Synthesis and Properties of Polyacetylenes Connecting Carbazole at the 2‐ and 3‐Positions: Effect of Polymerization Catalysts and Substitution Positions on the Optoelectronic Properties

Abstract

The new carbazole‐containing acetylene monomers, 2‐ethynyl‐9‐tert‐butoxycarbonylcarbazole (1) and 3‐ethynyl‐9‐tert‐butoxycarbonylcarbazole (2) were synthesized and polymerized with Rh+(nbd)[η6–C6H5B−(C6H5)3], [(nbd)RhCl]2–Et3N, [(nbd)RhCl]2–KN(SiMe3)2, and WCl6–Ph4Sn catalysts. The corresponding polyacetylenes with number‐average molecular weights ranging from 23 000 to 185 000 were obtained in 80%‐quantitative yields, except for the polymerization of 1 with W catalyst. Rh‐based poly(1) showed UV‐Vis absorption in the longer wavelength region than Rh‐based poly(2). W‐based poly(2) showed an absorption band edge at a wavelength longer than the Rh‐based polymer. W‐based poly(2) emitted fluorescence at 375 nm upon excitation at 291 nm, while the Rh‐based compound emitted almost no fluorescence. The polymers exhibited new absorption around 360–600 nm based on electrochemically doped species by application of an external voltage.magnified image

Synthesis and polymerization of phenylacetylene having two carbazole units and properties of the formed polymer

“…Unless otherwise stated, reagents were commercially obtained, and used without further purification. 3‐(Trimethylsilylethynyl)carbazole 2 was synthesized from 3‐iodocarbazole and trimethylsilyacetylene . 9‐(4‐Iodophenyl)carbazole 3 was synthesized from carbazole and 1,4‐diiodobenzene .…”

Synthesis and properties of helical polyacetylenes containing carbazole

“…2-and 3-trimethylsilylethynylcarbazoles were synthesized according to the literature [13]. Solvents for polymerization were purified before use by the standard methods.…”

“…13 C NMR (d in ppm, CDCl 3 ): 13.6,18.9,19.8,27.9,28.1,36.87,44.7,48.1,49.1,78.0 (C^CH),84.4 (C^CH),116.2,119.4,119.9,120.3,120.5,123.4,125.3,126.2,127.1,127.7,137.9,138.9 (Ar), 152.6 (CO 2 ). IR (cm À1 , KBr): 3290 (^CeH), 2103 (C^C), 2954, 2869, 1726, 1601, 1491, 1466, 1456, 1425, 1386, 1352, 1331, 1306, 1278, 1255, 1220, 1203, 1148, 1130, 1114, 1042.…”

“…One solution to this issue is incorporation of a flexible spacer between polyacetylene backbone and carbazole moiety [12]. We have recently found that transformation of NH of carbazole into NCOOR effectively enhances the solubility of carbazole-containing polyacetylenes, even when polyacetylene backbone is directly connected with carbazole at the benzene ring [13]. Adopting a chiral group to NCOOR enables us to obtain a chiral polyacetylene carrying carbazole, which possibly takes a helical structure.…”

Enhanced Photoluminescence, Mesomorphism and Conformation of Liquid‐Crystalline Conjugated Polymers with Terphenyl Mesogen Pendants

“…[17,18] The third type are the side-chain liquidcrystalline conjugated polymers (SCLCCPs), where the mesogen units as the side-chain are hung to the rigid main-chain. [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Particularly, SCLCCPs have been considered with growing interest by various research groups, [37][38][39][40][41][42][43][44][45][46] because their electrical and optical properties are expected to be controlled by the molecular orientation of LC side chain. Besides, SCLCCPs could be macroscopically aligned by an external perturbation, such as shear stress, electric or magnetic force field.…”