Colin White

Ethyltetramethylcyclopentadienyl complexes of cobalt, rhodium, iridium and ruthenium

SummaryThe syntheses of the ethyltetramethylcyclopentadienyl complexes Ru(η5-C5Me4Et)(CO)2Cl, CO(η5-C5Me4Et)(CO)2, and [M(η5-C5Me4Et)Cl2]2 (M = Rh or Ir) are described; the ruthenium complex reacts with triphenylarsine to give Ru(η5-C5Me4Et)(AsPh3)(CO)Cl.1H and13C n.m.r. spectra, i.r. spectra and the physical properties of the compounds are discussed and contrasted with the known C5H5 and C5Me5 analogues.

η6-Indene- and η5-indole-(pentamethylcyclopentadienyl)-rhodium(III) and -iridium(III) hexafluorophosphates and their reversible deprotonation and rearrangement reactions to η5-indenyl- and η5-indolyl-complexes

The preparations of [M(η5-C5Me5)(η6-indene)](PF6)2, (II), [M(η5-C5Me5)(η5-indenyl)](PF6),(III),[M(η5-C5Me5)(η5-indole)](PF6)2(M = Rh or Ir), and [Ir(η5-C5Me5)(η5-indolyl)]PF6 are reported; in the interconversion (III)+ H+⇌(II), for M = Ir protonation-deprotonation is fast and the rate-determining step is the movement of the metal from the 5- to the 6-membered ring and vice-versa.

Stereochemistry of hydrolysis at an acyclic phosphoryl centre leading to an achiral phosphorus acid

Alkaline hydrolysis of Sp-methyl methylphenylphosphinate in 60% H218O has been shown to involve predominant (>90%) inversion of configuration at phosphorus; esterification of the resulting acid with the diazocompounds (2) gave, inter alia, diastereoisomeric menthyl esters; the isotopic labelling of these was deduced from the 18O isotopic chemical shifts in their 31P n.m.r. spectra.

Pentamethylcyclopentadienyl-rhodium and -iridium complexes. Part X. The kinetics of the reactions of some cyclic and acyclic dienes with µ-hydrido-compounds

The µ-hydrido-complexes [{M(C5Me5)}2HCl3](2a; M = Rh) and (2b; M = Ir) react readily with cyclo-octa-1,3- and -1,5-diene, cyclohexa-1,3- and -1,4-diene, to give the cyclic η-allylic complexes which reductively decompose to give [MI(C5Me5)diene]. The rate of the reaction of the hydride with a variety of cyclic and acylic dienes was shown to be first order in hydride and zero order in diene and to be independent of the nature of the diene. The rate-determining step is proposed to be opening of the metal-halide and not the metal-hydride bridge of (2). Cyclopentadiene gives a cyclopentenyl complex with (2), but this loses 2 H to give [MIII(C5Me5)(C5H5)]+; norbornadiene gives a σ,η-norbornenyl complex that reductively eliminates to [MI(C5Me5)(norbornadiene)]. The reactions of the hydrido-complexes (2) with dienes are compared with those of [(MC5Me5Cl2)2] in alcohol–base.