Synthesis 2004(8): 1243-1248  
DOI: 10.1055/s-2004-822349
PAPER
© Georg Thieme Verlag Stuttgart · New York

Carbosilane Dendrimers with End-Grafted Silacrown- and Crown-Ether Units

Roy Buschbecka, Heinrich Lang*a, Shiva Agarwalb, Vipin K. Sainib, Vinod K. Guptab
a Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Lehrstuhl Anorganische Chemie, Straße der Nationen 62, 09111, Chemnitz, Germany
e-Mail: heinrich.lang@chemie.tu-chemnitz.de;
b Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttaranchal, India
Further Information

Publication History

Received 27 January 2004
Publication Date:
28 April 2004 (online)

Abstract

The synthesis of the vinyl-functionalized silacrown ethers 1-methyl-1-vinylsila-8-crown-3 (3) and 1-methyl-1-vinylsila-11-crown-4 (4) by the reaction of (H2C=CH)MeSi(OEt)2 (1) with HO(CH2CH2O)nH (2a, n = 2; 2b, n = 3) in presence of catalytic amounts of NaOMe is described. These species can be attached to 1st and 2nd generation carbosilane dendrimers by hydrosilylation. Treatment of Si(CH2CH2CH2SiMe2H)4 (5) or Si[CH2CH2CH2Si-Me(CH2CH2CH2SiMe2H)2]4 (8) with 3 or 4 produces the respective silacrown ether end-grafted carbosilane dendrimers 6, 7, 9 and 10 in nearly quantitative yield. In a similar manner 2-allyloxymethyl-12-crown-4 (11) gives with 5 and 8 the 12-crown-4 end-capped carbosilane dendrimers 12 and 13, respectively.

The formation of analytical pure and uniform carbosilane dendri­mers with crown ethers at the periphery is based on elemental analysis, IR, 1H, 13C{1H} and 29Si{1H} NMR spectroscopy. ESI-TOF MS studies reveal that 7, 10, 12 and 13 form complexes with alkali ions, which enables such species to function as possible ionophores for chemical sensors.