ChemInform Abstract: STEREOCHEMISTRY OF 3,3′‐BITHIENYLS PART 16, THE ABSOLUTE CONFIGURATIONS, CONFORMATIONS, CIRCULAR DICHROISM SPECTRA OF 4,4′‐DICARBOXY‐2,2′,5,5′‐TETRAMETHYL‐3,3′‐BITHIENYL, 4,4′‐DICARBOXY‐2,2′,5,5′‐TETRAMETHYL‐3,3′‐BISELENIENYL, 3,3′,6,6′‐TETRAMETHYL‐2,2′‐DIPHENIC ACID AND SOME RELATED COMPOUNDS