Complexes Containing Cyclic Conjugated Alkenes

The synthesis, redox chemistry and EPR data for mixed sandwich compounds of the type [M(r -arene)(r -C7H6R)] (M = Cr, Mo) have been reported. Crystallographic data show that on oxidation there is lengthening of the M-C bond lengths, and NMR data imply that the Ti-bound arene is more electron rich in the Cr complexes than in the corresponding Mo compounds. Compound 67 was unexpectedly obtained on reaction [W(CO)3(NCMe)3] with [CyMev] in the presence of Protonation of [Mn(CO)3(r -Ci4Hio)] afforded [Mn(CO)3(riC 

C14H11)]. The protonation was shown to occur regioselectively at the endo-position and was proved by labelling studies.  

Magnetisation experiments showed that the naphthalenyl-containing complex [Mn(CO)3(r -CioH9)] participates in a 1,4-hydrogen shift that exchanges the 

Cycloaddition reactions have also been used to prepare a range of [CpCo(ri -cyclopentadienonesuperphane)] complexes The [CpCo(CO)2]-mediated oligomerisation of ethynylazulenes has been described and shown to result in the preparation of [CpCo(ri -butadiene-like)] complexes as well as other metal-coordinated and free oligomers. Compound 88 has been prepared, which on treatment with Li in THF afforded the cyclobutadiene dianion 89 which essentially fulfils the criteria for aromaticity  

Compound 95 has been shown to be a useful precursor for the synthesis of a range of open and closed dienyl complexes, in particular, the preparation of open and closed ruthenocene. A series of 1,5-, 2,4- and 3-substituted pentadienyl complexes of ruthenium have been prepared and characterised. A series of heteroatom-containing diene complexes of type 96 have been synthesised. 1,2-Diketones were shown, however, not to coordinate in this fashion, rather to undergo a one-electron transfer reaction giving enediolato-containing complexes. Complexes of type 97 have been synthesised on treatment of the triple decker complex [ (CpR)Co 2(p-r r -C6F[5Me)] with acetone, cyclohexanone, and acetophenone. The mechanism of formation was said to proceed through a 

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