One-Dimensional Manganese Coordination Polymers Composed of Polynuclear Cluster Blocks and Polypyridyl Linkers: Structures and Properties

The synthesis, crystal structures and magnetic properties of five new manganese compounds are reported. These include a linear trinuclear cluster [Mn(II)3(O2CCHMe2)6(dpa)2]·2MeCN (1) (dpa = 2,2′-dipyridylamine), a tetranuclear cluster [Mn(II)2Mn(III)2O2(O2CCMe3)6(bpy)2] (3) (bpy = 2,2′-bipyridine), and chain coordination polymers composed of cluster blocks such as Mn3, Mn3O, and Mn4O2 bridged by 2,2′-bipyrimidine (bpm) or hexamethylentetramine (hmta) ligands to give ([Mn(II)3(O2CCHMe2)6(bpm)]·2EtOH) n (2), [Mn(II)2Mn(III)2O2(O2CCHMe2)6(bpm)(EtOH)4] n (4), and (([Mn(II)Mn(III)2O(O2CCHMe2)6(hmta)2]·EtOH) n (5). The magnetic analysis of the compounds was achieved using a combination of vector coupling and full-matrix diagonalization methods. Susceptibility data for compound 1 was fitted using a vector coupling model to give g = 2.02(1) and 2J/k B = −5.38(2) K. To model the trimer chain, we used vector coupling for initial values of J 1 and then diagonalization techniques to estimate J 2 to give g = 1.98(1), 2J 1/k B = −3.3(1) K and 2J 2/k B = −1.0(1) K by approximating the system to a dimer of trimers. The analysis of 3 was made difficult by the mixture of polymorphs and the difficulties of a three-J model, while for 4 an analysis was not possible because of the size of the computation and the relative magnitudes of the three couplings. Compound 5 was modeled using the same techniques as 2 to give g = 1.99(1), 2J 1/k B = +32.5(2) K, 2J 2/k B = −16.8(1) K, and 2J 3/k B = +0.4(1) K. The combination of techniques has worked well for compounds 2 and 5 and thus opens up a method of modeling complex chains.