Structural analysis of a dithiosquarylium dye

The MOPAC PM3 approach is used to study the structure of a dithiosquarylium dye (DTSQ). It was shown that the X-ray structure and the calculated results, are in good agreement. From the experimental and calculated structure of DTSQ, DTSQ-I is a more stables tructure than DTSQ-II. The structural analysis suggests that the DTSQ is extensively bond delocalized with relatively small torsion angles of 5°.