X-RAY STRUCTURES OF 2 METHOXYBENZO[B]THIOPHENES

The crystal and molecular structures of two methoxybenzoI[b]thiophenes have been determined by three-dimensional, single-crystal X-ray diffr actometry. Both 3-(4'-hydroxy-3',5'-dimethoxybenzoyl)-2-(4' -methoxyph enyl)-6-methoxybenzo[b]thiophene and hoxybenzoyl)-2-(4'-methoxyphenyl) -6-methoxybenzoyl (hereafter referred to as I and II, respectively) cr ystallize in the monoclinic centrosymmetric space group P2(1)/n (No. 1 4, C-2h(5)) with four formula units-per cell with a = 6.866(1), b = 28 .638(2), c = 11.830(2) Angstrom, and beta 105.52(1)degrees and a = 9.3 28(1), b = 7.977(1), c = 29.650(4) Angstrom, and beta = 97.87(1)degree s, respectively. The phase problems were solved by direct methods and the respective final full-matrix least-squares refinements converged t o R = 0.046 and 0.031. The structures differ in the positioning of the dimethoxy groups of the benzoyl ligands and the addition of a hydroxy l group in I. The molecules in the crystal lattice are held together b y van der Waals forces plus the addition of hydrogen bonding in compou nd I. Selected bond distances and angles and torsion angles are tabula rized.