Didentate phosphine ligands with alkenyl and alkynyl linker units as building blocks for dendrimer fixation
Abstract
Using CCH2C(CH3)(CH2PPh2)2
(7) and H2C
CHCH2C(CH3)(CH2PPh2)2
(13), containing alkynyl and
CCH2C(CH3)(CH2PPh2)2}PdCl2]
(8) and [{(CH3)3SiC
CCH2C(CH3)(CH2PPh2)2}PtCl2]
(9) as well as [{H2C
CHCH2C(CH3)(CH2PPh2)2}PdI2]
(14b), all of which were characterized by X-ray diffraction. Reaction of Si[(CH2)3SiMe2Cl]4
(=
“G[0]-[Cl]4”) with four molar equivalents of the in situ lithiated alkynyl diphosphine 7 cleanly yielded the four-fold functionalized derivative G[0]-[C
CCH2C(CH3)(CH2PPh2)2]4
(15) which was converted to the metallated derivative G[0]-[C
CCH2C(CH3)(CH2PPh2)2PdCl2]4
(16). Since the fixation of the alkenyl-functionalized diphosphine
CHCH2C(CH3)(CH2Cl)2
(12) was used. Hydrosilation of G[0]-[H]4 with four molar equivalents of 12 readily gave the functionalized dendrimer G[0]-[CH2CH2CH2C(CH3)(CH2Cl)2]4
(17) which was then reacted with eight equivalents of LiPPh2 to yield the phosphinated derivative G[0]-[CH2CH2CH2C(CH3)(CH2PPh2)2]4
(18).