MOLECULAR CONFORMATIONS AND CRYSTAL STRUCTURES OF 1,3- DITHIOCINES, 1,2,3-TRITHIOCINES, AND 1,2,3-TRITHIEPINES WITH CONDENSED PLANAR FRAGMENTS

Molecular and crystal structures of the following three cyclic compounds with condensed naphthyl fragments are studied: crystals of 1H,5H-naphtho[1,8-ef][1,3]dithiocine and 1H,5H-naphtho[1,8-ef][1,2,3]trithiocine, and an isomer of the latter compound with a seven-membered heterocycle 1,5-dihydronaphtho[2,3-e][1,2,3]trithiepine. The crystals of the first two compounds are isostructural. It is shown that eight-membered heterocycles and the seven-membered ring in the sulfur-containing molecules occur in boat and chair conformations, respectively, in contrast to acetals of a similar structure. The crystal structure of the studied compounds is determined by dispersion Van der Waals interactions.