Synthese, Strukturen, EPR‐ und ENDOR‐spektroskopische Untersuchungen an Übergangsmetallkomplexen von N, N‐Diisobutyl‐N′‐(2, 6‐difluor)benzoylselenoharnstoff

Abstract

AbstractSynthesis, Structures, EPR and ENDOR Investigations on Transition Metal Complexes of N, N‐diisobutyl‐N′‐(2, 6‐difluoro)benzoyl selenoureaThe synthesis and the structures of the NiII and PdII complexes of the ligand N, N‐diisobutyl‐N′‐(2, 6‐difluoro)benzoylselenourea HBui2dfbsu are reported. The ligands coordinate bidentately forming bis‐chelates. The structure of the ligand could not be obtained, however, the structure of its O‐ethyl ester will be reported. Attempts to prepare the CuII complex result only in the formation of oily products. However, the CuII complex could be incorporated into the corresponding NiII and PdII compounds. From this diamagnetically diluted powder and single‐crystal samples were obtained being suitable for EPR‐ENDOR measurements. We report X‐ and Q‐band EPR investigations on the systems [Cu/Ni(Bui2dfbsu)2] and [Cu/Pd(Bui2dfbsu)2] as well as a single‐crystal X‐band EPR study for [Cu/Ni(Bui2dfbsu)2]. The obtained 63, 65Cu and 77Se hyperfine structure tensors allow a determination of the spin‐density distribution within the first coordination sphere. In addition, orientation selective 19F Q‐band pulse ENDOR investigations on powder‐samples of [Cu/Ni(Bui2dfbsu)2] have been performed. The hyperfine structure tensors of two intramolecular 19F atoms could be determined. According to the small 19F couplings only a vanishingly small spin‐density of < 1 % was obtained for these 19F atoms.