Attractive interactions between functional groups in crowded molecules: The solid state structures of diethyl 2-cyano(2 '-nitrophenyl)methyltartronate and diethyl (2 '-,6 '-dinitrophenyl)methyltartronate

The molecular structures of two substituted diethyl tartronates show a variety of interactions between functional groups. Oxygen atoms interact with the electron deficient carbon and nitrogen atoms of nitrile and nitro groups which in response show small distortions from their normal geometries. Short O . . . H contacts between benzyl hydrogen atoms and ortho nitro groups indicate some weak hydrogen bonding effects. Crystal data: C15H16N2O7, Mr = 336.3, a = 7.668(2), b = 7.961(3), c = 15.244(3) Angstrom, alpha = 86.78(1), beta = 81.56(1), gamma = 61.92(1)degrees, triclinic, P (1) over bar, Z = 2; C14H16N2O9, MY = 356.3, a = 7.786(2), b = 10.324(2), c = 11.155(4) Angstrom, alpha = 71.43(2), beta = 77.21(2), gamma = 76.40(3)degrees, triclinic, P (1) over bar and Z = 2.