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

Two one-dimensional (1D) manganese complexes, [Mn-2(naphtmen)(2)(L)](ClO4)center dot 2Et(2)O center dot 2MeOH center dot H2O (1) and [Mn-2(naphtmen)(2)(HL)](ClO4)(2)center dot MeOH (2), were synthesized by using a bridging ligand with a nucleobase moiety, 6-amino-9-beta-carboxyethylpurine, and a salen-type manganese(III) dinuclear complex, [Mn-2(naphtmen)(2)(H2O)(2)](ClO4)(2) (naphtmen(2-) = N,N'-(1,1,2,2-tetramethylethylene)bis(naphthylideneiminato) dianion). In 1 and 2, the carboxylate-bridged Mn-III dinudear units are alternately linked by two kinds of weak Mn center dot center dot center dot 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.