Extremely strong OH⋯O hydrogen bonds in some 3-organophosphorus substituted pentane-2,4-diones

Abstract

Single crystal X-ray analysis showed that 2-(2′,4′-dioxo-3′-pentyl)-trans,trans-4,6-dimethyl-2-oxo-1,3,2-dioxaphosphorinane (I) exists in the enol form, exhibiting hydrogen bonding with an R(O⋯O) of 2.397 Å. X-ray and NMR data (δ, Δδ(HD)) for 3-organophosphorus substituted pentane-2,4-diones revealed strengthening of the hydrogen bonding by the introduction of phosphorus substituents into pentane-2,4-dione, as a result of steric effects. The content of the enol form has also been determined. © 1992.