Local-site dependency of magneto-chiral dichroism in enantiopure one-dimensional copper(II)–chromium(III) coordination polymers

Magneto-chiral dichroism (MChD) is a nonreciprocal directional dichroism emerged by applying a magnetic field to chiral materials, which provides a clear distinction between light propagating parallel and antiparallel to the magnetic-field direction. So far the correlation between the metal origin magnetization and MChD signal has been reported in homometallic complexes bearing chiral ligands, but that in hetero-metal systems with short-range correlations has never been investigated. Here, we demonstrate that MChD in d–d transitions of Cu^II bearing chiral ligands in an cyano-bridged copper(II)–chromium(III) chain is mainly proportional to the magnetization of local Cu^II center, which involves intra-atomic transition, rather than to the ferromagnetically correlated spin magnetization.