✍ Scribed by Christoph Elschenbroich; Reinhart Möckel; Alexander Vasil'kov; Bernhard Metz; Klaus Harms
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The sandwich complexes bis(η 6 -triphenylene)chromium ( ) minute metal slippage in the peripheral direction. The triphenylene complex 12 features the electrochemically and bis(η 6 -fluoranthene)chromium ( ) have been prepared by means of metal atom/ligand vapor cocondensation.
reversible redox couples 12 (+/0, metal-centered), 12 (0/-, ligand-centered) and 12 (-/2-, ligand-centered), the latter Whereas for triphenylene exclusive coordination to the peripheral rings is observed, the situation is more displaying a redox splitting of 300 mV. Conversely, for the fluoranthene complex 13, secondary reduction 13 (-/2-) is complicated for fluoranthene. According to NMR evidence initial metal coordination to the benzene (B) as well as to the irreversible. This finding is consistent with the larger redox splitting of ca. 480 mV which indicates more extensive naphthalene (N) section of the fluoranthene ligand occurs, leading to the isomers 13(I) (η 6 -B, η 6 -B), 13(II) (η 6 -B, η 6 -N) interligand interaction in the dianion 13 2-, thereby favoring metal-ligand cleavage. While the radical cations 12 +• and and 13(III) (η 6 -N, η 6 -N). Since the substitutional lability of the chromium-naphthalene bond largely exceeds that of the 13 +• are amenable to EPR study, the radical anions 12 -• and 13 -• are too unstable. Instead, the radical anions of the free chromium-benzene bond, the isomer distribution depends on the workup conditions; 13(I) is clearly the most stable ligands are observed by EPR upon electrochemical reduction.
In the case of 12, the temporary existence of the radical anion isomer. Crystal structure determinations performed for the salts [12][BPh 4 ] and [13][I] point to the preference for syn 12 -• is indicated, however. orientation of the polycyclic aromatic hydrocarbons and to a
📜 SIMILAR VOLUMES
A novel mode of containment for metal ions which participate in longer-range interactions with aryl rings (Ն 2.5 A ˚) is demonstrated in the preorganized cylindrical host 1. Three equatorial sulfur atoms in 1 hold metals in a trigonal planar ligand field between two apical benzene centroids at an M-