A theoretical study of the conformation of 2,2′-bifuran, 2,2′-bithiophene, 2,2′-bitellurophene and mixed derivatives: Chalcogen-chalcogen interactions or dipole-dipole effects?

► O/S, O/Se and O/Te interactions stabilize compounds related to 2,2′-bifuran. ► Chalcogen/chalcogen interactions influence the conformation of compounds related to 2,2′-bifuran. ► Barriers in bifuran, bithiophene, biselenophene, bitellurophene and their mixed derivatives. ► Dipole moments determine the conformation of 2,2′-bifuran and related compounds with S, Se, Te. ► MP2 calculations reproduce most experimental results of 2,2′-bifuran and related compounds.