Russian Journal of Coordination Chemistry最新文献

Heterometallic complexes, [M(L)₃][Y(NO₃)₅] (L = 2,2'-bipyridine, Вpy (I–III), and 1,10-phenanthroline, Рhen (IV–VI), M = Co (I, IV), Ni (II, V), Zn (III, VI)), were prepared and studied as anticancer agents. Pronounced in vitro toxicity vs. several cancer cell lines is demonstrated. Compared to homometallic [M(Рhen)₃](NO₃)₂ (MPhen) and Y(NO₃)₃·6H₂O (Y) references, complexes IV–VI exhibit the synergism in cytotoxicity vs. breast cancer cells and its doxorubicin-resistant subline (HBL-100 and HBL-100/Dox) while IV and VI are efficient vs., respectively, cutaneous melanoma (Mel IS) and glioblastoma (T98G) cells. On the other hand, the entire MPhen series show higher toxicity vs. renal cancer (Rpoch-1-KK) cells. Noteworthy, all studied complexes, except for II and V ones are of acceptable toxicity vs. normal cutaneous fibroblasts (PBK) cells. Such a selective toxicity arises from the interactions with key molecular targets such as chaperone proteins nucleolin and nucleophosmin which are over-expressed in cancer cells and play key role in their metabolism. As a result, cell death is induced via the apoptosis processing through several paths as well as the autophagy. The in vivo studies revealed the antitumor potential of complexes I, III, IV and VI vs. Mel IS xenografts. Noteworthy, these complexes are the first yttrium-containing ones with unambiguously demonstrated anticancer activity arising from the induction of various cell death paths. In the latter regard, homometallic [M(Рhen)₃](NO₃)₂ complexes, although on the in vitro level for now, are also of interest.

Manganese(II) complexes (DMSO){(DMSO)₂bis[5,7-di-tert-butyl-2-(2-hydroxyphenolato)-1,3-benzoxazol-4-ol]}manganese(II) (Ia) and (DMSO)₂{bis[5,7-di-tert-butyl-2-(2-hydroxyphenolato)-5-nitro-1,3-benzoxazol-4-ol]}manganese(II) (Ib) are synthesized from the tridentate sterically hindered Schiff bases: condensation products of 4,6-di-tert-butyl-2-aminophenol with salicylaldehyde derivatives N-(3,5-di-tert-butyl-2-oxyphenyl)salicylaldimine and N-(3,5-di-tert-butyl-2-oxyphenyl-5-nitro)salicylaldimine. The structures and compositions of the synthesized metal chelates are characterized by C, H, and N elemental analysis, IR spectroscopy, and magnetochemical measurement data. The EPR data in DMF and toluene are presented for complex Ia. The molecular structures of complexes Ia and Ib are proved by X-ray diffraction (XRD) results (CIF files CCDC nos. 2325776 (Ia) and 2325777 (Ib), respectively). In both complexes, the manganese ion exists in the octahedral {N₂O₄} ligand environment in which the coordination occurs due to two nitrogen atoms of the benzoxazole cycle and two oxygen atoms of the o-hydroxyphenol group and the apical positions are occupied by the oxygen atoms of two DMSO molecules.

The electrocrystallization of salts of the anionic spin-variable complex [Fe^III(L)₂]^‒ (L is 5-chlorosalicylaldehyde thiosemicarbazone (Н₂5Cl-thsa)) with cations Cat⁺ = K⁺ (I), Me₄N⁺ (II), and Et₄N⁺ (III) affords crystals of the neutral binuclear two-chain helicate [({text{Fe}}_{2}^{{{text{III}}}})(L¹)₂]⁰ (IV) (L¹ = (L^‒2)‒(L^‒) are transformed monoanionic and dianionic fragments of L, respectively, linked with each other by the disulfide S–S bridge), which are identified by XRD at 100 and 293 K as the same phase IV·n(H₂O) (n ≤ 6) with close lattice parameters. “Fresh” crystals of the complex obtained from salt I correspond to the composition IV·6(H₂O) at 293 K, rapidly lose 50% water molecules, and decrepitate to fine crystalline fragments IV·3(H₂O). The structure of crystals IV·6(H₂O) is monoclinic (space group С2/c) and characterized by cavities filled with disordered water molecules, which amount to more than 20% of the total unit cell volume. Complex IV has the point symmetry group С₂ and high-spin geometry of coordination nodes N₄O₂. As found by cyclic voltammetry, electrochemically inactive complex IV is formed by the two-electron oxidation of the [Fe^III(5Cl-thsa)₂]^– anion via the EEC mechanism.

The tetranuclear mercury(II) dithiocarbamatо-chloridо complex [Hg₄(S₂CNMe₂)₄Cl₄] (I), whose molecule includes the centrosymmetric 16-membered metallacycle [Hg₄S₈C₄], was prepared by the reaction of solutions of HgCl₂ and sodium dimethyldithiocarbamate (Me₂Dtc). The crystal, molecular, and supramolecular structures of I were established using direct method of single-crystal X-ray diffraction (CCDC no. 2364847). In complex I, the non-equivalent μ₂-bridging dithiocarbamate ligands link neighboring mercury atoms in pairs, thus forming a tetranuclear macrocyclic molecule. The intramolecular Hg···S and Hg···Cl secondary bonds stabilize the spatial configuration of this macrometallacycle. The supramolecular self-organization of the complex is due to the relatively weak, pairwise S···Cl and Hg···Cl secondary interactions, which combine the tetranuclear molecules of I into 2D pseudo-polymer layers; numerous non-classical C–H···Cl and C–H···S hydrogen bonds connect these layers to form a 3D framework. According to simultaneous thermal analysis data, the thermal decomposition of I is accompanied by the formation of HgS and release of HgCl₂.

Six coordination compounds [UO₂(L)₂(NO₃)₂] were prepared by the reaction of UO₂(NO₃)₂ with amide L (L = acetamide, N,N-dimethylacetamide, propanamide, valeramide, benzamide, N-methylurea) in water. The composition and the structure of the products were established by elemental analysis, IR spectroscopy, and powder and single-crystal X-ray diffraction. The molecular structure and the assignment of absorption bands for the obtained compounds were confirmed by quantum chemical calculations.

Calculational protocols are proposed for the estimation of direct spin–spin coupling constants ¹J_PtC in the platinum complexes with practically significant accuracy. To attain a good accuracy, calculations are required within the framework of a fully relativistic four-component level of the theory (RMSE = 24.7 Hz (2%)). A scalar relativistic approximation can be used as an alternative, but the accuracy will appreciably be lower (RMSE = 50.5 Hz (5%)).

Two approaches to the preparation of chromium complexes of condensed heterocyclic compounds bearing two nitrogen atoms are approved. The reactions of benzimidazole (L¹) and 2-methylbenzimidazole (L²) with triammine(tricarbonyl)chromium (I) give the corresponding pentacarbonylchromium derivatives [(η¹-C₇H₆N₂)]Cr(CO)₅ (II) and [2-Me-(η¹-C₇H₅N₂)]Cr(CO)₅ (III) characterized by the nitrogen–chromium σ-bond, and ammine(pentacarbonyl)chromium (Cr(NH₃)(CO)₅, IV) is formed as a by-product. Analogous reactions involving 1,2,3,4-tetrahydroquinoxaline (L³) and 3-phenyl-1,2-dihydroquinoxaline (L⁴) afford tricarbonylchromium π-complexes [(η⁶-C₆H₄)C₂H₆N₂)]Cr(CO)₃ (V) and [3-Ph-(η⁶-C₆H₄)C₂H₃N₂]Cr(CO)₃ (VI), respectively. The condensations of (η⁶-ortho-phenylenediamine)tricarbonylchromium (VII) with benzaldehyde and of ortho-phenylenediamine with (η⁶-benzaldehyde)tricarbonylchromium (VIII) afford acyclic compounds (azomethines [PhCH=N(η⁶-C₆H₄)NH₂]Cr(CO)₃ (IX) and [(η⁶-Ph)CH=NC₆H₄NH₂]Cr(CO)₃ (X), respectively), whereas the reaction of acetaldehyde with complex VII gives a mixture of heterocyclic products: exo-[1,3-bis(C₂H₄OEt)-2-Me-(η⁶-C₆H₄)CHN₂]Cr(CO)₃ (XI) and endo-[1,3-bis(C₂H₄OEt)-2-Me-(η⁶-C₆H₄)CHN₂]Cr(CO)₃ (XII). The spectral characteristics of the synthesized compounds are studied, and their purity and individual character are proved. The molecular structures of complexes III and XI are determined by XRD (CIF files CCDC nos. 2245463 (III) and 2362231 (XI)).

Single crystals of the Mn(III) complexes with tetradentate (N₂O₂) Schiff bases (L) and dicyanometallates [Mn(L)M(CN)₂]_n, where L = Salpn^2– = N,N'-bis(salicylidene)-1,3-diaminopropane, M = Ag⁺ (I), Au⁺ (II), were obtained for the first time. The molecular structures of I and II were determined by X-ray diffraction (CCDC no. 2351118 (I), 2351119 (II)). It was found that the dicyanometallate anion [M(CN)₂]ˉ in the crystal structure of these compounds acts as a bridge binding the Mn(III) moieties with the Schiff base into 1D. Using quantum chemical calculations, the (3, –1) type critical points were found near the C‒H…Ag/Au contact; this attests to the existence of weak hydrogen bonds between these atoms.

Three new coordination compounds, [Zn₂(Dpb)(2-Btc)(OH)]_n·0.5nH₂O (Ι), [Cd₂(Dpb)₂(m-Bdc)₂]_n (II), [Cd(Dpb)(HBtc)(H₂O)₂]·H₂O (III) (Dpb = 2,6-di(pyrazin-2-yl)-4,4'-bipyridine, H₃(2-Btc) = benzene-1,2,4-tricarboxylic acid, m-H₂Bdc = 1,3-benzenedicarboxylic acid, H₃Btc = benzene-1,3,5-tricarboxylic acid), were designed and synthesized. Their structures have been characterized by elemental analyses, infrared spectra and X-ray single-crystal diffraction analyses (CCDC nos. 2373881 (Ι), 2080659(II) and 2373880 (III)). Compound Ι and II exhibit 2D structure, and compound III shows a mononuclear structure. The differences in the structures of Ι–III reveal that the auxiliary ligand exerts an important effect on the ultimate structures. Moreover, Hirshfeld Surface analysis of coordination compounds Ι–III were performed by Crystal Explorer 21 program. Furthermore, the solid-state luminescence emissions, the fluorescence decays and the CIE chromaticity coordinates of Ι–III were also investigated.

The complexes of SnCl₄ with diglyme and 15-crown-5 polyethers, namely [SnCl₄(diglyme)] (I), [SnCl₄(H₂O)₂]₃·2(15-crown-5) (II) and [SnCl₄(15-crown-5)]₂·Et₂O (III), were obtained and characterized by single crystal X-ray diffraction (scXRD) analysis. The compounds I and III were additionally characterized by powder X-ray diffraction, thermal and elemental analyses. The crystal structures of I and III are composed of discrete [SnCl₄(diglyme)] and [SnCl₄(15-crown-5)] molecules, respectively. In these structures, the polyethers act as bidentate ligands, completing the octahedral environment of tin(IV). The crystal structure of II comprises the cis- and trans-SnCl₄(H₂O)₂ isomers, which form a hydrogen bonded network with 15-crown-5 molecules and chloride ligands through coordinated water molecules.