Adducts of Bicyclic (Alkyl)(Amino)Carbene with ECl3 and Three Electron Reduction Thereof: Syntheses of BICAAC Stabilized E‐E Bonded Compounds (E = P, Sb)

The stoichiometric reaction of bicyclic (alkyl)(amino)carbene (BICAAC) with group 15 chlorides, ECl3 (E = P, Sb) to form the Lewis adducts BICAAC:ECl3 (E = P (1), Sb (2)) has been investigated in the present work. The BICAAC smoothly reacts with PPhCl2 to form [BICAAC:PPhCl2] which on in‐situ two electron reduction with 2 equivalents of KC8 afforded the phosphinidene complex, BICAAC=P‐Ph (3). Complete dechlorination of the BICAAC‐ECl3 adducts 1 and 2 with 3 equivalents of KC8 leads to three‐electron reduction to afford low‐valent trans bent bis(BICAAC)E2 complexes (E = P (4) and Sb (5)). These complexes are the first examples of BICAAC adducts with pnictogens and all the complexes have been characterized by different spectroscopic techniques and their solid‐state structure have been elucidated by single crystal X‐ray diffraction.