A cyanide-bridged Fe^III–Mn^II heterobimetallic one-dimensional coordination polymer: synthesis, crystal structure, experimental and theoretical magnetism investigation

Abstract

A new cyanide-bridged Fe III -Mn II heterobimetallic coordination polymer (CP), namely catena-poly[[[N,N 0 FeMn(C 18 H 12 N 4 O 2 )(CN) 2 (C 10 H 8 N 2 ) 2 -(CH 3 OH) 2 ]ClO 4 } n , (1), was prepared by the self-assembly of the trans-Á6H 2 O and 4,4 0 -bipyridine, and was structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction analysis shows that CP 1 possesses a cationic linear chain structure consisting of alternating cyanide-bridged Fe-Mn units, with free perchlorate as the charge-balancing anion, which can be further extended into a two-dimensional supramolecular sheet structure via inter-chain interactions between the 4,4 0 -bipyridine ligands. Within the chain, each Mn II ion is six-coordinated by an N 6 unit and is involved in a slightly distorted octahedral coordination geometry. Investigation of the magnetic properties of 1 reveals an antiferromagnetic coupling between the cyanide-bridged Fe III and Mn II ions. A best fit of the magnetic susceptibility based on the one-dimensional alternating chain model leads to the magnetic coupling constants J 1 = À1.35 and J 2 = À1.05 cm À1 , and the antiferromagnetic coupling was further confirmed by spin Hamiltonian-based density functional theoretical (DFT) calculations.

Exchange Coupling in Binuclear Manganese and Cobalt Complexes with the Tetraimido Sulfate Anion [S(NtBu)4]2–

“…Indeed, it is directly correlated with the spin ground state of SMMs. − The nature and strength of coupling between paramagnetic metal centers have been investigated for various ranges of bridging ligands with predictable chelating modes, mainly with μ-bridging nitrogen or oxygen atoms. Recent examples display cyanate bridging between Mn II and Fe III or W V as well as oxo bridges between Mn III and Dy III and Mn II and Bi III . Heterobimetallic ligand-induced synergies are not limited to manganese but are also triggered by, e.g., Co II , Ni II , and Fe II .…”