SELENOLATO CHROMIUM COMPLEXES - SYNTHESIS, THERMOLYTIC DEGRADATION AND CRYSTAL-STRUCTURE OF [CR(ETA-C5H5)(CO)3(SEPH)]

The instantaneous reaction of [{Cr(cp)(CO)3}2] 1 (cp = eta-5-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-degrees-C. The structure of 2 was established by X-ray diffraction analysis: space group P2(1)/c (no. 14), a 10,401(3), b = 8.701(2), c = 15.604(4) angstrom, beta = 99.51(2)-degrees and Z = 4.