Ambidentate ligands : the preparation and study of phosphine crown systems

The aza crown, sym-1,2-benzo-aza-17-crown-5, was synthesized from 6-aza-3,9-dioxa-1,11-undecanediol, and , -dibromo-o-xylene in the presence of potassium tert-butoxide. This new crown ether was reacted with 4-bromobenzyl bromide and chloroacetyl chloride to form the N-substituted 4-bromobenzyl and chloroacetyl derivatives, respectively. The aza crown and its derivatives were identified with spectroscopic data. The bidentate phosphine amine, Ph2P(CH2)3NH2, was prepared via reduction of 3-(diphenylphosphino)propionitrile by lithium tetrahydroaluminate. Schiff-base reactions between the amine group in Ph2P(CH2)3NH2 and the aldehyde group in benzaldehyde and 4-formyl-benzo-15-crown-5 provided the respective phosphine derivatives. These products were identified with spectroscopic and analytical data. Finally, palladium derivatives of these phosphine-Shiff base ligands (Ph2P(CH2)3NCHR; R = Ph, benzo-15-crown-5) were synthesized from the reactions between (Ph2CN)2PdCl2 and the ligands.Thesis (M.S.