Isolation of (Aryl)‐ (Imino) Phosphide, and (Phosphaalkene) Amide Complexes of Alkali Metals from Carbene‐Phosphinidenes under Reductive‐Thermal Rearrangements

Two-electron reduction of cyclic alkyl(amino) carbene (cAAC)-supported chloro-phosphinidene cAAC=P−Cl (1), followed by the unprecedented thermal rearrangements afforded the alkali metal complexes of (aryl) (cyclic alkyl(imino)) phosphides (3a-3c, 4a) via migration of the dipp (2,6-diisopropylphenyl) group from N to the P center; and (aryl) (cyclic alkyl(phosphaalkene)) amide (5) via the cleavage of the CMe2−N bond followed by energetically favored 5-exo-tet ring-closure in presence of the alkali metals Cs (3a-3c), K (4a, 4b), and Li (5), respectively. 3a was found to be photoluminescent (PL), emitting bright orange light under a long UV lamp (365 nm) with PL quantum yield (ɸPL) of 2.6% (λem = 600 nm), and average lifetime (t) of 4.8 µs. Reaction of 3a with CuCl, and AgOTf afforded the (aryl)-(cyclic alkyl(imino)) phosphide-stabilized tetra-nuclear Cu(I) (6), and octa-nuclear Ag(I) (7) clusters, respectively. Moreover, the complexes 3a-3c provided a direct route for the stabilization of cyclic alkyl(aminoboryl) phosphaalkenes 8a-8c when treated with 1-bromo-N,N,N',N'-tetraisopropylboranediamine.