The structures of the Pruitt-Baggett adduct (PBA) and the Pruitt-Baggett catalyst (PBC) were studied in some detail. PBC extensively ionizes in acetonitrile (K(d)=3.48 x 10(-3) mol l-1 at 25-degrees-C) producing an anionic fragment composed of seven Fe atoms and a cationic fragment with two Fe atoms. Hittorf electrolysis showed that the anionic fragments exclusively bore the high molecular weight stereoregular poly(propylene oxide)s (K-polymers). However, study of the polymerization in the presence of anion and cation scavengers and in different dielectric media supported a previous conclusion that neither free anions nor cations were solely responsible for the stereoregular polymerization, but together with a monomer molecule they combine to yield catalytically active monomer-bound ion pairs. The study of the product showed that K-polymers were connected to each other with Fe atoms. However, these chains could be freed by extracting the Fe residues with hydrochloric acid. A mechanism for the stereoregular polymerization of propylene oxide that is consistent with the present and already published data was suggested.


YILMAZ, O; Usanmaz, Ali; ALYURUK, K (Elsevier BV, 1992-11-01)
The mechanism of the polymerization of n-butyl isocyanate by the Pruitt-Baggett adduct (PBA) was studied; on the basis of the experimental evidences, a coordinated mechanism was proposed and verified. This mechanism considers a monatomic active site, which is the Fe atom of PBA with Lewis acid character. The N atom of the isocyanate monomer is coordinated by the Fe atom and the resultant positive charge is transmitted to another N atom which covalently binds the growing chain to the active centre. Thus the ...
A thiazolothiazole containing multichromic polymer for glucose detection
Soylemez, S.; Kaya, H. Z.; Udum, Y. A.; Toppare, Levent Kamil (Department of Polymer Engineering, Scientific Society of Mechanical Engineering, 2019-10-01)
Donor-acceptor (DA) type monomers namely 2,5-di(thiophen-2-yl)thiazolo[5,4-d]thiazole (TTzTh) and 2,5-bis(3-methylthiophen-2-yl)thiazolo[5,4-d]thiazole (TTzMTh) were synthesized and their electrochemical and optoelectronic properties were investigated in detail. The spectro-electrochemical analysis showed that the alkyl chain substitution results in a shift in the onset of the pi-pi* transition towards longer wavelengths. Depending on the donor substituents, the polymers exhibited optical band gaps 1.65 and...
The Synthesis of Complex Polymer Electrolytes Based on Alginic Acid and Poly(1-vinylimidazole) and Application in Tyrosinase Immobilization
Kartal, Muejgan; Kayahan, Senem; Bozkurt, Ayhan; Toppare, Levent Kamil (Springer Science and Business Media LLC, 2009-01-01)
In this study, proton conducting polymer electrolyte networks consisting of alginic acid (AA) and poly(1-vinylimidazole) (PVI) were prepared. The polymer networks were obtained by mixing AA and PVI with several stoichiometric ratios, x (with respect to monomers). Polymer networks were characterized by FT-IR spectroscopy and their compositions were investigated by elemental analysis (EA). Enzyme entrapped polymer networks (EEPN) were produced by immobilization of tyrosinase in the AA/PVI matrix during comple...
Synthesis and optical properties of light-emitting π-conjugated polymers containing biphenyl and dithienosilole
LIAO, Liang; Çırpan, Ali; CHU, Qinghui; KARASZ, Frank E.; PANG, YI (Wiley, 2007-05-15)
Copolymers containing oligo(phenylene vinylene) (2.5), fluorene, and 4,4-dihexyldithienosilole (DTS) units were synthesized and characterized. The pi-conjugated monomers were joined with the palladium(0)-catalyzed Suzuki-Miyaura coupling reaction, thus forming either biphenyl- or phenyl-thiophene linkages. These polymers were photoluminescent, with the fluorescent quantum efficiency between 54 and 63% and with),lambda(max) for fluorescence at similar to 448 nm in tetrahydrofuran. The presence of 5% DTS in t...
A new soluble conducting polymer and its electrochromic devices
YİLDİZ, UMİT HAKAN; SAHİN, ELİF; Akhmedov, IM; Tanyeli, Cihangir; Toppare, Levent Kamil (Wiley, 2006-04-01)
A new polythiophene derivative was synthesized by both chemical and electrochemical oxidative polymerization of 1-(1-phenylethyl)-2,5-di(2-thienyl)-1H-pyrrole (PETPy). Of which the chemical method produces a polymer that is completely soluble in organic solvents. The structures of both the monomer and the soluble polymer were elucidated by nuclear magnetic resonance (H-1 and C-13 NMR) and Fourier transform infrared (FTIR) spectroscopy. The average molecular weight has been determined by gel permeation chrom...
Citation Formats
F. TAKROURI and K. ALYURUK, “A MECHANISTIC STUDY ON THE STEREOREGULAR POLYMERIZATION OF PROPYLENE-OXIDE BY THE PRUITT-BAGGETT CATALYST,” POLYMER, pp. 1518–1525, 1994, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/65523.