Unusual molecular structure of (C=O→Si←O′=C′) bis(2-methyl-4-pyrone-3-oxy)difluoro(λ6)siliconium

X-ray diffraction is used to determine the crystal and molecular structure of spirocyclic (C=O→Si←O′=C′) bis(2-methyl-4-pyrone-3-oxy)difluoro(λ⁶)siliconium containing a hypervalent silicon atom and the previously unknown F₂SiO₄ coordination center. The coordination polyhedron of the silicon atom is a slightly distorted octahedron.     

Gas-phase electronic absorption spectroscopy of substituted bis(η<Superscript>6</Superscript>-benzene)chromium derivatives: Rydberg transitions in bis(η<Superscript>6</Superscript>-anisole)chromium and bis(η<Superscript>6</Superscript>-2,6-dimethylpyridine)chromium

Gas-phase electronic absorption spectra of chromium bisarene complexes with oxygen- and nitrogen-containing ligands, (⁶-PhOMe)₂Cr (1) and (⁶-2,6-Me₂C₅H₃N)₂Cr (2), were first measured. Rydberg bands disappearing on going to the condensed-phase spectra were revealed. The first ionization potentials of complexes 1 and 2 (5.30 and 5.40 eV, respectively) were determined from the Rydberg frequencies. The Rydberg transitions were assigned and the corresponding Rydberg term values and quantum defects were determined. The effect of heteroatoms on the Rydberg structure parameters was revealed by comparing the spectra of complexes 1 and 2 with those of unsubstituted analogs. The appearance, in the ligand side chain, of an oxygen atom capable of being involved in conjugation with the -electron system of the aromatic ring results in substantial broadening of the observed Rydberg bands. This can be associated with an increased ligand contribution to the HOMO of the sandwich compound. The influence of the oxygen atom on the ionization energy of the molecule is insignificant. In contrast to this, introduction of a nitrogen atom into the carbocycle leads to a noticeable increase in the ionization potential of the molecule, while the ligand contribution to the HOMO of the complex remains practically unchanged.Based on materials of a lecture presented at the International Conference Modern Trends in Organoelement and Polymer Chemistry dedicated to the 50th anniversary of the A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences (Moscow, May 30–June 4, 2004).Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1854–1859, September, 2004.     

Synthesis and structure of novel coordination compounds based on [Re<Subscript>6</Subscript>Q<Subscript>8</Subscript>(CN)<Subscript>6</Subscript>]<Superscript>4–</Superscript> (Q = S,Se) and (SnMe<Subscript>3</Subscript>)<Superscript>+</Superscript>

The reactions of SnMe₃Cl with salts of the cluster anionic complexes [Re₆Q₈(CN)₆]^4? (Q = S, Se) gave novel complexes [{(SnMe₃)₂(OH)}₂{SnMe₃}₂{Re₆S₈(CN)₆}] (I), (Me₄N)₂[{SnMe₃(H₂O)}₂{Re₆Se₈(CN)₆}] (II), [{(SnMe₂)₄(μ₃-O)}₂{Re₆Se₈(CN)₆}] (III), and [(SnMe₂)₄(μ₃-O)₂(μ₂-OH)₂(H₂O)₂][{SnMe_{3 2}{Re₆Se₈(CN)₆}] (IV). The structures of I–IV were determined by X-ray diffraction. Compounds I, IV have the chain structures with the CN-SnMe₃-NC bridges between the cluster anions [Re₆Q₈(CN)₆]^4?. Compound II contains isolated fragments {SnMe₃(H₂O)}₂{Re₆Se₈(CN)₆}^2?. In the polymer framework of compound III, the cluster anionic complexes [Re₆Se₈(CN)₆]^4? are bound by the complex cations [(SnMe₂)₄(μ₃-O)₂]⁴⁺ formed due to the hydrolysis of the initial (SnMe₃)Cl.     

Synthesis of substituted 1-thia-3-aza-λ<Superscript>5</Superscript>-phosphacyclohex-2-ene

The addition of dimethylamine to O-phenyl 2-chloropropylisothiocyanatophosphonate afforded the six-membered cyclic product, viz., 1-thia-3-aza-4⁵-phosphacyclohex-2-ene.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1657–1659, August, 2004.     

Synthesis and crystal structure of a cyanide-bridged one-dimensional nickel(II) complex with alternating [Ni(En)<Superscript>2</Superscript>]<Superscript>2+</Superscript> and [Ni(CN)<Subscript>4</Subscript>]<Superscript>2−</Superscript> ions

The complex [Ni(En)₂][Ni(CN)₄] · 3.5H₂O (I) (En = ethylenediamine) was synthesized by the reaction of [Ni(En)₂](ClO₄)₂ and K₂[Ni(CN)₄] in an H-shaped tube. The crystal structure of I has been determined by single-crystal X-ray analysis. The crystal of complex I is orthorhombic, space group Pnna with a = 28.151(3), b = 8.3946(8), c = 14.5441(13)Å, M =404.76, Z = 8, V = 3437.0(5)ų. The structure of complex I reveals infinite zigzag chains shaped structure are formed by cis-Ni(En)₂-μ-(NC)₂, cis-μ-(NC)₂Ni(CN)₂, and trans-μ-(CN)₂Ni(En)₂.     

Nickel(II) tetraaqua bis(benzoate) tris(phenylacethydrazide) complex [Ni(HL<Superscript>1</Superscript>)<Subscript>3</Subscript>](L<Superscript>2</Superscript>)<Subscript>2</Subscript> · 4H<Subscript>2</Subscript>O: Synthesis and crystal and molecular structure

The synthesis, IR and Raman spectroscopic study, and X-ray diffraction analysis of [Ni(HL¹)₃](L²)₂ · 4H₂O (I), where HL¹ is phenylacetic acid hydrazide and L² is the benzoate monoanion, have been performed. The structural units of a crystal of complex I are complex [Ni(HL¹)₃]²⁺ cations, (L²)^– anions, and crystallization water molecules. The nickel atom is coordinated to the three oxygen atoms at octahedron apices and the three nitrogen atoms of three bidentate chelate (О, N) ligands HL¹ in cis,trans-meredianal (fac) conformation. The structural units of a crystal of complex I are bonded by a branched network of О–Н···О and N–H···O hydrogen bonds.     

Mercury complex [(HOCH<Subscript>2</Subscript>)<Subscript>3</Subscript>CNH<Subscript>3</Subscript>]<Stack><Subscript>2</Subscript><Superscript>+</Superscript></Stack> [HgI<Subscript>4</Subscript>]<Superscript>2−</Superscript>: Synthesis and structure

The complex [(HOCH₂)₃CNH₃] ₂ ⁺ [HgI₄]^2? (I) was synthesized by reacting (trioxymethyl)methylammonium iodide with mercury dioide (2: 1 mol/mol) in acetone. X-ray crystallography shows that the complex consists of two types of crystallographically independent [(HOCH₂)₃CNH₃]⁺ cations and tetrahedral anions [HgI₄]^2? (IHgI, 106.49(2)°–113.99(4)°; Hg-I, 2.7849(8)-2.8105(8) Å. [(HOCH₂)₃CNH₃]⁺ cations are linked via hydrogen bonds O…H-N and O-H…N (O…N, 2.84–2.92 Å) to form polymer chains, which are cross-linked with one another via anions (I…H, 2.81, 2.82 Å).     

Synthesis and structure of cobalt(III) dimethylglyoximate with [FeF<Subscript>5</Subscript>(H<Subscript>2</Subscript>O)]<Superscript>2−</Superscript> anion

A new complex [Co(DH)₂(Thio)₂]₂[FeF₅(H₂O)] · 2CH₃OH (where DH^? is dimethylglyoxime monoanion, Thio is thiourea molecule) was synthesized and its structure was determined. The coordination polyhedron of the Co(III) atoms in two centrosymmetric complex cations is an octahedron, formed by four N atoms of two dimethylglyoxime residues and two S atoms of coordinated Thio molecules. One of the Thio molecules is almost perpendicular to a metal cycle (the dihedral angle 87.8(1)°), which is responsible for realization of intermolecular hydrogen bond N-H···O (N···O 2.990(3) Å). The second Thio molecule is almost parallel to the equatorial CoN₄ fragment (the dihedral angle 159.4(1)°) to give rise to intramolecular π-π interaction between practically planar Thio molecule and one of the π-delocalized metal cycle. The Fe(III) coordination polyhedron is an octahedron, formed by five F atoms and by the O atom of coordinated water molecule. The key role in the crystal structure organization is played by intermolecular hydrogen bonds N-H···F, N-H···O, N-H···S, the intramolecular bonds O-H···O, formed by the donor NH₂ groups of a complex cation with the F atoms of the [FeF₅(H₂O)]^2? and the donor-acceptor groups of the Thio fragments.     

Structure and stability of endohedral complexes <Superscript>4/2</Superscript>X@(HAlNH)<Subscript>2</Subscript> (X = N,P, As,C<Superscript>−</Superscript>, Si<Superscript>−</Superscript>)

The structures of a closo-hedral cluster (HAlNH)₁₂ and endohedral complexes ^4/2X@(HAlNH)₁₂ (X = N, P, As, C⁻, Si⁻) are studied by density functional theory (DFT) at the B3LYP/6-31G(d) level. The geometries, natural bond orbital (NBO), vibrational frequency (ν₁), energetic parameters, magnetic shielding constants (σ), and nucleus independent chemical shifts (NICSs) are discussed. It is found that all guest species are minima at the cage center. Inclusion energies (ΔE _inc) of all species are negative except those of ⁴N and ^4/2P. In all species, the endohedral quartet states (⁴X) are energetically less favorable than their doublet states (²X). The calculations predict that caged X states only donate <0.50 e to the cage and preserve their unencapsulated ground states.     

Synthesis,structural and multinuclear natural abundance (<Superscript>13</Superscript>C, <Superscript>31</Superscript>P, <Superscript>195</Superscript>Pt) CP/MAS NMR studies of crystalline O,O′-dialkyldithiophosphate platinum(II) complexes

Platinum(II) O,O′-dicyclohexyl dithiophosphate [Pt{S₂P(O-cyclo-C₆H₁₁)₂}₂] (I) and platinum(II) O,O′-diisopropyl dithiophosphate [Pt{S₂P(O-iso-C₃H₇)₂}₂] (II) complexes were obtained and studied by solidstate ¹³C, ³¹P, and ¹⁹⁵Pt CP/MAS NMR spectroscopy. The dithiophosphate (Dtph) ligands in molecular structure I were found to be coordinated by platinum in S,S′-bidentate fashion to form the planar chromophore [PtS₄] (single-crystal X-ray diffraction data). For complex II, a new α-form (α-II) was obtained and identified by ³¹P MAS NMR spectroscopy. The ³¹P chemical shift anisotropy δ_aniso and the asymmetry parameter η of the ³¹P chemical shift tensor were calculated from the whole MAS spectra.     

Synthesis and crystal structure of bis(μ-periodato-<Emphasis Type="Italic">O,O′,O″</Emphasis>)bis(18-crown-6)dirubidium

A new binuclear complex, bis(μ-periodato-O,O′,O″)bis(18-crown-6)dirubidium [Rb₂(IO₄)₂(18-crown-6)₂] (I), is synthesized. Its crystal structure is studied by single-crystal X-ray diffraction analysis (space group P2₁/n, a = 11.942 Å, b = 8.394 Å, c = 19.664 Å, β = 101.08°, Z = 4, direct method, anisotropic full-matrix least-squares approximation, R = 0.030 for 2823 independent reflections, CAD-4 automated diffractometer, λMoK _α radiation). Complex I is binuclear and centrosymmetric, consisting of two cationic monomers [Rb(18-crown-6)]⁺ of the host-guest type linked through two tridentate IO ₄ ^? bridging ligands. The coordination polyhedron of the Rb⁺ cation (coordination number 9) can be described as a distorted hexagonal pyramid with a base of six O atoms of one 18-crown-6 ligand and one threefold vertex at three O atoms of the two IO ₄ ^? bridging ligands. The 18-crown-6 ligand has a usual crown conformation.     

Thiophosphorylation of calix[4]resorcinarenes with 2,4-diaryl-1,3-dithia-2λ<Superscript>5</Superscript>,4λ<Superscript>5</Superscript>-diphosphetane 2,4-disulfides

Reactions of 2,4-diaryl-1,3-dithia-2λ⁵,4λ⁵-diphosphetane 2,4-disulfides with tetraheptylcalix[4]-resorcinarene and octa-O-(2-hydroxyethyl)tetraoctylcalix[4]resorcinarene gave the corresponding octakis(aryldithiophosphonic acids).     

Stabilization of [Sc(NCS)<Subscript>6</Subscript>]<Superscript>3−</Superscript> anion by [M(18C6)]<Superscript>+</Superscript> complexes in solvation systems

The [M(18C6)]₄[Sc(NCS)₆]Cl · nH₂O complexes were established to form in the solutions ScCl _x -Solv-MNCS-18C6, where Solv is ethanol, THF, acetonitrile, or isopropyl alcohol; M = Na, K; 18C6 is 1,4,7,10,13,16-hexaoxocyclooctadecane. X-ray diffraction analysis of [K(18K6)]₄[Sc(NCS)₆]Cl · 3.33H₂O showed that the thiocyanate ion was coordinated by Sc through the N atom. The structure consists of octahedral Sc(NCS) ₆ ^3? that are united via nonvalent K-S interaction with macrocyclic dimers [M(18C6)]₂ into chains. Each 18C6 molecule coordinates one K atom.     

Erbium(III) and lutecium(III) complexes [Ln(H<Subscript>2</Subscript>O)<Subscript>8</Subscript>][Cr(NCS)<Subscript>6</Subscript>] · 5H<Subscript>2</Subscript>O: Synthesis and crystal structure

[Ln(H₂O)₈][Cr(NCS)₆] · 5H₂O aqua complexes, where Ln = Er (1), Lu (2), have been found in an aqueous solution instead of binary complex salts with an organic ligand in their cation, when crystal products of the reaction between Ln(NO₃)₃ · 6H₂O (Ln = Er, Lu), K₃[Cr(NCS)₆] · 4H₂O, and 8-oxyquinoline (C₉H₇NO) were studied by X-ray diffraction. Crystals of complexes 1 and 2 are isostructural and crystallize in triclinic system, space group P\(\bar 1\), Z = 2. For complex 1: a = 9.0677(4) Å, b = 9.3115(4) Å, c = 16.9595 Å, α = 81.526(2)°, β = 86.153(2)°, γ = 83.879(2)°, V = 1406.33(10) ų, ρ_calc = 1.894 g/cm³; for complex 2: a = 9.0438(3) Å, b = 9.2880(3) Å, c = 16.9181(3) Å, α = 81.7250(10)°, β = 86.1600(10)°, γ = 83.8850(10)°, V = 1396.38(7) ų, ρ_calc = 1.926 g/cm³.     

Crystal structure and quantum chemical investigation of [Cd(NTO)<Subscript>4</Subscript>Cd(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>] · 4H<Subscript>2</Subscript>O

[Cd(NTO)₄Cd(H₂O)₆] •4H₂O was synthesized by mixing the aqueous solution of 3-nitro-1, 2,4-triazol-5-one (NTO) and cadmium carbonate. The single crystal structure was determined by a four-circle X-ray diffractometer. The crystal is monoclinic, space group C2/c with crystal parameters of a = 2.1229(3) nm, b = 0.6261(8) nm, = 2.1165(3) nm, β= 90.602 (3)°, V= 2.977(6) nm₃, Z = 4, D_c = 2.055 g • cm_-3, μ = 15.45 cm_-1 and F(000) = 1824. 2523 observable independent reflections with F₀4σ(F₀) were used for the determination and refinement of the crystal structure. Lorentz-polarization and absorption correction were applied. The final R is 0.0282 and wR = 0.0792. The analytical results show that the Cd⁺² has two kinds of coordinate bonds in one crystal. One Cd⁺² coordinates with 4 NTO anions and another coordinates with 6 water molecules to form a binucleate complex with a structure of tetrahedron and tetragonal bipyramid, respectively. By using SCF-PM3-MO method, the electron structure of cadmium complex of NTO has been calculated. The analysis of the calculated results shows that when [Cd(NTO)₄Cd(H₂O)₆] • 4H₂O is heated, the crystallization waters will be dissociated first and the ligand waters second and NO₂ group has priority of leaving when NTO⁻ is decomposed. Analysis of the energy level and composition of localized molecular orbitals indicates that both the two Cd²⁺ bond to the coordinating atom with 5s     

Synthesis and pharmacological properties of 3-(2-methyl-furan-3-yl)-4-substituted-Δ<Superscript>2</Superscript>-1,2,4-triazoline-5-thiones

By the reaction of 2-methyl-furan-3-carboxylic acid hydrazide with isothiocyanates, 1-[(2-methyl-furan-3-yl)carbonyl]-4-substituted thiosemicarbazides 1 were obtained. Further cyclization with 2% NaOH led to the formation of 3-(2-methyl-furan-3-yl)-4-substituted-Δ²-1,2,4-triazoline-5-thiones 2. The pharmacological effects of 2 on the central nervous system in mice were investigated. Strong antinociceptive properties of the investigated derivatives were observed in a wide range of doses.      

Synthesis and steric structure of 3,4-dimethyl-2-(3-methyl-1-phenylbuta-1,2-dienyl)-5-phenyl-1,3,2λ<Superscript>5</Superscript>-oxazaphospholane 2-oxide

Allenic 1,3,2-oxazaphospholanes on the basis of d-pseudoephedrine were synthesized. The steric structure of 3,4-dimethyl-2-(3-methyl-1-phenylbuta-1,2-dienyl)-5-phenyl-1,3,2λ⁵-oxazaphospholane 2-oxide was determined by X-ray diffraction.     

Supramolecular Adduct of γ-Cyclodextrin and [{Re<Subscript>6</Subscript>Q<Subscript>8</Subscript>}(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>]<Superscript>2+</Superscript> (Q=S,Se)

Slow evaporation of water solution of [{Re₆S₈}(H₂O)₆]²⁺ generated in situ from [{Re₆S₈}(OH)₆]^4– in presence of γ-cyclodextrin (CD) leads to crystallization of {[{Re₆S₈}(H₂O)₆] ? [γ-CD]}(NO₃)₂·12H₂O (1·12H₂O) supramolecular complex, which was characterized by single-crystal X-ray diffraction crystallography, IR-spectroscopy, thermogravimetric and elemental analyses. X-ray analysis confirms the formation of 1:1 {[{Re₆S₈}(H₂O)₆] ? [γ-CD]}²⁺ inclusion compound in the solid state. However, no adduct formation was detected between [{Re₆S₈}(H₂O)₆]²⁺ and γ-cyclodextrin in solution, according to ¹H NMR spectroscopy. In the case of in situ generated [{Re₆Se₈}(H₂O)₆]²⁺ the reaction solution with γ-cyclodextrin is unstable and during the crystallization only amorphous precipitate has been obtained.     

Synthesis and crystal structure of [Et<Subscript>4</Subscript>N] [Cr(PzTp)Cl<Subscript>3</Subscript>] [PzTp<Superscript>−</Superscript> = Tetra(pyrazolyl) Borate]

Treatment of CrCl₃(THF)₃ with KPzTp in THF affords of the compound K[Cr(PzTp)Cl₃], and the K⁺ in this complex can be replaced by Et₄N⁺ in CH₂Cl₂. Well-defined green crystals of [Et₄N]r(PzTp)Cl₃] (I) suitable for X-ray diffraction are obtained at −₂0°C. In the anion the metal center shows a distorted octahedral geometry with the tetra(pyrazolyl) borate bonded as three N-donor tripod ligands and three chloride atoms completing the coordination sphere.