Homometallic {Mn10} and heterometallic {Mn6Ca4} supertetrahedra exhibiting an unprecedented {MnIII9MnII} oxidation state level and heterometal ions distribution

Abstract

Two novel decametallic clusters displaying a supertetrahedral structural core are discussed, a homometallic compound [MnIII9MnII(μ4-O)4(μ3-OMe)3(btH)3(ed)3(PhCO2)6]·6Η2Ο (1·6Η2Ο) (btH3 = (±)-1,2,4-butanetriol

edH2 = 1,2-ethanediol) and a heterometallic one [MnIII6CaII4(μ4-O)4(μ3-Cl)4(pd)6Cl2(MeOH)10] (2) (pdH2 = 1,3-propanediol). In particular complex 1·6Η2Ο is a new member of an extended family of homometallic Mn10 supertetrahedra which exhibits an unprecedented MnIII9MnII oxidation state level. It is based on a supertetrahedral [MnIII9MnII(μ4-O)4]21+ core with its peripheral ligation being completed by bridging alkoxy (OMe−, btH2−, ed2−) and carboxylate (PhCO2−) ligands. Complex 2 is a unique heterometallic analogue of the family of complexes displaying the well-known [MnIII6MnII4(μ4-O)4]18+ supertetrahedral core in which the MnII ions have been replaced by CaII ions. The peripheral ligation of the heterometallic [MnIII6CaII4(μ4-O)4]18+ core is completed by both bridging (μ3-Cl− and pd) and terminal (Cl−, MeOH) ligands. Magnetism studies revealed that complex 1·6Η2Ο displays dominant ferromagnetic exchange interactions and a large spin ground state value ST = 23/2 whereas complex 2 exhibits exclusively ferromagnetic exchange interactions and the maximum possible spin ground state ST = 12 for a complex consisting of six MnIII and four CaII ions.