8,9-Dimethoxybenzo[b]naphtho[2,3-d]thiophene

Abstract

In the title compound, C 18 H 14 O 2 S, the system of four fused rings is almost planar (r.m.s. deviation = 0.022 Å ). The C atoms of the methoxy groups deviate from the mean plane of the ring system by 0.373 (2) and À0.104 (2) Å . In the crystal, very weak aromaticstacking interactions [shortest centroid-centroid separation = 3.9286 (10) Å ] may help to establish the packing.

Synthesis and Properties of Thiophene-Fused Thiopyrylium Salts

“…The obtained structural parameters of the thiophene subunit in 1 are similar to those of the fused thiophene derivatives C and D (Chart ). The C–S bond lengths of 1.694(5) and 1.730(4) Å in the thiopyrylium unit of 1 are slightly longer than those in the parent thiopyrylium trifluoromethanesulfonate E (1.637(3)/1.664(3) Å) . Moreover, the C–S bond lengths fall in a range between those in the CS double bond of Ph 2 CS (1.635 Å) and more representative C–S single bonds (1.80–1.85 Å) .…”