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RESEARCH PRODUCT

Synthesis, Crystal Structure and Magnetic Properties of Three {Cr III Mn II } Heterodimetallic Complexes Based on Heteroleptic Cyanido‐Bearing Cr III Building Blocks

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The use of the heteroleptic [CrIII(AA)(CN)4]- complex as a ligand towards the preformed [MnII(tptz)]2+ and [MnII(pyim)2]2+ species afforded the heterometallic compounds: [MnII(tptz)(H2O)(NO3)(-NC)CrIII(ampy)(CN)3]CH3CN (1), [MnII(tptz)(H2O)(NO3)(-NC)CrIII(phen)(CN)3]H2O (2) and {[MnII(pyim)2][(-NC)Cr(phen)(CN)3]2}3H2O (3) [AA = 2-aminomethylpyridine (ampy) and 1,10-phenanthroline (phen), tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine and pyim = 2-(1H-imidazol-2-yl)pyridine]. 1 and 2 are neutral heterodinuclear complexes where a [CrIII(AA)(CN)4]- building block acts as a monodentate ligand through one cyanide group towards a seven coordinate MnII ion. Compound 3 is a neutral heterotrinuclear complex made up by two [CrIII(AA)(CN)4]- units acting as monodentate ligands through one cyanide group towards an inner [MnII(pyim)2]2+ entity, the MnII ion being six-coordinate. The magnetic properties of 1-3 were investigated in the temperature range 1.9-300 K. Overall AF behavior is observed for all three compounds, the antiparallel alignment of the local spins leading to either a ground spin triplet (1 and 2) or a spin doublet (3). The values of the magnetic coupling between the CrIII and MnII ions across the single cyanido bridges are J = -7.40(2) (1), -6.65(2) (2) and -6.41(2) and -4.65(2) cm-1 (3), the spin Hamiltonian being defined as H = -J(SCr1 SMn1) (1 and 2) and H = -J1(SCr1 SMn1) - J2(SCr2 SMn2) (3). These values could be correlated with the Mn-N-Ccyanide angle.