Selenolato chromium complexes. Synthesis, thermolytic degradation and crystal structure of [Cr(η-C5H5)(CO)3(SePh)]

Abstract

The instantaneous reaction of [{Cr(cp)(CO)₃}₂]1(cp =η⁵-C₅H₅) with 1 molar equivalent of Ph₂Se₂ at ambient temperature led to the isolation of [Cr(cp)(CO)₃(SePh)]2 and [{Cr(cp)(CO)₂(SePh)}₂]3 in 43.6% and ca. 7%, yields respectively. At elevated temperatures, compound 2 underwent decarbonylation with concomitant coupling to yield 3, [{Cr(cp)(CO)(SePh)}₂]4 and finally [{Cr(cp)(SePh)}₂Se]5 in 45.6% yield. The latter was also obtained in 49.8% yield from the reaction of [{Cr(cp)(CO)₂}₂] with Ph₂Se₂ at 60 °C. The structure of 2 was established by X-ray diffraction analysis: space group P2₁/c(no. 14), a= 10.401(3), b= 8.701(2), c= 15.604(4)Å, β= 99.51(2)° and Z= 4.