SN‐conducting polymers with heterocyclic spacer groups

Abstract

SynopsisPolymer-containing alternating sulfur nitrogen moieties separated by heterocyclic groups have been synthesized and characterized. The polymers have undoped conductivities of 10 -6 to 10 (Q crn)-l; the intrinsic carriers are negatively charged as shown by thermopower coefficient of -1.4 x lo3 to -1.9 x 10" pV K-'. The polymers are degraded by AsF5 and cannot be doped by iodine. Exposure to bromine resulted in reversible pdoping of the SN polymers to the thermopower values of +400 to + 820 pV K -' and conductivities of 0.01 to 0.002 (Q crn)-'. Removal ofdopant by evacuation returns most of the properties of the polymers to the undoped states. Magnetic properties of the materials have been studied.

A comparative study of ethylene and propylene polymerization over titanium–magnesium catalysts of different composition

“…[4][5][6], the introduction of the external donor (ED) into the catalyst already containing the internal donor gives narrower MWD values for atactic polypropylene in propylene polymerization, but does not affect MWD of isotactic fraction. Studies 7,8 were devoted to the effect of external donor (methyl-p-toluate) as a constituent of TMC (MgCl 2 /ethylbenzoate/p-cresol/AlEt 3 TiCl 4 -AlEt 3 ) on ethylene polymerization. In the presence of external donor, the number of active sites decreased twofold and M w of PE increased.…”

“…However, in Refs. [7,8] molecular weights of PE and PP were calculated using intrinsic viscosity, which does not allow one to estimate the MWD of the polymers being produced.…”

Polymerization of propylene catalyzed over highly active and stereospecific catalysts synthesized with Mg(OEt)2/benzoyl chloride/TiCl4

“…Isotacticity of polymers obtained with all catalysts was above 95%. However, the polymerization rates were reduced by twoor three-fold for the polymerization effects of external bases are mentioned 13~16, 21 (1) with KIPB, KIPC, and KIPE. No conspicuous change in rate profile and polymerization rate was observed in the polymerization with KIPD.…”

Synthesis and structural studies on thioimides, R2CNSR and sulfur diimides, R2CNSNCR2

“…Anal (4). A solution of fluorenone (1.00 g, 5.55 mmol) in toluene (30 mL) was added dropwise to a solution of Li[N(SiMe 3 ) 2 ] (0.93 g, 5.55 mmol) in toluene (30 mL) and the resultant yellow mixture stirred for 18 h at 70 °C.…”

“…The discovery 1,2 of the conducting and superconducting properties of (SN) x in 1973 generated a surge in interest in the physical properties of S/N compounds and, in particular, attempts to include C in the polymer backbone led to the blossoming of several new areas of C/N/S heterocycles. 3 With a few exceptions, 4 the incorporation of C into the polymer backbone has proved largely unsuccessful; few C/N/S containing polymers have been prepared and typically exhibit semi-conducting behaviour, 4 presumably due to mismatch in the energies of the thiazyl and phenylene π-systems. Whilst metallo-C/N/S conjugated polymers have also been proposed, 5 the introduction of metal binding groups has not been widely explored.…”