Synthesis and X-ray Studies of Novel Azaphenanthrenes

Abstract

Two azaphenanthrenes were synthesised by a facile synthetic pathway and characterised by X-ray crystallography. Molecular packing of 4-(2,4-dichlorophenyl)-2-methoxy-5,6-dihydrobenzo[ h]quinoline-3-carbonitrile exhibits C–H…N and C–H…Cl hydrogen bonds in addition to intermolecular C–H…π, Cl…π and π…π (π-ring) stacking interactions. However, molecules of the 2-ethoxy derivative are linked into chains by one hydrogen bond of the C–H…N type and the crystal structure reveals an intermolecular C–H…π (π-ring) interaction. Computational studies by AM1, PM3, and density functional theory (DFT) techniques provide good approximations to the experimental X-ray data. The root mean square errors between the experimental and calculated bond lengths using AM1, PM3 and DFT methods for the 2-methoxy and 2-ethoxy derivatives are 0.0187, 0.0193, 0.0120 and 0.0197, 0.0195 and 0.0116 respectively.