The N–H···X Hydrogen Bonds in the Crystal Structures of (Thio)Isochromene Derivatives

The 6-amino-8-(2,3-dichlorophenyl)-8,8a-dihydro-1H-isothiochromene-5,7,7(3H)- tricarbonitrile DMF solvate (1) and 6-amino-8-(2,4-dichlorophenyl)-8,8a-dihydro-1H-isochromene-5,7,7(3H)-tricarbonitrile DMF solvate (2) were synthesized and characterized by IR, 1H NMR and HRMS. The molecular structures were further confirmed by X-ray diffraction analysis. The former 1, C21H19Cl2N5OS, is monoclinic, space group P2(1)/c, a = 9.8139(3), b = 7.4629(2), c = 29.2903(9) A, β = 96.299(1), Z = 4, V = 2132.27(11) A3. The latter 2, C21H19Cl2N5O2, is monoclinic, space group P2(1)/c, a = 17.0495(4), b = 8.9021(2), c = 16.1718(4) A, β = 116.668(2), Z = 4, V = 2193.39(9) A3. It is very interesting that they are all form a inter-molecular hydrogen bond of N–H···O, linking a molecule of DMF. Another hydrogen atom on the same amino group forms a hydrogen bond of N–H···S, forming polymers in 1. However, it links adjacent molecules forming dimmers via hydrogen bond of N–H···N in 2.