Synthesis of model organosiloxanes containing perfluoroether side-chains

A series of organotrisiloxanes [(Me3SiO)(2)MeSi(CH2)(n)O(CH2)(m)R-f], (n = 3, m = 1, R-f = CF3; n = 3, m = 2, R-f = C4F9, C6F13, C8F17, C10F21, C7F15; n = 5, m = 1, R-f = CF3; n = 10, m = 0, R-f = C3HF6; n = 10, m = 1, R-f = CF3) have been prepared by the [Pt(cyclooctadiene)Cl-2] catalysed hydrosilylation reaction between heptamethyltrisiloxane and CH2=CH(CH2)(n-2)O(CH2)(m)R-f. Yields are dependent upon the alkene chain length and degree of branching of the R-f group. Isomeric products [(Me3SiO)(2)MeSi(CH2)(3)OCH2CF3] and [(Me3SiO)(2)MeSiCH(Me)CH2OCH2CF3] were detected in reactions involving CH2=CHCH2OCH2CF3 only.