title: Dual-channel-mediated spin coupling for one-electron-oxidized cobalt(II)-saddled porphyrin.
abstract: Saddle-shaped Co(II)[OET(p-R)PP] (R = CF3, H, CH3) can be readily oxidized with Cl2, Br2, and I2 to the corresponding one-electron-oxidation product Co[OET(p-R)PP]X (X = Cl, Br, I) with the clear character of a ring cation radical. With the series of (1)H and (13)C NMR spectra of these related complexes, both the axial ligand and peripheral substituent of the ring macrocycle are proven to act as a dual channel to tune spin coupling between low-spin Co(II) and a porphyrin π-cation radical. Density functional theory calculations have shown that the antiferromagnetic coupling between spins residing in d(z)(2) and a(2u) are expected to exist as the ground state. The paramagnetic properties are attributed to an a(1u)-type ferromagnetic excited triplet state.
authors.affiliation: Department of Chemistry, National Chung-Hsing University , 250 Kuo Kuang Road, Taichung 402, Taiwan.
authors.forename: Ru-Jen
authors.initials: RJ
authors.lastname: Cheng
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Chen
authors.forename: Ching-Chin
authors.initials: CC
authors.lastname: Chen
authors.forename: Gene-Hsiang
authors.initials: GH
authors.lastname: Lee
authors.forename: Shie-Ming
authors.initials: SM
authors.lastname: Peng
authors.forename: Peter Ping-Yu
authors.initials: PP
authors.lastname: Chen
mesh_terms: D066241:Carbon-13 Magnetic Resonance Spectroscopy; D003035:Cobalt / Q000737:chemistry*; D004583:Electrons; D011166:Porphyrins / Q000737:chemistry*; D013113:Spin Labels
chemical_list: D011166:Porphyrins; D013113:Spin Labels; D003035:Cobalt