2020 Volume 36 Pages 11-13
Phthalonitrile-3-yl (PN3) substituted indole derivative 1 was structurally characterized. The compound was crystallized in a monoclinic system and characterized as follows: P21/c, a = 23.232(5), b = 7.4413(14), c = 15.361(4)Å, β = 106.818(5)°, Z = 8, V = 2542.0(10)Å3. 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)°. Theoretical studies revealed that the rotational barrier of PN3 is 8.82 kcal mol−1. 1H 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-d6). The double-bond character of the bond connecting these protons is responsible for this phenomenon.
