[ n + 2]‐Cycloadditionsreaktionen des (Arylimino)phosphenium‐Ions, [P≡NAr] + –kationische PN‐Heterocyclen mit ungewöhnlicher Struktur und Bindungssituation

[ n + 2] Cycloaddition Reactions of the (Arylimino)phosphenium Ion, [P≡NAr] + –Kationic PN Heterocycles with Unusual Structure and Bonding Situation The iminophosphenium ion [P≡NAr] + (Ar=2,4,6‐ t Bu 3 C 6 H 2 ) ( 1 ) reacts with aminoiminophosphanes R 2 N–P=N t Bu (R= i Pr, Me 3 Si) ( 2 ) and alkyl azides RN 3 (R= t Bu, Et 3 C) ( 6 ) to yield the corresponding [ n + 2] cycloadducts [R 2 NP (NAr)P(N t Bu) + ( 3 ) and [PN(Ar)NNN(R)] + ( 7 ), respectively. Single‐crystal X‐ray diffraction studies show that 3a can be considered as an intramolecular donor‐acceptor complex while 7 can be regarded as a cyclic diaminophosphenium cation coupled to a diimine fragment, which is in accordance with results of ab initio calculations.