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A new iron(III)/vanadium(III) phosphate, K3[Fe3.26V0.74(OH)O(PO4)4(H2O)2]·2H2O (1), has been obtained by hydrothermal synthesis and characterized by single crystal X-ray diffraction, Scanning electron microscopy–energy dispersive X-ray spectroscopy, Inductively coupled plasma atomic emission spectroscopy (ICP), thermogravimetric analysis, and FTIR spectroscopy. Single crystal X-ray diffraction reveals a 3D open framework (monoclinic, space groupP21/n,a = 9.6391(7) Å,b = 9.8063(7) Å,c = 9.7268(7) Å,β = 100.71(1)°, andV = 903.38(11) Å3). This structure presents FeIIIand VIIIin a 4.4 : 1 M ratio with the metal ions in two different crystallographic sites. Both metallic centers have distorted octahedral environments, linked by PO4tetrahedra, forming channels along thea-axis. The asymmetric unit of K3[Fe3.26V0.74(OH)O(PO4)4(H2O)2]·2H2O presents a {M4(OH)O(PO4)4(H2O)2}3−anionic entity, charge balanced by three K+, which are located within the channels. It is also possible to distinguish M4O2units whose MIIIpolyhedra are linked by vertex and edges. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we present the synthesis and optical study of the binuclear zinc(II) macrocyclic complexes, derived from 4-methyl-2,6-diformylphenol and 1,2-diaminobenzene (H2L). Two zinc macrocyclic complexes with different anions were prepared and characterized: [Zn2LCl2]·H2O (1) and [Zn2L](NO3)2 (2). The complexes are emissive, both in the solid state and in solution at room temperature. Spectroscopic properties of the macrocyclic complexes were investigated using stationary and time resolved methods in solutions of dimethylsulfoxide (DMSO), and in solid state. DMSO solutions show two emission bands centered at 480 and 521nm for complex (1), and at 527nm with a shoulder at 480nm for (2). The emission spectra of these compounds in solid state show a red shifted band, presenting the maxima at 565nm for (1) and 575nm for (2). The emission lifetimes for these compounds are very short, viz. 650 and 480ps for macrocycles (1) and (2), respectively. [Copyright &y& Elsevier]

Abstract: Two organo-inorganic hybrid manganese(II) vanadates [Mn(phen)2(VO3)2]∞ (1) and [{Mn(bipy)(VO3)2}{VO2(bipy)}(VO3)(V2O6)]∞ (2) were synthesized hydrothermally. Compound 1 is a chain consisting in VO3 units propagating along the b axis, decorated with {Mn(phen)2}+2 subunits. Compound 2 is a ladder like structure propagating along the a axis, consisting of two helical chains connected by the heterobinuclear {Mn(bipy)VO4 (2,2′-bipy)} moieties, generating a double helical structure. Magnetization measurements reveal that dominant antiferromagnetic interactions are mediated between the manganese(II) centers for both structures through oxovanadate bridges. Magnetic data of compound 1 were fitted with the analytical expression for a regular chain model, estimating a J value of −0.30cm−1. The DAVE code was use to fit experimental data and calculate the values of the super exchange constants for 2, assuming four different exchange pathways, J 12 =−0.17cm−1; J 23 =−0.12cm−1; J 13 =−0.08cm−1; J 24 =−0.05cm−1. DFT calculations on a tetranuclear fragment of 2, using diamagnetic substitutions, gave super exchange values of J 12 =−17.5cm−1 and J 23 =−8.5cm−1, corroborating the antiferromagnetic nature of the interactions as observed experimentally. [Copyright &y& Elsevier]

Abstract: The intercalation of the cationic binuclear macrocyclic complex [Zn2L]2+ (LH2: macrocyclic ligand obtained by the template condensation of 2-hydroxy-5-methyl-1,3-benzenedicarbaldehyde and 1,2-diaminobenzene) was achieved by a cationic exchange process, using K0.4Mn0.8PS3 as a precursor. Three intercalated materials were obtained and characterized: (Zn2L)0.05K0.3Mn0.8PS3 (1), (Zn2L)0.1K0.2Mn0.8PS3 (2) and (Zn2L)0.05K0.3Mn0.8PS3 (3), the latter phase being obtained by an assisted microwave radiation process. The magnetic data permit to estimate the Weiss temperature θ of ≈−130K for (1); ≈−155K for (2) and ≈−130K for (3). The spin canting present in the potassium precursor remains unperturbed in composite (3), and spontaneous magnetization is observed under 50K in both materials. However composites (1) and (2) do not present this spontaneous magnetization at low temperatures. The electronic properties of the intercalates do not appear to be significantly altered. The reflectance spectra of the intercalated phases (1), (2) and (3) show a gap value between 1.90 and 1.80eV, lower than the value observed for the K0.4Mn0.8PS3 precursor of 2.8eV. [Copyright &y& Elsevier]