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Abstract The reaction of the tridentate ligand 4-(2,6-bis(5-tert-butyl-1-(2,6-dichlorophenyl)-1H-pyrazol-3-yl)pyridin-4-yl)benzonitrile (L) with iron(II) salt gave the complex [Fe(L)2](BF4)2, which was isolated in a pure state and characterized by elemental analysis, NMR spectroscopy, and X-ray diffraction as two crystal polymorphs differing in the nature of the solvent molecule in the crystal (solvatomorphs I and II). According to the results of X-ray diffraction study (CCDC nos. 2104367 (I), 2104368 (II)), the iron(II) ion in these compounds occurs in different spin states and does not undergo a temperature-induced spin transition, which was previously observed for this complex in solution. The details of supramolecular organization of two solvatomorphs that prevent this transition were studied using the Hirshfeld surface analysis.

In this work we report on new examples of phenanthrolindiamides containing asymmetric centers in amide substituents.

Reprocessing of spent nuclear fuel (SNF) is an important task in a frame of ecology and rational use of natural resources. Uranium, as the main component of SNF (95%), can be recovered for further use as fresh nuclear fuel. To minimize an amount of solid radioactive waste generated during SNF reprocessing, new extractants are under investigation. Diamides of 1,10-phenanthroline-2,9-dicarboxylic acid are perspective tetradentate N-donor ligands that form strong complexes with

The reaction of barium(II) hydroxide with 2-furoic acid (pyromucic acid, Hfur) gave 1D coordination polymer {[Ba3(fur)6(Hfur)2(H2O)8]}n·4nH2O (I). According to X-ray diffraction data, I contains two symmetrically independent barium cations, which have different environments: Ba(1) coordinates six fur– anions, while Ba(2) is a fragment of heteroleptic coordination (fur–, Hfur, and H2O) (CIF file CCDC no. 2063380). The supramolecular polymeric architecture of I is determined by bridging water molecules and numerous hydrogen bonds between coordinated and solvation water molecules to form a 1D motif. The arrangement of Ba2+ ions in the trinuclear moiety {Ba3(fur)6(Hfur)2(H2O)8} of the polymer is nearly linear. The thermal behavior of I, investigated by simultaneous thermal analysis (argon atmosphere), showed a stepwise character of thermal decomposition caused by gradual destruction of the hydrogen-bonded framework and the subsequent partial destruction of the organic part. Analysis of the biological activity of I against the non-pathogenic Mycolicibacterium smegmatis strain showed low sensitivity of the bacterial wall to the complex.

The reaction of new 2,6-bis(pyrazol-3-yl)pyridine ligand (L) containing a redox-active ferrocenyl substituent with cobalt(II) salt gave the cobalt(II) complex [Co(L)2](ClO4)2 (I), which was isolated in a pure state and characterized by elemental analysis, NMR spectroscopy, cyclic voltammetry, and X-ray diffraction. According to X-ray diffraction data (CIF file CCDC no. 2049714) and the Evans method, which allows determining the spin state of paramagnetic compounds in solution on the basis of NMR spectra, the cobalt(II) ion in complex I occurs in the high-spin state and does not undergo temperature-induced spin transition in the temperature range of 120–370 K.

The reactions of lead bromide with 7,7,8,8-tetracyanoquinodimethane and anthracen-9-ylmethanamine hydrobromide in dimethylformamide (DMF) afford the known low-dimensional perovskite {PbBr2(DMF)}n (I) with an impurity of a new hybrid 1D perovskite {Ca(DMF)6[PbBr3]2}n (II), which is isolated in the individual form and characterized by X-ray diffraction analysis. In the crystal of compound II, lead bromide forms infinite chains of PbBr5 octahedra with one vacant vertex between which calcium cations coordinated by the DMF molecules are arranged. The calcium cations presumably have got into the reaction mixture from water used for the washing of the reaction vessel for crystallization after the previous attempt of the synthesis. An attempt of the purposeful preparation of this hybrid 1D perovskite from various calcium salts as sources of this metal ion gives one more new low-dimensional perovskite {Ca(DMF)6[PbBr2.3Cl0.7]2}n (III) in which halide anions (bromide and chloride anions from lead bromide and calcium chloride, respectively) build up the coordination sphere of the lead ion to an octahedral one inducing no noticeable changes in the crystal packing compared to that of compound II. The X-ray diffraction results are deposited with the Cambridge Crystallographic Data Centre (CIF files CCDC nos. 2045586 (I), 2047219 (II), and 2047220 (III)).

Heteroleptic cadmium(ii) carboxylates with anions of pentafluorobenzoic (pfb), benzoic (bz), and 2-furancarboxylic (fur) acids were prepared by the crystallization from aqueous solutions. The cadmium(ii) pentafluorobenzoate-benzoate complex is structurally similar to the starting compound [Cd(pfb)(H2O)4]n • n(pfb): bz anions are involved in the cationic 1D polymer {[Cd(bz)(H2O)3]n}n+, whereas pfb anions are outer-sphere. The pentafluorobenzoate-2-furan-carboxylate compound [Cd(fur)(pfb)(H2O)2]n•n(H2O) is a 1D coordination polymer. The heteroleptic TbIII complex [Tb2(bz)2(pfb)4(H2O)2(EtOH)2]•2Hbz has a molecular structure. The supramolecular crystal structures of the new compounds are stabilized by non-covalent interactions.

A new metal-organic framework {Zn4(BDC)3(OAc)2(DMF)4} (BDC = terephthalate anion) was synthesized under solvothermal conditions in a 3D-printed polypropylene autoclave. The product was isolated in a pure state and characterized by elemental analysis and X-ray diffraction (CIF file CCDC no. 2025811). The formation of this product, instead of the expected {Zn4O(BDC)3} (MOF-5), was probably due to a change in the conditions of solvothermal synthesis caused by disruption of the integrity of the polypropylene autoclave. This is a drawback of this method of screening of metal-organic frameworks, which, however, in some cases givs rise to new representatives of this class of crystalline materials.

The design of new redox-switchable molecules requires the development of simple and efficient synthetic approaches. This study demonstrates the possibility of ortho-lithiation of ferrocenecarboxaldehyde (aryl)imines (Ia–Ic) followed by the reaction with ketones to give 1,2-disubstituted ferrocenes (IIa–IIc). These products, in turn, can be cyclized by treatment with trimethylsilyl triflate to give the cationic precursors of ferrocene-containing N-heterocyclic carbenes (IIIa–IIIc), in which the heterocycle is annulated to one of the ferrocene cyclopentadienyl ring. Treatment of IIIa–IIIc with a base in the presence of a source of rhodium afforded rhodium carbene complexes (IVa, IVb) in which the carbene ligand resembled cyclic alkylaminocarbenes in the electron-donor properties. Compounds Ib and IVa were studied by X-ray diffraction (CIF file CCDC nos. 2000413 and 2000414, respectively).

The spin states of three earlier described cobalt(II) clathrochelates as films on the quartz supports are studied for the first time. The magnetochemical study shows that the temperature-induced spin transition observed previously in the crystalline samples is retained in the films, which makes it possible to consider this class of coordination compounds with high chemical and thermal stability as promising components for molecular spintronic devices.

Abstract The tetrahedral cobalt(II) complex [CoL2](HNEt3)2 (I), where L is 1,2-bis(methanesulfonamido)benzene, exhibiting the properties of a single-molecule magnet is synthesized and characterized. The electronic structure parameters of complex I are determined by paramagnetic NMR spectroscopy. They completely reproduce the results of less available methods of studying single-molecule magnets. The value of axial anisotropy of the magnetic susceptibility estimated for complex I (Δχax = 34.5 × 10–32 m3 at 20°C) is record-breaking among all transition metal complexes studied by the NMR method, which provides wide possibilities for the use of complex I as a paramagnetic label for structural biology or as a contrast agent and even a temperature sensor for medical diagnostics. The data obtained indicate the advantages of paramagnetic NMR spectroscopy as a method of investigation of the magnetic properties and electronic structures of highly anisotropic transition metal complexes, which are precursors of many functional materials.

Single crystals of tetramethoxysilane (I), which is liquid at room temperature, are grown using an original setup for in situ crystallization. The X-ray diffraction analysis of compound I at two temperatures (CIF files CCDC nos. 2006156 and 2006157 for 150 and 200 K, respectively) shows the phase transition accompanied by the disordering of the methoxy groups. The setup developed that is different from commercial analogs by an unusually low cost and a possibility of modifying all components provides wide opportunities for crystal growth directly on a diffractometer for structure determination of various organoelement compounds and, possibly, metal complexes in the liquid or even gaseous state.

The mononuclear complexes [M(Fur)2(Bpy)(H2O)] (M = Cu (I), Zn (II)) were prepared by the reactions of copper(II) and zinc(II) acetates with 2-furoic acid (HFur) anion and 2,2'-bipyridine (Bpy) in acetonitrile. A similar reaction with ZnCl2 used instead of Zn(OAc)2 · 2H2O gave the complex [Zn(Fur)2(Bpy)] (III). The cobalt(II) complex [Co(Fur)2(Bpy)] (IV) was obtained by the reaction of cobalt trimethylacetate with HFur and Bpy. The structure of mononuclear complexes was determined by X-ray diffraction (CIF files CCDC nos. 1993168 (I), 1993169 (II), 1993170 (III), and 1993171 (IV)). Compounds I, III, and IV were studied for the biological activity in vitro against the nonpathogenic mycobacterial strain Mycolicibacterium smegmatis. It was found that I and III have high biological activity and are promising for further studies for antituberculosis activity.

Two earlier described polymorphous modifications of the cobalt(II) (pseudo)clathrochelate are studied by EPR spectroscopy in the terahertz range, where the complex exhibits the properties of a single-molecule magnet (including the record-breaking barrier for magnetization reversal at the moment). Different values of the magnetization reversal barrier found previously for the corresponding crystalline phases by the results of magnetometric measurements in an alternating magnetic field are observed in the EPR spectra in the terahertz range. A combined analysis of these two methods allows one to more precisely estimate the magnetization reversal barrier for two polymorphous modifications and also the contribution of different magnetic relaxation mechanisms to the spin dynamics. This unambiguously confirms that slight changes in the crystalline environment of the molecule of even such structurally rigid metal complexes as cobalt(II) (pseudo)clathrochelates can result in high differences in the magnetization reversal barrier, which is the key characteristic of single-molecule magnets.

The reaction of Cd(NO3)2 · 4H2O and Eu(NO3)3 · 6H2O or Tb(NO3)3 · 6H2O with potassium 3,5-di-tert-butylbenzoate (Kbzo) and N-donor ligands (1,10-phenanthroline (phen), 2,4-lutidine (2,4-lut), 3,4-lutidine (3,4-lut), phenanthridine (phtd), 2,3-cyclododecenopyridine (cdpy), acridine (acr)) afforded heterometallic LnCd2 complexes: [EuCd2(bzo)7(EtOH)2(phen)] (2), [LnCd2(bzo)7(2,4-lut)4] (Ln = Eu (3), Tb (4)), [EuCd2(bzo)7(H2O)2(2,4-lut)2] · MeCN (5), [EuCd2(NO3)(bzo)6(EtOH)2(2,4-lut)2] (6), [EuCd2(bzo)7(H2O)(EtOH)(3,4-lut)2] · 5EtOH (7), 3[EuCd2(bzo)7(H2O)2(phtd)2] · 4phtd (8), [EuCd2(bzo)7(EtOH)3(cdpy)] (9), 2[EuCd2-(bzo)2(EtOH)4] · acr (10). The structures of complexes 2, 3, and 5–10 were determined by single-crystal X-ray diffraction. The isostructurality of complexes 3 and 4 was confirmed by powder X-ray diffraction. The structure of the trinuclear {Ln2Cd} metal core is stable and independent of the type of peripheral ligands coordinated to cadmium atoms. Photoluminescent properties of compounds 3 and 4 were studied.

The reactions of cadmium(II) and europium(III) pentafluorobenzoates ([Cd(Pfbz) $$\left( {{{{\text{H}}}_{{\text{2}}}}{\text{O}}} \right)_{{\text{4}}}^{ + }$$ }n ∙ n(Pfbz)–] (I) and [Eu2(Pfbz)6(H2O)8] ∙ 2H2O (II), respectively; Pfbz is pentafluorobenzoic acid anion) with the N-donor ligands (pyridine (Py), 2-phenylpyridine (Phpy), and 3-ethynylpyridine (Etypy)) afford a series of new Cd–Ln complexes with Pfbz– anions and Py or its substituted analogues: [Cd2Eu2(Pfbz)10(Py)4] (III), [Cd2Eu2(Pfbz)10(Phpy)2(MeCN)2] · 5MeCN (IV), and [CdEu2(Pfbz)8(Etypy)(H2O)2]n ∙ 3nMeCN ∙ n(Etypy) (VI). Similar reactions of compounds I and II with 2,4-lutidine (Lut), isoquinoline (Iquin), 2,2'-biquinoline (Biquin), and 7,8-benzoquinoline (Bquin) give the following cadmium complexes as the major products of crystallization from the reaction solutions: [Cd(Pfbz)2(Lut)]n (V), [Cd(H2O)(Pfbz)2(Iquin)2]n (VII), [Cd(Рfbz)2(Biquin)] (VIII), and $$[{\text{Cd}}{{({\text{Pfbz}})}_{{\text{3}}}}]_{n}^{-}$$ ∙ n(HBquin)+ (IX), respectively. The X-ray diffraction data (CIF files CCDC nos. 1987805 (I), 1987808 (III), 1987829 (IV), 1987817 (V), 1987822 (VI), 1987823 (VII), 1987824 (VIII), and 1987826 (IX)) are examples of the formation of new unusual coordination polymers.

The reaction of a new tridentate ligand 2,6-bis(5-tert-butyl-1-(2,6-difluorophenyl)-1H-pyrazol-3-yl)pyridine (L) with the divalent iron salt affords the iron(II) complex [Fe(L)2](BF4)2 (I), which is isolated in the individual state and characterized by elemental analysis, NMR spectroscopy, and X-ray diffraction analysis. According to the X-ray diffraction results and data of the Evans method, which makes it possible to determine the spin state of paramagnetic compounds in a solution from the NMR spectra, the iron(II) ion in complex I exists in the high-spin state (S = 2 for Fe(II)) and undergoes no temperature-induced spin transition in a range of 120–345 K.

A new binuclear iron(III) oxo complex [(L)FeOFe(L)](PO2F2)4 (1) with PO2F2– counterions resulted from the oxidation of the hexafluorophosphate anion has been prepared by oxidation of an iron(II) complex with the tridentate ligand 2,6-bis(5-(4-fluorophenyl)-1H-pyrazol-3-yl)pyridine (L). According to X-ray diffraction studies, the iron(III) ions adopt the high-spin state, as in the previously described iron(III) oxo complex with tert-butyl substituted bis(pyrazol-3-yl)pyridine. At the same time, the presence of aromatic para-fluorophenyl substituents and $${\text{P}}{{{\text{O}}}_{2}}{\text{F}}_{2}^{ - }$$ counterions in oxo complex 1 decreases the twisting of bis(pyrazol-3-yl)pyridine ligands relative to each other, thus ensuring a less distorted molecular geometry of this complex.

Mono- and binuclear complexes [Cu(Fur)2(Phen)] (I), [Cu2(Fur)4(Py)2] (II), [Cu(Fur)2-(Py)2(H2O)] (III), and [Zn2(Fur)4L2] (L = Py (IV), Phpy (V)) are synthesized using the reactions of copper(II) and zinc(II) acetates with anions of pyromucic acid (2-furancarboxylic acid (HFur)) and N‑donor ligands (pyridine (Py), 4-phenylpyridine (Phpy), and 1,10-phenanthroline (Phen)) in acetonitrile. The copper complexes with pyridine are successively formed from the same reaction mixture: at first binuclear complex II is formed and then mononuclear complex III is formed. All compounds are isolated as single crystals, and their structures are determined by X-ray structure analysis (CIF files CCDC nos. 1974386 (I), 1974388 (II), 1974389 (III), 1974387 (IV), and 1974385 (V)). The thermal behavior of complexes II and III is studied by simultaneous thermal analysis. The biological activity in vitro of all complexes is determined toward the nonpathogenic mycobacterial strain Mycolicibacterium smegmatis. Complexes I and V exhibit a high biological activity and are promising for further studies of antitubercular activity.

The reactions of 2,6-bis(1,4-diphenyl-5-hydroxy-1H-pyrazol-3-yl)pyridine (L), which is the first representative of a series of 2,6-bis(pyrazol-3-yl)pyridine ligands bearing substituents in positions 1 and 4 of the pyrazol-3-yl ring, with the divalent iron and cobalt salts afford new Со(II) and Fe(II) complexes: [Co(L)2](ClO4)2 (I) and [Fe(L)2](ClO4)2 (II). The compounds are isolated in the individual state and characterized by elemental analysis, NMR spectroscopy, and X-ray diffraction analysis (CIF files CCDC nos. 1967892 (I) and 1967893 (II)). According to the data obtained, the transition metal ion in complexes I and II exists in the high-spin state (S = 3/2 for Co(II) and S = 2 for Fe(II)) in a range of 120–345 K, and the proposed modification of the ligand does not lead to the temperature-induced spin transition in both the solution and crystalline state.

Double adducts of norbornadiene-2,5 and anthracene derivatives have been synthesized using the Diels–Alder reaction. The possibility of selective preparation of both symmetrical and unsymmetrical adducts depending on the reaction conditions has been shown. For these cycloadducts exclusively consisting of carbon and hydrogen, an unusual and interesting feature has been revealed, namely, the signals of the protons of the bridge methylene groups in the 1H NMR spectra have chemical shifts in the negative region. In this work, double adducts of anthracene derivatives and norbornadiene (2,5-(bicyclo-[2.2.1]-hepta-2,5-diene)) have been synthesized and their structure investigated. The synthesized compounds possess a rigid, branched, and bulky structure suitable for the fabrication of composite membrane materials.

The known metal-organic framework {Zn4O(BDC)3} (MOF-5 (I), where BDC is terephthalate anion) is synthesized by the solvothermal method in autoclaves prepared by 3D printing from polypropylene. The synthesized polymer is isolated in the individual state and characterized by elemental analysis and powder X-ray diffraction analysis. The crystal structures of MOF-5 and another coordination polymer based on zinc(II) terephthalate {Zn4O(BDC)3} · (ZnO)0.125 (SUMOF-2 (II)) obtained as a by-product of the solvothermal synthesis are confirmed by X-ray diffraction analysis (СIF files ССDС nos. 1920366 (I) and 1926136 (II)).

The reactions of the complex [Co(DAP)2(Piv)2] · Piv (Ia), where Piv is the pivalate anion, DAP is 1,3-diaminopropane, with Cd(II) and Li(I) pivalates afford heterometallic compounds, molecular complex [CdCo(DAP)2(Piv)5] (I) and polymeric complex [LiCo(DAP)2(Piv)4]n (II) (CIF files CCDC nos. 1908223 and 1908224, respectively). According to X-ray photoelectron spectroscopy, the electronic structure of cobalt ions in complexes Ia and I corresponds to low-spin Co(III) surrounded by strong-field ligands. The thermal destruction of I and II, studied by synchronous thermal analysis, includes stages of desorption of solvate molecules, destruction of the 1,3-diaminopropane molecule with nitrogen evolution, and degradation of carboxylate anions. The final product of thermolysis of I is the complex oxide CdCoO2.

The cobalt(II) and iron(II) complexes with 2,6-di(5-amino-1H-pyrazol-3-yl)pyridine (L), CoL2(ClO4)2 (I) and FeL2(ClO4)2 (II), are synthesized by the template reaction, isolated in the individual form, and characterized by elemental analysis, NMR spectroscopy, and thermogravimetry. The structures of complexes I and II (including the iron(II) complex obtained as two new solvate forms (FeL2(ClO4)2 ∙ 2(C2H5)2O ∙ H3CN (IIa) and FeL2(ClO4)2 ∙ (C2H5)2O ∙ CH3CN ∙ 0.75H2O (IIb)) are confirmed by X-ray diffraction analysis. The data obtained in the crystal (by the X-ray diffraction method) and in solutions (using the proposed approach to an analysis of paramagnetic shifts in 1H NMR spectra) indicate that the metal ion in the complexes exists in the high-spin state (S = 3/2 for Co(II) and S = 2 for Fe(II)) and undergoes no temperature-induced spin transition in a range of 120–300 K.

Methods for the syntheses of a series of high-energy 4(10)-2-fluoro-2,2-dinitroethyl and 4(10)-2,2-dinitroethyl derivatives of polynitrohexaazaisowurtzitanes were developed. The enthalpy of formation, molecular crystalline density, sensitivity to mechanical impact, and thermal stability were experimentally determined for two compounds.

Novel continuous-flow cascade reactions are developed for producing 1,4-diaryl-disubstituted dipolar γ-carbolines 2 that contain a carboxylate group and their two pentacyclic precursors 6, 7 from hemiindigos 1. The nucleophilic and pro-electrophilic chemistry described is new to the hemiindigos 1, and it led to the discovery of antimycobacterial scaffold characteristic of rimino-type pentacycles 6, 7 and potent drug clofazimine. The new scaffold like clofazimine appears to be useful in developing lead agents active against drug-resistant/dormant TB.

The direct template reactions afford the cobalt(II) complexes (I–III) with the hydroxy- and acetyl-substituted 2,6-bis(pyrazol-3-yl)pyridine ligands containing the phenyl and 4-tert-butylphenyl group in position 1. All compounds are isolated in the individual state and characterized by elemental analysis and NMR spectroscopy. The X-ray diffraction data obtained for crystals of compound I (СIF file CCDC 1577238) and the data for solutions (using the proposed approach to analysis of paramagnetic NMR shifts on the basis of quantum chemical calculations) show that in the complexes the metal ion exists in the high-spin state (S = 3/2) and undergoes no temperature-induced spin transition in a temperature range of 120–300 K.

The exchange reaction of CdCl2 ⋅ 2H2O with KPiv affords cadmium(II) trimethyl acetate complexes (K[Cd6(Piv)12Cl] ⋅ 2MeCN (I), [K2Cd3(Piv)8(H2O)6] (II), and [Cd(Piv)2(Н2О)2] (III) as a mixture with complex II and [K3Cd2(Piv)7(MeCN)2]n (IV) (HPiv is trimethylacetic acid). The exchange reaction of CdSO4 ⋅ 8/3H2O with Ba(Piv)2 makes it possible to obtain complex III in a quantitative yield. Complex III can also be isolated by the recrystallization of {Cd(Piv)2} from water. The recrystallization of complex III or {Cd(Piv)2} from MeCN affords hexanuclear complex [Cd6(Piv)12(MeCN)2] (V), which transforms into complex III upon recrystallization from water. All new compounds are characterized by the data of single-crystal X-ray diffraction analysis (CIF files CCDC no. 1572202–1572206), IR spectroscopy, and C,H,N analysis.

α-(1,2,3-Triazole)-substituted acetals were obtained using the click procedure. Under acid hydrolysis conditions these acetals were converted into earlier unknown stable gem-diols containing a triazole ring.

A reaction of iodide [(η5-indenyl)IrI2]n (1) with thallium dicarbollide Tl[Tl(η-7,8-C2B9H11)] leads to (indenyl)iridacarborane (η5-indenyl)Ir(η-7,8-C2B9H11) (2) in 32% yield. The X-ray diffraction study showed that in the structure of 2, the five-membered rings C5 and C2B3 have a cisoid conformation, in which the bridgehead carbon atoms of the indenyl ligand are arranged opposite to the carborane cage carbon atoms. The DFT calculations showed that the Ir—indenyl bond in compound 2 is weaker than the Ir—Cp bond in the complex (η-7,8-C2B9H11)IrCp.

A synthesis of hitherto unknown bicyclic nitroso acetals possessing two annulated six-membered rings is accomplished. The synthesis comprises formal [3+3] cycloaddition of six-membered cyclic nitronates with donor-acceptor cyclopropanes. Some chemical transformations and conformational preferability of the obtained nitroso acetals are discussed.

Crystals of a new silicate, Na3Tb3[Si6O18] · H2O, space group \(P\bar 1\), are obtained under hydrothermal conditions. The formula of the compound is determined in the course of structure solution. The silicate is a synthetic analogue of the gerenite mineral (Ca1.21Na0.57)(Y2.24Dy0.68)Si6O18 · 2H2O, whose structure contains six-membered rings formed by SiO4 tetrahedra. The [Si6O18] rings are connected by TbO6 octahedra into a mixed microporous framework with voids filled by Na atoms and water molecules. The new silicate differs from gerenite by the occupation of the Ca position by Na atoms and population of the pores sandwiched between six-membered rings. By virtue of conditions of hydrothermal synthesis in the absence of Ca and excess of Na in the system, an additional Na position appears in the void. It is populated statistically, and in gerenite it was occupied by water molecules only. In the new structure, the position of water is split into two statistically populated positions. The inclusion of Na atoms in additional positions in framework pores and their high thermal vibrations are indicative of ion-exchange properties of the structure. Possible paths of ion exchange are discussed.

A sample of holotypic calcium catapleiite from the Burpala alkaline massif (Northern Baikal, Russia) is studied by single crystal X-ray analysis at 120 K and IR spectroscopy. The empirical formula of calcium catapleiite is Ca0.97Na0.02Zr1.01Si3O9 • 2H2O (Z = 4). The X-ray diffraction study confirms the orthorhombic unit cell with the following parameters: a = 7.406(1), b = 12.687(1), and c = 10.112(1) A; V = 950.1(2) A3; space group Pbnn. The crystal structure is refined in the anisotropic approximation of atomic displacement parameters using 1177 reflections with I > 2σ(I) to the final R = 2.91%. The structure of calcium catapleiite under study is based on the microporous heteropolyhedral framework formed by ZrO6 octahedra and threemembered silicon–oxygen rings [Si3O9]. It is on the whole analogous to the structures of the samples studied earlier, but differs from them by a high degree of ordering of calcium and vacancies at extraframework positions. The distribution of calcium over Ca1 and Ca2 positions in the calcium catapleiite structure leads to the formation of zigzag chains of the …Сa1–Zr–Ca1–Zr… and …Сa2–h–Ca2–□… types. Low occupancy of the Ca2 position and its alternation with the vacancy are prerequisites for potential Ca2+ cationic conduction.

The results of high-resolution X-ray diffraction studies of the charge density distribution in crystals of three europium trinitrate complexes, including those with N-donor "antenna"-ligands are summarized. It is shown that the charge transfer between lanthanide ion and "antenna" correlates with the energy of interaction between the metal and nitrate anion, and the total stabilization energy of the metal polyhedron depends weakly on the coordination number of the metal and the nature of the ligands. The statistical treatment of the crystal structural data for similar complexes and the energies of the corresponding metal—ligand interactions allowed us to suggest the stability of mer-arrangement of the coordinated nitrate anions and to propose a semiempirical relationship to estimate the energy of Eu—O interactions. The influence of vibration processes on the electron density distribution in the EuO2NO fragment was additionally considered, and a feasibility to estimate the energy of interaction between the ligand and lanthanide ion at non-stationary points on the potential energy surface was validated.

A combined electron density study from X-ray diffraction and quantum chemistry for an organic nitroxide radical TEMPONE, with an unpaired electron residing on its NO group, allowed expansion of the applicability of the invariom approach to open-shell compounds. Although this approach was not able to reproduce an additional electron accumulation at the oxygen atom (earlier found in a nitronyl-nitroxide radical by C. Lecomte et al.) as compared to the multipole refinement of high-resolution X-ray diffraction data (possible reasons for this being thermal motion and crystal environment), it provided a good approximation to the experimental electron density using both the ‘open-shell’ invarioms and a series of their ‘closed-shell’ analogues. All of them were shown to describe weak intermolecular interactions in TEMPONE very well; these may serve as superexchange pathways in magnetic materials and tune their magnetic behavior.

Upon treatment with thiophenol or neomenthyl mercaptane, chloroacetand propionamides with an additional Nor S-donor substituent in the amine part gave new multidentate ligands readily undergoing direct cyclopalladation in the reaction with PdCl2(NCPh)2. The realization of κ3-X, N, S-coordination (X = N, S) in the complexes obtained was confirmed by IR and NMR spectroscopy and, in some cases, by single-crystal X-ray crystallography. The evaluation of catalytic activity of the palladocycles in the Suzuki cross-coupling of aryl bromides with PhB(OH)2 allowed us to establish the principal structure—activity correlations.