Chemistry Journal of Moldova

DOI: dx.doi.org/10.19261/cjm.2006.01(1).03

Graphical Abstract: The magnetic susceptibility (χT) of an unusual dissymmetric binuclear manganese corboxylate complex has been measured from 2 to 300K. The magnetic data which have been fitted with help of the Heisenberg Dirac Van Vleck HDVV spin-exchange Hamiltonian H = − J S 1 S 2 , indicate that an antiferromagnetic interaction equal to J = -0.90(1) cm-1 is present. A correlation between J values and Mn-H2O-Mn angles has been tempted.


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DOI: dx.doi.org/10.19261/cjm.2006.01(1).04

Graphical Abstract: Reaction in methanol solution of the trinuclear ‘basic’ chromium(III) acetate with Pr(NO₃)₃⋅5H₂O and further extraction by chloroform-acetone mixture led to the formation of novel unusual [Cr₃O(CH₃COO)₆(H₂O)₃]NO₃⋅HNO₃⋅H₂O (1) cluster with one “free” molecule of nitric acid. Complex 1 crystallizes in the monoclinic space group P21/c with, at room temperature, a = 13.624(2), b = 15.032(2), c = 15.180(2) Å, β = 112.98(3) °, Z = 4, and V = 2862.09 Å3. The obtained crystalline compound has been synthesized and characterized by IR and UV/Vis methods.


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DOI: dx.doi.org/10.19261/cjm.2006.01(1).05

Graphical Abstract: Heterometallic complexes of chromium (III) with some 3d metals have been synthesized based on nitrilotriacetic acid (H₃nta), like M(bpy)₂Cr₂(OH)₂(nta)₂·nH₂O, where M = Mn²⁺, Co²⁺, Ni²⁺ and Zn²⁺; bpy = α,α′- bipyridine; n = 8 or 9. Their chemical composition has been determined from the results of the elemental analysis and thermogravimetric study. The coordination modes of the nta3 ̄ ligand and the type of chemical bonds have been proposed basing on IR spectra.


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DOI: dx.doi.org/10.19261/cjm.2006.01(1).09

Graphical Abstract: The novel bis(μ3-oxo) tetranuclear trichloracetate cluster, [Fe₄O₂(CCl₃COO)₈(THF)₂(DMF)(H₂O)]⋅THF (1), has been synthesised and subsequently characterised by X-ray structure analysis, magnetic measurements and infra red (IR). The structure of cluster is “butterfly” type. The Fe···Fe separation has the value of 2.883(1) - 3.441(7) Å. The coordination number of iron (III) is 6. Magnetic studies reveal the presence of an antiferromagnetic exchange in the parallelogram skeletons of the tetranuclear species. Using the spin Hamiltonian H = -2Jwb(Ŝ1Ŝ2 + Ŝ2Ŝ3 + Ŝ3Ŝ4 + Ŝ4Ŝ1) - 2JbbŜ2Ŝ4v+ gμβ(Ŝ1z + Ŝ2z +Ŝ3z + Ŝ4z)B, the fitting parameters Jbb = - 14.3 cm-1, Jwb = - 32.1 cm-1 , g = 2.07, ρparam. -5 impur. = 4.2 %, ΘCurie-Weiss const. = -0.5 K and R = 6.8·10 were obtained.

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DOI: dx.doi.org/10.19261/cjm.2006.01(1).11

Graphical Abstract: The complexes of general formula Cu(H₂L) (II); [CuLn(L)(NO₃)(H₂O)_n] (where H₄L=N,NI-bis[2- hydroxy(3-

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