Boron trifluoride complexes. Part VI. The complexes and conjugate acids of p-dimethyl- and -diethylaminobenzaldehyde

Abstract

Boron trifluoride forms three different complexes with p-dialkylaminobenzaldehyde, two 1 : 1 complexes (IV) and (V) and one 2 : 1 complex (VI). The structure of these complexes has been elucidated from their spectral properties. The strong electron-withdrawing pseudo-substituent BF₃:NR₂ is discussed and compared with the analogous H:NR₂ function. The kinetically controlled formation of (IV) and the thermodynamically controlled formation of (V) are discussed and compared with the bahaviour of the conjugate acids.