Extending the range of stabilised, primary and secondary phosphanes containing ferrocenyl or ruthenocenyl groups

•Range of ferrocene (Fc)-derived secondary and long-chain primary phosphines synthesised.•Ruthenocene-derived phosphine RcCH2PH2 also synthesised.•Phosphines show appreciable air-stability.•X-ray structure of Fc(CH2)6PH2(BH3) reported.

Alkylation reactions of FcCH2P(CH2OH)2 [Fc = (η5-C5H5)Fe(η5-C5H4)] with MeI or p-BrCH2C6H4NO2, or of CyP(CH2OH)2 with [FcCH2NMe3+]I− gave hydroxymethylphosphanes FcCH2PR(CH2OH) (R = Me, Cy or p-O2NCH2C6H4) which were converted to the new secondary phosphanes FcCH2PHR on treatment with Na2S2O5. A series of longer-chain ferrocenylalkyl primary phosphanes Fc(CH2)nPH2 was also prepared by reactions of the bromoalkylferrocenes Fc(CH2)nBr (n = 4, 6 or 11) with P(CH2OH)3 to give intermediate hydroxymethylphosphanes Fc(CH2)nP(CH2OH)2, followed by reaction with Na2S2O5. Fc(CH2)6PH2 was converted into its crystalline BH3 adduct, which was structurally characterised. The synthesis of the new ruthenocene (Rc)-derived primary phosphane RcCH2PH2, the first example of a ruthenocene-derived primary phosphane, is also reported.

Graphical abstractA series of new ferrocenyl-substituted secondary FcCH2PHR [R = Me, Cy or p-CH2C6H4NO2] and long-chain Fc(CH2)nPH2 primary phosphanes (n = 4, 6, 11), together with the ruthenocenyl primary phosphane RcCH2PH2, have been synthesised and characterised; the X-ray structure of the borane adduct Fc(CH2)6PH2BH3 (illustrated) is also reported.Figure optionsDownload full-size imageDownload as PowerPoint slide