Dimerisation and reactivity of HCCCCFc at ruthenium centres

In contrast to the simple diynyl complexes formed in reactions between HCCCCFc and MCl(dppe)Cp∗; (M = Fe, Ru), an analogous reaction with RuCl(PPh3)2Cp∗; in the presence of KPF6 and dbu resulted in dimerisation of the diyne at the Ru centre to afford a mixture of [Ru{η1,η2-C(CCFc)C(L)CHCCCHFc}(PPh3)Cp∗]PF6 (L = dbu 1, PPh32). Similar reactions with RuCl(PR3)2L gave [Ru{η1,η2-C(CCFc)C(dbu)CHCCCHFc}(PR3)L]PF6 (L = Cp, R = Ph 3, m-tol 4; L = η5-C9H7, R = Ph 5). The reaction between 3 and I2, followed by crystallization of the paramagnetic product from MeOH, afforded the dicationic [Ru{C(CCFc)C(dbu)CHC(OMe)C(OMe)CHFc}(PPh3)Cp](I3)26. The molecular structures of 2·2CH2Cl2 and 6.S (S = 2CH2Cl2, C6H6) were determined by single-crystal XRD studies.

The reactions between HCCCCFc and RuCl(PR3)2Cp′ in the presence of KPF6 and dbu afford [Ru{η1,η2-C(CCFc)C(L)CHCCCHFc}(PR3)Cp′]PF6 (Cp′ = Cp∗, R = Ph, L = dbu 1, PPh32; L = dbu, Cp′ = Cp, R = Ph 3, m-tol 4; Cp′ = η5-C9H7, R = Ph 5). The reaction between 3 and I2, followed by crystallization of the paramagnetic product from MeOH, gives [Ru{C(CCFc)C(dbu)CHC(OMe)C(OMe)CHFc}(PPh3)Cp](I3)26. The molecular structures of 2·2CH2Cl2 and 6.S (S = 2CH2Cl2, C6H6) were determined by single-crystal XRD studies.Figure optionsDownload as PowerPoint slideResearch highlights
► Dimerisation of 1-ferrocenylbuta-1,3-diyne on Ru affords a substituted octa-1,2,3,5-tetraen-7-ynyl ligand.
► Donor ligands (dbu, PPh3) bond to C(5).
► Oxidation with I2 affords a dication containing one ferrocene, one ferricinium centre.