Synthesis, structure, and reactivity of fluorous phosphorus/carbon/phosphorus pincer ligands and metal complexes†
Abstract
Reactions of the diphosphine 1,3-C6H4(CH2PH2)2 and fluorous CHRfn
(Rfn
=
(CF2)n−1CF3; n
= 6, 8) at 75 °C in the presence of AIBN give the title
P(CH2CH2Rf8)2
CH2-1,3-C6H4CH2P
(CH2CH2Rf8)2C
H2]2+2Br−, which upon treatment with LiAlH4 yields 3-Rf8
(20%), 4-Rf8, and other products. Efforts to better access 3-Rf8, either by altering stoichiometry or using various combinations of the phosphine borane (H3B)PH(CH2CH2Rf8)2 and base, are unsuccessful. Reactions of 3-Rfn with Pd(O2CCF3)2 and [IrCl(COE)2]2
(COE =
P(CH2CH2Rfn)2)2)Pd
(O2CCF3)
(10-Rfn; 80–90%) and (2,6,1-C6H3(CH2
P(CH2CH2Rf8)2)2)Ir
(Cl)(H)
(11-Rf8; 29%), which exhibit CF3C6F11/