title: Reversible O-ylide formation in carbene/ether reactions.
abstract: p-Nitrophenylchlorocarbene reacted reversibly with diethyl ether, di-n-propyl ether, or tetrahydrofuran (THF) to form O-ylides, which were visualized by their UV-visible spectroscopic signatures. Equilibrium constants (K(eq)) were determined spectroscopically and ranged from 0.10 M(-1) (di-n-propyl ether) to 7.5 M(-1) (THF) at 295 K. Studies of K(eq) as a function of temperature afforded ΔH(o), ΔS(o), and ΔG(o) for the di-n-propyl ether and THF/O-ylide equilibria. ΔH(o) was favorable for ylide formation, but ΔS(o) was quite negative, so that ΔG(o)s for the equilibria were small. Electronic structure calculations based on density functional theory provided structures, spectroscopic signatures, and energetics for the carbene/ether O-ylides.
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, USA.
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Hoijemberg
authors.forename: Robert A
authors.initials: RA
authors.lastname: Moss
authors.forename: Karsten
authors.initials: K
authors.lastname: Krogh-Jespersen