Methyllithium (MeLi) is the parent archetypical organolithium complex and its monomeric form is vital for understanding the ubiquitous organolithium-mediated reactions. However, despite being pursued for decades, to the best of...

In this work, a rare monomeric organolithium complex was reported, stabilised by a neutral tetradentate amine ligand. Its structure and decomposition/reactivity were studied.

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Organosodium chemistry is underdeveloped compared with organolithium chemistry, and all the reported organosodium complexes exhibit similar, if not identical, reactivity patterns to their lithium counterparts. Herein, we report a rare organosodium monomeric complex, namely, [Na(CH 2 SiMe 3 )(Me 6 Tren)] (1-Na) (Me 6 Tren: tris[2-(dimethylamino)ethyl]amine) stabilized by a tetra-dentate neutral amine ligand Me 6 Tren. Employing organo-carbonyl substrates (ketones, aldehydes, amides, ester), we demonstrated that 1-Na features distinct reactivity patterns compared with its lithium counterpart, [Li(CH 2 SiMe 3 )(Me 6 Tren)] (1-Li). Based on this knowledge, we further developed a ligand-catalysis strategy to conduct ketone/aldehyde methylenations, using [NaCH 2 SiMe 3 ] ∞ as the CH 2 feedstock, replacing the widely used but hazardous/expensive C�O methylenation methods, such as Wittig, Tebbe, Julia/Julia-Kocienśki, Peterson, and so on.

This work comprehensively investigated the coordination chemistry of a hexa -dentate neutral amine ligand, namely, N,N′,N” - tris -(2- N -diethylaminoethyl)-1,4,7-triaza-cyclononane (DETAN), with group-1 metal cations (Li + , Na + , K + , Rb + , Cs + ). Versatile coordination modes were observed, from four-coordinate trigonal pyramidal to six-coordinate trigonal prismatic, depending on the metal ionic radii and metal’s substituent. For comparison, the coordination chemistry of a tetra -dentate tris -[2-(dimethylamino)ethyl]amine (Me 6 Tren) ligand was also studied. This work defines the available coordination modes of two multidentate amine ligands (DETAN and Me 6 Tren), guiding future applications of these ligands for pursuing highly reactive and elusive s-block and rare-earth metal complexes.

This perspective explores the strategies that have been employed to isolate low aggregate and, in particular, monomeric complexes of the most common alkali metal alkyls and the relationship between aggregation, structure and reactivity.

Herein we report two new monomeric lithium and sodium silylbenzyl complexes, which can efficiently convert CO bond in ketones, aldehydes and amide into CC bond, i.e., conducting olefination.

Multidentate neutral amine ligands play vital roles in coordination chemistry and catalysis. In particular, these ligands are used to tune the reactivity of Group-1 metal reagents, such as organolithium reagents. Most, if not all, of these Group-1 metal reagent-mediated reactions occur in solution. However, the solution-state coordination behaviors of these ligands with Group-1 metal cations are poorly understood, compared to the plethora of solid-state structural studies based on single-crystal X-ray diffraction (SCXRD) studies. In this work, we comprehensively mapped out the coordination modes with Group-1 metal cations for three multidentate neutral amine ligands: tridentate 1,4,7-trimethyl-1,4,7-triazacyclononane (Me 3 TACN), tetradentate tris[2-(dimethylamino)ethyl]amine (Me 6 Tren), and hexadentate N,N′,N″-tris-(2-N-diethylaminoethyl)-1,4,7-triaza-cyclononane (DETAN). The macrocycles in the Me 3 TACN and DETAN are identified as the rigid structural directing motif, with the sidearms of DETAN providing flexible “on-demand” coordination sites. In comparison, the Me 6 Tren ligand features more robust coordination, with the sidearms less likely to undergo the decoordinating–coordinating equilibrium. This work will provide a guidance for coordination chemists in applying these three ligands, in particular, the new DETAN ligand to design metal complexes which suit their purposes.