A novel dinuclear manganese(II) compound incorporating two bis(imidazolyl) based ligands with single μ_2-η~1:η~1-carboxylato bridges. Molecular and crystal structure and magnetic properties of [Mn_2Cl(BIP)(HBIMAM)(H_2O)_5]Cl_3?4H_2O (BIP = 3,3-di(2-1H-2-imidazolyl)propanoate; BIMAM = N-methyldi(1H-2-imidazolyl)methanamine)

摘要

This paper reports the synthesis, X-ray structure and magnetic characterization of [Mn_2Cl(BIP) (HBIMAM)(H_2- O)_5]Cl_3?4H_2Oa noveldinuclearmanganese(II) incorporating tworelatedbis(imidazolyl)-based ligands, BIP (3,3- di(2-1H-2-imidazolyl)propanoate)andBIMAM(N-methyldi(1H-2-imidazolyl)methanamine).Themetal atoms in the dinuclear entity are bridged by a μ_2-η~1:η~1 carboxylate group (from the propionate armof the BIP ligand) acting inananti-anti coordinationbridgingmode,withanintramolecularMn? ? ?Mndistanceof 6.47 ?.Thecoordination around theMn(II) ions shows a distorted octahedral geometry for bothMnClN_2O_3 andMnN_2O_4 chromophores. Between the imidazole rings of neighbouring dinuclear units there significant aromatic-aromatic interactions. The propagation of these interactions generates chains of p-stacked dinuclear units, roughly running along the [100] direction.Magnetic susceptibilitymeasurements in the range 2-300 Kshowweak antiferromagnetic exchange interactions which were analysed by means of the isotropic S_1 = S_2 = 5/2 spin-coupled dimermodel ? = -2J(?_1 ? ?_2). Finally, the observedmagnetic behavior (2J = -0.38(1) cm~(-1)) is comparedwith that observed in relatedmanganese(II) compounds with single [Mn(μ_2-η~1:η~1-carboxylato)Mn] core.