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One new hexanuclear Cu(II) complex [Cu 4 (L 1 ) 4 Na 2 (ClO 4 )(H 2 O)](ClO 4 )(H 2 O) 0.5 ( 1 ) and two new tetranuclear Ni(II) complexes [Ni 4 (L 2 ) 4 (CH 3 OH) 4 ] ( 2 ), [Ni 4 (o-vanillinate) 4 (μ 3 -N 3 ) 4 (CH 3 OH) 4 ] ( 3 ) have been synthesized and structurally characterized. All the three complexes 1 , 2 , and 3 have been characterized by elemental analysis, FTIR, and single crystal X-ray diffraction studies. Single crystal X-ray diffraction studies reveal that all three complexes consist of a cubane core in which the four Cu(II)/Ni(II) centers in 1 and 2 are linked by μ 3 -alkoxo bridges and Ni(II) ions in 3 are linked by azido bridge in end-on fashion. The skeleton structures of the cubane cores are all distorted from the idealized cube and most show a further distortion. The variable-temperature (2–300 K) magnetic susceptibilities and magnetizations of the three compounds were measured. Variable-temperature magnetic susceptibility data exhibit dominant antiferromagnetic interaction in complex 1 while ferromagnetic interactions in complexes 2 and 3 . [ABSTRACT FROM AUTHOR]

Two dinuclear iron(III) compounds, [Fe2(HL1)2(L1)2] · MeOH (1) and [Fe2(μ- )3] (2) [L1 = N-(2-hydroxypropyl)(3-methoxysalicylaldimine) and  = 1,2-bis(2-hydroxybenzylidene) hydrazine], have been synthesized and characterized. Structural analysis of 1 shows that the six-coordinate Fe(III)'s are linked by two alkoxo oxygen atoms from two Schiff-base ligands to form a rectangular arrangement of metal ions and oxygen atoms. The distance of these two Fe(III) ions is 3.2122(8) Å. In 2, three Schiff-base ligands coordinate two Fe(III) ions in a tetradentate mode; each iron is six coordinate with octahedral geometry. The Fe–Fe distance is 3.9304(10) Å. Magnetic susceptibility (2–300 K) indicates an antiferromagnetic interaction between the two oxygen-bridged Fe(III) ions with J = −13.6 cm−1 for 1. [ABSTRACT FROM PUBLISHER]

Abstract: Three new zinc(II) complexes Zn(L1)2 (1), Zn2L2(OAc)3 (2) and Zn2L3(OAc)3 (3) have been synthesized by using Zn(OAc)2·2H2O and potentially multidentate Schiff base ligands HL1 (2-((1-hydroxybutan-2-ylimino)methyl)-6-methoxyphenol), HL2 (2-((1-hydroxy-2-methyl-propan-2-ylimino)methyl)-6-methoxyphenol) and HL3 (2-((2-hydroxypropylimino)-methyl)-6-methoxyphenol), respectively. These Schiff base ligands are the condensation product of o-vanillin and corresponding amino alcohols. All the three complexes 1, 2 and 3 have been characterized by elemental analysis, IR, single crystal X-ray diffraction and fluorescence studies. Structural studies reveal that 1 is a mononuclear complex whereas in dinuclear complexes 2 and 3 the two Zn(II) centers are held together by deprotonated Schiff base ligands and acetates. All the synthesized complexes display intraligand (π→π*) fluorescence and can potentially serve as photoactive materials. [Copyright &y& Elsevier]

Four new polynuclear clusters [NaMnIII3MnII(HL)3(μ4-O)(μ1,1-N3)3]ClO4·CH3CH2OH·(H2O)3 (1), [NaMnIII3MnII(HL)3(μ4-O)(μ1,1-N3)2(μ1,3-N3)]ClO4·CH3CH2OH·H2O (2), [NaMnIII3MnII(HL)3(μ4-O)(HCOO)3]ClO4·(H2O)4 (3) and [NaMnIII3MnII(HL)3(μ4-O)(PhCOO)(H2O)2](ClO4)2·H2O·PhCOO·PhCOOH·CH3OH (4) have been obtained via self-assembly between 3-((2-hydroxy-3-methoxybenzylidene)amino)propane-1,2-diol (H3L: condensed from o-vanillin and 3-amino-1,2-propanediol) and the auxiliary bridges (N3−, HCOO−, PhCOO−, H2O) with Mn(ClO4)2·6H2O in the air-exposed methanol solution. The structures of 1–4 all contain [NaMnIII3MnII] units and show a very similar trigonal propeller-like shape. The valences of the metal ions were determined by detection of the Jahn–Teller distortion visible for MnII,III, and confirmed by bond-valence sum (BVS) calculations. Three MnIII ions and one MnII ion take the shape of a super-tetrahedron with the MnII ion lying above the triangular [Mn3O] plane constructed from three MnIII ions linked by a central μ4-O atom. The NaI ion which lies below the [Mn3O] plane is linked with MnIII ions through the oxygen atoms from Schiff base ligands. The main structural difference in the four clusters is caused by the different bridging modes among MnIII ions. A structural comparison of 1–4 demonstrates that the auxiliary ligands play a key role in governing the coordination motifs. Moreover, the magnetic properties of these clusters exhibit dominating antiferromagnetic exchange interaction between spin carriers of MnII,III. [ABSTRACT FROM AUTHOR]

Three new phenolate oxygen bridged transition metal complexes [Zn3(HL1)3(μ3-CH3O)]·(ClO4)2(H2O)3 ( 1), [Ni2(HL1)2(μ1,1-N3)(o-vanillin)]·H2O ( 2), [Ni3(HL2)2(PhCOO)2(PhCOOH)2(EtOH)2] ( 3) have been synthesized by metal ions and potentially multidentate Schiff base ligands (H2L1 = 2-((1-hydroxy-2-methylpropan-2-ylimino) methyl)-6-methoxyphenol; H3L2 = ( E)-1-((2-hydroxy-3-methoxy-benzylidene)amino)ethane-1,2-diol). All the three complexes 1, 2, and 3 have been characterized by elemental analysis, FT-IR spectroscopy, and single-crystal X-ray diffraction studies. Crystal structures reveal that complex 1 is a trinuclear incomplete cubane-like zinc cluster whereas complex 2 is a dinuclear nickel complex bridged by azide, and compound 3 is a trinuclear nickel complex. The luminescent property for complex 1 and magnetic behaviors for complexes 2 and 3 have been investigated. [ABSTRACT FROM AUTHOR]