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Reactions of 1,10-phenanthroline-2,9-dicarboxylic acid (H2phenda) with MnCl2·4H2O or MCl2·6H2O (M = Co, Ni) under solvothermal conditions yielded three octahedral clusters, (H3O)[MnII6(μ6-Cl)(phenda)6]·8MeOH (1·8MeOH), (H3O)[MII6(μ6-Cl)(phenda)6]·6H2O (M = Co, 2·6H2O; M = Ni, 3·6H2O). In the title compounds, the six metal centers are bridged by a μ6-Cl− and surrounded by six H2phenda ligands, forming an octahedral cluster. Magnetic studies show that the antiferromagnetic interactions are present in 1·8MeOH, 2·6H2O and 3·6H2O. Moreover, 3·6H2O clearly shows a nonzero out-of-phase χ″ signal with a peak at ca. 11 K, accompanied by a broad one for χ′.

Solvothermal reactions of 1,10-phenanthroline-2,9-dicarbaldehyde dioxime (H(2)phendox) with FeCl(3)·6H(2)O or FeBr(3) under solvothermal conditions yielded two trinuclear iron(III) clusters [Fe(III)(3)(mu(3)-O)(phendox)(3)]X·14H(2)O (X = Cl 1·14H(2)O, Br 2·14H(2)O) and three hexanuclear iron(III) and iron(II) clusters, [Fe(III)(6)(mu(4)-O)(2)(MeO)(6)X(4)(phendox)(2)]·MeOH (X = Cl , Br 4) and (H(3)O)[Fe(II)(6)(mu(6)-Cl)(phenda)(6)]·6H(2)O (5·6H(2)O). The phendox(2-) ligand is very useful in constructing magnetically active and stable high-nuclearity metal clusters in that the phenanthroline rings and the oxime nitrogen atoms grasp the metal ions tightly while the two oxygen atoms on the oximates can link other metal centres in the shortest pairwise magnetic exchange pathway. Adjacent Fe(3)(mu(3)-O)(phendox)(3)(+) motifs in 1 and 2 are packed by off-set pi-pi interactions of the aromatic rings on phendox(2-) to generate a 3D supramolecular architecture in the honeycomb topology and with 1D hexagonal channels in the dimension of 13 x 13 Å along the c-axis. 2 is stable upon the removal of guest molecules and the desolvated compound absorbed considerable amount of N(2), CO(2) and H(2). 3 and 4 are isostructural. Two mu(4)-O(2-) and two phendox(2-) units link four metal atoms into a coplanar butterfly-shaped unit with the mu(4)-O(2-) slightly above and below the plane (+/-0.264 Å). The other two Fe(III) ions are capped on the alternate planes via the three bridging mu(2)-methoxides and accordingly form an unprecedented hexanuclear Fe(III) cluster. Furthermore, the oximes underwent hydrolysis to yield carboxylate groups and the resulted 1,10-phenanthroline-2,9-dicarboxylate link the iron atoms to form a hexanuclear cluster of 5. Magnetic studies show that the antiferromagnetic interactions are present in the Fe(3)O core of 2 and in the (mu(6)-Cl)Fe(6)(mu-O)(12) core of 5.

Two unique dysprosium(III) coordination compounds with similar dodecanuclear clusters composed of four vertex-sharing cubane-like units, [2Cl− ⊂ {Dy12(OH)16(phenda)8(H2O)8}]2+, were reported. Magnetic studies reveal that both compounds exhibit slow magnetic relaxation.

In the title mononuclear complex, [Cu(C8H7O2)Cl(C12H8N2)(H2O)], the CuII atom is coordinated by one carboxylate O atom from a monodentate 4-methyl­benzoate ligand, two N atoms from the 1,10-phenanthroline ligand, one chloride ion and one water mol­ecule in a square-pyramidal geometry. The crystal structure exhibits inter- and intra­molecular C—H⋯Cl, C—H⋯O, O—H⋯Cl and O—H⋯O hydrogen bonds, as well as C—H⋯π inter­actions of phenanthroline and methyl H atoms towards the π-systems of neighboring 4-methyl­benzoate units and the pyridine rings of the phenanthroline system [centroid–centroid distances are 2.706 (2) and 2.992 (1) A, respectively].