Fixation and Release of Intact E 4 Tetrahedra (E=P, As)

By the reaction of [NacnacCuCH 3 CN] with white phosphorus (P 4 ) and yellow arsenic (As 4 ), the stabilization and enclosure of the intact E 4 tetrahedra are realized and the disubstituted complexes [(NacnacCu) 2 (μ,η 2:2 ‐E 4 )] ( 1 a : E=P, 1 b : E=As) are formed. The mono‐substituted complex [NacnacCu(η 2 ‐P 4 )] ( 2 ), was detected by the exchange reaction of 1 a with P 4 and was only isolated using low‐temperature work‐up. All products were comprehensively spectroscopically and crystallographically characterized. The bonding situation in the products as intact E 4 units (E=P, As) was confirmed by theory and was experimentally proven by the pyridine promoted release of the bridging E 4 tetrahedra in 1 .