One-Pot, One-Step Precatalysts through Mechanochemistry

Abstract

The development and implementation of transition-metal-based precatalysts have played crucial roles in modern organic synthesis. However, while the use of such species greatly improves sustainability, their preparative routes often rely on multiple time-, energy-, and solvent-intensive steps. By leveraging solvent-free mechanochemical synthesis through vibratory ball milling, we report the one-pot, one-step synthesis of a range of first-row transition-metal bis­(imino)­pyridine complexes, where both the ligand and coordination complex are assembled in situ. Bis­(imino)­pyridine complexes of the first-row transition metals have an extensive history of application as precatalysts for numerous bond-forming transformations. The method reported herein facilitates access to such species in a time-, solvent-, and space-saving manner which can easily be adapted to any laboratory setting regardless of prior experience with coordination complex synthesis.

Disentangling the Effect of Pressure and Mixing on a Mechanochemical Bromination Reaction by Solid‐State NMR Spectroscopy**

“…The influence of mechanical forces on chemical reactions has attracted chemists for many decades, for instance, due to the possibility of opening alternative synthetic pathways otherwise unachievable using different means of energetic input, such as light and temperature. [1][2][3][4] The field of mechanochemistry 5 has experienced enormous advances in the past years, reflected in versatile chemical and biological applications (for selected reviews see [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] ), ranging from the solid-state synthesis of inorganic materials, [24][25][26][27] metal-organic [28][29][30][31][32] and organic compounds, [33][34][35][36] covalent organic frameworks, 37 and polymers [38][39][40][41][42][43] to enzymatic reactions 19,[44][45]…”

Multigram Mechanochemical synthesis of a Salophen Complex: A Comparative Analysis

“…Mechanosynthesis is an attractive alternative to conventional solution-based synthesis, since it not only addresses several environmental concerns associated with the use of large volume of solvents but also often offers shorter reaction times and higher yields. , Uniquely, mechanochemistry also offers opportunities to prepare chemical compounds that are otherwise difficult or impossible to prepare by solution methods owing to limited solubility of the starting material and the limited stability of the product in solution. , In recent years, mechanochemistry has increasingly been applied as a solvent-free (or nearly solvent-free) synthetic route in a wide range of fields. − (e.g., organometallic complexes, − organo-catalysts, cocrystals, − metal–organic frameworks, − alloys, composites, , etc . )…”

Postsynthetic Modification of Half-Sandwich Ruthenium Complexes by Mechanochemical Synthesis

“…For example, Bantreil et al recently reported the mechanochemical synthesis of half-sandwich ruthenium complexes with N-heterocyclic carbene (NHC) and [Ru­( p -cymene)­(μ-Cl)­Cl] 2 , in situ obtaining the Ag-NHC complex with only a small amount of water (0.3 μL/mg of reactants) . Jurca and co-workers reported the mechanochemical synthesis of bis­(imino)­pyridine-MX 2 (M = Mn, Fe, Co, Ni, Cu, Zn; X = Cl, Br) complexes via a one-pot, one-step process from diacetylpyridine, panisidine, and a MX 2 precursor in the presence of MgSO 4 and p -toluenesulfonic acid …”

“…31 Jurca and co-workers reported the mechanochemical synthesis of bis(imino)pyridine-MX 2 (M = Mn, Fe, Co, Ni, Cu, Zn; X = Cl, Br) complexes via a one-pot, one-step process from diacetylpyridine, panisidine, and a MX 2 precursor in the presence of MgSO 4 and p-toluenesulfonic acid. 32 Following our interest in studying half-sandwich metal complexes' catalytic activities with diverse functional ligands, 33−37 we report herein an efficient and more sustainable method to synthesize a new, previously unreported halfsandwich ruthenium complex 2, to the best of our knowledge. Complex 2 bears an aldehyde functional group that can enable postsynthetic modification, which could be carried out via a mechanochemical Wittig reaction.…”