A Quasi-Liner {MnIIDyIIIMnII} Cluster Featuring In Situ Schiff Base Ligand Transformation

Abstract

Employing tripodal Schiff base ligand of tris[4-(2-hydroxy-3-methoxyphenyl)-3-aza-3-butenyl]amine (H3L1) and auxiliary ligand of 2-hydroxy-5-chlorobenzaldehyde, a 3d–4f cluster of $$\left[ {{\text{Dy}}^{{{\text{III}}}} {{{\text{Mn}}}}_{ 2}^{{{\text{II}}}} \left( {{{\text{L}}}^{ 2} } \right)_{ 2} } \right]\left[ {{{\text{NO}}}_{ 3} } \right] \cdot 5 {{{\text{CH}}}}_{ 3} {{{\text{OH}}}}$$ (1) was synthesized. Intriguingly, the H3L1 ligand has transformed into another Schiff base ligand of {N-[4-(2-hydroxy-5-chlorophenyl)-3-aza-3-butenyl]-N′,N′′-bis[4-(2-hydroxy-3-methoxyphenyl)-3-aza-3-butenyl]}amine (H3L2) in situ during the coordination process, that one of terminal groups of H3L1 ligand was substituted. A pair of such (L2)3− ligands chelate a DyIII and two MnII ions to form a quasi-liner {MnIIDyIIIMnII} skeleton of 1, in which the adjacent MnII and DyIII ions were bridged by three Ophenol. To the best of our knowledge, this in situ substitution of the terminal group of Schiff base ligand has not been reported in previous literature. DC magnetic susceptibility measurements were conducted on 1, revealing the weak antiferromagnetic interactions between the DyIII and MnII centers. A quasi-liner a {MnIIDyIIIMnII} cluster has been constructed from tripodal Schiff base ligand of H3L1. The H3L1 ligands underwent an in situ substitution in the coordination, which has been not reported in previous literature so far as we known. Magnetic studies reveal the weak antiferromagnetic interactions between DyIII and MnII ions.