A new end-on azido bridged Mn < sup > III < /sup > single-chain magnet and its dimeric single molecule magnet polymorph. Synthesis, structure and magnetic properties of [Mn(5-Clsalpn)N < inf > 3 < /inf > ] < inf > n < /inf > and phenoxo bridged [Mn(5-Clsalpn)N < inf > 3 < /inf > ] < inf > 2 < /inf >

Abstract

An end-on azido bridged MnIII coordination chain polymer [Mn(5-Clsalpn)N3]n (complex 1) and its dimeric polymorph, [Mn(5-Clsalpn)N3]2 (complex 2), where 5-Clsalpn is N,N′-bis(5-chlorosalicylidene)-1,3-diaminopropane, were prepared. Complex 1, which is obtained as two concomitant polymorphs (1a and 1b) with nearly identical molecular structures but different crystal packing, has μ-1,1(end-on) azido bridges. This single atom bridge is unsymmetrical and leads to a -1 cm-1 antiferromagnetic interaction among Mn III centers of the one-dimensional coordination polymer. Mn III anisotropy is manifested through Jahn-Teller elongation along the N(azido)-Mn-N(azido) axis, and results in single-chain magnet behavior. The phenoxo-bridged dimer (complex 2) has terminal azido ligands and a ferromagnetic interaction is mediated by the unsymmetrical bis-phenoxo bridge. Mn III anisotropy is manifested through Jahn-Teller elongation along an N-Mn-O axis, and results in single molecule magnet behavior. The dimers are organized into a two-dimensional network structure via Cl⋯Cl and Cl⋯H-phenyl interactions which are also ferromagnetic. © 2013 The Royal Society of Chemistry.