- High-spin ribbons and antiferromagnetic ordering of a Mn II-biradical-MnII complex
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A binuclear metal coordination complex of the first thiazyl-based biradical ligand 1 is reported (1 = 4,6-bis(1,2,3,5-dithiadiazolyl)pyrimidine; hfac =1,1,1,5,5,5,-hexafluoroacetylacetonato-). The Mn(hfac)2-biradical- Mn(hfac)2 complex 2 is a rare example of a discrete, molecular species employing a neutral bridging biradical ligand. It is soluble in common organic solvents and can be easily sublimed as a crystalline solid. Complex 2 has a spin ground state of ST = 4 resulting from antiferromagnetic coupling between the Sbirad = 1 biradical bridging ligand and two SMn = 5/2 MnII ions. Electrostatic contacts between atoms with large spin density promote a ferromagnetic arrangement of the moments of neighboring complexes in ribbon-like arrays. Weak antiferromagnetic coupling between these high-spin ribbons stabilizes an ordered antiferromagnetic ground state below 4.5 K. This is an unusual example of magnetic ordering in a molecular metal-radical complex, wherein the electrostatic contacts that direct the crystal packing are also responsible for providing an efficient exchange coupling pathway between molecules.
- Fatila, Elisabeth M.,Clerac, Rodolphe,Rouzieres, Mathieu,Soldatov, Dmitriy V.,Jennings, Michael,Preuss, Kathryn E.
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- Unexpected Ni(ii) and Cu(ii) polynuclear assemblies - A balance between ligand and metal ion coordination preferences
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Polytopic ligand design involves matching the coordination pocket composition with the metal ion coordination 'algorithm', but despite targeting [4 × 4] grids as the final outcome, metal ion preferences and ligand control can lead to widely varying complexes in the self-assembly process with Ni(ii) and Cu(ii).
- Shuvaev, Kontantin V.,Tandon, Santokh S.,Dawe, Louise N.,Thompson, Laurence K.
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