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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′.

Three new eremophilane sesquiterpenes were isolated from the MeOH extract of the roots of Senecio nemorensis. Their structures were identified as 8α-hydroxy-6β-(isobutanoyloxy)-1-oxoeremophila-7(11),9-dieno-12,8β-lactone (1), 6β,8β-dimethoxy-1-oxoeremophila-7(11),9-dieno-12,8α-lactone (2), and 10α-hydroxy-6β-(isobutanoyloxy)-1-oxoeremophila-7(11),8-dieno-12,8-lactone (3), respectively, based on spectroscopic data, including IR, EI-MS, HR-ESI-MS, and 1D- and 2D-NMR data.

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.

In the title mononuclear complex, [Cu(C(8)H(7)O(2))Cl(C(12)H(8)N(2))(H(2)O)], the Cu(II) atom is coordinated by one carboxylate O atom from a monodentate 4-methyl-benzoate ligand, two N atoms from the 1,10-phenanthroline ligand, one chloride ion and one water mol-ecule in a square-pyramidal geometry. The crystal structure exhibits inter- and intra-molecular C-H⋯Cl, C-H⋯O, O-H⋯Cl and O-H⋯O hydrogen bonds, as well as C-H⋯π inter-actions of phenanthroline and methyl H atoms towards the π-systems of neighboring 4-methyl-benzoate units and the pyridine rings of the phenanthroline system [centroid-centroid distances are 2.706 (2) and 2.992 (1) Å, respectively].

850 0009-3130/11/4705-0850 2011 Springer Science+Business Media, Inc.1) Marine College, Shandong University at Weihai, Weihai 264209, P. R. China, fax: +86 631 5688303, e-mail:wdxie@sdu.edu.cn; 2) Department of Chemical Engineering, Inha University, Incheon 402-751, Korea, fax: +82 32 8720959,e-mail: rowkho@inha.ac.kr. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 742–743, September–October, 2011.Original article submitted June 19, 2010.

In the title complex, [Cu(C5H3N2O2)2(NH3)4], the CuII atom lies on a site of symmetry 2/m and has distorted elongated octa­hedral coordination geometry defined by four N atoms from ammonia mol­ecules and another two N atoms from two pyrazine-2-carboxyl­ate ligands. The crystal packing is governed by inter­molecular N—H⋯O and C—H⋯O hydrogen bonds.

In the title complex, [Mn(C5H3N3)2(H2O)2], the MnII atom, located on an inversion center, is coordinated by four N atoms from two 5-(2-pyrazin­yl)tetra­zolate ligands and two water mol­ecules in a distorted octa­hedral geometry. The packing is governed by inter­molecular O—H⋯N hydrogen bonds.

Two unique octa- and hendeca-nuclear dysprosium(III) clusters incorporating [Dy(4)(μ(3)-OH)(4)](8+) cubane units have been synthesized with the 1,10-phenanthroline-2,9-dicarbaldehyde dioxime (H(2)phendox) ligand and DyCl(3)·6H(2)O or Dy(OAc)(3)·4H(2)O. They are [Dy(8)(OH)(8)(phendox)(6)(H(2)O)(8)]Cl(2)(OH)(2)·18H(2)O·18MeOH (1) and [Dy(11)(OH)(11)(phendox)(6)(phenda)(3)(OAc)(3)](OH)·40H(2)O·7MeOH (2). Adjacent Dy(8) in 1 or Dy(11) in 2 motifs are packed by off-set π-π interactions of the aromatic rings on phendox(2-) to generate a 3D supramolecular architecture in the honeycomb topology and with 1D or 3D channels along the c-axis. Adsorption research shows that complex 1 has selective adsorption ability for H(2)O over small gas molecules (H(2), N(2), CO(2)). Complex 2 is stable upon the removal of guest molecules and the desolvated compound absorbed a considerable amount of CO(2). Furthermore, the oximes underwent hydrolysis to carboxylic acid and the resulting 1,10-phenanthroline-2,9-dicarboxylate link the dysprosium atoms to form a hendecanuclear cluster of 2. Magnetic studies reveal that both clusters exhibit slow magnetic relaxation behavior, expanding upon the recent reports of the pure 4f type single-molecule magnets (SMMs).

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.