Seda Yurteri

From Invisible Structures of SWCNTs toward Fluorescent and Targeting Architectures for Cell Imaging

Single-walled carbon nanotubes (SWNTs) are unique nanostructures used as cargo systems for variety of diagnostic and therapeutic agents. For taking advantage of these structures in biological processes, they should be visible. Therefore, fluorescence labeling of SWCNTs with various probes is a significant issue. Herein, we demonstrate a simple approach for cell specific imaging and diagnosis by combining SWCNTs with a copolymer poly(para-phenylene) (PPP) containing polystyrene (PSt) and poly(ε-caprolactone) (PCL) side chains (PPP-g-PSt-PCL). In this approach PPP-g-PSt-PCL is noncovalently attached on carboxyl functional SWCNTs. The obtained fluorescent probe is bound to folic acid (FA) for targeted imaging of folate receptor (FR) positive HeLa cells. In vitro studies demonstrate that this conjugate can specifically bind to HeLa cells and indicate great potential for targeting and imaging studies.

Benzophenone based addition fragmentation agent for photoinitiated cationic polymerization

Abstract Photoactive allyl ammonium salt (BPEA) containing benzophenone moiety in the structure was synthesized and characterized. Its capability to act as a self-initiating addition fragmentation agent in the photoinitiated cationic polymerization of oxiranes such as cyclohexene oxide and vinyl monomers such as butylvinyl ether was investigated. These monomers turned out to be polymerizable in the presence of BPEA provided free radicals are generated photochemically at λ>300 nm by hydrogen abstraction of excited benzophenone moiety. Accordingly, a free radical adds to the carbon–carbon double bond of a ground state BPEA and fragmentation of the adduct radical results in the formation of reactive ammonium radical cation which is essentially responsible for the initiation.

Synthesis and characterization of poly(ε-caprolactone)-b-polystyrene macromonomer by combined ring-opening and atom transfer radical polymerizations and its use for the preparation of grafted polyphenylenes by Suzuki polycondensation

A poly(ε-caprolactone) (PCL) hydroxy telechelic having a central 2,5-dibromo-1,4-phenylene moiety was reacted with 4-bromomethyl benzoyl chloride to give a bifunctional macroinitiator for ATRP. The polymerization of styrene (St) in the presence of benzyl bromide functionalized PCL afforded a well-defined block-co-polymer having 25 repeating units of ε-caprolactone and 19 of styrene and low polydispersity. The resulting polymer, still preserving the central aromatic di-bromo groups, can be used in Suzuki or Yamamoto polycondensations for the synthesis of poly(p-phenylenes) (PPPs) bearing block-co-polymers as side chains. The bromo-functional macromonomer was tested in a Suzuki-type cross-coupling reaction in combination with 2,5-dihexylbenzene-1,4-diboronic acid. This way a polymer with alternating hexyl and PCL-b-PSt side chains was obtained. The intermediate polymers and final PPPs were analyzed by spectral, GPC and DSC measurements.

New Polymers with Optoelectronic Properties by Combination of ATRP, Rop And Coupling Processes

The present chapter describes the synthetic strategies used for the preparation of electroluminescent conjugated polymers via metal catalyzed coupling reactions. Synthesis of these polymeric materials having complex macromolecular architectures, composition or functionalities involves the use of several controlled polymerization methods, namely Atom Transfer Radical Polymerization (ATRP) and Ring Opening Polymerization (ROP). Essentially, new functional compounds as initiators in the above-mentioned methods, were designed, synthesized and used to obtain different types of telechelics or macro-monomers. New poly(p-phenylene) (PP) and poly(p-phenylene vinylene) (PPV) derivatives bearing macromolecular side chains were readily synthesized by cross-coupling processes (Suzuki or Yamamoto coupling) or/and Wittig reaction of appropriate combination of these well-defined macromolecules. The final soluble and processable conjugated polymers could find applications as high technology materials due to their properties such as conductivity and luminescence.