One-Dimensional Coordination Polymers from Hexanuclear Manganese Carboxylate Clusters Featuring a {Mn^II₄Mn^III₂(μ₄-O)₂} Core and Spacer Linkers

The bridging of hexanuclear mixed-valent carboxylate coordination clusters of the type [Mn6O2(O2CR)10] (R = CMe3; CHMe2) featuring a {MnII4MnIII2(μ4-O)2} core by geometrically rigid as well as flexible spacer ligands such as pyrazine (pyz), nicotinamide (na), or 1,2-bis(4-pyridyl)ethane (bpe) results exclusively in one-dimensional (1D) coordination polymers. The formation of {[Mn6O2(O2CCMe3)10(Me3CCO2H)(EtOH)(na)]·EtOH·H2O}n (1), {[Mn6O2(O2CCHMe2)10(pyz)3]·H2O}n (2), and {[Mn6O2(O2CCHMe2)10(Me2CHCO2H)(EtOH)(bpe)]·Me2CHCO2H}n (3) illustrates a surprising preference of the interlinked {Mn6} units toward 1D coordination chains. In the solid-state, the observed chain propagation axes are either colinear (1 and 3) or perpendicular (2), whereby crystal packing is further influenced by solvent molecules. Magnetic properties of these network compounds can be rationalized based on that the magnetism of discrete [Mn6O2(O2CR)10]-type coordination clusters with all-antiferromagnetic intramolecular exchange and weak antiferromagnetic intercluster coupling in 1, 2, and 3 follows the expected exchange coupling strength of the employed spacer linkers.