Crystal structure of <Emphasis Type="Italic">ortho</Emphasis>-toluidinium hexafluorosilicate

The structure of the complex (o-CH₃C₆H₄NH₃)₂SiF₆ was determined by X-ray diffraction. In the ionic structure of the complex, the SiF ₆ ^2? anions (Si-F, 1.595(9)-1.683(17)Å) and the o-CH₃C₆H₄NH ₃ ⁺ cations are combined by NH?F hydrogen bonds (N?F 2.757(10)-3.25(2) Å). The components of the structure are combined into a layer whose central part is formed by the SiF ₆ ^2? anions and the outer hydrophobic surfaces are formed by the aromatic rings of the cations.     

Thermal behavior of quinoline <Emphasis Type="Italic">N</Emphasis>-oxide hydrates and deuterohydrate

Spectral and thermochemical investigation of physicochemical properties of quinoline N-oxide crystallohydrates with H₂O and D₂O is carried out. Quinoline N-oxide is established to form with H₂O a stable dihydrate where two water molecules are energetically not equal. Complete dehydration of quinoline N-oxide occurs when temperature reaches 150°C. With accounting for the obtained thermochenical data, quinoline N-oxide and its mono- and dihydrates are isolated in the individual state and their IR spectra are registered and considered. It is established that at boiling quinoline N-oxide in D₂O proceeds chemical reaction affording isoindoline-1,3-dione (phthalimide). The product is identified by elemental analysis and ¹H NMR and IR spectroscopy. The band assignment in the IR spectra of quinoline N-oxide, phthalimide and of the complex of the latter with D₂O is based on the quantum-chemical DFT calculations.     

Synthesis and crystal structure of <Emphasis Type="Italic">N,N</Emphasis>-dimethylbiguanidinium hexafluorosilicate

The complex [(CH₃)₂NC(NH₂)NHC(NH₂)NH₂]SiF₆ (I) was synthesized and its structure was determined by X-ray crystallography. The crystals are monoclinic: a = 7.4346(10) Å, b = 12.7628(10) Å, c = 11.0828(10) Å, β 104.080(10)°, V = 1020.01(18) ų, ρ_calc = 1.780 g/cm³, μ(MoK _α) = 0.302 mm^?1, Z = 4, space group P2₁/c. The crystals of I are composed of SiF ₆ ^2? anions (Si-F, 1.657(2)–1.699(2) Å) and N,N-dimethylbiguanidinium (H₂L²⁺) cations combined in a framework by interionic H-bonds NH···F. In the cations, protonation sites are the terminal imide groups.     

Binuclear copper(II) complexes with acyldihydrazones of <Emphasis Type="Italic">N</Emphasis>-benzenesulfonyl-<Emphasis Type="Italic">L</Emphasis>-aspartic acid

The structure and the EPR spectra of copper(II) coordination compounds with acyldihydrazones of N-benzenesulfonyl-L-aspartic acid and salicylaldehyde (2-hydroxyacetophenone) were described. The compounds were studied by chemical and thermal analyses, IR spectroscopy, and EPR. The molecular and crystal structures of copper(II) complexes with N-benzenesulfonyl-L-aspartic acid bis(salicylidene)hydrazone (H₄L¹) [Cu₂L¹ · 2Py] · 1.5 H₂O was determined by X-ray diffraction. The crystals are triclinic: a = 10.4714(4) Å, b = 12.9702(5) Å, c = 14.6187(9) Å, α = 104.763(2)°, β = 93.082(2)°, γ = 111.4240(10)°, space group P \(\bar 1\), Z = 2. The binuclear complexes containing copper cations whose coordination polyhedra are connected by an aliphatic spacer (Cu...Cu, 8.669 Å) are additionally linked by phenoxy bridges (Cu...Cu, 3.398 Å). The EPR spectra of these compounds in solutions exhibit an isotropic signal of seven HFS lines due to two equivalent copper ions with the spin Hamiltonian parameters g = 2.115?2.120, a _Cu = (35.5?38.0) × 10^?4 cm^?1, which is indicative of weak exchange interactions between the paramagnetic sites.     

Crystal Structure of <Emphasis Type="Italic">DL</Emphasis>-Valinium Tetrafluoroantimonate(III) Monohydrate

The crystal structure of an antimony(III) fluoride complex of the composition (C₅H₁₂NO₂)SbF₄·H₂O (I) involving a cation of α-amino isovaleric acid (DL-valine, Val) is determined. Crystals are monoclinic: a = 12.2024(2) Å, b = 6.1636(1) Å, c = 15.5167(3) Å, Z = 4, space group P2₁/c. The structure is formed of DL-valinium (C₅H₁₂NO₂)⁺ cations, complex [SbF₄]_n^n? anions having a polymeric chain structure, and crystallization water molecules. The [SbF₄]_n^n? complex anions consist of trigonal SbF4E bipyramids joined together by asymmetric bridging Sb–F(3)···Sb bonds. The structural units are organized into a threedimensional framework via N–H···F, N–H···O, and O–H···F hydrogen bonds.     

Crystallographic and conformational analysis of (<Emphasis Type="Italic">E</Emphasis>)-2-isopropyl-4-(<Emphasis Type="Italic">p</Emphasis>-tolyldiazenyl)phenol

The molecular and crystal structures of the title compound, C₁₆H₁₈N₂O, were characterized and determined by single crystal X-ray diffraction method in addition to spectroscopic means such as IR, UV–VIS and ¹H NMR. The compound crystallizes in orthorhombic space group P bca, with a = 9.3350(5) Å, b = 23.4878(13) Å, c = 26.5871(12) Å, Z = 16, D _calc. = 1.1591(1) g/cm³, μ (MoK_α) = 0.073 mm^?1. Monomers of the compound in the crystal structure are linked into C(7) and C(8) chains generated by translation along the [1 0 0] direction with the aid of O–H···N type H-bonds which serve to the stabilization of periodic organization of the molecules beside major and minor component in the disordered azo fragment. In order to describe conformational flexibility and the crystal packing effects on the molecular conformation, potential barriers regarding the rotation along both Ar–N bonds were calculated by varying the related torsional degrees of freedom in every 10° ranging from ?180° to +180° via quantum chemical calculations at DFT/B3LYP level.     

Reaction of <Emphasis Type="Italic">o</Emphasis>-aminophenol and <Emphasis Type="Italic">o</Emphasis>-aminobenzyl alcohol with palladium(II) bis(isocyanide) complexes

Reactions of palladium(II) bis-isocyanide complexes cis-[PdCl₂(CNR)₂] (R = 2,6-Me₂C₆H₃, 2-Me-6-ClC₆H₃) with an equimolar amount of chelating N,O-binucleophiles, 2-aminophenol and (2-aminophenyl)-methanol, in acetonitrile at room temperature in 24 h selectively afforded the corresponding open-chain monocarbene complexes. The complexation involved one isocyanide ligand and amino group of the aromatic amine. Neither bis(carbene) complexes (in the reactions with 4 equiv of the nucleophile under harsh conditions) nor C,O-chelate structures were detected. The isolated complexes were characterized by elemental analyses, IR, NMR, and mass spectra, and X-ray diffraction data.     

Synthesis and antibacterial activity of new <Emphasis Type="Italic">N</Emphasis>-substituted 7-amino-4-methyl-2<Emphasis Type="Italic">H</Emphasis>-chromen-2-ones

N-Substituted 7-amino-4-methyl-2H-chromen-2-ones containing one or two functionalized azole or azine moieties were synthesized. The structures of all synthesized compounds were confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy. Some of the synthesized compounds exhibited weak antibacterial activity against Rhizobium radiobacter, Escherichia coli, and Xanthomonas campestris.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-aryl-2-methyl-4-oxo-3,4,5,6-tetrahydro-2<Emphasis Type="Italic">H</Emphasis>-2,6-methano-1,3,5-benzoxadiazocine-11-carboxamides

N-Aryl-2-methyl-4-oxo-3,4,5,6-tetrahydro-2H-2,6-methano-1,3,5-benzoxadiazocine-11-carboxamides were synthesized by three-component reactions of N-aryl-3-oxobutanamides with salicylaldehyde and urea in ethanol in the presence of NaHSO₄ as catalyst. The product structure was determined by IR and ¹H NMR spectroscopy and X-ray analysis.     

Complexes of cobalt(II) halides with 2-(1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)-4(3<Emphasis Type="Italic">H</Emphasis>)-pyrimidinone

The electronic structures of complexes of cobalt(II) halides with 2-(1H-pyrazol-1-yl)-4(3H)-pyrimidinone have been studied by X-ray photoelectron spectroscopy. The Co2p _3/2 lines of cobalt atoms, N1s lines of nitrogen atoms, and O1s lines of oxygen atoms in the X-ray photoelectron spectra have been analyzed. Based on these data for the free and coordinated ligands, the atoms of the ligand coordinated to the central metal atom are determined. The coordinated organic compound serves as an electron-donating ligand. The results obtained are consistent with IR and UV-Vis spectroscopic data.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-and <Emphasis Type="Italic">C</Emphasis>-trimethylsilyl-substituded anililes

N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl)bromoanilines depending on the structure of substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline, 2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylaniline, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilyl-N-trimethylsilylaniline, 2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The structures of the compounds obtained were established by the chromato-mass spectrometry and ¹H, ¹³C, and ²⁹Si NMR spectroscopy.     

Conformations and properties of <Emphasis Type="Italic">O</Emphasis>-Alkyl-<Emphasis Type="Italic">S</Emphasis>-(2-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dialkylamino)-ethylmethylthiophosphonates

Conformers of the biologically active compounds CH₃P(O)(OR)(SCH₂CH₂NR ₂ ^′ ), where (I) R = i-C₄H₉, R′ = C₂H₅ and (II) R = C₂H₅, R′ = i-C₃H₇, are calculated within the AM1 level of theory. The elongated and twisted forms with maximum and minimum distances between a nitrogen atom and those of a phosphorus tetrahedron, respectively, and bearing a syn and anti oriented alkoxy group relative to a phosphoryl oxygen, are studied. It is found that the differences between the energy, electronic, and geometric parameters of these forms are apparent in differences between their properties, e.g., the ability to participate in complexation and protonation, reactions that to some extent simulate the interaction between a substance and a biological object.     

Synthesis and structure of Pt(II) acetamidate complexes containing <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethyl-substituted ethylenediamine and trimethylenediamine

Reactions of acetamide with platinum(II) diamines [Pt(N,N-DimeEn)Cl₂], [Pt(Tm)Cl₂], and [Pt(N,N-DimeTm)Cl₂] (N,N-DimeEn = (CH₃)₂N(CH₂)₂NH₂, Tm = NH₂(CH₂)₃NH₂, N,N-DimeTm = (CH₃)₂N(CH₂)₃NH₂) with preliminary precipitation of chlorine ions by silver salts gave binuclear Pt(II) acetamidates [Pt₂(CH₃)₂N(CH₂)₂NH₂)₂(μ-NHCOCH₃)₂](NO₃)₂ · H₂O (I), [Pt₂(NH₂(CH₂)₃NH₂)₂)(μ-NHCOCH₃)₂](NO₃)₂ · H₂O (II), and [Pt₂(CH₃)₂N(CH₂)₃NH₂)₂(μ-NHCOCH₃)₂](HSO₄)₂ (III), whose crystal structures were determined. Crystals of I are monoclinic: a = 14.459(2) Å, b = 17.197(3) Å, c = 9.822(2) Å, β = 105.923(10)°, V = 3348.6(8) ų, space group P2(1)/c, Z = 4, R _hkl = 0.0419 for 6663 reflections. Complex I is a binuclear acetamidate with bridging (NHCOCH₃)^? ligands, one of which is bound to two Pt atoms through the N and O atoms, and the other ligand is bound only through the N atom. The Pt-Pt distance is 2.987(1) Å. Crystals of II are monoclinic: a = 10.213(7) Å, b = 13.373(9) Å, c = 16.533(11) Å, β = 97.971(9)°, V = 2236(3) ų, space group P2(1)/n, Z = 4, R _hkl = 0.557 for 6462 reflections. The Pt-Pt distance is 3.057(1) Å. Crystals of III are monoclinic: a = 10.557(12) Å, b = 18.531(2) Å, c = 14.4744(17) Å, β = 108.705(2)°, V = 2682(5) ų, space group P2(1)/n, Z = 4, R _hkl = 0.569 for 8506 reflections. The Pt-Pt distance is 3.202(1) Å. Complexes II and III are binuclear acetamidates, in which two chelating Pt(Tm) or Pt(N,N-DimeTm) moieties are coordinated through the N and O atoms of (NHCOCH₃)^? cis-bridges.     

Structural characterization of a mixed-ligand complex of copper(II) with 1,10-phenanthroline and the <Emphasis Type="Italic">m</Emphasis>-aminobenzoate ion

A new copper(II) complex of 1,10-phenanthroline (C1₂H₈N₂) and the meta-aminobenzoate ion (m-amb; C₇H₆NO ₂ ^? ), having the formula Cu(C₁₂H₈N₂)(C₇H₆NO₂)Cl?0.5H₂O, is prepared and characterized by elemental analysis, IR spectroscopy, and single crystal X-ray diffraction. The structure is built up from monomeric units in which the coordination environment around the metal ion is a square plane arising from a bidentate 1,10-phenanthroline molecule, a monodentate m-amb anion, and a chloride ion. A very long (Cu–N = 2.856(5) Å) bond to the nitrogen atom of an adjacent m-amb ion generates [101] polymeric chains in the crystal. The crystal structure is consolidated by N–H???O and O–H???O hydrogen bonds and C–H???O, C–H???Cl, and aromatic π–π stacking interactions. Crystal data: C₁₉H₁₅ClCuN₃O_2.5, M _r = 424.33, monoclinic, P2₁/n (No. 14), a = 9.8200(5) Å, b = 10.9291(7) Å, c = 16.3803(9) Å, β = 105.293(3)°, V = 1695.74(17) ų, Z = 4, R(F) = 0.043, wR(F ²) = 0.122.     

Crystal structures of <Emphasis Type="Italic">tris</Emphasis>-hexafluoro-acetylacetonates of aluminum and scandium

The structures of tris-hexafluoroacetylacetonates Al(hfa)₃ and Sc(hfa)₃·H₂O are determined by single crystal X-ray crystallography (Bruker-Nonius X8 Apex diffractometer, MoK _α radiation, T = 150(2) K). The Al(hfa)₃ complex is trigonal, a = 17.8944(11) Å, c = 12.4061(11) Å, P-3c1 space group, V = 3440.3(4) ų, Z = 6, R = 0.076. The Sc(hfa)₃·H₂O complex is monoclinic, a = 16.0926(4) Å, b = 14.7980(3) Å, c = 24.4020(5) Å, β = 125.641(1)°, P2₁/c space group, V = 4722.54(18) ų, Z = 8, R = 0.060. The structures of the complexes are formed by neutral molecules; the coordination environment of the metal atom involves six oxygen atoms of three β-diketone ligands (Al(hfa)₃) and, additionally, a water oxygen atom (Sc(hfa)₃·H₂O). The shortest Al...Al distance is 6.203(6) Å. The Sc(hfa)₃·H₂O molecules are joined in dimers by hydrogen bonds with Sc...Sc separations of 5.6992(8) Å and 5.6853(8) Å. In the crystals, the molecules are joined by van der Waals interactions, moreover, there are intermolecular contacts F...H ～ 2.5 Å in the structure of Sc(hfa)₃·H₂O.     

Tautomerism of aza cycles: II. Synthesis and structure of 5-substituted 3-(2-hydroxyethylsulfanyl)-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazoles and their salts. Preference of the 1H,4<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazolium tautomers

New complexing agents, potentially tautomeric 3-(2-hydroxyethylsulfanyl)-1H-1,2,4-triazole, its 5-methyl-and 5-phenyl-substituted analogs, and some their salts, were synthesized, and their structure was discussed on the basis of the ¹H and ¹³C NMR, IR, and mass spectra, X-ray diffraction data, and published data. In keeping with the rule formulated previously for N-unsubstituted 1,2,4-triazoles having dissimilar substituents, the synthesized compounds were found to exist as 3-(2-hydroxyethylsulfanyl)-5-R-1H-1,2,4-triazole tautomers (3-R_A-5-R_D-1H-1,2,4-triazoly). They are protonated at the nitrogen atom in position 4 of the triazole ring. The ¹H and ¹³C NMR spectra of these compounds in trifluoroacetic acid suggest the presence of two forms due to equilibrium between the neutral and protonated species. Analysis of the crystallographic data for the triazolium salts and published data showed preference of the 1H,4H-1,2,4-triazolium tautomer.     

Mononuclear and heterodinuclear phenanthrolinedione complexes of <Emphasis Type="Italic">d</Emphasis>- and <Emphasis Type="Italic">f</Emphasis>-block elements

1,10-Phenanthroline-5,6-dione (Phd) complexes of group 3 and lanthanide elements having formulae Ln(hfac)₃(Phd) (Ln = Y, Eu, Yb; hfac = hexafluoroacetylacetonate) were synthesised and characterised. Complexes of d-block elements of the type [MCl(Phd)(p-cymene)]⁺ (M = Ru, Os) were also prepared. In all these species, coordination of the polydentate ligand occurs by the N-donor moieties, as indicated by DFT calculations. The novel compounds were tested, together with fac-ReBr(Phd)(CO)₃, as precursors for the preparation of heterobimetallic d/f derivatives. The reaction of the rhenium complex with yttrium or lanthanide anhydrous triflate salts led to the formation of the complexes ReBr(CO)₃(N,N′-Phd-O,O′)Ln(OTf)₃(THF) (Ln = Y, Eu, Yb), where the trivalent ions interacted with the quinonoid moiety. The redox properties of the rhenium centre were strongly affected by the coordination of Ln(OTf)₃, as observed by comparing the cyclic voltammetry measurements carried out on fac-ReBr(Phd)(CO)₃ and on ReBr(CO)₃(N,N′-Phd-O,O′)Y(OTf)₃.     

The <Emphasis Type="Italic">pVT</Emphasis> properties and phase equilibria in the <Emphasis Type="Italic">n</Emphasis>-pentane-water binary system

The pVT properties of the 0.075 n-C₅H₁₂ + 0.925H₂O binary system were studied experimentally. Thermal properties were measured along nine different isochores over the density and temperature ranges 87–698 kg/m³ and 303–684 K at pressures up to 60 MPa. Measurements were performed using a constant-volume piezometer. Inflection and break points of the p(T) dependences were used to construct phase equilibrium curves, which were described by scaling equations.     

Synthesis and X-ray study of 6<Emphasis Type="Italic">H</Emphasis>-chromeno[3,4-<Emphasis Type="Italic">e</Emphasis>][1,3,4]triazolo[2,3-<Emphasis Type="Italic">a</Emphasis>]pyrimidine

2-Dimethylamino methylenechromanone 1 reacted with 4H-1,2,4-triazol-3-amine in acetic acid to give only one isolated product which was identified by X-ray study as 6H-chromeno[3,4-e][1,3,4]triazolo[2,3-a]-pyrimidine. The molecular structure of 3, C₁₂H₈N₄O, was determined to be monoclinic, P2₁/c, a = 16.3875(5), b = 8.8378(3), c = 13.8392(5) Å, β = 101.190(1)°, V = 1966.22(11) ų, Z = 8.     

Electronic effect of substituents in coupling reactions between <Emphasis Type="Italic">para</Emphasis>-substituted benzamidoximes and nitrile ligands in <Emphasis Type="Italic">cis</Emphasis>-[PtCl<Subscript>2</Subscript>(EtCN)<Subscript>2</Subscript>] complex

The rate constants were determined for a number of reactions of nucleophilic addition of para-substituted benzamidoximes 4-RC₆H₄C(NH₂)=NOH to cis-[PtCl₂(EtCN)₂] at 23°C in acetone. A linear correlation between log (k _R/k _H) and σ _para was found, and reaction constant ρ²⁹⁶(σ _para ) was calculated. The prepared compounds were characterized by IR, ¹H NMR, and HR ESI⁺-MS.