The Importance of a β-β Bond for Long-Range Antiferromagnetic Coupling in Directly Linked Copper(II) and Silver(II) Diporphyrins

摘要

Magnetic exchange coupling between distant metal centers is a major topic in the field of magnetochemistry.[1] Although a great number of covalently linked oligomacrocycles (e.g. porphyrins or phthalocyanines) have so far been prepared, only a few such molecules have been tested for the exploitation of long-range magnetic coupling.[2], [3] One difficulty in the use of these metalated macrocycles for magnetic coupling may be exemplified by the work of Eaton et al., in which a -J value of only about 0.5 cm-1 was detected for a face-to-face coplanar bis-CuII diporphyrin with a short center-to-center distance of around 4.1 ?.[2a] However, suitably arranged intervening bridges may help magnetic communication between distant metal centers.[3]