Substituting group induced structural transformation from 1D zigzag chain to 2D grid network in cyano-bridged dimetallic complexes derived from MnIII(Schiff-base) and [CrI(CN)5NO]3−: Synthesis, crystal structure and magnetic properties

Two cyano-bridged dimetallic complexes derived from MnIII(Schiff-base) and [CrI(CN)5NO]3−, [Mn(3-CH3)salen]3[Cr(CN)5NO]·2.5H2O (1) and [Mn(5-CH3)salen]6[Cr(CN)5NO]2·2CH3OH·16H2O (2) [salen = N,N′-ethylenebis (salicylideneiminato)dianion] were synthesized and characterized. The reaction conditions of the two complexes are identical. The substituting group (CH3–) in the salen-type ligands gives different assembly styles for the two complexes, 1D zigzag chain for 1 while 2D grid network for 2. The magnetic investigation indicates the dominant antiferromagnetic interactions between the Mn(III) and Cr(I) mediated by the CN bridge. Due to the weak interchain antiferromagnetic interactions, no magnetic ordering phase was observed in complex 1. Interestingly, complex 2 showed the long range ferrimagnetic magnetic ordering with Tc = 9 K, in contrast to 1. Furthermore, the hysteresis loop confirms the nature of complex 2 as soft ferrimagnet.

Graphical abstractTwo cyano-bridged dimetallic complexes derived from MnIII(Schiff-base) and [CrI(CN)5NO]3−, [Mn(3-CH3)salen]3[Cr(CN)5NO]·2.5H2O (1), [Mn(5-CH3)Salen]6[Cr(CN)5NO]2·2CH3OH·16H2O (2) (salen = N,N′-ethylenebis(salicylideneiminato)dianion) are synthesized and characterized. Structural analysis indicates 1D zigzag chain for 1 while 2D grid network for 2. Magnetic investigation reveals that 1 behaves as a simple magnetic chain, while 2 is a ferrimagnet below 9 K.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Proving the importance of substituting group effect in the design of molecular magnets. ► Interesting 1D zigzag chain and 2D grid network. ► The long range ferrimagnetic ordering is observed.