Novel 5-(4-alkoxyphenyl)thieno[3,2-b]thiophene-2-carboxylate esters: Highly efficient synthesis and mesogenic evaluation of a new class of materials exhibiting the smectic C phase |
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Authors: | Jonathan I Tietz James R Mastriana Paul Sampson |
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Institution: | Department of Chemistry and Biochemistry , Kent State University , Kent , OH , 44242-0001 , USA |
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Abstract: | A series of alkyl 5-(4-alkoxyphenyl)thieno3,2-b]thiophene-2-carboxylates were prepared via a direct, efficient Pd(0)-catalysed Suzuki–Miyaura coupling approach. A series of long-chain alkyl thieno3,2-b]thiophene-2-carboxylate esters, synthesised from newly reported alkyl mercaptoacetates, were elaborated into the target compounds via regioselective (C-5) halogenation followed by cross-coupling with 4-alkoxyphenyltrifluoroborate salts. As expected, these target alkyl 5-(4-alkoxyphenyl)thieno3,2-b]thiophene-2-carboxylate ester mesogens exhibited the orthogonal smectic A phase; notably, they are the first materials built on the thieno3,2-b]thiophene motif to also exhibit the smectic C mesophase. |
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Keywords: | esters organotrifluoroborates smectic C thieno[3 2-b]thiophene |
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