Functionalized arene-ruthenium(ii) complexes: Dangling vs. tethering side chain

摘要

The reactivity of compounds [RuCl_2(η~6-C _6H_5OCH_2CH_2OH)(L)] (L = phosphine or phosphite) towards the chloride abstractor AgSbF_6 has been investigated. Thus, the treatment of the triphenylphosphite complex [RuCl _2(η~6-C_6H_5OCH_2CH _2OH){P(OPh)_3}] with one equivalent of AgSbF_6 gave rise to the formation of the dinuclear dichloro-bridged species [{Ru(μ-Cl)(η~6-C_6H_5OCH_2CH _2OH){P(OPh)_3}}_2]~(2+) as the hexafluoroantimonate salt. On the other hand, the triphenylphosphine analog [RuCl_2(η~6-C_6H_5OCH _2CH_2OH)(PPh_3)] led, under the same experimental conditions, to the di-ruthenium derivative [{RuCl(η~6-C _6H_5OCH_2CH_2OH)(PPh_3)} _2(μ-Cl)][SbF_6] containing only one Cl-bridge. In sharp contrast, treatment of precursors [RuCl_2(η~6-C _6H_5CH_2CH_2CH_2OH)(L)] (L = P(OPh)_3, PPh_3, P(OEt)_3) with AgSbF_6 resulted in the clean formation of the tethered compounds [RuCl{η ~6:κ~1(O)-C_6H_5CH _2CH_2CH_2OH}(L)][SbF_6]. The differences in reactivity observed have been rationalized by theoretical calculations.