title: Molecular orbital calculations on polythiophenes containing heterocyclic substituents: effect of structure on electronic transitions.
abstract: Molecular orbital calculations have been performed on thiophene oligomers bearing heterocyclic substituents at the third position in order to understand the interplay of effects such as the nature of substituent, skeletal substitution pattern, heteroatom identity, etc. on electronic transitions. The geometry optimization was carried out using the semiempirical AM1 method, and the electronic transitions predicted for the oligomers were extrapolated for polymers using an oligomeric approach. The experimentally determined optical transitions were found to follow the predicted trend of electronic transitions of monomers and polymers.
authors.affiliation: Central Leather Research Institute, Adyar, Chennai 600 020, India.
authors.forename: S
authors.initials: S
authors.lastname: Radhakrishnan
authors.forename: R
authors.initials: R
authors.lastname: Parthasarathi
authors.forename: V
authors.initials: V
authors.lastname: Subramanian
authors.forename: N
authors.initials: N
authors.lastname: Somanathan
mesh_terms: D004563:Electrochemistry; D004583:Electrons; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D011789:Quantum Theory; D013237:Stereoisomerism; D013876:Thiophenes / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D006571:Heterocyclic Compounds; D011108:Polymers; D013876:Thiophenes; C066730:polythiophene