New Approach for Designing Single-Chain Magnets: Organization of Chains via Hydrogen Bonding between Nucleobases

Two one-dimensional (1D) manganese complexes, [Mn2(naphtmen)2(L)]­(ClO4)·2Et2O·2MeOH·H2O (1) and [Mn2(naphtmen)2(HL)]­(ClO4)2·MeOH (2), were synthesized by using a bridging ligand with a nucleobase moiety, 6-amino-9-β-carboxyethylpurine, and a salen-type manganese­(III) dinuclear complex, [Mn2(naphtmen)2(H2O)2]­(ClO4)2 (naphtmen2– = N,N′-(1,1,2,2-tetramethylethylene)­bis­(naphthylideneiminato) dianion). In 1 and 2, the carboxylate-bridged MnIII dinuclear units are alternately linked by two kinds of weak Mn···O interactions into 1D chains. As a result, canted antiferromagnetic and ferromagnetic interactions are alternately present along the chains, leading to a 1D chain with non-cancellation of anisotropic spins. Since the chains connected via H-bonds between nucleobase moieties are magnetically isolated, both 1 and 2 act as single-chain magnets (SCMs). More importantly, this result shows the smaller canting angles hinder long-range ordering in favor of SCM dynamics.