2,2′-Bridged biphenyls with 12-membered heterocyclic bridging rings. Part 1. Tetrabenzo[b,d,h,j][1,6]diazacyclododecines
Abstract
Four tetrabenzo[b,d,h,j][1,6]diazacyclododecines and their tetrahydro-derivatives have been prepared. 1H N.m.r. and u.v. spectroscopy are used to determine the geometry of the tetrabenzodiazadodecines. It is concluded that they have the EE configuration, with dihedral angles in the biphenyl moieties of 55–60° and with angles of twist about the ArC–CHN and ArN–NCH single bonds of 10–20 and 80–70° respectively. N.m.r. spectra in the presence of chiral lanthanide shift reagents show that at least two of the compounds are chiral.