Structural studies on (3,4,8,9)-dibenzo-2,7-dioxa-5, 10-diaza[4.4.4]propellanes (DDDP)

The methyl and nitro derivatives of (3,4,8,9)-dibenzo-2,7-dioxa-5,10-diaza[4.4.4]propellanes P2, P3, P7 and P9 were synthesized. The X-ray diffraction studies showed that 16,20-dinitro derivative (P7) crystallizes in non-centrosymmetric Pcn2 space group making this crystal to be promising in non-linear optics. The geometry of molecules is discussed in relation to the intramolecular interaction and charge distribution. Very helpful appeared from this point of view the C-13 NMR spectra. In packing of molecules an important role play the N-(HO)-O-... and C-(HO)-O-... hydrogen bonds reflected both in the crystal structures and IR spectra. (C) 2003 Elsevier Science B.V. All rights reserved.