Chiral sandwich compounds of ruthenium(II) and (IV): X-ray crystal structure of [Ru{η5-C5H4(neomenthyl)}2I]I3

The chiral ruthenocenes Ru(Cpnm)Cp′ (where Cpnm=neomenthylcyclopentadienyl and Cp′=Cpnm or C5Me5) have been synthesised and oxidised by halogens to the corresponding ruthenium(IV) salts [Ru(Cpnm)Cp′X]Xn (where X=Br or I; Cp′=Cpnm, n=3; Cp′=C5Me5, n=1). These ruthenium(IV) compounds all have, to varying degrees, a tendency to revert back to the ruthenocene(II) compounds (X, Br>I; Cp′, Cpnm>C5Me5). Thus, for [Ru(Cpnm)2Br]Br3 this conversion is complete within two days whereas [Ru(Cpnm)2I]I3 is stable enough for the X-ray structure to have been determined. The electrochemistry and preliminary catalytic studies are reported.