Monophosphine and diphosphine ligands for diplatinum polyynediyl complexes: Efficient syntheses of new functionality-containing systems and model compounds

Br(CH2)4Br and NaO(CH2)2CHCH2 react under suitable conditions to give Br(CH2)4O(CH2)2CHCH2 (55%), which is treated with KPPh2 to yield the ether-containing phosphine Ph2P(CH2)4O(CH2)2CHCH2 (83%). The reaction of CH3CH2OC(O)CHC(CH3)2 and BrMg(CH2)3CHCH2 in the presence of CuCl (cat.) and ClSiMe3 yields CH3CH2OC(O)CH2C(CH3)2(CH2)3CHCH2 (67%), which is reduced to an alcohol that is brominated, reacted with Grubbs’ catalyst, hydrogenated, and treated with KPPh2 to give the bis(geminally dimethylated) diphosphine Ph2P(CH2)2C(CH3)2(CH2)8C(CH3)2(CH2)2PPh2 (47% overall). The photochemical reaction of I(CF2)8I and H2CCHCH2SnBu3 yields H2CCHCH2(CF2)8CH2CHCH2 (52%), which is converted with 9-BBN to a diol (92%) that is brominated and treated with LiPR2 to give the fluorinated diphosphines R2P(CH2)3(CF2)8(CH2)3PR2 (R = a, p-tol, 67%; b, t-Bu, 69%; c, o-tol, 86%). Reactions of Br(CH2)mBr and LiPR2 similarly yield R2P(CH2)mPR2 (m/R = 8/a, 95%; 14/a, 96%; 14/p-C6H4-t-Bu, 98%). Reactions of KPPh2 with Br(CH2)m′CHCH2and Br(CH2)7CH3 give the corresponding monophosphines Ph2P(CH2)m′CHCH2 (m′ = 7, 82%; 10, 84%) and Ph2P(CH2)7CH3 (85%). When the former is combined with [Pt(μ-Cl)(C6F5)(tht)]2 (tht = tetrahydrothiophene), trans-(C6F5)(Ph2P(CH2)m′CHCH2)2PtCl (77–70%) is isolated. When the latter (excess) is combined with trans,trans-(C6F5)(p-tol3P)2Pt(CC)4Pt(Pp-tol3)2(C6F5) (RT, 65 °C), trans,trans-(C6F5)(Ph2P(CH2)7CH3)2Pt(C C)4Pt(Ph2P(CH2)7CH3)2(C6F5) (53%) is isolated.

A variety of oxygen- fluorine-, geminal dimethyl-, and alkene-containing monophosphines and diphosphines are prepared that are useful precursors to diplatinum polyynediyl complexes in which two flexible sp3 chains span the termini. Model platinum complexes are also reported.Figure optionsDownload as PowerPoint slide