24th International Conference on Phosphorus Chemistry (ICPC24)

Hydrocarbon compounds are the most basic materials used as fuels and for the production of specialized chemicals. However, already hundreds of years ago, chemists discovered the inorganic equivalents made up by elements of group 13 and 15, forming isoelectronic 13/15 compounds. Starting with the preparation of H₃N∙BF₃ by Gay-Lussac in 1809, many milestone discoveries such as borazine B₃N₃H₆ and (CH₃)₃N∙BH₃ followed. In the last decades, the focus has more and more shifted to the heavier homologues, mainly phosphorus and arsenic on the group 15 side and gallium and aluminium on the group 13 side, partially owed due to practical applications of 13/15 compounds such as GaAs in the semiconductor industry.

The reaction of Me(OTf) (OTf = SO₃CF₃) with NHC∙GaH₃ (NHC = IDipp (1,3-Bis-(2,6-diisopropylphenyl)-imidazolin-2-ylidene), IMes (1,3-Bis-(2,4,6-trimethylphenyl)-imidazolin-2-ylidene), IPrMe (1,3-Bis-(diisopropyl)-4,5-dimethylimidazolin-2-ylidene)) cleanly generates donor-stabilized galliummonotriflates in high yields. The mechanism of this reaction is elucidated by extensive computational studies, showing that selective monotriflation represents a kinetic effect rather than a thermodynamic one. The obtained compounds contain an excellent leaving group and can be used as stable [NHC∙GaH₂]⁺ synthons. Reactions with phosphanylboranes and gallanes led to unprecedented cationic 13/15 chain compounds [NHC∙GaH₂PH₂EH₂∙D][OTf] (E = B, Ga; D = donor).