r - Fen Bilimleri Enstitüsü - Dokuz Eylül Üniversitesi

CRYSTALLOGRAPHIC AND CONFORMATIONAL INVESTIGATIONS
OF SOME ORGANIC COMPOUNDS
ABSTRACT
Molecular and crystal structure of 4-(2-furylmethylene)-2-(4-methylphenyl)-5-
oxazolone and N,N'-Bis-(3,5-dioxo-4-azatricyclo[5.2.1.02,6]dec-8-en-4-yl)
oxalamide have been determined by single crystal X-ray diffraction study.
The oxazolone compound which was crystallized in monoclinic crystal system
and solved by direct methods with using a total of 950 reflections. Structure was
refined by least-square and difference-Fourier methotds to a conventional R=0,048
for 204 parameters. The bond lenghts and angles of the oxazolone ring are
comparable in the literature. The C atom between the furyl and oxazolone rings
displays a distorted trigonal bonding geometry. The molecule is almost planar and
adopts the Z configuration. Besides, this result proved by PM3 semi-empirical
method and according as the selected torsion angle T(N1-C9-C10-C11) in the
molecule, energy profile is calculated. The crystal structure stabilized C-H…O type
intermolecular, pi- pi and C-O...pi weak interactions.
The oxalamide compound which was crystallized in triclinic system is related to
P-1 space group. The molecular structure was solved by direct methods with using a
total of 3428 reflections. The structure was refined by least-square and difference-
Fourier methotds to a conventional R=0.041 for 234 parameters. The half
oxalamide molecule is in the asymmetric unit together with one dimethylformamide
solvent molecule. The molecule has a inversion centre on the middle point of the
molecule. The two C=O groups lie on opposite sides of the bond C10-C10i and the
molecule adopts the trans conformation. The bicycloheptene ring adopts a boat
conformation. The crystal structure stabilized by N-H…O and C-H…O type
intermolecular interactions.
Key words: Crystal structure, molecular structure, oxazolone, oxalamide, PM3.
v