Mechanochemical Synthesis of a Sodium Anion Complex [Na(2,2,2-cryptand)Na] and Studies of Its Reactivity: Two-Electron and One-Electron Reductions.

Group 1 metal molecular chemistry is dominated by a +1 oxidation state, while a 0 oxidation state is widespread in the metals. A more exotic, yet still available, oxidation state of group 1 metal is -1, i.e.

Lithium, sodium and potassium enolate aggregates and monomers: syntheses and structures.

In this , we report the syntheses and comparative structural studies of lithium, sodium, and potassium anthracen-9-yl enolates, as their aggregates (Li, Na: hexamer; K: tetramer) and ligand-stabilized monomers (for Li and Na). The monomers add new members to the rare collection of group-1 metal monomeric enolates. Moreover, the series covers different group-1 metal cations (Li, Na and K) and aggregate sizes, allowing comparative structural studies to elucidate how the metal identity and aggregate size influence the enolate structure.

Reduction of K or Li in the Heterobimetallic Electride K[LiN(SiMe)]e.

Given their very negative redox potential (e.g., Li → Li(0), -3.

Monomeric lithium and sodium silylbenzyl complexes: syntheses, structures, and CO bond olefination.

Herein we report the syntheses, structures and reactivity studies of two new monomeric alkali metal silylbenzyl complexes stabilised by a tetradentate amine ligand, tris[2-(dimethylamino)ethyl]amine (MeTren). The two complexes, namely [MR'(MeTren)] (R': CH(Ph)(SiMe)) (2-Li: M = Li; 2-Na: M = Na), exhibit significant different coordination modes according to their metal identity (Li: σ-coordination; Na: π-coordination). Reactivity studies of 2-Li and 2-Na reveal that they are efficient in promoting a widely-used class of organic functional group interconversion: CO bond olefination of ketones, aldehydes and amides, to produce tri-substituted internal alkenes.

The quest for organo-alkali metal monomers: unscrambling the structure-reactivity relationship.

Organo-alkali metal reagents are essential tools in synthetic chemistry. Alkali metal organometallics aggregate in solution and solid-state forming clusters and polymers. The structure of these aggregates and their structure-reactivity relationship have been of great interest for many decades.

Li vs Na: Divergent Reaction Patterns between Organolithium and Organosodium Complexes and Ligand-Catalyzed Ketone/Aldehyde Methylenation.

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(CHSiMe)(MeTren)] (-Na) (MeTren: tris[2-(dimethylamino)ethyl]amine) stabilized by a -dentate neutral amine ligand MeTren. Employing organo-carbonyl substrates (ketones, aldehydes, amides, ester), we demonstrated that -Na features distinct reactivity patterns compared with its lithium counterpart, [Li(CHSiMe)(MeTren)] (-Li).

Elucidating Solution-State Coordination Modes of Multidentate Neutral Amine Ligands with Group-1 Metal Cations: Variable-Temperature NMR Studies.

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.

Versatile Coordination Modes of Multidentate Neutral Amine Ligands with Group 1 Metal Cations.

This work comprehensively investigated the coordination chemistry of a -dentate neutral amine ligand, namely, --(2--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 -dentate -[2-(dimethylamino)ethyl]amine (MeTren) ligand was also studied.

A monomeric (trimethylsilyl)methyl lithium complex: synthesis, structure, decomposition and preliminary reactivity studies.

Monomeric organolithium (LiR) complexes could provide enhanced Li-C bond reactivity and suggest mechanisms for a plethora of LiR-mediated reactions. They are highly sought-after but remain a synthetic challenge for organometallic chemists. In this work, we report the synthesis and characterisation of a monomeric (trimethylsilyl)methyl lithium complex, namely [Li(CHSiMe)(κ-,',''-MeTren)] (1), where MeTren is a tetradentate neutral amine ligand.

A monomeric methyllithium complex: synthesis and structure.

Methyllithium (MeLi) is the parent archetypal organolithium complex. MeLi exists as aggregates in solutions and solid states. Monomeric MeLi is postulated as a highly reactive intermediate and plays a vital role in understanding MeLi-mediated reactions but has not been isolated.