Photochemische Reaktionen von Cyclopentadienylbis(ethen)rhodium mit Phenanthren,Acenaphthylen und Triphenylen,sowie ungewöhnlicher H-Austausch zwischen η2-koordinierten Phenanthren- bzw. Acenaphthylen- und η5-Cyclopentadienyl-Liganden |
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Authors: | J rn Mü ller,Cordula Hirsch,Ke Qiao,Kwang Ha |
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Affiliation: | Jörn Müller,Cordula Hirsch,Ke Qiao,Kwang Ha |
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Abstract: | Photochemical Reactions of Cyclopentadienylbis(ethene)rhodium with Phenanthrene, Acenaphthylene, and Triphenylene, and Unusual H Exchange between η2-Coordinated Phenanthrene or Acenaphthylene and η5-Cyclopentadienyl Ligands During UV irradiation of [CpRh(C2H4)2] (Cp = η5-C5H5) in hexane/ether in the presence of phenanthrene one ethene ligand is displaced by coordination of the 9,10 double bond of phenanthrene, and (η5-cyclopentadienyl) (η2-ethene)(η2-9,10-phenanthrene)rhodium ( 1 ) is formed. The analogous reaction in hexane in the presence of acenaphthylene occurs with formation of the complexes (η2-1,2-acenaphthylene)(η5-cyclopentadienyl)(2-ethene)rhodium 2 and bis(η2-1,2-acenaphthylene)(η5-cyclopentadienyl)rhodium 3 in which one and two ethene molecules of [CpRh(C2H4)2], respectively, are substituted by η2-1,2-acenaphthylene. The irradiation of [CpRh(C2H4)2] with triphenylene in hexane yields the compounds [CpRh(η4-1,2,3,4-triphenylene)] ( 4 ), [(CpRh)2(μ-η3: η3-triphenylene)] ( 5 ), and [(CpRh)3(μ3-η2: η2: η2-triphenylene)] ( 6 ). Despite the partially very low yields the new complexes could be unequivocally characterized spectroscopically and in the case of 1 and 3 by X-ray structural analysis. The compounds 1 and 2 in solution reveal a novel dynamic behaviour; via an intramolecular C? H activation, exchange occurs between the protons of the η2-coordinated arene and the Cp ligand. The complex 4 in solution is fluxional, too. |
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Keywords: | Cyclopentadienyl rhodium complexes η 2-phenanthrene and η 2-acenaphthylene ligands η 4-triphenylene ligand bridging η 3: η 3- and η 2: η 2: η 2-triphenylene ligands photochemical synthesis X-ray crystallography dynamic hydrogen exchange |
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