The hydrolysis of (π-C₆H₆)Cr(π-C₆F₅CO₂C₂H₅): an unexpected decarboxylation

Abstract

The attempted basic hydrolysis of the ester sandwich compound (C6H6)Cr(C6F5CO2Et) did not yield the expected carboxylic acid but instead produced (C6H6)Cr(C6F5H) in good yield together with traces of (C6H6)Cr(C6HF4OMe). Attempts to trap a benzyne intermediate were unsuccessful and the mechanism of decarboxylation is discussed in terms of internal chelation at the chromium centre.

π-Complexed polyfluoroarenes: a reactivity, bonding and spectroscopic study of (η6-C6F6)Cr(η6-C6H6) and related molecules

“…The most evident observation was a marked shielding of the 19 F NMR chemical shifts in fluorochromarenes by 30-50 ppm relative to the free arenes. 32,33 Moreover, there is clear electronic interaction between the rings. Typically, (Z 6 -C 6 F 6 )Cr(Z 6 -C 6 H 6 ) exhibits binomial septets in both the 19 F and 1 H NMR regimes with an inter-ring J HF coupling constant of 1.44 Hz.…”