Cyano-bridged Fe 2 Cu clusters: Control of magnetic properties through cis–trans arrangement

Abstract It remains a challenge to control the magnetic properties of molecule-based magnetic materials through chemical modification. Utilizing two tricyanometalate precursors with different steric hindrance, the cis–trans arrangement can be tuned in cyano-bridged {Fe 2 Cu} trinuclear complexes. The cis trinuclear [Fe III (Tp)(CN) 3 ] 2 Cu II (dpa) 2 ·2H 2 O ( 1 ) (Tp = hydrotris(pyrazolyl)borate, dpa = 2,2-dipyridylamine) was obtained with tricyanometalate possessing smaller steric hindrance, whereas the tran s trinuclear [Fe III (pzTp)(CN) 3 ] 2 Cu II (dpa) 2 ( 2 ) (pzTp = tetrakis(pyrazolyl)borate) was obtained using tricyanometalate with larger steric hindrance. The cis and trans arrangement leads to ferromagnetic and antiferromagnetic behaviors, respectively. Density functional theory (DFT) calculations were carried out to further substantiate the magnetic behaviors of both complexes. DFT computations show that the calculated magnetic coupling constant J was in agreement with the experimental results.