Synthesis and structure of ferrocenylmethylphosphines, their borane adducts, and some related derivatives

摘要: Abstract Syntheses of the known ferrocenylmethylphosphines FcCH2PH2 (2, Fc = (η5-C5H4)Fe(η5-C5H5)), (FcCH2)2PH (3), and (FcCH2)3P (4) have been reinvestigated. The reaction [FcCH2NMe3][I] with P(CH2OH)3, generated from [P(CH2OH)4][Cl] KOH, gave a mixture major product (FcCH2)P(CH2OH)2 (1) over-alkylated (FcCH2)2P(CH2OH) (9). Treatment pure 9 Na2S2O5 secondary phosphine 3; slow addition to 1 2 in improved yield. Reaction [FcCH2NMe3][I], followed by treatment NEt3, tertiary (4), along phosphonium salt [(FcCH2)4P][I] (5), which could be prepared higher yield adjusting stoichiometry. Phosphine 4 oxidized slowly air (FcCH2)3P(O) (12), was protonated HBF4(OMe2) give [(FcCH2)3PH][BF4] (13), reacted Pt(COD)Cl2 or PtCl2 cis- trans-Pt(P(CH2Fc)3)2Cl2 (14). Silylation n-BuLi/Me3SiCl FcCH2P(SiMe3)2 (10); Me3SiCl/Et3N FcCH2P(CH2OSiMe3)2 (11). phosphine-borane adducts FcCH2PH2(BH3) (6), (FcCH2)2PH(BH3) (7), (FcCH2)3P(BH3) (8) (FcCH2)P(CH2OSiMe3)2(BH3) (15) were corresponding phosphines BH3(SMe2). 2, 3, 4, salts 5 13, oxide 12, Pt complex trans-14, phosphine-boranes 6, 7 8 structurally characterized X-ray crystallography. solid cone angle (FcCH2)3P, 139°, 14 showed that bulkier than PPh3, but less sterically demanding P(t-Bu)3. structural changes observed on quaternization P (shorter P–C bonds larger angles at P), results NMR IR spectroscopy DFT calculations, consistent expected rehybridization phosphorus. Related observations for analogous methylphosphines suggest methyl ferrocenylmethyl phosphorus substituents similar properties.