The synthesis and structures of four new copper(II) adamantoid clusters

Four new copper(II) compounds with an inorganic, adamantane-like core have been prepared and structurally characterized: [(2-aminopyridine)4(μ2-Br)6Cu4(μ4-O)].(2-aminopyridinium) bromide monohydrate (1), the open cage structure (2-aminopyridinium) [(2-aminopyridine)4(μ2-Cl)5(Cl)2Cu4(μ4-O)] (2), bis(2-amino-5-methylpyridinium) [(2-amino-5-methylpyridine)2(μ2-Cl)6(Cl)2Cu4(μ4-O)] (3) and the co-crystal [(2-amino-5-fluoropyridine)4(μ-Cl)6Cu4(μ4-O)]2 [(2-amino-5-fluoropyridine)4Cu2Cl4] (4). All four include additional components in the lattice ranging from a non-coordinated ancillary ligand (1) to a co-crystallization with a distinct coordination complex (4). The compounds crystallize as: 1, triclinic, P-1; 2, monoclinic, P21/c; 3, monoclinic, P21/c; 4, triclinic, P-1. Analysis of the geometric parameters within the adamantoid cores of the compounds indicates significant structural resilience as parameters are little changed by the presence of additional components in the lattice. Breaking of the central core by coordination of an additional chloride ion in 2 significantly affects the geometry about those two Cu(II) ions but has little effect on other parts of the core.