Synthesis and characterization of bis(2-aminophenyl)disulphide diimine derivatives and their ruthenium complexes

Condensation of bis(2-aminophenyl)disulphide with aromatic aldehydes yielded the corresponding dithiophenyldiimines. Dinuclear ruthenium complexes were obtained by reacting the diimines (3) [bis(3-nitrobenzaldehyde)-phenyldisulphide diimine], (5) [bis(2-chlorobenzaldehyde)-phenyldisulphide diimine], (8) [bis(2-methoxybenzaldehyde)-phenyldisulphide diimine] and (9) [bis(2-hydroxybenzaldehyde)-phenyldisulphide diimine], with RuCl₃ in the presence of L (L=2,2-bipyridine, 1,10-phenanthroline, 3,4-diaminotoluene, pyridine and PPh₃) in EtOH. The two metal centres, connected through bridging chlorides, are in octahedral environments with one metal centre coordinated to sulphur and water while the other is coordinated to L.     

Reaction of carbon disulphide with bis(γ-mercaptopropylamine) nickel(II)

Summary Carbon disulphide reacts with bis(-mercaptopropylamine)nickel(II) by insertion into the Ni-N bond to yield a planar dithiocarbamate complex, in which the Ni-S bond is broken and a sulphydryl group is formed.     

Gas chromatography electron ionization mass spectrometric analysis of trimethylsilyl derivatives of bis(2-hydroxyethylthio)alkanes and bis(2-hydroxyethylsulfonyl) alkanes

This communication describes GC-MS analysis of bis(trimethylsilyl) (bis-TMS) derivatives of bis(2-hydroxyethylthio)alkanes (BHETAs) and bis(2-hydroxyethylsulfonyl) alkanes (BHESAs) which are important markers of sulfur mustard class of chemical warfare agents. The study was undertaken with a view to develop spectral database of these compounds for verification analysis of Chemical Weapons Convention (CWC). Based on the obtained mass spectra of bis-TMS derivatives of BHETAs and BHESAs, the fragmentation routes are proposed, which explain most of the characteristic ions.     

Preconcentration of microamounts of elements in natural waters with 8-mercaptoquinoline and bis(8-quinolyl) disulphide for their atomic-absorption determination

A method has been developed for the group concentration of microamounts of metals (Fe, Co, Ni, Mn, Cu, Zn, Cd, Hg, Pb, Bi, Sb, Mo, W, V, Cr, Ga, In, Sn, Ag, Au, Pd, Pt) in the form of their 8-mercaptoquinolinates co-precipitated on bis(8-quinolyl) disulphide as collector, the latter being an oxidation product of 8-mercaptoquinoline. The collector is formed during the co-precipitation process, which is the reason for its high co-precipitating power. The elements thus concentrated are determined by atomic-absorption spectrometry after dissolution of the precipitate in dilute nitric acid.     

Synthesis of new electron-donor compounds: Bis(2-thia-1,3-propylenedithio)teterathiafulvalene and bis(2-oxo-1,3-propylenedithio)tetrathiafulvalene

1,3-Dithiole-2-thione derivatives, which are starting compounds for the synthesis of new electron donors of the tetrathiafulvalene class, viz., bis(2-thia-1,3-propylendithio)tetrathiafulvalene and bis(2-oxo-1,3-propylendithio)tetrathiafulvalene, were obtained by the reaction of bis(tetraalkylamonium) bis(1,3-dithiole-2-thione-4,5-dithiolato)zincates with 1,3-dichlorodimethyl sulfide and 1,3- dibromoacetone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 471–474, April, 1990.     

Preparation and characterization of bis(trifluoromethyl)phosphanide salts of outstanding stability

The stable compounds [NEt(4)][P(CF(3))(2)] and [18-crown-6-K][P(CF(3))(2)] were synthesized in quantitative yields by treatment of HP(CF(3))(2) with ionic cyanides at low temperature. These novel salts were characterized by multinuclear NMR spectroscopy, elemental analysis, and vibrational spectroscopy. Excellent agreement of experimental and theoretical vibrational frequencies, calculated at the B3PW91 level of theory, clearly confirms the saltlike character of these compounds. Due to their ionic nature, these salts are excellent nucleophilic reagents for the transfer of P(CF(3))(2) groups, suitable for the synthesis of chiral bidentate bis(trifluoromethyl)phosphine containing compounds.     

Asymmetric Michael addition of nitroalkanes to nitroalkenes catalyzed by C2-symmetric tridentate bis(oxazoline) and bis(thiazoline) zinc complexes

The first asymmetric synthesis of 1,3-dinitro compounds through Michael addition of nitroalkanes to nitroalkenes catalyzed by C2-symmetric chiral tridentate bis(oxazoline) and bis(thiazoline) zinc complexes was achieved with high enantioselectivities (up to 95% ee).     

Specific and selective reduction of aromatic nitrogen heterocycles with the bis-pyridine complexes of bis(1,4-dihydro-1-pyridyl)zinc and bis(1,4-dihydro-1-pyridyl)magnesium

Aromatic nitrogen heterocycles, e.g. quinoline, 2,2‘-bipyridyl and 1,10-phenanthroline, are reduced in a uniquely specific and selective way by the bispyridine complexes of bis(1,4-dihyro-1-pyridyl)zinc and bis(1,4-dihydro-1-pyridyl)magnesium. The reactions occur by hydrogen transfer from the metal-bound 1,4-dihydropyridyl moieties to the substrates and yield zinc or magnesium salts of the 1,4-dihydroazaaromatic derivatives. Upon hydrolysis, the 1,4-dihydroazaaromatic compounds are liberated from the metal ions. The isolation and purification of several of the (novel) reduced compounds, e.g. 1,4-dihydroquinoline and 1,4-dihydro-1,10-phenanthroline, are described.     

Bisindoles. 15. Acidic condensation of bis(2-ethoxycarbonyl-5-indolyl) oxide and bis(2-ethoxycarbonyl-5-indolyl)methane with aromatic aldehydes

The acidic condensation of bis (2-ethoxycarbonyl-5-indolyl) oxide and bis(2-ethoxycarbonyl-5-indolyl)methane with aromatic aldehydes was studied. Bis(3-chloro) compounds with labile chlorine atoms, by nucleophilic substitution of which the corresponding dimethylamino, hydroxy, methoxy, acetoxy, cyano, and mercapto derivatives were obtained, were isolated.See [1] for communication 14.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 365–368, March, 1983.     

A contribution to the theory of accelerated sulphur vulcanization of natural rubber and polybutadiene BR with tetramethyl thiuram disulphide and bis(2-benzothiazolyl) disulphide

A number of simple natural rubber (NR) and polybutadiene (BR) formulations were vulcanized in a differential scanning calorimeter. From the shapes of the exothermal cure curves the interaction of curatives can be examined. It is suggested that polysulphidic-accelerator-terminated pendent groups could either crosslink, or be chelated with zinc ions. The latter reaction allows interaction with accelerator molecules to reform the unchelated pendent group, and a zinc accelerator complex, that, in turn, can react with sulphur and rubber molecules to give pendent groups. Differences in the behavior of NR and BR are attributed to the relative rates of these two reactions in the elastomers. Bis(2-benzothiazolyl) disulphide does not react with zinc, and it is suggested that it coordinates with the zinc dithiolate accelerator complex, increasing its activity.     

The crystal and molecular structures of bis (pentafluorophenyl)disulphide and bis(pentafluorophenyl)diselenide

The structures of (C₆F₅)₂S₂ and (C₆F₅)₂Se₂ have been determined by single crystal, X-ray diffraction techniques. The compounds are isostructural although the molecules are packed differently in the crystal in comparison with their phenyl analogues. Important bond lengths and angles are: SS, 2.059(4)Å; SeSe, 2.319(4)Å; SC, 1.770Å; SeC, 1.910(15)Å; SSC, 101.3(3)°; SeSeC, 98.8(1)°.     

Influence of the Nature of Carboxylic Acid on the Luminescence and Spectral Properties of (Carboxylato)bis(dibenzoylmethanato)europium(III) Complexes

A series of (carboxylato)bis(dibenzoylmethanato)europium(III) complexes containing anions of both saturated and unsaturated carboxylic acids were synthesized to compare the luminescence and spectral properties of heteroligand Eu(III) complexes. (Carboxylato)bis(dibenzoylmethanato)europium(III) complexes with unsaturated acid anions were synthesized for the first time. The compounds obtained were characterized using elemental analysis and luminescence and IR spectroscopy. These studies revealed two types of influence of the nature of an acid substituent on the luminescence spectra of (carboxylato)bis(dibenzoylmethanato)europium(III) complexes. The anomalous Stark structure of the luminescence spectra of one group of compounds is attributed to the charge transfer state at 77 K.     

双（亚烷二硫基)四硫富瓦烯衍生物的合成及其电化学性质

以四(氰乙硫基)四硫富瓦烯为原料经醇钠消去氰乙基生成四硫富瓦烯四硫盐， 再与二元卤代烷烃化反应，除了得到三种文献报道的双(亚烷二硫基)四硫富瓦烯衍 生物外，还得到三种新的“四桥”双—四硫富瓦烯衍生物，为“桥式”双—四硫富 瓦烯衍生物的合成提出了一种新的方法．并研究了它们的循环伏安图、电化学性质 和紫外—可见光光谱．     

Photochromism of bis(2-alkyl-1-benzofuran-3-yl)perfluorocyclopentene derivatives

[reaction: see text] Photochromic diarylethene derivatives having benzofuran heteroaryl groups, bis(2-methyl-1-benzofuran-3-yl)perfluorocyclopentene and bis(2-butyl-1-benzofuran-3-yl)perfluorocyclopentene, were synthesized, and their photochromic performance was examined in hexane solution as well as in the single-crystalline phase. The compounds exhibited photochromic reactivity even in the single-crystalline phase.     

A new tetrahedrally distorted copper(II) complex derived from disulphide coupled N-(2-ethanethiol)salicylideneimine

Copper(II) acetate reacts with N-(2-ethanethiol)salicylideneimine forming an ONNO chelate of α,α′-(diethylenedisulphide)-N,N′-disalicylideneimine with an uncoordinated disulphide. This copper(II) complex can also be obtained in higher yield if the thiol is first oxidized to disulphide with iodine. The geometry about copper(II) is distorted from planar to a flattened tetrahedron.     

Effect of solute-co-ordinating solvent interactions and temperature on the EPR and electronic spectra of bis(dithiophosphato)copper(II)

The self-redox reaction proceeding between two molecules of the complex bis(disubstituted-dithiophosphato)copper(II), CuII(R2-dtp)2, is studied by EPR and UV-VIS spectroscopy in DMFA, DMSO and pyridine. The effect of temperature and disulphide concentration in the solutions is also evaluated. The EPR spectra show that the g-values of CuII(R2-dtp)2 increase when it is dissolved in co-ordinating solvents, whereas the copper hyperfine splitting decreases compared to the corresponding values in non-co-ordinating solvents. Under the same conditions, a hypsochromic shift is observed in the maximal absorption at 420 nm of the electronic spectra which corresponds to the ligand-to-metal charge-transfer (LMCT) transition of the complex. The results are explained with the formation of axial or equatorial adducts between CuII(R2-dtp)2 and the co-ordinating solvents used. On the other hand, the molar absorptivity of the LMCT band and the intensity of the EPR spectrum increase strongly with the nature of the used co-ordinating solvent, the time after dissolution and the quantity of added disulphide. Both also depend on the size and shape of remote ligand substituents and they increase in the order Me < Et < i-Pr. Beer's law is not obeyed immediately after dissolution of copper bis-dithiophosphate complexes. However, after standing for 24 h in the dark, DMFA solutions exhibit linear absorption/concentration dependence with approximately 70% higher molar absorptivity. An additional increase of the LMCT band and EPR intensity is found after heating the solution up to 50 degrees C for a short time, as well as after addition of the corresponding disulphide of dithiophosphate [(RO)2P(S)S-S(S)P(RO)2] to the CuII(R2-dtp)2 solution. As a result, the molar absorptivity value at the maximum of the LMCT band of Cu[(i-PrO)2-dtp]2 increases from 7.9 x 10(3) m(-1) dm3 cm(-1) immediately after dissolution to 2.9 x 10(4) m(-1) dm3 cm(-1). In DMSO and pyridine, the intensity of both the EPR signal and LMCT band of CuII(R2-dtp)2 continuously decrease after the preparation of the solutions. A small increase is only observed immediately after the addition of the corresponding disulphide of dithiophosphate. While DMFA forms stable adducts with Cu[(i-PrO)2-dtp]2, adduct formation with DMSO and pyridine destroys the initial complex.     

Preparation of bis(diazo) compounds incorporated into butadiyne and thiophene units, and generation and characterization of bis(carbene) from these compounds

[9-[10-(4-t-Butyl-2,6-dimethyl)phenyl]anthryl](4-bromo-2,6-dimethylphenyl)diazomethane (1-N(2)) was found to be stable enough to survive under Sonogashira and Suzuki coupling reaction conditions, and bis(diazo) compounds incorporated into the 1,4-positions of butadiyne (3-2N(2)) and the 2,5-position of thiophene (4-2N(2)) were prepared. Irradiation of those bis(diazo) compounds generated bis(carbenes), which were characterized by ESR and UV-vis spectroscopic techniques in a matrix at low temperature, as well as time-resolved UV-vis spectroscopy in solution at room temperature. These studies revealed that both of the bis(carbenes), 3 and 4, have a singlet quinoidal diradical ground state with a very small singlet-triplet energy gap of less than 1 kcal/mol. A remarkable increase in the lifetime of bis(carbenes) as opposed to that of monocarbene (1) was noted and was interpreted to indicate that bis(carbenes) are thermodynamically stabilized as a result of delocalization of unpaired electrons throughout a pi-net framework. Despite the stability, both bis(carbenes) are readily trapped by molecular oxygen to afford bis(ketones) as main products.     

Reactivity of bis(mu-hydroxo) divanadium site in gamma-H2SiV2W10O40(4-) with hydroxo compounds

The reactivity of divanadium-substituted silicotungstate, gamma-H2SiV2W10O40(4-) (I), with hydroxo compounds of alcohols, carboxylic acids, and water is reported. The reaction of the bis(mu-hydroxo) divanadium site in I with primary alcohols and formic acid smoothly proceeds to form corresponding monoesters and monoformate, respectively, and the crystal structures of the monomethyl and monoethyl esters and the monoformate of I are determined. The oxygen exchange between the hydroxo group and water proceeds easily. On the other hand, bulky compounds of 2-propanol, tert-butyl alcohol, and acetic acid hardly react with the bis(mu-hydroxo) divanadium site (equilibrium constant < 0.01) because of the steric crowding between the methyl groups and the polyoxometalate framework.     

High-frequency and -field EPR of a pseudo-octahedral complex of high-spin Fe(II): bis(2,2'-bi-2-thiazoline)bis(isothiocyanato)iron(II)

A pseudo-octahedral complex of high-spin Fe(II), bis(2,2'-bi-2-thiazoline)bis(isothiocyanato)iron(II), which has a cis-FeN'2N4 chromophore, has been investigated by high-frequency, high-field electron paramagnetic resonance (HFEPR). Complementary M?ssbauer and DC magnetic susceptibility studies were also performed. HFEPR spectra of powder samples were recorded at frequencies up to 700 GHz and over a magnetic field range of 0-25 T. Analysis of the field-frequency data set yields the following set of spin Hamiltonian parameters for S = 2: D = +12.427(12) cm-1, E = +0.243(3) cm-1; gx = 2.147(3), gy = 2.166(3), gz = 2.01(1). The parameters are analyzed by use of a simple crystal-field model. This study represents the first precise determination by HFEPR of spin Hamiltonian parameters in six-coordinate high-spin Fe(II) and indicates the applicability of HFEPR to the study of high-spin Fe(II) in coordination complexes and biological model compounds.     

Crystal structure and in vitro antitumor activity of bis(dicyclohexylammonium) bis(2-sulfobenzoato)dibutylstannate

An X-ray structure determination is presented for bis(dicyclohexylammonium) bis(2-sulfobenzato)dibutylstannate, and its antitumor properties against mammary and colon carcinoma cell lines are reported.