Magneto–Structural Correlations in Discrete MnII‐WV Cyano‐Bridged Assemblies with Polyimine Ligands

Abstract

AbstractWe present the magneto–structural correlations for two novel discrete cyano‐bridged assemblies based on cationic complexes of manganese(II) with diimine ligands and octacyanotungstate(V) ions. The crystal structure of [MnII(terpy)(dmf)(H2O)2][MnII(terpy)(H2O)(dmf)(μ‐NC)WV(CN)7]2·6H2O (1) (terpy = 2,2′;6′,2″‐terpyridine, dmf = dimethylformamide) contains dinuclear {MnIIWV}– cyano‐bridged anions, while the crystal structure of [MnII(phen)3]2[MnII(phen)2(μ‐NC)2WV(CN)6]2(ClO4)2·9H2O (2) (phen = 1,10‐phenanthroline) is built of tetranuclear {MnII2WV2}2– square anions. Intramolecular Mn–W magnetic interactions through the cyano bridges are represented by magnetic coupling constants J = –39 cm–1 for the {MnIIWV}– unit in 1 and J1 = –25.7 and J2 = –16.7 cm–1 for the {MnII2WV2}2– unit in 2. J and J1 represent relatively strong W–CN–Mn interactions and are ascribed to the bridges in b positions of TPRS‐8 (trigonal prism square‐face bicapped) of [W(CN)8]3– polyhedra, favoring the strongest electronic interactions between the d–d orbital of W and the π* orbitals of CN–, whereas J2 is related to the m vertex of [W(CN)8]3–. The magnetic properties of 1 and 2 are compared with reference compounds and discussed in the context of the type of coordination polyhedra of [W(CN)8]3– as well as the metric parameters of cyano‐bridged W–CN–Mn linkages. We found the type of coordination polyhedra and bridging mode of [W(CN)8]3– to be the most important factors influencing the magnitude of the Mn–W magnetic interaction.