Syntheses, structures, and magnetic properties of three new cyano-bridged complexes based on the [Mn(CN)6]3− building block†
Abstract
With three pentadentate macrocyclic ligands, three new [Mn(CN)6]3− based complexes, [Mn(LN3O2)(H2O)]2[Mn(CN)6](ClO4)·3H2O (1), {[Mn(LN5)]3[Mn(CN)6]2}n (2) and {[Mn(LN5Me)]3[Mn(CN)6]2}n·10nH2O (3) (LN3O2 = 2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene, LN5 = 2,13-dimethyl-3,6,9,12,18-pentaazabicyclo-[12.3.1]octadeca-1(18),2,12,14,16-pentaene, LN5Me = 2,6-bis[1-(2-(N-methylamino)ethylimino)ethyl]-pyridine), have been synthesized and characterized structurally and magnetically. The structure of 1 was found to be a linear MnII2MnIII trinuclear cluster with two MnII capping groups and one MnIII ion connected via two trans-cyano groups. In contrast, compounds 2 and 3 are cyano-bridged 2D networks. Magnetic investigation revealed antiferromagnetic coupling between the MnIII and MnII ions via the bridging cyanide groups. Complex 1 showed paramagnetic behavior down to 2.0 K with no sign of SMM behavior. The magnetic coupling constant of J = −1.63 cm−1 with the Hamiltonian H = −2J(SMn(III)·SMn(II)1 + SMn(III)·SMn(II)2) was obtained from the fitting of the magnetic susceptibility. For 2 and 3, ferrimagnetic ordering was observed with magnetic phase transition temperatures (Tc) being 7.5 K and 7.0 K, respectively. These compounds are rare examples of a small number of [Mn(CN)6]3− based magnetic materials.
- This article is part of the themed collection: New Talent: Asia-Pacific