A theoretical study of spin excitations in [2,2]-paracyclophane skeleton substituted with two dicarbene units

Abstract

The different spin states in pseudo-ortho-, pseudo-meta- and pseudo-para-dicarbene substituted [2,2]-paracyclophanes have been studied using a Heisenberg spin model. The ground state is always a quintet in pseudo-ortho and -para isomers and the lowest energy spin excitation is to a triplet state while the pseudo-meta isomer possesses a singlet ground state. The spin densities in the quintet states are provided to enable an estimate of the exchange constants from ESR studies. Our studies confirm the possibility of obtaining high-spin molecules and eventually an organic ferromagnet in one-dimension as proposed by McConnell.