Solution-state chemistry

Group-1 metal reagents (e.g., organolithium) are arguably the most-used organometallic reagents, but their structure-reactivity relationship, to almost everyone's surprise, is poorly understood.

The ubiquitous Group-1 Metal reagents are likely to form aggregates with bridging M-E (M: Li-Cs; E: C, N, P, O, H...) bonds, which feature sluggish reactivity and muddled structures. Isolating corresponding monomeric, discrete Group-1 metal complexes could enhance the M-E reactivity, and could provide ideal platforms for mechanism studies. Monomeric Group-1 complexes, especially monomeric organolithiums, has been one of the most topical areas in Main-Group coordination chemistry since the 1990s.

Ligand design is the key. We designed a bespoke DETAN ligand, which enabled the isolating and characterising of the first monomer of the archetypical organolithium: a MeLi monomer (Chem. Commun. 2021, 57, 6205. https://doi.org/10.1039/D1CC01420J). We are endeavouring to synthesise more monomeric, highly-reactive Group-1 metal M-E complexes (especially alkyls and hydrides), and study their stoichiometric and catalytic reactivity in small molecule and inert chemical bond activations.

Selected publications:

• Elucidating Solution-State Coordination Modes of Multidentate Neutral Amine Ligands with Group-1 Metal Cations: Variable-Temperature NMR Studies. N. Davison, J. A. Quirk, C. Wills*, C. Dixon, P. G. Waddell, J. A. Dawson*, E. Lu*. Inorg. Chem. 2022, 61, 15204-15212. https://doi.org/10.1021/acs.inorgchem.2c02457

• A monomeric (trimethylsilyl)methyl lithium complex: synthesis, structure, decomposition and preliminary reactivity studies. N. Davison, P. G. Waddell, C. Dixon, C. Wills, T. J. Penfold*, E. Lu*. Dalton Trans. 2022, 51, 10707. https://doi.org/10.1039/D1DT03532K (Invited for the themed issue 'New Talent: Europe') (Outside back cover).

• Versatile Coordination Modes of Multidentate Neutral Amine Ligands with Group 1 Metal Cations. N. Davison, K. Zhou, P. G. Waddell, C. Wills, C. Dixon, S. -X. Hu*, E. Lu*. Inorg. Chem. 2022, 61, 3674. https://doi.org/10.1021/acs.inorgchem.1c03786

• A monomeric methyllithium complex: synthesis and structure. N. Davison, E. Falbo, P. G. Waddell, T. J. Penfold, E. Lu*. Chem. Commun. 2021, 57, 6205. https://doi.org/10.1039/D1CC01420J

Solid-state chemistry

Minimizing energy consumption, pollution, and the usage of hazardous chemicals in organic synthesis are grand challenges faced by the scientific community. A sustainable vision of organic synthesis requires new enabling reagents, preferably using no precious metals and solvents, and enabling challenging transformations under facile conditions.

We designed a class of unprecedented Group-1 metal reagents: hetero-bi-metallic Group-1 metal ROom-temperature Stable Electrides (ROSEs). The ROSE reagents can be synthesized from cheap starting materials (Li/Na/K metals, metal amides), via rapid and scalable mechanochemistry ball milling method. The ROSE reagents feature highly-reactive anionic electrons, which unlock a vast unexplored space of reactions. For example, we reported the ROSE-enabled facile benzene/pyridine C-H activation and C-C coupling. Moreover, the ROSE reagent can phase out the notorious metal-liquid ammonia condition, and organic solvents at all, from a classic textbook reaction: Birch reduction.

Selected publications:

• A room-temperature stable electride and its reactivity: reductive benzene/pyridine couplings and solvent-free Birch reductions. N. Davison, J. A. Quirk, F. Tuna*, D. Collison, C. L. McMullin*, H. Michaels, G. H. Morritt, P. G. Waddell, J. A. Gould, M. Freitag, J. A. Dawson*, E. Lu*. Chem 2022, pending.