2-n-propylaminopyridine n-oxide complexes formed from Cu(II) salts

Cu(II) complexes have been prepared with 2-n-propylaminopyridine N-oxide (nP) employing the perchlorate, tetrafluoroborate, nitrate, chloride and bromide salts. Preparative molar ratios of 4:1 and 2:1 ligand to Cu(II) salt yielded the following unique salts: Cu(nP)₄X₂(X=ClO₄⁻, BF₄⁻, NO₃^staggeredt-) and Cu(nP)₂X₂)(X=NO₃⁻, Cl⁻, Br⁻). Characterization has been accomplished primarily by IR, electronic and electron spin resonance measurements of the solid state. nP binds as a monodentate ligand via its N-oxide oxygen in the complexes prepared from the Cu(II) salts of polyatomic anions and as a bidentate ligand in the halogen solids. Anion coordination occurs in the halogen complexes as well as in Cu(nP)₂(NO₃)₂.     

Cu(II) complexes of N-propyl-2-picolinamine N-oxide

Cu(II) complexes have been prepared with N-propyl-2-picolinamine N-oxide(PA) employing the perchlorate, tetrafluoroborate, nitrate, chloride and bromide salts. The following unique solids have been isolated and characterized: Cu(PA)₂X₂ (X = ClO₄^?, BF₄^? and NO₃^?) and Cu(PA)X₂ (X = Cl^?, Br^?). Characterization has been accomplished primarily by IR, electronic and ESR measurements of the solid state since considerable alteration of the complexes occurs on dissolution. PA bonds as a bidentate ligand via its N-oxide oxygen and amine nitrogen in all of the complexes. Anion coordination occurs in the halogen complexes and the nitrate ions appear to be bound to Cu(II) as monodentate ligands in Cu(PA)₂(NO₃)₂. In addition, there appears to be a rhombic distortion of the CuO₂N₂ chromophore of the perchlorate and tetrafluoroborate solids which is probably due to the steric requirements of the propyl substituents.     

Synthesis and crystal structure of diaquabis(nitrato-O,O′)ethanoliron(III) 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane trinitrate

A new complex salt diaquabis[nitrato-O,O′)ethanoliron(III)] 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane trinitrate, [Fe(NO₃)₂(EtOH)(H₂O)₂]⁺ · [H₂(Crypt-222)]²⁺ · (NO ₃ ^? )₃, is synthesized. Its crystal structure has been determined by X-ray diffraction analysis: space group P 2₁/c, a = 14.147 Å, b = 11.443 Å, c = 23.127 Å, β = 103.66°, Z = 4. The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.064 for 5050 independent measured reflections (CAD-4 automated diffractometer, λMoK _α radiation). In the [Fe(NO₃)₂(EtOH)(H₂O)₂]⁺ complex cation, the coordination polyhedron of the Fe³⁺ cation is a distorted pentagonal bipyramid with its base formed by four O atoms of two bidentate NO ₃ ^? ligands, one O atom of the water molecule, and its axial vertices occupied by the O atoms of the EtOH molecule and the second water molecule. The alternating complex cations and NO ₃ ^? anions multiplied by the 2₁ axis are hydrogen-bonded into infinite chains running along the y axis.     

Room-Temperature Synthesis of the Bi5[GaCl4]3 Salt From Three Different Classes of Ionic Liquids

Following the development in the synthesis of subvalent cluster compounds, we report on the use of three different classes of room-temperature ionic liquids for the synthesis of the pentabismuth-tris(tetragallate) salt, Bi₅[GaCl₄]₃, characterized by X-ray diffraction. The Bi₅[GaCl₄]₃ salt was prepared by reduction of BiCl₃ using gallium metal in ionic liquid reaction media containing a strong Lewis acid, GaCl₃. The ionic liquids; trihexyltetradecyl phosphonium chloride [Th-Td-P⁺]Cl^?, 1-dodecyl-3-methylimidazolium chloride [Dod-Me-Im⁺]Cl^? and N-butyl-N-methylpyrrolidinium chloride [Bu-Me-Pyrr⁺]Cl^? from three of the main classes of ionic liquids were used in synthesis. Reactions using ionic liquids composed of the trihexyltetradecyl phosphonium cation [Th-Td-P⁺] and the anions; tetrafluoroborate [BF₄ ^?], bis(trifluoro-methyl sulfonyl) imide [(Tf)₂N^?] and hexafluorophosphate [PF₆ ^?] were also investigated.     

4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane Penta(nitrato)lanthanate(III): Synthesis and Crystal Structure

A new complex salt, 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane penta(nitrato)lanthanate(III) (H₂(Crypt-222)]²⁺ · [La(NO₃)₅]^2?), is synthesized. Its crystal structure is studied using X-ray diffraction analysis (space group Pbcm, a = 9.517 Å, b = 13.358 Å, c = 24.585 Å, Z = 4; direct method, full-matrix least-squares in the anisotropic approximation, R = 0.039 for 4650 measured independent reflections). The [La(NO₃)₅]^2? complex anion lies on the m plane, and the 2 axis passes through the 2.2.2-cryptand dication with two protonated nitrogen atoms. The coordination polyhedron of the La³⁺ cation (coordination number 11) is a distorted octahedron with five bifurcated vertices, each containing two O atoms from the same NO ₃ ^? . ligand. The [La(NO₃)₅]^2? anions are joined into infinite polymer chains along the y axis through the NO ₃ ^? bridging ligand.     

Temperature effects on positronium formation and inhibition: a contribution to the elucidation of early spur processes. I. Glycerol/water mixtures

In order to elucidate the mechanism of positronium (Ps) formation in liquids, the effect of temperature, T, on the inhibiting properties of various solutes has been investigated in glycerol/water mixtures. Whereas the inhibition constants of Cl^? and I^? are found to increase markedly with T, that of CH₃NO₂ is T insensitive and that of NO₃^? diminishes with T. These findings are consistent with our previous model, according to which Ps would be formed via two pathways, either through the quasi-free entities or by the reaction of localized, not yet fully solvated, electrons and positrons. The increase with T of the Ps yield is found to be due to the fraction arising from the latter reaction. The results confirm Cl^? and I^? react with e_loc⁺, while CH₃NO₂ and NO₃^? scavenge quasi-free electrons. Regarding the behaviour of the inhibition constants of these latter solutes, a provisional explanation is given: CH₃NO₂ would scavenge epithermal electrons while NO₃^? would react with electrons at a lower energy state, in competition with the localization process. Hot Ps atoms are not likely to be involved.     

The Structural Systematics of Protonation of Some Important Nitrogen‐base Ligands. II. Some Univalent Anion Salts of Singly Protonated Bis(2‐pyridyl)amine

Syntheses and single crystal X‐ray structure determinations are recorded for a number of normal and ‘acid’ salts of bis(2‐pyridylamine), ‘dpa’, with univalent anions, X, variously hydrated, i.e. [dpaH]X·nH₂O, and [dpaH]X·HX·nH₂O. The ‘normal’ salt arrays so characterized are for X = Br^? (n = 2, isomorphous with the previously described chloride compound) and, I^?, ClO₄^?, ‘tca^?’ (≡ Cl₃CCO₂)^? (all n = 1); acid salt arrays are described for X = NO₃^? and tca (both n = 0). In all cases except those of X = ClO₄^?, NO₃^?, there is one independent formula unit devoid of crystallographic symmetry comprising the asymmetric unit of the structure. In all cases, the proton associated with the cation is ‘chelated’ by the pair of ring nitrogen atoms, disposed ‘endo’; in the tca adducts and the nitrate salt, the total cation is disordered in each case by inversion about a real or putative inversion centre between the rings. In the perchlorate compound, the (ordered) cation lies on a crystallographic 2‐axis, as does the water molecule, and the perchlorate ion, which is disordered about such an axis; in the nitrate compound, the acid hydrogen atom is modelled as disposed on a crystallographic inversion centre between a pair of symmetry‐related nitrate groups, containing, like the Htca adduct, the [XHX]^? moiety rather than a diprotonated cation.     

An electrical conductivity (EC) study of the thermal dissociation of [Co(NH3)6]X3 and [Co(en)3]X3 complexes

The thermal dissociation of the [Co(NH₃)₆]X₃ (X = Cl^?, Br^?, I^?, and NO^?₃), [Co(en)₃]X₃ (X = Cl^?, Br^?, I^?, NO^?₃, HSO^?₄ and $\text{1}\text{2}$ C₂O^2?₄), cis- [Co(en)₂Cl₂]Cl, and trans-[Co(en)₂ClBr]NO₃ complexes was investigated by an electrical conductivity (EC) technique. During the thermal dissociation reactions, liquid or semi-liquid phases are formed which cause large increases in the EC of the compound. The effect of concentration of the complex in a matrix medium as well as the composition of the matrix material on the EC curves were also determined.     

Behavior of nitrite forms of nitrosylruthenium on extraction and back extraction of heterometalic Ru/Zn complexes with trioctylphosphine oxide

The state of ruthenium in conjugated phases upon extraction of trans-[Ru(¹⁵NO)(¹⁵NO₂)₄(OH)]^2? complex with tri-n-octylphosphine oxide (TOPO) in the presence of Zn²⁺ and subsequent back extraction with H¹⁵NO₃ and NH₃(concd.) solutions was studied by ¹⁵N NMR. Binuclear complexes [Ru(NO)(NO₂)_5?n (μ-NO₂) _n?1(μ-OH)Zn(TOPO) _n ] and [Ru(NO)(NO₂)_4?n (ONO)(μ-NO₂) _n?1(μ-OH)Zn(TOPO) _n ], where n = 2, 3, are predominant forms in extract. Kinetic restrictions for ruthenium extraction with TOPO solution in hexane and its back extraction with aqueous solutions of nitric acid and ammonia are eliminated in the absence of direct coordination of extractant to ruthenium. fac-Dinitronitrosyl forms [Ru(NO)(H₂O)₃(NO₂)₂]⁺, [Ru(NO)(H₂O)₂(NO₂)₂(NO₃)]⁰ (3 and 6 M HNO₃) and [Ru(NO)(H₂O)(NO₂)₂(NO₃)₂]^? (6 M HNO₃) prevail in nitric acid back extracts. Equilibrium constant at ambient temperature (0.05 ± 0.01) was assessed for the coordination of second nitrate ion to nitrosylruthenium dinitronitrato complex. Complex species [Ru(NO)(NO₂)₄(OH)]^2? and [Ru(NO)(NO₂)₃(ONO)(OH)]^2? prevail in ammonia back extract.     

Schwingungsspektroskopische hochdruckschemata einfacher verbindungen

Infrared spectroscopic investigations show that the following schemes are valid for the triatomic ions N₃^? and NO₂^? at high pressure. (1) High pressure strongly increases the stretching force constants of a linear system like N₃^? compared with the data at normal pressure. For statistical reasons the bond angle α is unchanged, in agreement with the fact that the bending force constant f_α is unaffected within experimental accuracy. (2) Statistical considerations predict a decrease in α for bent molecules XY₂(C_2v at high pressure. For NO₂^?, this decrease is about 3° at 35 kbar, combined with a significant increase in the bending force constant f_°. Both the stretching force constant f_NO and the interaction force constant f_NO/NO decrease considerably.     

Synthesis and crystal structure of hexa(nitrato-<Emphasis Type="Italic">O,O</Emphasis>′)dysprosium(III) Bis[4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane] nitrate dihydrate

A new complex salt 2[H₂(Crypt-222)]²⁺ · [Dy(NO₃)₆]^3? · NO ₃ ^? · 2H₂O is synthesized, and its crystal structure is studied by X-ray diffraction analysis (space group R \(\bar 3\), a = 11.445 Å, c = 38.981 Å, Z = 3; direct method, full-matrix least-squares method in the anisotropic approximation, R = 0.027 for 3555 independent reflections; CAD4 automated diffractometer, λMoK _α radiation). The [Dy(NO₃)₆]^3? anion and 2.2.2-cryptand dication lie on axis \(\bar 3\). The [Dy(NO₃)₆]^3? ligand in the [Dy(NO₃)₆]^3? anion is disordered. The Dy³⁺ cation has slightly distorted octahedral coordination with all six split vertices at the O atoms of the six symmetrically equivalent disordered NO ₃ ^? ligands.     

Theoretical study of interactions between 1-alkyl-3-methyimidazolium tetrafluoroborate and dibenzothiophene: DFT,NBO, and AIM analysis

Density functional theory is employed to study the interaction energies between dibenzothiophene (DBT) and 1-alkyl-3-methylimidazolium tetrafluoroborate ([C _n mim]⁺[BF₄]^?). The structures of DBT, 1-ethyl-3-methylimidazolium tetrafluoroborate ([C₂mim]⁺[BF₄]^?), 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim]+[BF₄]?), 1-hexyl-3-methylimidazolium tetrafluoroborate ([C₆mim]⁺[BF₄]^?), 1-octyl-3-methylimidazolium tetrafluoroborate ([C₈mim]⁺[BF₄]^?), [C₂mim]⁺[BF₄]^?–DBT, [C₄mim]⁺[BF₄]^?–DBT, [C₆mim]⁺[BF₄]^?–DBT and [C₈mim]⁺[BF₄]^?–DBT systems are optimized systematically at the B3LYP/6-31G(d,p) level, and the most stable geometries are obtained by NBO and AIM analyses. The results indicate that DBT and imidazolium rings of ionic liquids are parallel to each other. It is found that the [BF₄]^? anion prefers to be located close to a C1–H9 proton ring in the vicinity of the imidazolium ring and the most stable gas-phase structure of [C _n mim]⁺[BF₄]^? has four hydrogen bonds between [C _n mim]+ and [BF₄]?. There are hydrogen bonding interactions, π–π and C–H–π interactions between [C₈mim]⁺[BF₄]^? and DBT, which is confirmed by NBO and AIM analyses. The calculated interaction energies for the studied ionic liquids can be used to interpret a better extracting ability of [C₈mim]⁺[BF₄]^? to remove DBT, due to stronger interactions between [C₈mim]⁺[BF₄]^? and DBT, in agreement with the experimental results of dibenzothiophene extraction by [C _n mim]⁺[BF₄]^?.     

Electrochemical disk generation and ring identification of carbanions from organomercurials in acetonitrile

A rotating disk-ring electrode was used for study of a series of organomercury compounds R₂Hg, where R = CN, CF(NO₂)₂, C₆F₅, PhCC, p-NO₂C₆H₄OCC, PhSCH₂CC, PhCOCH₂, CH₂CN, CCl₂CCl, 2-phenyl-o-carboranyl. Reduction of these compounds at a Pt-disk in acetonitrile is a two-electron process and results in generation of the carbanion R^?. The carbanions generated at the disk interact with the solvent during their convective diffusion to the ring electrode where there may be oxidized. The main reaction in solution, shown using chromatography-mass spectrometry techniques, is acid-base interaction of carbanions with the solvent acetonitrile, which acts as a Brönsted acid. Reaching the ring, the carbanions may be oxidized at anodic potentials of the ring; oxidation potentials depend significantly on carbanion structure (e.g.+0.28 V (vs. SCE), for PhCC^? and +2.20 V for CN^?. It is shown that PK_a value of the carbanions do not correlate with the oxidation potentials, however, a linear correlation is observed between pK_a values and a special parameter called the efficiency coefficient.     

Structure and phase transitions of azomethine biligand complexes of iron(III) based on 3,4,5-tri(tetradecyloxy)benzoyloxy-4-salicylidene-N′-ethyl-N-ethylenediamine

New biligand complexes of iron(III) are synthesized based on 3,4,5-tri(tetradecyloxy)benzoyloxy-4-salicylidene-N′-ethyl-N-ethylenediamine azomethine with the outer sphere NO₃^?, PF₆^?, Cl^?, BF₄^?, ClO₄^?, and CNS^– anions. All the target compounds are characterized by gel exclusion chromatography, elemental analysis, and electron, IR, and NMR spectroscopy. The presence of complex-forming ions is confirmed by FT-IR spectra in the far region. The formation of biligand polychelate complexes with an octahedral packing of the iron ion is observed. Phase transitions in the resulting coordination compounds are studied by differential scanning calorimetry and optical polarizing thermomicroscopy. The presence of several polymorphic crystalline modifications, as well as mesophases, is established. Mesomorphic properties are found for complexes with chloride and tetrafluoroborate anions.     

4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]-hexacosane tetra(nitrato)zinc(II): Synthesis and crystal structure

A new complex salt 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]-hexacosane tetra(nitrato)zinc(II), [H₂(Crypt-222)][Zn(NO₃)₄]^2?, is synthesized and studied by X-ray diffraction analysis: space group $P\bar 1$ , a = 10.556 Å, b = 11.089 Å, c = 14.536 Å, α = 104.63°, β = 109.23°, γ = 99.22°, Z = 2. The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.031 for 3897 independent reflections (CAD-4 automated diffractometer, λMoK _α radiation). The structural units of the crystal are the [Zn(NO₃)₄]^2? complex anion and somewhat disordered 2.2.2-cryptand dication (with two protonated nitrogen atoms). The Zn²⁺ cation forms four strong coordination bonds with the O atoms of four NO ₃ ^? ligands and four weak (secondary) bonds with the second O atoms of these ligands. While ignoring the latter, the Zn²⁺ cation has a strongly distorted tetrahedral configuration. The [H₂(Crypt-222)]²⁺ dication contains trifurcate hydrogen bonds N-H(…O)₃.     

The addition of benzocyclobutenylidene to benzene : The facile rearrangement of spiro[benzocyclobutene-1,7'-cyclohepta-1',3',5'-triene] to 9a,10-dihydrobenz[α]azulene

Thermal decomposition of the sodium salts of benzocyclobutenone tosylhydrazone and 2-methylbenzocyclobutenone tosylhydrazone in benzene affords 9a,10-dihydrobenz[α]azulene 4 and trans-10-methyl-9a, 10-dihydrobenz[α]azulene 3, respectively. A mechanism involving initially the addition of the carbene benzocyclobutenylidene, or its 2-Me derivative, to the benzene ring is postulated. A proposed intermediate in the reaction, spiro [benzocyclobutene 1,7' cyclohepta-1',3',5'-triene] 12 has been synthesised, and shown to give rise to 4 under the reaction conditions. The rate of rearrangement of 12 → 4 has been measured, and the activation energy determined: E_a = 125.9 ± O.8 KJmol^?1 and A = 1.38 × lO¹⁴sec^?1. The mechanism for the rearrangement must involve ring opening of the benzocyclobutene moiety of 12 to give an o- xylylene intermediate which is postulated to possess considerable diradical character. At 71.8 °, this ring opening is 2.7 × 10⁶ times faster than the ring opening of the parent benzocyclobutene molecule. The decomposition of the sodium salt of 2-(7' -cyclohepta-1',3',5' trienyl)benzaldehyde tosylhydrazone has also been investigated and is shown to yield 4a,10-dihydrobenz[α]azulene, 9,10-dihydrobenz[α]azulene and 8,9-benzotricyclo [5.3.0.0^2.10]deca-3,5,8-triene. A mechanism involving intramolecular 1,3-dipolar addition of a diazo grouping to a cycloheptatriene Π-bond, followed by decomposition of the resulting pyrazoline intermediate, is proposed.     

Reactions of nitrosonium ion with anionic carbonyl monomers and clusters. Crystal and molecular structure of FeCo2(μ3-NH)(CO)9

The reactions of several mono- and poly-nuclear carbonyl metallates with nitrosonium ion have been studied. Besides simple substitution of a carbon monoxide with NO⁺ some reactions yielded products containing other nitrogeneous ligands. When [CoRu₃(CO)₁₃]^? reacts with NO⁺, low yields of the new nitrido cluster CoRu₃N(CO)₁₂ are formed. Prior conversion of [CoRu₃(CO)₁₃]^? to the new hydrido cluster [H₂CoRu₃(CO)₁₂]^? under hydrogen, followed by nitrosylation, forms the new imido cluster H₂Ru₃(NH)(CO)₉ in very low yield. The reaction of [FeCO₃(CO)₁₂]^? with NO⁺ also generates an imido cluster, FeCo₂(NH)(CO)₉, in 15% yield. This cluster has been characterized by X-ray crystallography and was found to be similar to the tricobalt alkylidyne clusters. (Triclinic crystal system, P$\text{1}$ space group, Z=2, a 6.787(1), b 8.016(1), c 13.881(2) Å, α 95.50(1), β 100.77(1), γ 107.93(1)°. Modifications of the nitrosylations using NO⁺ were studied. In particular, the addition of triethylamine or N-t-butylbenzaldimine allowed the use of NO⁺ in THF without solvent decomposition. With [CpMo(CO)₃]^? and [CpFe(CO)₂]^? the N-nitrosoiminium species appears to form transient alkylmetals which further react to give the dimers [CpMo(CO)₃]₂ and [CpFe(CO)₂]₂.     

Poly(2-amino-5-(4-pyridinyl)-1, 3, 4-thiadiazole) film modified electrode for the simultaneous determinations of dopamine, uric acid and nitrite

Poly(2-amino-5-(4-pyridinyl)-1,3,4-thiadiazole) (PAPT) modified glassy carbon electrode (GCE) was fabricated and used for the simultaneous determinations of dopamine (DA), uric acid (UA) and nitrite (NO₂ ^?) in 0.1 mol?L^?1 phosphate buffer solution (PBS, pH 5.0) by using cyclic voltammetry and differential pulse voltammetry (DPV) techniques. The results showed that the PAPT modified GCE (PAPT/GCE) not only exhibited electrocatalytic activities towards the oxidation of DA, UA and NO₂ ^? but also could resolve the overlapped voltammetric signals of DA, UA and NO₂ ^? at bare GCE into three strong and well-defined oxidation peaks with enhanced current responses. The peak potential separations are 130 mV for DA–UA and 380 mV for UA–NO₂ ^? using DPV, which are large enough for the simultaneous determinations of DA, UA and NO₂ ^?. Under the optimal conditions, the anodic peak currents were correspondent linearly to the concentrations of DA, UA and NO₂ ^? in the ranges of 0.95–380 μmol?L^?1, 2.0–1,000 μmol?L^?1 and 2.0–1,200 μmol?L^?1 for DA, UA and NO₂ ^?, respectively. The correlation coefficients were 0.9989, 0.9970 and 0.9968, and the detection limits were 0.2, 0.35 and 0.6 μmol?L^?1 for DA, UA and NO₂ ^?, respectively. In 0.1 mol?L^?1 PBS pH 5.0, the PAPT film exhibited good electrochemical activity, showing a surface-controlled electrode process with the apparent heterogeneous electron transfer rate constant (k _s) of 25.9 s^?1 and the charge–transfer coefficient (α) of 0.49, and thus displayed the features of an electrocatalyst. Due to its high sensitivity, good selectivity and stability, the modified electrode had been successfully applied to the determination of analytes in serum and urine samples.     

Effect of the Nature of a Quaternary Ammonium Salt and the Addition of a Neutral Carrier on Analytical Characteristics of Sulfate-Selective Electrodes

A film polyvinyl chloride sulfate-selective electrode based on the sterically accessible higher quaternary ammonium salt, 3,4,5-tris(dodecyloxy)benzyl(oxyethyl)3trimethylammonium chloride, using 1-bromonapthalene as a plasticizer and heptyl p-trifluoroacetylbenzoate as a solvating agent was developed. The limit of detection of the electrode was 6.7 × 10^?7 M, lifetime was 1 month, and the slope of the electrode function was 27 mV/decade. The electrode is selective in the presence of interfering Cl^?, C₂O₄^?, Br^?, and NO₃^?ions. The interference of carbonate ions was eliminated by maintaining pH at 3.2 ± 0.1. Based on IR spectroscopic and potentiometric studies, it is most likely that the solvation of sulfate ions with heptyl p-trifluoroacetylbenzoate occurs through interaction with the trifluoroacetyl carbonyl carbon atom rather than with hydroxyl groups of the hydrate form.