The interaction of Co2(CO)8 with [NP(OPh)L7(OC6H4PPh2)03]n(1), N3P3(OPh)5(OC6H4PPh2) (2), PPh2-linked polystyrene (3), or triarylphosphine [PPh3, P(p-CH3C6H4)3] yielded species of the type Co2(CO)7PR3, [CO(CO) 3PR3]2, and [Co(CO)3(PR3)2]+Co(CO)4~ as identified by infrared spectroscopy and 31P NMR. Catalysts derived from 1 were expected to have higher thermal stability based on the inherent thermal stability of 1 vs. 3. A study of the catalyst system 1 /Co2(CO)8 for 1-hexene hydroformylation revealed an initial activity equal to its homogeneous analogue. This has been rationalized as due to cleavage of cross-linking P-Co-P sites during reaction with CO/H2 to give soluble hydride HCo(CO)3PR3 type species. All of the catalysts also revealed a time-dependent decrease in catalytic activity, due to a cobalt-mediated phosphorus-carbon bond cleavage. Benzene, toluene, benzyl alcohol, and p-MeC6H4CH2OH were detected as primary cleavage products. When olefin was omitted from these reactions, R2PH was observed.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry