(PI-ALLYL)PALLADIUM COMPLEXES WITH N,N'-DIPHENYLBISPIDINONE DERIVATIVES AS A NEW-TYPE OF CHELATING NITROGEN LIGAND - COMPLEXATION STUDIES, SPECTROSCOPIC PROPERTIES, AND AN X-RAY STRUCTURE OF ETHYLBISPIDINONE)[(1,3-ETA(3)-PROPENYL)-PALLADIUM] TRIFLUOROMETHANESULFONATE

A series of 3,7-diazabicyclo[3.3.1]nonane (bispidine) derivatives have been synthesized, and their properties as bidentate nitrogen ligands for (pi-allyl)palladium complexes have been investigated. Complexes of these ligands and of N,N'-diphenylpiperazine (7) and N,N'-diphenyl-1, 5-diazacyclooctane (8) with (1,3-eta(3)-propenyl)palladium are describ ed, in particular their effects on the proton chemical shifts of the p i-allyl ligand. Ligand dynamics of the complexes is discussed. The str ucture of [(3,7-diphenyl-1,5-dimethylbispidinone) (propenyl)Pd]CF3SO3 (15) has been determined by X-ray crystallography. N,N'-Diphenylbispid ine derivatives show an unusually large steric interaction with the pi -allyl ligand, indicated by a tilt of the pi-allyl plane toward the N- Pd-N plane by 122.8(8)degrees. Chemical shift changes of the pi-allyl protons due to the aromatic ring current are related to the geometry o f the complexes. The ligands are tested on the larger -6,6-dimethylbic yclo[3.1.1]hept-2,3,10-eta(3)-enyl ligand, demonstrating their potenti al as chemical shift reagents.