Hydrogen-Bonded Dicubane Co7II Single-Molecule-Magnet Coordinated by in Situ Solvothermally Generated 1,2-Bis(8-hydroxyquinolin-2-yl)-ethane-1,2-diol Arranged in a Trefoil

A novel sigle vertex-shared dicubane-based cobalt(II) compound, [Co-7(II)(bhqe)(3)(OH)(2)(H2O)]center dot 2C(2)H(5)OH center dot H2O (1), was obtained through the solvothermal generation for 1,2-bis(8-hydroxyguinolin-2-yl)ethane-1,2-diol, H(4)bhqe, from 2-(hydroxymethyl)quinolin-8-ol, H(2)hmq, by in situ C-C coupling reaction in ethanol containing Co(NO3)(2)center dot 6H(2)O and triethylamine. The crystal structure consists of dicubane Co-7 cores with six ligands wrapped around it in a trefoil through strong intramolecular pi-pi interactions and features an unusual one-dimensional hydrogen-bonded (OHwater center dot center dot center dot O-bhqe) supramolecular organization (along the c-axis). The key factor of the cluster is that every pair of coblat atoms are bridged by a single oxygen atoms making an average angle of approximately 95 degrees and is expected theoretically and experimentally to generate ferromagnetic coupling. The temperature dependence magnetization exhibits a blocking temperature at approximately 3 K which is confirmed by observation of large frequency dependence of the ac-susceptibilities in zero dc-field, and detailed analysis of the dynamics properties allows an unambiguous demonstration of the single-molecule magnet (SMM) behavior in 1, though some interesting complexities in the slow magnetization relaxation processes may be influenced by the crystal system, the large anisotrophy of cobalt(II) and the supramolecular interactions.