The synthesis and study of some of the physical properties of diphenylated fatty derivatives and their chromium tricarbonyl complexes

Abstract

A series of 1,1-diphenyl-1-alkanols were synthesised by the reaction of phenyl magnesium bromide (PhMgBr) with n-alkanoates. The infrared spectral analysis showed a medium sharp absorption band at 3400 cm −1 for the tertiary OH stretching vibration. The 1H-NMR analysis gave signals at 7.1–7.5 δ for the aromatic protons, and the protons of the remaining carbons of the short chain diphenylated alkanols were readily distinguished by their chemical shifts and splitting pattern. The 13C-NMR results permitted the aromatic carbon nuclei to be differentiated, and the β- and γ-effect exerted by the hydroxy and phenyl groups on the adjacent methylene carbon atoms allowed facile assignments of these nuclei in the short chain homologues. The mass spectral analysis confirmed the quaternary carbon position of the derivatives. The 1H- and 13C-NMR spectral analyses of the chromium tricarbonyl complexes of some of these derivatives showed strong upfield shifts for the aromatic and neighbouring protons or carbon nuclei, due to the electron withdrawing behaviour of the chromium tricarbonyl ligand.