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[摘要]：Novel highly functionalized polysiloxanes have been synthesized, which bear small pendant dendritic wedges containing two different redox-active organometallic moieties, namely the electron-donating ferrocenyl group and the electron withdrawing (eta(6)-aryl)tricarbonylchromium entity. Hydrosilylations of vinylsilyl-functionalized (CH(2)=CH)MePhSiFc (1) and allyisilyl-terminated dendron (CH(2)=CHCH(2))PhSi[CH(2))(2)MePhSiFc](2) (3), with the Si-H-containing polysiloxane backbones (Me(3)SiO)(MeSiHO)(n)-(Me(2)SiO)(m)(SiMe(3)) (n = 30-35%, m = 65-70%), and (Me(3)SiO)(MeSiHO)(n)(SiMe(3)) (n similar to 35) successfully afforded the novel siloxane-based copolymers 8 and 9 and homopolysiloxanes 10 and 11 possessing appended organometallic dendritic side chains. Thermal treatment of 8 with Cr(CO)(6) and reaction of 10 with (CH(3)CN)(3)Cr(CO)(3) further increased metal density of the polymers affording polysiloxanes 12 and 13 carrying (eta(5)-C(5)H(4))Fe(eta(5)-C(5)H(5)) and (eta(5)-C(6)H(5))Fe(eta(5)-C(5)H(5)) moieties hanging from their polysiloxane chain. Similar reactions, starting from 1,1,3,3-tetramethyldisiloxane and phenyltris(dimethylsiloxy)silane, were also a convenient way to prepare the corresponding homo and heterometallic model compounds [MePhFcSi(CH(2))(2)Me(2)Si](2)O (5), [{eta(6)-C(6)H(5))Cr(CO)(3)}MeFcSi(CH(2))(2)Me(2)Si](2)O (6), and PhSi[OMe(2)Si(CH(2))(2)MePhSiFc](3) (7). These model compounds and the metallopolysiloxanes were characterized by IR, multinuclear NMR spectroscopies and mass spectrometry. Thermogravimetric analysis (TGA) established that dendronized polysiloxanes 9 and 11, with ferrocenyl dendrons derived from 3, possess higher thermal stability than parent ferrocenyl polysiloxanes 8 and 10. Ferrocenyl dendronized polysiloxanes 9 and 11 yield ceramic products, which have been characterized by SEM and EDX microanalyses. Solution electrochemical studies showed that all the ferrocenyl units present in polysiloxanes 8-13 are electrochemically independent. Ferrocenyl polysiloxanes 8-11, deposited electroactive films onto electrode surfaces. Their well-defined and persistent redox waves are characteristic of electrochemically stable, surface-confined reversible redox couples. |
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