Crystalline network form of Gefitinib molecule stabilized by non–covalent interactions: DFT–D calculations

The crystalline network of a stable form of Gefitinib (C22H24ClFN4O3) as a new anticancer has been theoretically studied. DFT calculations demonstrated that the packed network of Gefitinib was constructed by hydrogen bonds as the main constructor force. Hydrogen bond interactions link the molecular layers result to 2D structure formation along the bc plane of unit cell. However, network grows through π–stacking of the fragments along a direction. Dispersion corrected density functional theory calculations (DFT−D) were applied for evaluation of the binding energy value of the non–covalent forces which demonstrate N H⋯O and C H⋯O as the primary creator interactions of the intended 3D network. Moreover, the intermolecular HBs and π⋯stacking interactions were studied by Bader’s theory of AIM. Calculated/FP-LAPW visible region of optical spectra was shown that this molecule is approximately transparent in the x and z directions with greater interacting power in the z-direction than x and y ones. The maximum absorption is related to the x direction and it is low in the y and z directions because of the hydrogen bonds existence in bc plan.