Poly coupling

C.H. Liu, K.T. Liao, and H.J. Huang, Amperometric immunosensors based on protein A coupled poly-aniline-perfluorosulfonated ionomer composite electrodes. Anal. Chem. 72, 2925-2929 (2000). 

R.S. Loewe, P.C. Ewbank, J. Liu, L. Zhai, and R.D. McCullough, Regioregular, head-to-tail coupled poly(3-alkylthiophenes) made easy but the GRIM method investigation of the reaction and the origin of regioselectivity, Macromolecules, 34 4324-4333, 2001. 

Several soluble poly(3-alkoxythiophenes) have also been studied by the group of Heinze [6] and Leclerc [7,40- 2]. In particular, regioregular, HH-TT coupled poly(3,3 -dialkoxy-2,2 -bithiophenes) were found to be extremely interesting compounds from the electrochemical and spectroelectrochemical points of view. Their properties will be discussed in this part of the chapter which is devoted to spectroscopic characterization of doped polymers. 

These results unequivocally indicate that IIH-TT coupled poly(4,4 -dialkyl-2,2 -bithiophenes) are less... 

In view of the above findings it is expected that H-H coupling defects in H-T coupled poly(3-alkylthio-phenes) may also lower the conjugation. This is indeed the case. In regioregular poly(3-alkylthiophene) the maximum of the n—n absorption peak is red shifted as compared to FeClj prepared, non-regioregular poly(3-alkylthiophene) (see Table 4.1). 

The introduction of an alkoxy substituent instead of an alkyl one leads to a significant improvement of the conjugation. The maximum of the 7t—rt absorption peak in HH-TT coupled poly(3,3 -dibutoxy-2,2 bithiophene) is about 200 nm red shifted with respect to the corresponding peak in poly(3,3 -dibutyl-2,2 -bithiophene) [56,57]. 

Similar doping induced spectral changes are observed in poly(alkoxythiophenes) however, in pure head to head-tail to tail coupled poly(dialkoxybithio-... 

To demonstrate unidirectional charge flow via electron mediation, Murray s group electrochemically polymerized complexes [Ru(bpy)2(vpy)2] " ", A, and [Ru(bpy)2(vpy)Cl]+, B, on Pt electrodes in CH3CN. (vpy is 4-vinylpyridine.) The order of deposition of the fllms is crucial of course since Eg f [Ru +z2+(a)] = +1.23 and Eg j. [Ru " " (B) ] = +.76 V vs SSCE and the inner film mediator (poly(A)) would not be expected to move electrons uphill. The results are summarized in Figure 2, where it is clear that both redox waves associated with the outer film couple (poly (B)) are missing in the dual layer system (Fig 2(b)). The (A + B) copolymerized single film electrode (Fig 2(c)) shows the electronic presence of both couples at the Pt/polymer interface. 

Block copolymers of IB and methyl methacrylate (MMA), monomers that are polymerizable only by different mechanisms, can be prepared by several methods. The prerequisite for the coupling reaction is that the reactivities of the end groups have to be matched and a good solvent has to be found for both homopolymers and copolymer to achieve quantitative coupling. Poly(IB-f)-MMA) block copolymers were synthesized by coupHng reaction of two corresponding hving... 

McCullough, R.D. 1998. Regioregular, head-to-tail coupled poly(3-alkylthiophene) and its derivatives. In Handbook of conducting polymers, 2nd ed., eds. T.A. Skotheim, R.L. Elsenbaumer, J. R. Reynolds. NewYork Marcell Dekker, pp. 225-258. 

McCullough, R.D., R.D. Lowe, M. Jayaraman, R.C. Ewbank, D.L. Anderson, and S. Tristramnagle. 1993. Synthesis and physical-properties of regiochemically well-defined, head-to-tail coupled poly(3-Alkylthiophenes). Synth Met 55 (2-3) l 198-1203. 

Zhang J.F., Sun X., Physical characterization of coupled poly (lactic acid)/starch/maleic anhydride blends by triethyl citrate, Macromol. BioscL, 4, 2004,1053-1060. 

Scheme 2.1) followed by selective cross-coupling gives head-to-tail coupled poly(3-alkylthiophene)s. Substituents may be limited by the organolithium intermediates required to access the cross-coupling competent monomer. However, designing for post polymerization functionalization provides a partial solution [46-48]. Telechelic synthesis [43, 49] or isolable monomers, allowing polymerization in diverse solvents, are notable advantages. 

A poly(uridylic acid)-cellulose resin has been prepared by coupling poly-(uridylic acid) oxidized with periodate at one end to a hydrazide derivative of carboxymethylcellulose. The resin was used as a column-bound ribosome system in studies of translocation in ribosomes. 

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