NITROGEN-BASED LEWIS ACIDS AND A FIRST PREPARATION OF TRIAZANES

Lewis acids and their interactions with Lewis bases are among the most fundamental facets of chemistry. An employment of Lewis acids in various chemical enterprises (catalysis, frustrated Lewis pairs, supramolecular architectures, etc.) is indispensable.

Classical main group element Lewis acids, largely based on boron, aluminum, tin or phosphorous, provide a free low-lying orbital for Lewis base interactions. Conversely, nitrogen-centered species are usually considered as Lewis bases due to available lone pair of electrons of the relatively high energy.

In this lecture we will demonstrate that based on the nitrenium ions we have discovered:

(1) A first example of robust and stereoelectronically modifiable nitrogen-centered Lewis acids, which form well-defined adducts with Lewis bases.

(2) Preparation and full characterization of triazanes – an entirely new class of organic compounds bearing consecutive three all-saturated nitrogen (N-N-N) atoms.

(3) An unprecedented for amines umpolung reactivity of N-H bond, possessing both protic and hydridic character.