Synthesis of Tellurophene and its 2,5‐Disubstituted Derivatives

Abstract

R Con v e r s i o I70 92-93/0.8 18 116/0.5 76 130/2 11 155/1 59 125-1 26/0.3 11 190-200/0.4 71 m.p. 87-88 18 58 155/3 27 135--139/1 -n?o D 1.5835 1.5941 1.5640 1.5645 1.6296 1.6630 --1.6004 1.5624 Chlorination (at room temperature without solvent) of compound (2.) does not, like that of ethyl pentachloro-1,3butadienyl ether, cause ether fission with formation of an acid chloride [31, but instead leads to a-chloroethyl pentachloro-1,3-butadienyl sulfide (4) (84 %, b.p. 119 '(72.2 mm,Reaction of the compound (2a) with sulfuric acid [conc. H2SO4: glacial acetic acid: ( I ) =3.5:1.5:0.5; 60°C; 45 hr] occurs with formation of S-ethyl2,3,4,4-tetrachloro-3-butenethioate (5) (61 %, b.p. 92 "Cjl mm, n'," = 1.5350).Oxidation of (2.) with 60 % peracetic acid leads to ethyl pentachloro-l,3-butadienyl sulfoxide (6) (83 %, m.p. 39 to 41 "C), from which the corresponding sulfone (7) (89 %, m.p.43-45 "C) is obtained on further oxidation with peracetic acid.The ring system of tellurophene has so far been encountered only in the form of its tetraphenyl"] and tetrachloror7-1 derivatives. Attempts to prepare the parent compound were unsuccessful [31. A method of broad scope for the preparation of tellurophene and its 2,5-disubstituted derivatives has now been found in the reaction of sodium telluride and diacetylenes.R -C = C -C -C -R + NazTe 2ooc :qJG ( I ) . R: -H [3), R: -CH20H ( 4 ) , R: -C(CHs)zOH A solution of sodium telluride in methanol is treated with an equivalent quantity of the diacetylene. The reaction is complete when the violet color of the telluride has disappeared. The majority of the methanol is distilled off and a little water is added to the residue. The tellurophene is then extracted with ether and purified by distillation or recrystallization after evaporation of the ether from the extract. Tellurophene (1) is obtained in this way in 69 % yield as a pale yellow liquid with a faint odor, b.p. 148'C/714 mm, m.p. ca. -36OC, n'," = 1.6856, di2 = 2.13. The positions of the N M R multipletsr41 at 7.83 (protons on C-3 and C-4) and 8.94 ppm (protons on C-2 and C-5) indicate that ( I ) must have marked aromaticity.The infrared spectrum of ( I ) shows peaks at 3080 (m), 3030 (m), 1425 (s), 1310 (m), 1240 (s), 1220 (s), 1100 (m), 975 (m), 785 (m), and 665(s) cm-1.In cyclohexane, ( I ) has A,,, at 280 m p (log E = 3.62). Its mass spectrum contains the parent peak at m/e = 182 (relative intensity = 0.33) expected for 12C41H4130Te. Other signals of high intensity are due to Te and C4 fragments. Cryoscopic molecular-weight determinations indicate that the compound occurs in the form of its dimer in benzene. A solution of bromine in methanol reacts with ( I ) to give an orange, insoluble precipitate of (2), m.p. 125 "C (decomp.). Aqueous HSOT reduces (2) back to ( I ) . 2,5-Bis(hydroxymethyl)tellurophene (3) is obtained ana-logously in 25 % yield as water-soluble crystals, m.p. 107 "C.Its N M R signals occur at 7.43 (protons on C-3 and C-4), 4.85 (methylene protons), and 2.16 ppm (hydroxyl protons). 2,5-Bis(dimethylhydroxymeth...

Structure of 3,5-dimethyl-1,2-tellurazole

“…They are rather stable solids, which can be crystallized from the usual organic solvents and from the melt without decomposition. Their melting point is considerably higher than that of the selenium-containing isologues, which are liquid at room temperature (Lucchesini, Bertini & De Munno, 1984); it is also higher than that of the tellurophene analogues (Mack, 1966). Low solubility and high melting point were also found for 1,2,5-telluradiazole, with respect to the selenium homologue (Bertini, Dapporto, Lucchesini, Sega & De Munno, 1984).…”

Hydroelementation of diynes

“…433,456 Among many synthetic strategies towards unsaturated organotellurium compounds, the hydrotelluration of diynes is a highly efficient and stereoselective method for enynyl tellurides which are useful building blocks in modern chemistry. Since the first synthesis of tellurophene by the interaction of 1,3-butadiyne 1a and 1152 with Na 2 Te 1153 in methanol developed by Mack's in 1966, 457 the several papers describing hydrotelluration of diynes appeared [458][459][460][461][462][463][464][465][466][467][468] which was also covered by Detty 431 and Zeni. 446,469 In this chapter the recent development of functionalisation of diynes by tellurium compounds will be presented.…”

Tellurophenes and Their Emergence as Building Blocks for Polymeric and Light-emitting Materials

“…6 Moreover it was demonstrated that tellurophene could be directly converted into the Te(IV) dibromide heterocycle 2 via treatment with elemental bromine (Scheme 1). The reverse of this process, re-reduction of 2 into the parent tellurophene (1), was also possible by addition of HSO 3 ¹ .…”

“…Polymer 14 was obtained with relatively high molecular weight (M n = 23.2 kDa) and had an optical band gap, determined from the onset of absorption, of 1.28 eV in orthodichlorobenzene. Solar cells consisting of a blend of 14 and PC 71 BM ( [6,6]-phenyl-C71-butyric acid methyl ester) as an active layer gave power conversion efficiencies (PCEs) as high as 4.4%. 23 The same group reported solar cells consisting of molecular donor molecules with capping benzotellurophene substituents, leading to elevated PCE values of up to 5.8%.…”