Pentamethylcyclopentadienyl‐substituiertes Selenadiphosphiran und Selenatriphosphetan: Synthese, Struktur, Dynamik und einige Reaktionen

Pentamethylcyclopentadienyl‐Substituted Selenadiphosphirane and Selenatriphosphetane: Synthesis, Structure, Dynamic, and Some Reactions Herrn Prof. R. Schmutzler zum 60. Geburtstag gewidmet. 1,2,3‐Tris(pentamethylcyclopentadienyl)cyclotriphosphane (1) reacts with selenium to form the insertion product 2,3,4‐tris(pentamethylcyclopentadienyl)selenatriphosphetane (2) , which is trapped as the selenium‐coordinated pentacarbonylchromium complex 4 . Compound 4 is the first isolated selenatriphosphetane complex. Reaction of 2 with selenium yields 2,3‐bis(pentamethylcyclopentadienyl)selenadiphosphirane (3) . 3 replaces thf of Cr(CO) 5 thf to give the chromium complex 5 . The reaction of 3 with K[Fe(CO) 2 Cp*] leads to the substitution product 6 and the bicyclic phosphane 7 . The X‐ray structures of 3 and 4 are presented. The dynamic behavior of 3–6 is discussed.