Synthesis and Electrical Properties of Poly(1,4-diethynyl-2,5-dibutoxybenzene)

Abstract

ABSTRACT:Poly(l ,4-diethynyl-2,5-dibutoxybenzene ), a polymer containing diacetylene group in the main chain, was synthesized by oxidative coupling polymerization. This polymer was confirmed to have relatively high molecular weight and expected to have polydiyne structure without defects. In solid state 13 C NMR spectrum of this polymer, the peaks assigned to phenyl carbons were splitted to doublet because there were any kinds of conformation around the single bonds between triple bonds of diacetylene groups. A DSC curve of the polymer indicated that it was cross-linked at 620 K because of starting of the rotation around the single bond. Although conductivity of the polymer was very low, the polymer exhibited relatively high photoconductivity attributed to the nature of the repeating unit.KEY WORDS Poly(l,4-diethynyl-2,5-dibutoxybenzene) / Conjugated Polymer/ Oxidative Coupling Polymerization/ Solid State CP/MAS 13 C NMR / Solid State Structure / Main Chain Conformation / Thermal Reactivity / Photoconductivity / Diacetylene compounds are attracting increasing attention worldwide. 1 The reason for this interest is that these compounds are polymerized in solid state and afford single crystal polymers. Since the pioneering work of Wegner in late 1960's, 2 there have been many studies on the polymerization process 3 and the physics of quasi-one-dimensional materials. 4 Many kinds of applications were studied, such as conductive materials 5 and nonlinear optical devices 6 by using unique conjugated main chain of the polymers.tributed to the change of the mam chain conformation. 8 Whitesides and coworkers investigated thermal curing of soluble polydyines. 9Hay reported that m-diethynylbenzene was polymerized to polydiyne by oxidative coupling polymerization, 7 and the polymers with diacetylene groups have been investigated for thermal and optical curing materials. Recently, Lando and coworkers reported that poly(l ,8-nonadiyne) which has alkylene spacer exhibited thermochromism and solvatochromism atPolym.

The preparation and some properties of substituted phenylene-ethynylene and phenylenebuta-1,3-diynylene polymers

“…Iodine doping was reported to increase the conductivity threefold 52 as compared with our increase using ferric chloride doping of 2.13 × 10 3 . The range of increase in conductivity of our diynyl polymers was from 2.0 × 10 4 for 27 to 10.9 for polymer 26, the effect of the methoxy substituents being very marked.…”

“…Doping has far less effect on the conductivities of these polymers than on polymers 2. 12 Polymer 24 has been previously prepared 30, 52 and solid state 13 C NMR suggested that it was defect free and of high molecular weight.…”

“…δ H 6.82 (2H, s, H-3), 3.92 (4H, t, OCH 2 ), 2.90 (2H, s, HO-), 1.76 (4H, m, OCH 2 CH 2 ), 1.61 (12H, s, C(OH)-CH 3 ), 1.51 (4H, m, CH 2 CH 3 ), 0.97 (6H, t, CH 3 CH 2 ). δ C 153.56 (C-2), 117.13 (C-3), 113.48 (C-1), 99.28 (C-4Ј), 78.37 (C-3Ј), 31 52 Potassium carbonate (0.25 g, 1.85 mmol) was added to a 250 ml round-bottomed flask charged with 12 (0.5 g, 1.85 mmol) and methanol (100 ml). The mixture was stirred at room temperature for 16 h during which time the K 2 CO 3 dissolved.…”

Monolayers and Langmuir-Blodgett multilayer films of a conjugated azo polymer

“…1). In this way the conjugation might not be disturbed by torsion of the planar backbone [32]. The general idea was that, because of the trans conformation of the azo group and the interaction of the hydrophilic ester groups with the water phase, the backbone is forced to lie flat on the water surface.…”