Tetradecanuclear polycarbonatolanthanoid clusters: diverse coordination modes of carbonate providing access to novel core geometries

The synthesis of two high nuclearity lanthanoid clusters demonstrates the versatility of the carbonate anion as a robust cluster forming agent, potentially allowing for the formation of otherwise inaccessible core topologies. The complexes, [Gd-14(CO3)(13)(ccnm)(9)(OH)(H2O)(6)(phen)(13)(NO3)]-(CO3)(2.5)center dot(phen)(0.5) (1) and [Dy-14(CO3)(13)(ccnm)(10)(OH)(H2O)(6)-(phen)(13)](CO3)(2.5)center dot(phen)(0.5) (2) (ccnm = carbamoylcyano-nitrosomethanide, phen = 1,10-phenanthroline), contain a [Ln(14)(CO3)(13)(OH)] core in which the carbonate anions display four unique coordination modes. The complexes are chiral, and the ccnm ligands also display four unique coordination modes. Extensive intra- and intermolecular pi-pi stacking between phen ligands leads to the formation of 1D chains in the crystal structure. Both complexes display magnetic properties that are indicative of antiferromagnetic coupling, with complex 2 displaying behaviour consistent with possible single molecule magnet properties.