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New complex compounds [Cd(μ-L1)2]n (I), [Cd(μ-L2)(μ-Cl)(μ-DMSO)]n (III), and [Cd2(μ-L2)(μ-Cl)3(μ-DMSO)DMSO/EtOH]n (IV) are synthesized by the reactions of 1-(4-methoxyphenyl)-1,4-dihydro-5H-tetrazole-5-thione (HL1) and 1-(2-methoxyphenyl)-1,4-dihydro-5H-tetrazole-5-thione (HL2) with cadmium chloride. The molecular and crystal structures of the complexes are determined by X-ray structure analysis (CIF files CCDC nos. 1993455 (I), 1869249 (III), and 1993497 (IV)). Complexes I, III, and IV have uniform polymeric structures. The О···Н, Cl···H, and C···S contacts are observed between 1D polymeric chains in the crystal cells of complexes I, III, and IV. Complexes III and IV contain DMSO molecules. Under other equivalent conditions, the reaction of HL1 or HL2 with cadmium chloride in ethanol affords complex I or II of different compositions. Complex II contains the chlorine atom as found by scanning electron microscopy, whereas no chlorine is observed in complex I according to the X-ray structure analysis data.

In the title compound, C15H12N2O3, pairs of molecules are linked into dimers by N-H center dot center dot center dot O hydrogen bonds, forming an R-2(2)(12) ring motif, with the dimers stacked along the a axis. These dimers are connected through pi-pi stacking interactions between the centroids of the benzene and furan rings of their 2,3-dihydro-1-benzofuran ring systems. Furthermore, there exists a C-H center dot center dot center dot pi interaction that consolidates the crystal packing. A Hirshfeld surface analysis indicates that the most important contacts are H center dot center dot center dot H (40.7%), O center dot center dot center dot H/H center dot center dot center dot O (24.7%), C center dot center dot center dot H/H center dot center dot center dot C (16.1%) and C center dot center dot center dot C (8.8%).

In the crystal, mol­ecules of the title compound are connected through C—H⋯π, C—Cl⋯π, Cl⋯Cl and Cl⋯H inter­actions, generating a three-dimensional network., In the mol­ecule of the title compound, C22H14Cl4N4, the central benzene ring makes dihedral angles of 77.03 (9) and 81.42 (9)° with the two approximately planar 2,2-di­chloro-1-[(E)-phenyl­diazen­yl]vinyl groups. In the crystal, mol­ecules are linked by C—H⋯π, C—Cl⋯π, Cl⋯Cl and Cl⋯H inter­actions, forming a three-dimensional network. The Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (30.4%), C⋯H/H⋯C (20.4%), Cl⋯H/H⋯Cl (19.4%), Cl⋯Cl (7.8%) and Cl⋯C/C⋯Cl (7.3%) inter­actions.

Three new organoselenium compounds are synthesized: N-phenyl-2-(2-thienylacetyl)hydrazinecarboselenoamide (I), 4-phenyl-5-(2-thienylmethyl)-2,4-dihydro-3H-1,2,4-triazole-3-selone (II), and 3,3'-di[4-phenyl-5-(2-thienylmethyl)-4H-1,2,4-triazolyl] diselenide (III). Two of them (compounds II and III) are characterized by X-ray diffraction analysis (CIF files CCDC nos. 1956602 (II) and 1956603 (III)). Compound II crystallizes in the monoclinic crystal system (space group P21/n) with two crystallographically independent molecules A and B being different conformers relative to rotation about the NTrz–CTrz–C(H2)–CTph bond, where Trz is triazole and Tph is thiophene (gauche-A (51.4(3)°) and cis-B (4.2(4)°)). In the crystal of compound II, molecules A and B form chains along the crystallographic axis a due to strong hydrogen bonds N–H···Se. Then the chains are bound into a three-dimensional framework via intermolecular nonvalent interactions Se···S (3.3857(11) A). Owing to the anomeric effect, diselenide III is characterized by the typical gauche conformation of the substituents at the Se–Se bond (torsion angle СSeSeС 83.5(4)°) stabilized by a weak intramolecular hydrogen bond С–H···π. In the crystal of compound III, the molecules form chains along the crystallographic acid b due to intermolecular noncovalent interactions Se···π(C–C) (3.404(6) and 3.458(12) A), Se···Se (3.8975(11) A), and S···N (3.250(5) A). Bactericidal and fungicidal activity of the synthesized compounds is studied.

In the crystal of the title compound, C7H5FN4S, the molecules are non-planar, with dihedral angle formed by least-squares planes of tetrazole and benzene rings of 59.94 (8) °. The crystal packing is formed by N—H...S hydrogen bonds, which link the molecules into centrosymmetric dimers with an R 2 2(8) ring motif, and by the offset face-to-face π–π stacking interactions between the benzene rings, which join the dimers into layers parallel to (100). The Hirshfeld surface analysis shows that the most important contributions to the surface contacts are from N...H/H...N (21.9%), S...H/H...S (21.1%), H...H (14.6%), F...H/H...F (11.8%) and C...H/H...C (9.5%) interactions.

In the crystal, mol­ecules are connected by C—H⋯π and π–π stacking inter­actions, forming a layer lying parallel to the (11 ) plane., In the title compound, C16H14N2O2, the 2,3-di­hydro-1-benzo­furan ring system is essentially planar and makes a dihedral angle of 3.69 (7)° with the di­methyl­phenyl ring. The mol­ecular conformation is stabilized by an intra­molecular N—H⋯O hydrogen bond with an S(6) ring motif. In the crystal, mol­ecules are connected by C—H⋯π and π–π stacking inter­actions, forming a layer lying parallel to the (11 ) plane. One methyl group is disordered over two orientations, with occupancies of 0.67 (4) and 0.33 (4). Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (51.2%), O⋯H/H⋯O (17.9%), C⋯H/H⋯C (15.2%) and C⋯C (8.1%) contacts.

Novel compounds 2-(2-(2-hydroxy-4-nitrophenyl) hydrazono)-1,3-diphenyl propane-1,3-dione and 2-(2-(2-hydroxy-4-nitrophenyl) hydrazono)-1-phenyl butane-1,3-dione are prepared on the base of β-diketones. Crystal and molecular structures of synthesized compounds are determined by X-ray diffraction analysis. The crystals are found to be monoclinic. The compounds are represented only by their hydrazo forms. The structural data for the two obtained compounds are compared with previously reported data.

Compound 4-(2-methoxyphenyl)-5-(thiophen-2-ylmethyl)-2,4-dihydro-1H-1,2,4-triazole-3-thione (LН) and its complex with cadmium(II) C42.12H39.50N9O3.12S6Cl2Cd (I) are synthesized. Their molecular and crystal structures are determined by X-ray diffraction analysis (СIF files CCDC nos. 1835776 (LН) and 1547251 (I)). Free ligand LН is thione and in the crystal forms H-bonded centrosymmetric dimers by two hydrogen bonds N–H···S. Complex I has a distorted trigonal bipyramidal structure: the sulfur atoms lie in the base and the chlorine atoms occupy the axial positions. Compound LН manifests itself as a monodentate ligand (S) when forming complex I and retains the thione form. The molecule of complex I is stabilized due to strong intramolecular contacts N–H···Cl. The crystal packing of compounds LН and I is formed due to the intermolecular contacts C–H···π, H···S, H···O, and H···N.

Cadmium (C20H16Cd2N4O4Se4) (I) and nickel (C10H8N2NiO2Se2) (II) selenolates are synthesized by the exchange reactions of sodium 1-oxypyridyl-2-selenolate and cadmium(II) and nickel(II) chlorides. The molecular and crystal structures of the complexes are determined by X-ray structure analysis (CIF files CCDC nos. 1585246 (I) and 1585251 (II)). Complex I forms a centrosymmetric dimer in which the coordination polyhedron of the cadmium atom is a distorted trigonal bipyramid and the selenium atoms take the trans configuration. Complex II containing the solvate C2H5OH molecule has a square structure and is a monomer. Unlike complex I, in complex II the selenium atoms of the ligands take the cis configuration. The crystal packings in complexes I and II are formed by weak intermolecular hydrogen bonds C–H···O and C–H···Se.

As a result of triple condensation of malonodinitrile with benzaldehyde and ethyl 2-chloro-3-oxobutanoate a compound with 3-azabicyclo[3.1.0]hexane framework is formed whose crystal structure is determined by X-ray crystallography. In the crystal structure a layered character of the molecular packing is found. Molecules are linked in the layer by H bonds of N-H…O=C and C-H…O=C types and also a large number of atom-atom contacts whose energy corresponds to potential wells.

The molecular and crystal structures of 1-(2-methoxyphenyl)-1,4-dihydro-5H-tetrazole-5-thione (L) and its complex with cadmium(II) (II) are studied by X-ray diffraction analysis (CIF files CCDC nos. 1567109 (L) and 1547252 (II)). Free ligand L is nonplanar thione. The dihedral angle between the tetrazole and benzene cycles is 85.21(7)°. These cycles form centrosymmetric dimers in the crystal by two hydrogen bonds N–H···S. The dimers contain the central planar eight-membered ring {S=C–N–H···S=C–N–H···}. Complex II has a chain structure of the composition [(C8H7N4OS)2Cd]n. The coordination mode of the Сd(II) atom is a distorted tetrahedron consisting of two nitrogen atoms and two sulfur atoms of four ligands L. The 1D chains contain the eight-membered rings {←S=C–N–Cd ← S=C–N–Cd} in the boat conformation. Weak intermolecular hydrogen bonds C–H···N are observed between the adjacent 1D chains along the c axis in the crystal.

In the crystal, mol­ecules are linked by pairs of N—H⋯S hydrogen bonds, forming inversion dimers with an (8) ring motif. The dimers are linked by the offset face-to-face π–π stacking inter­actions., In the crystal of the title compound, C7H5FN4S, the mol­ecules are non-planar, with dihedral angle formed by least-squares planes of tetra­zole and benzene rings of 59.94 (8) °. The crystal packing is formed by N—H⋯S hydrogen bonds, which link the mol­ecules into centrosymmetric dimers with an R 2 2(8) ring motif, and by the offset face-to-face π–π stacking inter­actions between the benzene rings, which join the dimers into layers parallel to (100). The Hirshfeld surface analysis shows that the most important contributions to the surface contacts are from N⋯H/H⋯N (21.9%), S⋯H/H⋯S (21.1%), H⋯H (14.6%), F⋯H/H⋯F (11.8%) and C⋯H/H⋯C (9.5%) inter­actions.

We report an unprecedented multicomponent reaction of acetoacetanilide with malononitrile leading to a structurally novel bicyclic product (9) in a high yield. The structure has been confirmed by X-ray crystallography and comparative Hirshfeld surface analysis of 5-cyano-2-hydroxy-2-methyl-N-phenyl-4-(yridine-4-yl)-6-(thiophen-2-yl)-3,4-dihydro-2H-pyran-3-carboxamide 2, 5-cyano-2-hydroxy-2-methyl-6-oxo-N-phenyl-4-(thiophen-2-yl)piperidine-3-carboxamide 4 and 2-(8-amino-7,8a-dicyano-1-imino-4a-methyl-3-oxo-2-phenyl-1,3,4,4a,5,8a-hexahydroisoquinolin-6(2H)-ylidene)-N-phenylacetamide 9.

The central cyclo­hexenone ring of the non-planar title compound adopts an envelope conformation. The crystal structure of the compound is stabilized by C—H⋯O and C—H⋯π inter­actions, forming a three-dimensional network., In the title compound, C25H20O2, the central cyclo­hexenone ring adopts an envelope conformation. The mean plane of the cyclo­hexenone ring makes dihedral angles of 87.66 (11) and 23.76 (12)°, respectively, with the two attached phenyl rings, while it is inclined by 69.55 (11)° to the phenyl ring of the benzoyl group. In the crystal, the mol­ecules are linked by C—H⋯O and C—H⋯π inter­actions, forming a three-dimensional network.

The molecular and crystal structures of 1-(4-fluorophenyl)-1,4-dihydro-1H-tetrazole-5-thione (I) and its complex with cadmium(II) (II) are studied by single crystal XRD. Free ligand I is thione; it has a nonplanar structure (the torsion angle between the tetrazole and benzene rings is 54.99(7)°) and forms H-bonded centrosymmetric dimers via two N–H…S hydrogen bonds in the crystal. The dimers contain a central planar eight-membered {S=C–N–H…S=C–N–H…} ring. Complex II has a chain structure with the composition [(C7H4N4FS)2Cd]n. The environment of the Cd(II) atom consists of two nitrogen atoms and two sulfur atoms from four ligands I and represents a distorted tetrahedron. When complex II forms, ligand I converts into the thiol form. Infinite 1D chains contain eight-membered {←S=C–N–Cd←S=C–N–Cd} rings in a chair conformation. The chains in the crystal are arranged in layers parallel to the (101) plane due to secondary intermolecular F…F and π–π-stacking interactions.

We report a novel three-component condensation of benzalacetophenone, ethyl acetoacetate, and malonodinitrile in a 1:1:1 molar ratio respectively, involving an equimolar amount of morpholine acetate to form ethyl-4,6(R,S)-diphenyl-2-dicyanomethylenecyclohex-3-ene-1(R,S)-carboxylate whose crystal structure is determined by single crystal XRD. The intermolecular interaction is analyzed using an atomatom potential model, and infinite chains of energetically tightly coupled molecules in the crystal structure are identified and described. A weak hydrogen bond of the CAr–H…O type is found.

C14H17NO3, monoclinic, P21/n (no. 14), a = 11.1445(7) Å, b = 8.5442(5) Å, c = 14.2503(8) Å, β = 97.5684(11)°, V = 1345.10(14) Å3, Z = 4, R gt(F) = 0.0668, wR ref(F 2) = 0.1680, T = 296(2) K.

Ethyl 3,3,5,5-tetracyano-2-hydroxy-2-methyl-4,6-diphenylcyclohexane-1-carboxylate was synthesized for the first time by three-component condensation of benzaldehyde with ethyl acetoacetate and malononitrile in the presence of trichloroacetic acid. The product structure was proved by X-ray analysis.

The title compound 4-(3-methoxyphenyl)-3-(2-thienylmethyl)-4,5-dihydro-3H-1,2,4-triazole-3-selone 2 was synthesized by two-step procedure including condensation of 1-isoselenocyanato-3-methoxybenzene with 2-(2-thienyl)acetohydrazide to selenosemicarbazide 1 and its intramolecular cyclization. Oxidation of selone 2 by atmospheric oxygen or hydrogen peroxide furnished corresponding diselenide 3 or product of elimination of selenium 1,2,4-triazole 4. Alkylation of compound 2 by benzyl chloride leads to the formation of selenide 5. The synthesized compounds have been characterized by spectroscopic techniques and the structures of 3,4 and 5 were confirmed by X-ray diffraction techniques and the supramolecular contacts were analyzed by Hirshfeld surface analyses.

According to an X-ray diffraction study, pyridine-2-selenenyl chloride (1) characterized by unusually high stability both in solutions and in the solid state adopts a dimeric structure formed by two secondary intermolecular Se···N interactions. However, it slowly transforms into zwitterionic T-shaped pyridinium-2-selenenyl dichloride (2) in a dichloromethane solution. Conformational features, electronic structures, and reactivities of 1 and 2 are discussed on the basis of experimental and theoretical (quantum chemical calculations) data.

The reaction of aromatic aldehydes with Meldrum's acid and malononitrile dimer in the presence of triethylamine led to the formation of (4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridin-2-yl)malononitrile triethylammonium salts, which were converted upon acidification to (4-aryl-3-cyano-6-oxopiperidin-2-ylidene)malononitriles. The reaction of these compounds with thioglycolic acid anilide was observed to produce derivatives of 1,6-naphthyridine or thieno[2,3-h][1,6]naphthyridine, depending on the conditions. Structures of (3-cyano-6-oxo-4-phenylpiperidin-2-ylidene)malononitrile and its triethylammonium salt were studied by X-ray structural analysis.

A new copper(II) complex with acetylacetone and ethylenediamine is obtained using the template synthesis. It is studied by single crystal X-ray diffraction. The crystals are monoclinic: а = 7.7563(4) A, b = 24.0157(12) A, c = 24.6353(13) A, β = 91.9490(10)°, V = 4586.2(4) A3, space group P2(1)/c, Z = 2, d calc = 1.713 g/cm3, R = 0.0695. The copper atom environment consists of two oxygen and two nitrogen atoms of the ligand, forming a slightly distorted square.

2-(Chloro­selan­yl)pyridine 1-oxide represents the first monomeric organoselenenyl chloride stabilized by an intra­molecular secondary Se⋯O inter­action., The title compound, C5H4ClNOSe, is the product of the reaction of sulfuryl chloride and 2-selanyl-1-pyridine 1-oxide in di­chloro­methane. The mol­ecule has an almost planar geometry (r.m.s. deviation = 0.012 Å), and its mol­ecular structure is stabilized by an intra­molecular secondary Se⋯O inter­action of 2.353 (3) Å, closing a four-membered N—C—Se⋯O ring. The title compound represents the first monomeric organoselenenyl chloride stabilized intra­molecularly by an inter­action of this type. The non-valent attractive Se⋯O inter­action results in a substantial distortion of the geometry of the ipso-carbon atom. The endo-cyclic N—C—Se [102.1 (3)°] and exo-cyclic C—C—Se [136.9 (3)°] bond angles deviate significantly from the ideal value of 120° for an sp 2-hybridized carbon atom, the former bond angle being much smaller than the latter. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, forming zigzag chains propagating along [010]. The chains, which stack along the a-axis direction, are linked by offset π–π inter­actions [inter­centroid distance = 3.960 (3) Å], forming corrugated sheets parallel to the ab plane.

A new complex of copper (II) with 3-(2-hydroxy-3-sulfo-5-nitrophenylazo)-pentadione-2,4 (HL) is synthesized and analyzed by single crystal XRD. The crystals are monoclinic: a = 7.7563(4) A, b = 24.0157(12) A, c = 24.6353(13) A, β = 91.9490(10)°, V = 4586.2(4) A3, space group P21/c, Z = 2, ρcalc = 1.713 g/cm3, R = 0.0695. The environment of the copper atom is formed by three oxygen atoms, the nitrogen atom of tetradentate ligand, and the oxygen atom of a water molecule.

The reaction of diethyl-5-methyl-3-oxo-1,2,3,6-tetrahydro-[1,1′-diphenyl]-2,6-dicarboxylate with (1-(4-bromophenyl)ethylidene)hydrazine is conducted, and the crystal structure of the product of this reaction (diethyl-5-(2-(1-(4-bromophenyl)ethylidene)hydrazinyl)-3-methyl-1,2-dihydro-[1,1′-diphenyl]-2,6-dicarboxylate) is determined by single crystal X-ray diffraction. The conformation of the cyclohexadiene ring in the form of a strongly distorted half-chair is determined based on the X-ray diffraction data. The presence of the intramolecular hydrogen bond of the N–H…O=C type is noted.

The condensation of diethyl 4-hydroxy-4-methyl-6-oxo-2-(4-substitutedphenyl)-cyclohexane-1,3-dicarboxylates and N′-(2-chloropropyl)ethane-1,2-diamine leads to diethyl 1-(2-chloropropyl)-9-hydroxy-9-methyl-7-phenyl-1,4-diazaspiro[4.5]decane-6,8-dicarboxylate ( 2 ) and its para -substituted methyl ( 1 ), chloro ( 3 ), bromo ( 4 ), and nitro ( 5 ) derivatives with a new stereogenic center, which were fully characterized by elemental analysis, ESI-MS, IR, 1 H and 13 C NMR spectroscopies and X-ray single-crystal analysis (for 2 ). The condensation reaction is regioselective, only cyclohexanone carbonyl moiety undergoes the transformation, leaving the β-keto ester carbonyls unreacted. Withing the compounds 1 – 5 , the increase in the Hammett’s σ p , related normal σ p n , inductive σ I , negative σ p - and positive σ p + polar conjugation and Taft’s σ p o substituent constants generally leads to the corresponding drift of δ O H and δ N H NMR chemical shifts to lower field.

The complexes [Co(HL2)2]·H2O·3CH3OH (3), [Ni(HL1)2]·4H2O·CH3OH (4) and [Ni(HL2)2]·4H2O·CH3OH (5) with 4-((2-hydroxybenzyl)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (H2L1, 1) and 4-((5-bromo-2-hydroxybenzyl)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (H2L2, 2) ligands were synthesized and characterized by elemental analysis, ESI-MS, IR spectroscopy and X-ray single-crystal analysis. Compounds 1 and 2 were prepared by the Schiff condensation of 4-aminoantipyrine and salicylaldehyde or its 5-bromo-derivative with subsequent reduction. 1 and 2 were characterized by elemental analysis, ESI-MS, IR, 1H and 13C NMR spectroscopies. All the complexes 3–5 have a metal-to-ligand ratio of 1:2, the ligands being coordinated in the ONO mode, while the Co(II) and Ni(II) ions display a distorted octahedral geometry. In the solid state, 3–5 are arranged as 1D supramolecular chains through H-bonded water–methanol clusters placed in the voids of the metal-organic units.

New arylhydrazone derivatives of β-diketones, 2-(4-bromophenylhydrazono)-5,5-dimethylcyclohexane-1,3-dione ( 1 ), 5-(4-bromophenylhydrazono)pyrimidine-2,4,6(1 H ,3 H ,5 H )-trione ( 2 ) and ( E )-2-(4-bromophenylhydrazono)-1-phenylbutane-1,3-dione ( 3 ), were prepared by coupling of β-diketone with the respective para -bromophenyldiazonium chloride, and characterized by IR, 1 H and 13 C NMR spectra. The IR and NMR spectral data disclose an effective intramolecular hydrogen bonding in all the cases. The single crystal X-ray analysis of 3-(4-bromophenyl-hydrazono)pentane-2,4-dione ( 4 ) evidences the intramolecular resonance-assisted hydrogen bonding (RAHB) which is significantly strengthened in view of the planarity of the six atoms involved in the resonance cycle. Compound 3 derived from the unsymmetric 1-phenylbutane-1,3-dione exists in solution as a mixture of the enol-azo and hydrazone tautomeric forms and an increase of the solvent polarity shifts the tautomeric balance to the enol-azo form, while for 1 , 2 and 4 , derived from the symmetric β-diketones, the hydrazone form is dominating under all the studied conditions.

New azoderivatives of pentane-2,4-dione, 3-(4-bromophenylhydrazo)pentane-2,4-dione (HL1) and 3-(4-acetylphenylhydrazo)pentane-2,4-dione (HL2), have been synthesized by reaction between pentane-2,4-dione and the corresponding aryldiazonium salts, and characterized by IR, UV–vis, 1H and 13C NMR spectroscopies, potentiometry, X-ray diffraction analysis (for HL2) and thermogravimetry. The collected data confirm that HL1–2 exist in DMSO solution and in solid phase exclusively in the hydrazo form, being stabilized by an intramolecular hydrogen bonding. The thermodynamics of proton dissociation of HL1–2 and of the related known 3-(4-nitrophenylhydrazo)pentane-2,4-dione (HL3), in water–ethanol media, were studied quantitatively and the corresponding functions were calculated, showing a dependence on the inductive electron-acceptor character of the substituent in para-position of the aromatic part of the molecule. The thermal decompositions of HL1–3 were also investigated showing their high thermal stability with well-defined peaks of phase transition at 413–418 K. The wavelengths (or wavenumbers) of maxima of absorption bands in the UV–vis spectra of HL1–3 and the corresponding absorption coefficients are dependent on the para substituent, but no correlation was found with any particular property of the solvent, such as polarity, H-bond donating or accepting ability.

The structural and tautomeric characteristics of 3-(4-fluorophenylhydrazone)pentane-2,4-dione were studied using IR, 1H and 13C NMR spectroscopy, X-ray diffraction analysis and quantum-chemical calculations. Crystallographic data shows that the compound has a hydrazone structure that contains intramolecular H-bonds assisted by resonance, with a N–O distance of 2.5872 A. The effective atomic charges in the tautomeric forms of the colorant (enol-azo, keto-azo and hydrazone), was calculated using an MO LCAO quantum-chemical method employing the Huckel approximation; the compound was stabilized in the hydrazone form and displayed high reactivity. The thermodynamic functions of the proton dissociation constant of the colorant were determined by potentiometry; the dissociation process was unspontaneous, endothermic and entropically unfavorable. The findings reveal that the colorant has the same structure in both DMSO solution and the solid state.

The copper(II) complex with 3-(2-hydroxy-3-sulfo-5-nitrophenylhydrazo)pentane-2,4-dione (H3L) is studied, and its crystal structure is studied by X-ray diffraction analysis. The crystals of [Cu(H2O)2]2(μ-L)2[Cu(H2O)4] (I) are triclinic (space group P\( \bar 1 \)) at 100 K, a = 7.085(3), b = 10.373(5), c = 12.265(6) A, α = 0.842(5)°, β = 104.996(6)°, γ = 99.156(6)°, Z = 1). The C=O and NH groups of hydrazone and the OH and SO3H groups from the aromatic moiety of the molecule are involved in coordination with the copper(II) atom. In the centrosymmetric trinuclear molecule the central Cu(2) atom has the coordination number six, and the terminal Cu(1) atoms have the coordination number five. The thermal properties of complex I are studied. The complex formation of copper(II) with the H3L ligand in an aqueous solution at temperatures 298 ± 0.5, 308 ± 0.5, and 318 ± 0.5 K is studied by potentiometric titration. The standard thermodynamic functions of the complex formation are determined.

The synthesis and anion binding properties of a neutral macrocyclic receptor bearing H-bond donor coordination sites are described. The anion binding studies by use of UV-vis and 99Tc NMR methods revealed that the receptor can coordinate perrhenate and pertechnetate in dimethylsulfoxide and chloroform solutions with the relatively high binding constants, viz. log Ka > 4. The coordination mode of the perrhenate to the receptor was determined by a single-crystal X-ray diffraction analysis.

The crystal structures of ethyl-4-(5-bromo-2-hydroxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate and ethyl-1-methyl-15-oxo-2-oxa-14,16-diazatetracyclo[11.3.1.03.12.06.11]heptadeca-3,5,7, 9,11-pentaene-17-carboxylate were determined by XRD, and the conformations of their structures were determined.

New multicomponent condensation of dimedone, benzaldehyde, acetacetic ester, and allylamine in the 1:2:1:1 molar ratio respectively is revealed. It proceeds with the formation of ethyl-3(allylamino)-9,9-dimethyl-7,11-dioxo-1.5-diphenyl-spiro[5.5]undec-2-en-2-carboxylate whose crystal structure is determined by single crystal X-ray diffraction.