title: Simple but useful scheme toward understanding of intramolecular magnetic interactions: benzene-bridged oxoverdazyl diradicals.
abstract: It has recently been shown that the types of intramolecular magnetic interactions of diradical systems can be changed by the types of radical group: syn-group (or α-group) and anti-group (or β-group). The aim of this study is to establish a useful scheme to understand and explain the intramolecular magnetic interactions in diradical systems regardless of radical groups and the topology of a coupler. We investigated the intramolecular magnetic coupling constant (J) of six oxoverdazyl diradicals (i-vi) coupled with a benzene ring based on the unrestricted DFT calculations. On the basis of our results, we devised a simple but useful scheme by combining the spin alternation rule and the concept of radical group classification. Consequently, it was found that the calculated J values and plots of spin density distributions were consistent with our proposed scheme. In addition, we discussed the closed-shell singlet (CS) state and the dihedral angle effect on J values in detail to comprehensively understand the magnetic interactions of diradical systems. Our scheme can provide the basic framework to design future organic high-spin molecules and organic magnetic materials.
authors.affiliation: Department of Chemistry, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Kyoung Chul
authors.initials: KC
authors.lastname: Ko
authors.forename: Young Geun
authors.initials: YG
authors.lastname: Park
authors.forename: Daeheum
authors.initials: D
authors.lastname: Cho
authors.forename: Jin Yong
authors.initials: JY
authors.lastname: Lee