Crystal Structure of 3-(3-Methyl-1H-indole-1-yl)phthalonitrile

Abstract

Phthalonitrile-3-yl (PN3) substituted indole derivative 1 was structurally characterized. The compound was crystallized in a monoclinic system and characterized as follows: P2(1)/c, a = 23.232(5), b = 7.4413(14), c = 15.361(4)angstrom, beta = 106.818(5)degrees, Z = 8, V = 2542.0(10)angstrom(3). The crystal structure was solved by direct methods and refined by full-matrix least-squares on F2 to the final values of R1 = 0.0660 and wR2 = 0.1610. 1 has two crystallographically independent molecules in the asymmetric unit. The dihedral angle between indole and PN3 is 42.17(8)degrees. Theoretical studies revealed that the rotational barrier of PN3 is 8.82 kcal mol(-1). H-1 NMR spectroscopy demonstrated an interesting long-range spin-spin coupling between benzylic H of the methyl group and the adjacent aromatic H through four bonds with a coupling constant of 1.3 Hz (in acetone-d(6)). The double-bond character of the bond connecting these protons is responsible for this phenomenon.