The Importance of Synthetic Conditions on Manganese-Based 12-Metallacrown-4 Formation

Abstract

Alterations to synthetic conditions either by varying stochiometric ratios of the reactants or solvent choice yield two new metallacrowns (MCs): Mn(Hsal)2[12-MCMnIII(N)shi-4](DMF)6·4DMF, 1, where −Hsal is salicylate, shi3− salicylhydroximate, and DMF is N,N-dimethylformamide, and {Na2(OAc)2[12-MCMnIII(N)shi-4](MeOH)4(H2O)22MeOH}n, 2, where −OAc is acetate and MeOH is methanol. Compound 1 crystallizes in the monoclinic space group C2/c with a = 19.0264 (6) A, b = 23.1440 (8) A, c = 18.6704 (5) A, α = 90°, β = 90.3600 (10)°, γ = 90°, V = 8221.3 (4) A3, and Z = 4. Compound 2 crystallizes in the triclinic space group P $$\stackrel{-}{1}$$ with a = 7.8995 (7) A, b = 11.2374 (10) A, c = 14.5559 (13) A, α = 112.535 (3)°, β = 91.987 (3)°, γ = 98.558 (3)°, V = 1174.22 (18) A3, and Z = 1. Compound 1 is a discrete metallacrown molecule that contains four ring MnIII ions and a MnII ion captured in the metallacrown central cavity. The MnII ion is tethered to the metallacrown via two salicylate bridges that also bridge to the ring MnIII ions. Compound 2 is a one-dimensional chain of metallacrowns. The metallacrown consists of four ring MnIII ions and two sodium ions which are bound on opposite faces of the metallacrown cavity. Each di-sodium metallacrown is then linked to neighboring metallacrowns through acetate anion bridges to form a one-dimensional chain. The complex Na2(OAc)2[12-MCMnIII(N)shi-4](MeOH)4(H2O)2·2MeOH forms a one-dimensional chain of metallacrowns by linking together neighboring metallacrowns through acetate anion bridges.