Crystal structure, Hirshfeld surface analysis and DFT calculations of 7-bromo-2,3-di-hydro-pyrrolo[2,1-b]quinazolin-9(1H)-one.

The mol-ecular structure of the title compound, C11H9BrN2O, is almost planar. The benzene and pyrimidine rings are essentially coplanar, with r.m.s. deviations of 0.0130 Å, and the largest displacement is for the flap atom of the di-hydro-pyrrole moiety [0.154 (7) Å]. Hirshfeld surface analyses revealed that the crystal packing is dominated by H⋯H, Br⋯H/H⋯Br and O⋯H/H⋯O inter-actions, and Br⋯Br inter-actions in the crystal structure are also observed. Theoretical calculations using density functional theory (DFT) with the B3LYP functional basis set gave numerical parameters for the frontier molecular orbitals.

2,3-Dihydro-pyrrolo-[2,1-b]quinazoline-9(1H)-thione.

In the crystal, mol-ecules of the title compound, C(11)H(10)N(2)S, are connected by C-H⋯N inter-actions around threefold axes. Furthermore, they form stacks along the c axis showing π-π inter-actions between pyrimidine rings [centroid-centroid distance = 3.721 (1) Å]. The central ring is essentially planar with an r.m.s. deviation of 0.007 Å. The five-membered ring adopts an envelope conformation with the flap atom deviating by 0.241 (4) Šfrom the mean plane (r.m.s. deviation = 0.002 Å) through the other four ring atoms.