New Aryl Edge - Edge Packing Interactions Involving the N-Oxide Functional Group.

Abstract

The X-ray crystal structures of 5b,6,12b,13-tetrahydropentaleno[1,2-b:4,5-b´]diquinoline 5,12-dioxide (5) and (6α,7α,14α,15α)-7,15-dibromo-6,7,14,15-tetrahydro-6,14-methanocycloocta[1,2-b:5,6-b´]diquinoline 5,13- dioxide (6) reveal two new packing modes of potential importance as supramolecular synthons for molecular assembly. Both involve intermolecular edge–edge association of an aryl ring and an N-oxide functionality. One is a bifurcated Ar–H···O(N)···H–Ar interaction which on repetition gives infinite chains of the molecules. The second is a 10-membered centrosymmetric dimer also involving Ar–H···O–N interactions but which merely links two neighbouring molecules of (6). The latter arrangement is a structural analogue of a recently reported dimeric centrosymmetric eight-membered Ar–H···N synthon.