| Popis: |
Chemistry of the η1-Rhenium-Coordinated Triphenylcyclopropenyl Ligand The s-coordinated pentacarbonyl[η1-1,2,3-triphenylcyclopropenyl)rhenium complex 1 is transformed into the green tetracarbonyl(η2-1,2,3-triphenylpropenetriyl)rhenium compound 2 with loss of CO by heating or irradiation. In addition, tetracarbonyl(η3-4-oxo-1,2,3-triphenylcyclobutenyl)rhenium (3a) and Tricarbonyl(η5-1,2,3,4,5,6-hexaphenylcyclohexadienyl)-rhenium (4) were obtained from this reaction. Treatment of 1 with trimethylamine N-oxide leads under oxygen transfer to tetracarbonyl(η2-3-oxo-1,2,3-triphenyl-1-propenyl)rhenium (5) and tricarbonyl(trimethylamine)(η2-3-oxo-1,2,3-triphenyl-1-propenyl)rhenium (6). The NMe3 ligand in 6 can be substituted either by CO or trimethyl phosphite to yield 5 or tricarbonyl-(trimethyl phosphite)(η2-oxo-1,2,3-triphenyl-1-propenyl)-rhenium (7), respectively. Complex 1 reacts with trimethyl-phosphane or trimethyl phosphite to give tetracarbonyl(phosphorus donor)(η1-4-oxo-1,2,3-triphenyl-2-cyclobuten-1-yl)rhenium 8b [L = PMe3] or 8c [L = P(OMe)3]. The derivatives Re(CO)3L2-η1-C3Ph3CO [L = CO, 8a; L = PMe3, 8d; L = P(O-Me)38e] were obtained by treatment of 3a with CO or two equivalents of PMe3 or P(OMe)3. The formation of 8d and 8e proceeded via the tricarbonyl(phosphorus donor)(η3-4-oxo-1,2,3-triphenylcyclobutenyl)rhenium compounds 3b and 3c. The unusual η1-coordination of the cyclobutenone system in 8 was established by an X-ray structure analysis of 8c. Furthermore, 4 and 5 were characterized by single-crystal X-ray diffraction. Reactions of 2 with alkynes led to substituted tricarbonyl(cyclopentadienyl)rhenium derivatives Re(η5-C5Ph3RR')(CO)39 (R = R' = Ph, 9a; R = R' = CO2Me, 9b; R = R' = CO2Et, 9c; R = Ph, R' = H, 9d). |
Plný text