Spectroscopic studies on [(DD18C6H2)(HPA)2](PA)2 and [(DD18C6H2)(DDQ)2](DDQH)2 formed in the reaction of N,N′-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane with HPA and DDQ

The interaction of the mixed oxygen-nitrogen cyclic base, N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooetadecane (DD18C6) with pi-acceptors such as picric acid (HPA) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) has been studied spectrophotometrically in chloroform at 25 degrees C. The results obtained indicate the formation of 1:4 charge-transfer complexes with the general formula (DD18C6)(acceptor)(4). The electronic and infrared spectra of charge-transfer complexes along with the H-1 NMR spectra were recorded and discussed. Based on the data obtained, the complexes were formulated as [(DD18C6H(2))(HPA)(2)](PA)(2) and [(DD18C6H(2))(DDQ)(2)](DDQH)(2). A general mechanism explaining the formation of the DDQ complex has been suggested. (c) 2004 Published by Elsevier B.V.