Thiophene-fused heteroarenes

S-Containing Polycyclic Heteroarenes Thiophene-Fused and Thiadiazole-Fused Arenes as Organic Semiconductors... 

Tetrathiabenzo[l,3-cfirst time by dimerization of thieno[2,3- >]thiophene (142) (92PS73). More recently, it was found that catalytic reduction of 3,4-dibromothieno[2,3-i]thiophene (227) with an excess of activated zinc in the presence of bis(triphenyl-phosphine)nickel(II) chloride and tetraethylammonium iodide afforded only 4,4 -dibromo-3,3-bis(thieno[2,3- )]thiophene) (228) (in a maximum yield of 28%) (89AG1254). However, the reaction in the presence of a larger amount of the nickel catalyst afforded also dipenatlene 225. Optimization of the reaction conditions made it possible to increase the yield of the latter to only 14%. An alternative procedure was employed to transform thienothiophene 227 into trimethylstannyl derivative 229. The reaction of thienothiophene 227 with organotin intermediate 229 in the presence of the palladium triphenylphosphine complex afforded dipentalene 225 (13% yield). Derivatives 226 were prepared by lithiation of... 

Incorporation of other heteroatoms to phosphole-containing heteroarenes also leads to interesting molecular properties. One common example is the incorporation of thiophene units (Figure 12.10). These phospholes have high photoluminescence quantum yields due to their limited degrees of freedom from the rigid, fused ring system. Like many of the compounds discussed herein, these... 

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