TRANSITION-METAL COMPLEXES OF NITROXIDE R ADICALS - PALLADIUM, PLATINUM, PENTAMETHYLCYCLOPENTADIENYL RHODIUM AND IRIDIUM COMPLEXES, AND ALPHA-AMINOCARBOXYLATE COMPLEXES WITH DERIVATIVES OF 2,5-DIHYDROIMIDAZOLE-1-OXYLS
F. Hintermaier et al., TRANSITION-METAL COMPLEXES OF NITROXIDE R ADICALS - PALLADIUM, PLATINUM, PENTAMETHYLCYCLOPENTADIENYL RHODIUM AND IRIDIUM COMPLEXES, AND ALPHA-AMINOCARBOXYLATE COMPLEXES WITH DERIVATIVES OF 2,5-DIHYDROIMIDAZOLE-1-OXYLS, Zeitschrift fur Naturforschung. B, A journal of chemical sciences, 53(1), 1998, pp. 101-109
2,5-Dihydroimidazoline-1-oxyl radicals I, II with imino substituents c
oordinate to Pd(II) and Pt(II) complexes with formation of the N,N che
late complexes 1 - 6. With oxygen containing substituents either monod
entate N-coordination to give 8 or N,O chelate formation to give 9 tak
es place, depending on the position of the oxygen atom relative to the
ring nitrogen atom. With radicals III that also have the second ring
nitrogen atom oxidized and the Rh(III) or Ir(III) complexes [CpMCl2](
2) the O,O chelates 11-13 could be obtained, while with Na2PdCl4 the h
eterocycle was destroyed with formation of a N,N chelate complex 10 of
an alpha-nitrosooxime ligand. The orthopalladated 2,2,5,5 tetramethyl
-4-phenyl-2,5-dihydroimidazoline-1-oxyl complex 7a reacts with several
alpha-amino acidates under splitting of the dichloro bridge with form
ation of the C,N/N,O-bis-chelate complexes 7b-f. The molecular structu
res of 2 and 10 were determined by X-ray diffraction.