| Abstract
| - A series of monocationic palladium BINAP complexes, [Pd(rac-BINAP)(an oxazolidinone anion)][X]and [Pd(rac-BINAP)(an acetylacetonate anion)][X] (X = a, CF3SO3-; b, BF4-) (9−13), have beensynthesized and characterized. A dicationic intermediate, pertinent to the Pd-catalyzed hydroaminationreaction, arising from the reaction of the bis-aquo complex [Pd(H2O)2(rac-BINAP)]2(CF3SO3)2 and 1equiv of an oxazolidinone, has been characterized via low-temperature NMR studies. The structures ofthe complexes [Pd(rac-BINAP)(CH3−C(O)−C(CH3)−C(O)−CH3)](BF4), 12b, and [Pd(μ-OH)(rac-BINAP)]2(CF3SO3)2 have been determined by X-ray diffraction. The solid-state structures of two separateforms of the BF4- salt 12b were obtained. One form of the salt can be thought of as a tight ion pair,whereas the second form contains a dichloromethane solvent molecule, packed in approximately a fifthcoordination position together with a relatively remote BF4- anion. These structures represent a rareexample where both ion pairing and strong solvation could be individually characterized. PGSE diffusioncoefficients (D values) were measured for both the CF3SO3- and BF4- salts of 9−13 in CD2Cl2. Inaddition, D values were obtained for the CF3SO3- salts in THF and CDCl3 solutions. The amount of ionpairing decreases in the sequence CDCl3> THF > CD2Cl2. The 1H,19F-HOESY spectra for the salts inCDCl3 suggest that the CF3SO3- is approaching the positive metal and phosphorus centers via a pathwaythat brings it closest to the P-phenyl groups but remote from the chelating anion.
- New Pd-BINAP salts containing oxazolidinone and acetylacetonate ligands are reported. A dynamic dicationic oxazolidinone salt, pertinent to the Pd-catalyzed hydroamination reaction, has been characterized at 203 K. The structures of two separate forms of the BF4- cationic acetylacetonate complex 12b (left) have been determined and represent a rare example of a salt showing both ion pairing and strong solvation in the solid state.
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