STRUCTURAL STUDY OF A NEW 1-(2-THIENYL)-3-(3-METHYL-2-THIENYL)-PROPENONE, IN SITU RADIATION-INDUCED DIMERIZATION PRODUCTS

The new conjugated system ("chalcone kind") reported herein, 1-(2-thienyl)-3-(3-methyl-2-thienyl)-propenone, C12H10OS2 presents a monomeric molecular structure, and it most interesting aspects are to be found in it intermolecular interactions, of varied type (C-H-O, C-H---7C, n-n) and strength. Some anomalies detected in the refinement process, however, provided evidence that an unexpected in-situ, radiation-induced dimerization reaction had taken place during data collection, with the starting and final products coexisting in a topotactic fashion. This effect is depended of structural packing; that is not all this kind of conjugated system presents this effect. The main factor is the distance between the double bonds of neighboring monomers (about 3 A).