Ruthenocenyl derivatives

RUTHENOCENYL DERIVATIVES AND OTHER COMPLEXES OF r/ -CYCLOPENTADIENYL AND RELATED LIGANDS... 

The monodentate examples were seen to differ in terms of their polymerization behavior from the bidentate species. Although the monodentate ruthenocenyl derivative was found to polymerize, albeit at a higher temperature (300 °C) than the bidentate derivative, changing the metal to iron caused no polymerization to be evident and the trimer decomposed at 300 °C. Lowering the temperature to 250 °C failed to produce any polymerized products, even after a 17-day reaction time. However, polymerization at 250°C was accomplished by the addition of 0.1mol% hexachlorocyclotriphosphazene as catalyst. AH linear polymers were treated with 2,2,2-trifluoroethoxide (as the sodium salt) to remove labile fluorines and create stable materials for analysis (see Scheme 4.9). 

Other heterobimetallic aryl-phosphine-gold(I) complexes with different ferrocenyl derivatives, such as A-[2-A/,A/-(dimethylaminoethyl)-A-methyl-aminoethyl]-ferrocenyl (FcN,N), 2-nitroferrocenyl or ruthenocenyl, have also been reported. 

Similar to ferrocene, the ruthenocene derivatives (89) substituted with a CR R group are greatly stabilized in comparison to noncomplexed carbenes or carbonium ions. In fact, from the enhanced barrier to internal rotation in the a-ruthenocenyl carbonium ion Ru-CHMe+ (>130kJmol ) compared with the related ferrocene derivative (70kJmol ), even greater stabilization in ruthenocene is expected. 

The ortholithiation route has also been used in the synthesis of the related ruthenocenyl system (24). Metallation of ferrocenecarboxaldehyde with the lithiiun derivative of monomethylpiperazine, followed by treatment with chloro-diphenylphosphine, provides a one-pot route to the l,l -disubstituted system... 

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