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Two novel Co(II) and Ni(II) complexes Co(dpza)2 (1) and Ni(dpza)2 (2) (Hdpza is 2,2-di(1H-pyrazol-1-yl)acetic acid) were successfully synthesized via solvothermal method. The two complexes namely, 1 and 2 are isostructural exhibiting lantern-shaped configurations as illustrated by the structural analysis. The structures of the two complexes have been determined by single-crystal X-ray diffraction, FT-IR, and TGA. Magnetic property of 1 in the 2–300 K also has been investigated which displays dominant ferromagnetic behavior. Hirshfeld surface analysis reveals that the main interactions for complex two are O···H/H···O and H···H contacts. [ABSTRACT FROM AUTHOR]

A hollow cage-like Au12C68 structure with Th symmetry was investigated based on first-principles density functional theory calculation. This structure is seamed together of 12 AuC13 subunits, and there are three pentagons and one hexagon in each AuC13 subunits. The 12 gold atoms form an icosahedral configuration with Th symmetry. Subsequently, the stability of Au12C68 cage has been verified by vibrational frequency analysis and ab initio molecular dynamics simulations. Electronic structure analysis shows that clearly sp–d hybridizations between Au atoms and C atoms are of great importance for the stability of Au12C68 cage. Moreover, the Au12C68 molecule is magnetic with spin magnetic moment of 3.97 µB. This hollow Au12C68 cage with magnetic properties may lead to important applications in single-molecule devices. [ABSTRACT FROM AUTHOR]

The reaction of Cu(Ac)2·4H2O with 2-[(3,5-dichloro-2-hydroxy-benzylidene)-amino]-2hydroxymethyl-propane-1,3-diol (H4L) and 4,4′-bipyridyl-N,N′-dioxide (4,4′-bipy-NO) in DMF under solvothermal conditions leads to the formation of a di-radical dinuclear copper complex [Cu2(4,4′-bipy-NO)(dcdmap)4] (1) (dcdmap is the anion of 2,4-dichloro-6dimethylaminomethyl-phenol, synthesized by anin situreaction). Compound1was characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Complex1displays dominant anti-ferromagnetic interaction between oxyradicals and copper ion and oxyradical. [ABSTRACT FROM AUTHOR]

Abstract: Using the solvothermal method, we present the comparative preparation of [Ni(L 1)Cl(CH3CN)]4 (1), [Ni(L 2)Cl(C2H5OH)]4 (2) and [Ni(HL 3)2(CH3COO)2]·2DMF (3), where HL 1 is (1H-benzimidazol-2-yl)-methanol, HL 2 is (6-methyl-1H-benzoimidazol-2-yl)-methanol and HL 3 is 1-(1H-benzoimidazol-2-yl)-ethanol. All the compounds were characterized by elemental analysis, IR and X-ray single-crystal diffraction. Compounds 1 and 2 are tetranuclear clusters with a cubane topology, in which the metal ions and the oxygen atoms from the L ligands occupy alternate vertices of the cubane. However, compound 3 is a mononuclear nickel complex with the triclinic crystal system, space group, different from that of compounds 1 and 2. These results show that the position and space steric hindrance of the substituents groups are essential in determining the final structures of the assemblies. The magnetic properties of 1 and 2 in the 2–300K temperature range have also been discussed. The {Ni4O4} core displays dominant ferromagnetic interactions. [Copyright &y& Elsevier]

Abstract: Five tetranuclear complexes with the composition of [M4(L)4(μ 3-OMe)4(MeOH)4], (M=Ni (1) or Co (2), HL is 3,5-dichloro-2-hydroxy-benzaldehyde (Hdchb); M=Ni (3) or Co (4), HL is 2-hydroxy-3-methoxy-benzaldehyde (Hhmb); M=Ni (5), HL is 5-bromo-2-hydroxy-benzaldehyde (Hbhb)), were prepared by reaction of salt perchloride hexahydrate with 2-hydroxy-benzaldehyde ramification under solvothermal conditions. All compounds were characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. Compounds 1–5 have tetranuclear clusters with a cubane topology in which the metal ions and the oxygen atoms from the methanol ligands occupying the alternate vertices of the cubane. The {M4O4} cores display dominant ferromagnetic interactions from the nature of the binding modes through μ 3-OCH3 −. No single-molecule magnets (SMMs) behaviors have been observed in complexes 1–3 and 5. In contrast, compound 4 has been observed obviously slow relaxation for the S 4 site symmetry and exhibits the behavior of SMMs. The results further support that judicious choice of harmonious mixed ligands provides the means to create a rich variety of new isolated individual {M4O 4 } cubic system and allows a systematic magnetic study of the effect of intermolecular interactions and correlation. [Copyright &y& Elsevier]