| Abstract: | Photochemical Reactions of Cyclopentadienylbis(ethene)rhodium with Benzene Derivatives During UV irradiation of CpRh(C2H4)2] ( 1 ) (Cp = η5‐C5H5) in hexane in the presence of hexamethylbenzene the di‐ and trinuclear arene bridged complexes (CpRh)2(μ‐η3 : η3‐C6Me6)] ( 3 ) and (CpRh)3(μ3‐η2 : η2 : η2‐C6Me6)] ( 4 ) are formed besides known CpRh(η4‐C6Me6)] ( 2 ). It was shown by a separate experiment that 3 besides small amounts of 4 is formed by attack of photochemically from 1 arising CpRh fragments at the free double bond of the η4‐bonded benzene ring in 2 . Irradiation of 1 in the presence of diphenyl (C12H10) affords the compounds (CpRh)2(μ‐η3 : η3‐C12H10)] ( 5 ) and (CpRh)3(μ3‐η2 : η2 : η2‐C12H10)] ( 6 ) as analogues of 3 and 4 , in the presence of triptycene (C20H14) only (CpRh)2(μ‐η3 : η3‐C20H14)] ( 7 ) is obtained; the bridging in 5 , 6 , and 7 always occurs via the same six‐membered ring of the corresponding ligand system. During the photochemical reaction of 1 in the presence of styrene (C8H8) substitution of the ethene ligands by the vinyl groups with formation of CpRh(C2H4)(η2‐C8H8)] ( 8 ) and known CpRh(η2‐C8H8)2] ( 9 ) is observed exclusively. The new complexes were characterized analytically and spectroscopically, in the case of 3 also by X‐ray structure analysis. |
