9.5 mm balls of PTFE, ZrO2 and SS each used in jars o...
Figure 5: Correlation between the ball mass (orange line) or kinetic energy (blue line) with the crystallinit...
Figure 6: Metal contamination of milled chitin determined by ICP–OES, as a function of the milling medium. Th...
Graphical Abstract
Scheme 1: Solid-state exchange reaction through ball-mill grinding under neat ball-mill-grinding conditions (...
Figure 1: Solid-state studies reacting 1-1 and 2-2 in an equimolar ratio in the presence of DBU as catalyst t...
Scheme 2: Schematic representation of a solid + solid mechanochemical reaction. Subscript denote macroscopic ...
Scheme 3: Simplified reaction equation for the mechanochemical transformation. Note that [AB] is a physical c...
Figure 2: Reaction profiles for mechanochemical milling according to Equation 4. (a) Kinetic profiles for 30 Hz, 25 Hz,...
Figure 3: Modelled kinetic profiles for 15 Hz neat milling, with variation in the magnitude of the mixing ter...
Figure 4: Reaction profiles for LAG mechanochemical milling according to Equation 4. The modelled curves are given for ...
Graphical Abstract
Scheme 1: FCR of pyrene and phthalic anhydride.
Scheme 2: Scope of acylation reagents in FCR under mechanochemical activation conditions and comparison with ...
Scheme 3: Scope of aromatic substrates in FCR under mechanochemical activation conditions. aIsolated yields.
Scheme 4: Mechanochemical regiodirected FCR of anthracene dimer and succinic anhydride.
Scheme 5: Regioselectivity direction by protection of 9,10-anthracene ring positions.
Scheme 6: Double FCR of phthaloyl chloride and aromatics.
Figure 1: In situ Raman monitoring of reaction of phthalic anhydride with p-xylene.
Graphical Abstract
Scheme 1: The reaction of CDs with oxiranes.
Figure 1: Jar-temperature changes during the reaction of 1,2-propylene oxide and cyclodextrins in the presenc...
Figure 2: Comparative SEM pictures of a β-CD bead and β-CDP (20 mmol, Table 3, entry 10).
Figure 3: Comparison of β-CDP (Table 3, entry 9) and γ-CDP (Table 3, entry 12) prepared in a ball mill on 2 mmol scale.
Figure 4: Normalised particle-size distribution of insoluble CD polymers (entries 9, 10, and 12 of Table 3).
Figure 5: UV–vis spectra and adsorption isotherm of the insoluble β-CDP polymer in 10 ml 0.050 mM MO solution...
Figure 6: UV–vis spectral changes of 0.050 mM MO solution by GPTS-β-CD (left) and GPTS-γ-CD (right), as prepa...
Figure 7: UV–vis spectral changes of 0.050 mM MO solution by GPTS-β-CD (left) and GPTS-γ-CD (right), as prepa...
Graphical Abstract
Scheme 1: Oxidation of 3-pheny-1-propanol (1a) with N-chlorosuccinimide (NCS) in the presence of (2,2,6,6-tet...
Scheme 2: Hypothesized pathways for the TEMPO-assisted oxidation of alcohols in a) basic or b) acidic reactio...
Scheme 3: TEMPO-assisted oxidation of 3-pheny-1-propanol (1a) under mechanical activation conditions. aPercen...
Scheme 4: Scope of primary alcohol oxidation under mechanical activation conditions. aAll yields refer to iso...
Scheme 5: Proposed mechanism for the oxidation of benzylic alcohols 6a and 7a under mechanochemical condition...
Scheme 6: Scope of secondary alcohols in the oxidation under mechanical activation conditions. aAll yields re...
Scheme 7: Possible mechanism for the TEMPO-mediated oxidation of primary and secondary alcohols by using NaOC...
Graphical Abstract
Figure 1: Portion of the polymeric chain of [CsKA'2], with thermal ellipsoids drawn at the 50% level. Hydroge...
Figure 2: Partial packing diagram of [CsKA'2], illustrating some of the interchain contacts, predominantly K1…...
Figure 3: Portion of the polymeric chain of [(C6H6)KA']∞, with thermal ellipsoids drawn at the 50% level. Hyd...