2,2,8,9-Tetramethyl-1,2-dihydropurine-6-carboxamide

Abstract

Fig. 3. A stereoscopic projection on the bc plane displaying one layer of crystal packing. The tilt of the acridine molecules with respect to the PMDA molecules can be seen clearly.The 2:1 donor-acceptor complex can be appropriately characterized as a sandwich of one acceptor between two donor molecules, Fig. 3. A schematic drawing of the packing and of the dipole orientations is displayed in Fig. 4. The angle between the plane normals of the donor and acceptor molecules is 7.3°. The average distance of an Ac atom (excluding H atoms) from the plane of the acceptor is 3.434 A, which is approximately 0.1 A greater than that in the 1:1 complex. The angle between the intrasandwich stack axis (as determined from the coordinates of the molecular centroids neglecting H atoms) and the plane of the acceptor molecule is ca 25 o.Space-group symmetry (e.g. the glide reflection operator) generates a second unit of the complex as