A. G. Evans, J. Evans, Michael W. Baker
1975
Citations
0
Influential Citations
16
Citations
Journal
Journal of The Chemical Society-perkin Transactions 1
Abstract
We have studied the e.s.r. spectra of methanol solutions of the morphamquat {bis-1,1′-[(2,6-dimethylmorpholin-4-yl)carbonylmethyl]bipyridyl} radical cation (I) from +40 to –80°. The value of the splitting constants obtained are A(pyridyl N) 0.400, A[pyridyl H(3)] 0.142, A[pyridyl H(2)] 0.048, A(NCH2) 0.245, and A(morpholine N) 0.024 mT. It is found that as the temperature decreases the concentration of the radical cation decreases until at –80° there is no e.s.r. spectrum. This process is reversible. Concentration experiments show that the morphamquat radical cation is in equilibrium with a dimeric diamagnetic species. The ΔH° value for the equilibrium is found to be –45.05 ± 0.3 kJ mol–1. The ΔG° and ΔS° values at 25 °C are –10.6 kJ mol–1 and –115.6 J mol–1 K–1 respectively.