Vol 43, No 4 (2017)

The computer simulation (DFT B3LYP*/6-311++G(d,p)) is performed for the adducts of divalent cobalt diketonates with di-o-quinones in which the quinone rings are separated by the cycloalkane spacers. The isomers containing dianion–diradical forms of the redox-active ligand, the character of exchange between unpaired electrons of which depends on the spacer structure, correspond to the ground states of the considered compounds. Strong antiferromagnetic interactions (J > 400 cm^–1) are predicted for the most stable electromers of the adducts of Co(II) bis(chelates) with 9,10-dimethyl-9,10-ethanoanthracene-2,3,6,7(9H,10H)-tetraone, whereas a weak exchange favoring paramagnetism in a wide temperature range is expected for the ground states of the binuclear complexes with the isomeric 5,10-dimethyl-4b,5,9b,10-tetrahydroindeno[2,1-a]indene-2,3,7,8-tetraone spacer. The electromers of the complex with the hexafluoroacetylacetone ligands are characterized by close values of the total energies, due to which the complex becomes a promising object for the development of spin qubits.

Complexes Pd(LH)Cl₂ (LH is the N-derivative of β-alanine based on (–)-α-pinene) and PdL^EtCl₂ (L^Et is ethyl ester of LH) are synthesized. The X-ray diffraction analysis (СIF file ССDC no. 1471432) shows that the single crystals of the [PdL^EtCl₂] complex belong to the racemate. The crystal structure contains (+)- and (–)-enantiomeric molecules of the mononuclear complex. Ligand L^Et is bidentate chelating. The coordination PdCl₂N₂ core is a distorted square. The contacts Pd…Cl and hydrogen bonds N–H…Cl between molecules of the (+)- and (–)-enantiomers result in the formation of dimeric ensembles, which are joined into chains due to the C–H…Cl hydrogen bonds. According to the X-ray powder diffraction data, the products of the synthesis of complex [PdL^EtCl₂] contain both the racemate and (+)-enantiomer. The (+)-enantiomer is isolated by the recrystallization of the synthesis product. Complex Pd(LH)Cl₂ is an optically active right-handed compound. According to the NMR data, complex PdL^EtCl₂ does not dissociate in a CDCl₃ solution. The results of IR and NMR spectroscopy indicate that the molecular structure of complex Pd(LH)Cl₂ is similar to that of [PdL^EtCl₂].

The reactions of pentaphenylantimony with oximes or triphenylantimony dioximates in toluene afford tetraphenylantimony oximates Ph₄SbON=CHR (R = C₆H₄Br-2 (I), C₆H₄NO₂-2 (II), and C₄H₃S-2 (III)). Triphenylantimony dioximates are synthesized by oxidative addition from triphenylantimony and oxime in diethyl ether in the presence of tert-butyl hydroperoxide. According to the X-ray diffraction data (CIF files CCDC no. 1055414 (I), 1055634 (II), and 1061727 (III)), the coordination mode of the antimony atoms in the molecules of compounds I–III is a distorted trigonal bipyramid with the oxygen atom of the oximate ligand in the axial position. The structural organization of the crystals is caused by weak hydrogen bonds.

Three new complexes, namely {[Ln(L)₃(2,2′-Bipy)]_n · H₂O} (Ln = Pr (I), Sm (II), and Nd (III)) (HL = 3-(2-hydroxyphenyl)propanoic acid), have been synthesized and structurally characterized. The structural determinations indicated (CIF files CCDC nos. 1472729 (I), 1472730 (II), 1472734 (III)) that I–III have similar dinuclear structures, which can be further linked into 2D sheet via the hydrogen bond interactions. Furthermore, the luminescent properties of I–III show the strong emissive power and feature.

The reactions of [Mn^III(3-MeOSalen)(H₂O)₂]⁺ (Salen = N,N-ethylenebis(salicylideneaminato) dianion) with (Et₄N)₄[M(CN)₈] (M = Mo, W) have been investigated and one mononuclear manganese(II) complex [Mn^II(Salen)(H₂O)] (I) and one bimetallic ion-pair complex [Mn^III(3-MeO-Salen)(H₂O)₂]₄[W(CN)₈] · DMSO · 4H₂O (II) were obtained unexpectedly and characterized by element and single crystal structure analysis. Single crystal X-ray diffraction (CIF files CCDC nos. 1456365 (I) and 1456366 (II)) showed that the Mn²⁺ ion in complex I is five-coordinated involving in a distorted square pyramid. Furthermore, with the help of the intermolecular hydrogen bond interactions, this complex can be constructed into interesting one-dimensional zig-zag chain structure. For complex II, the coordination sphere of Mn³⁺ ion is an elongated octahedron. Additional, the four mononuclear manganese(III) units are self-complementary through the coordinated aqua ligand from one molecule and the free O(4) compartment from the neighboring molecule, giving supramolecular dimmers structure. Investigation of the magnetic susceptibility of the two complexes reveals the overall weak antiferromagnetic interactions between the adjacent manganese centers caused by H-bond interactions.