Title

Living Photolytic Ring-Opening Polymerization of Amino-Functionalized [1]Ferrocenophanes: Synthesis and Layer-by-Layer Self-Assembly of Well-Defined Water-Soluble Polyferrocenylsilane Polyelectrolytes

Document Type

Article

Publication Date

10-8-2007

Abstract

Facile synthetic routes have been developed that provide access to cationic and anionic water-soluble polyferrocenylsilane (PFS) polyelectrolytes with controlled molecular weight and narrow polydispersity. Living photolytic ring-opening polymerization of amino-functionalized [1]ferrocenophane (fc) monomers [fcSiMe{CCCH2N(SiMe2CH2)2}] (3), [fcSi{CCCH2N(SiMe2CH2)2}2] (10), [fcSiMe(CCCH2NMe2)] (14), and [fcSiMe(p-C6H4CH2NMe2)] (20) yielded the corresponding polyferrocenylsilanes [(fcSiMe{CCCH2N(SiMe2CH2)2})n](5), [(fcSi{CCCH2N(SiMe2CH2)2}2)n] (11), [{fcSiMe(CCCH2NMe2)}n] (15), and [{fcSiMe(p-C6H4CH2NMe2)}n] (21) with controlled architectures. Further derivatization of 5, 15, and 21 generated water-soluble polyelectrolytes [(fcSiMe{CCCH2N(CH2CH2CH2SO3Na)2})n] (6), [{fcSiMe(CCCH2NMe3OSO3Me)}n] (7), and [{fcSiMe(p-C6H4CH2NMe3OSO3Me)}n] (22), respectively. The polyelectrolytes were readily soluble in water and NaCl aqueous solutions, with 6 and 22exhibiting long-term stability in aqueous media. The PFS materials 6 and 22, have been utilized in the layer-by-layer (LbL) self-assembly of electrostatic superlattices. Our preliminary studies have indicated that films made from controlled low molecular-weight PFSs possess a considerably thinner bilayer thickness and higher refractive index than those made from PFSs that have an uncontrolled high molecular-weight. These results suggest that the structure and optical properties of LbL ultra-thin films can be tuned by varying polyelectrolyte chain length. The water-soluble low molecular weight PFSs are also useful materials for a range of applications including LbL self-assembly in highly confined spaces.

Journal

Chemistry: A European Journal

Volume

13

Issue

33

First Page

9372

Last Page

9383