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Volume 50, Nº 7 (2024)
Articles
Dynamic Magnetic Susceptibility Method in Studies of Coordination Compounds
Resumo
The measurement of the dynamic magnetic susceptibility is a universal method, which is used for the evaluation of magnetic properties of single molecule magnets by scientists all over the world. An information in the Russian scientific literature that can be useful for practical mastering of this method is presently insufficient. To fill this gap, in this work we present a detailed procedure of a magnetochemical experiment for observing slow magnetic relaxation in coordination compounds of 3d- and 4f-element ions and the complete characterization of the dynamics of the magnetic behavior. Special attention is given to usually omitted but important details related to all stages of studying the magnetic relaxation dynamics. The main variants of sample preparation are described, the logics of the construction of a measuring sequence and the procedure of experimental data processing are discussed, and advantages and drawbacks of some programs of the calculation of magnetic relaxation dynamics data are considered. The main concepts and equations used in experimental data analysis are presented, and the primary conclusions that can be made from the obtained results are proposed.
413-428
Template Synthesis of the Iron(III) Complex with the Ligands Based on Acylpyrazolonepyridines
Resumo
The reaction of new bidentate ligand, 1-(5-hydroxy-1-methyl-3-(pyridin-2-yl)-1Н-pyrazol-4-yl)ethan-1-one (L), with iron(III) chloride affords the mononuclear iron(III) complex FeL₂Cl₃, which is characterized by XRD (CIF file CCDC no. 2309481). The intramolecular hydrogen bond between the protonated pyridyl and acetyl groups in ligand L, which exists in the crystal as a zwitterion, provides the formation of rarely met iron complexes in which the β-diketonate fragment coordinates via the η1 mode. A similar coordination mode along with a possibility of a more favorable η2 coordination provides new possibilities for the design of heteropolynuclear compounds of various structures used in the fabrication of molecular devices of data storage and processing.
429-437
Trinuclear Lutetium(III) Cyclopentadienyl Complex with the 2,2´-Bipyridine Dianion
Resumo
The reaction of lutetium cyclopentadienyl anthracenide complex (C5H5)Lu(C14H10)(THF)2] with 1 equiv. of 2,2´-bipyridine in THF gives the trinuclear complex [{(η5-C5H5)Lu}3(μ₂-Bipy)₃] (I), containing a 2,2´-bipyridine dianion. The complex was isolated as a powder with the composition I·0.1(C14H10)·0.8(C7H8). The recrystallization from a toluene/hexane mixture resulted in the crystals of I·0.084(C14H10)·0.831(C7H8)· · 0.500(C6H14), which were studied by X-ray diffraction (monoclinic group P21/c; CCDC no. 2311508). Complex I has an unusual μ2-κ2N1,N1´:η4N1,C2,C2´,N1´-bridging coordination of the dianion.
438-446
Coordination Compounds of Alkali and Rare Earth Metals Based on Centrosymmetric Chlorine-Substituted Bis-Mercaptooxazole. Synthesis, Structure, and Luminescence
Resumo
New coordination polymers were synthesized. A ditopic centrosymmetric organic ligand containing oxazole heterocycles, 4,8-dichlorobenzo[1,2d:4,5d´]bis(oxazole)-2,6(3H,7H)-dithione (H2L), was prepared and structurally characterized. It was shown that deprotonated H2L forms non-luminescent binuclear molecular complexes Li2L(THF)6 (I) and Na2L(DME)4 (II) with alkali metals, while complexes of H2L with lanthanides are ionic compounds [Ln(DMSO)8][L]1.5 (Ln = Nd (III), Yb (IV)) exhibiting moderate metalcentered emission in the near-infrared (IR) range, despite the absence of coordination of the ligand L to lanthanide ions. The molecular structures of H2L·2DMSO and I–III were established by X-ray diffraction (CCDC no. 2320461 (H2L·2DMSO), 2320462 (I), 2320463 (II), 2320464 (III)).
447-459
Nickel(II) and Copper(II) Dicyanoargentate Complexes with Ethylenediamine and 4,4´-Bipyridyl Ligands
Resumo
The reactions of an aqueous solution of potassium dicyanoargentate with a mixture of nickel(II) or copper(II) chloride and ethylenediamine or 4,4´-bipyridyl in ethanol afford coordination polymers [Ni(En)2(Ag(CN)2)][Ag(CN)2] (I), [Cu(En)2(Ag(CN)2)][Ag(CN)2] (II), and [Cu(4,4´-Bipy)2(Ag(CN)2)2] (III) characterized by XRD (CIF files CCDC nos. 2225984 (I), 2214320 (II), and 2229270 (III)) and IR spectroscopy. According to the XRD data, the crystals of complexes I and II are formed by 1D chains {··NC– Ag–CN–M(En)2··}n (M = Ni (I), Cu (II)) linked with each other by the dicyanoargentate anions via argentophilic contacts (Ag···Ag 3.288(8) Å (I), 3.1616(14) Å (II)). The crystal of compound III consists of independent interpenetrating 3D networks built of polymer layers {Cu[Ag(CN)2]2}n bound to each other by the 4,4´-bipyridyl molecules. The bipyridyl linkers connect the Cu centers with the Ag centers of the [Ag(CN)2]– anions thus providing the tridentate coordination of the silver atoms. No Ag···Ag interactions are observed in the crystal of complex III.
460-468