Mono-and Bis Research Articles

Synthesis of [1,3,2]dithiazolo[4,5-b][1,2,5]oxadiazolo[3,4-e]pyrazines

The reaction temperature has a strong impact on the results of chlorination of 5,6-bis(tertbutylthio)[1,2,5]oxadiazolo[3,4-b]pyrazine that is readily prepared from 5,6dichloro[1,2,5]oxadiazolo[3,4-b]pyrazine and sodium tert-butylsulfide. Monoand bis(sulfenylchlorides) were selectively obtained in high yield and their structure was confirmed by the reaction with morpholine. Treatment of [1,2,5]oxadiazolo[3,4-b]pyrazine-5,6-disulfenyl dichloride with primary aliphatic amines and benzylamine afforded N-substituted [1,3,2]dithiazolo[4,5-b][1,2,5]oxadiazolo[3,4-e]pyrazines in moderate yields. Novel pentacyclic [1,2,5]oxadiazolo[3'',4'':5',6']pyrazino[2',3':5,6][1,2,4]thiadiazino[3,4-b][1,3]benzothiazole, whose structure was confirmed by X-ray diffraction, was obtained by the reaction of this disulfenyl dichloride with 2-aminobenzothiazole.

Complex formation and photochemical properties of the crown-containing mono- and bis(styryl)bipyridine derivatives with transition metal cations

Complex formation of 15-crown-5 ether containing monoand bis(styryl)bipyridine with transition metal perchlorates was studied. The complex stoichiometry, complex structure and stability constants were determined by electronic spectroscopy. The influence of metal ions on occurrence of E,Z-isomerization was analyzed; the optical characteristics of two isomers were calculated from the photolysis data.

Thio derivatives of cyclopentanone and cyclohexanone

Mono-and bis(methylthiomethyl) substituted derivatives of cyclopentanone and cyclohexanone were obtained on the basis of natural methylmercaptan via the alkylthiomethylation of ketones, and these derivatives were converted into the corresponding γ-hydroxysulfides and ketosulfones via reduction with sodium borohydride and oxidation with hydrogen peroxide, respectively.

Effect of arrangement of the styryl fragment on the optical properties and complexation of mono-and bis(styryl)-substituted N-methylpyridinium perchlorates containing benzo-15-crown-5 ether moieties

Using 1H NMR spectroscopy and steady-state and time-resolved electronic spectroscopy, the optical properties of mono-and bis(styryl)pyridinium perchlorates and their complexes with Mg2+, Ba2+ cations were studied. The stability constants of the complexes were determined using spectrophotometric titration. The formation of inclusion complexes for Mg2+ and sandwich type complexes for Ba2+ results in fluorescence enhancement and increases the lifetimes of the excited states of the initial bis-styryl ligands. The variation of position of the styryl fragment in the pyridinium aromatic ring gives rise to photochromic crown ethers with different optical and photophysical characteristics and is also an easy route to bis(crown-ethers) of symmetrical and unsymmetrical structure.

Mono-and bis(5-O-nitro-1,4:3,6-dianhydro-D-sorbit-2-yl) phosphates: synthesis and reactions with hydroxy-and amino-containing compounds

The reaction of 1,4:3,6-dianhydro-D-sorbitol 5-nitrate with POCl3 afforded mono-and bis(5-O-nitro-1,4:3,6-dianhydro-D-sorbit-2-yl) phosphorochloridates, whose hydrolysis resulted in phosphoric acid mono-and diesters. The subsequent treatment of these compounds with bases gave sodium and cyclohexylammonium salts. The reactions of phosphorochloridates with phenol, pentaerythritol dibromohydrin, and ethylenimine in the presence of organic bases afford mixed phosphates and phosphoramidates.

Synthesis and properties of polyenic oligosulfides derived from acetylene and elemental sulfur

Oligosulfides derived from ethyne-1,2-dithiol were synthesized in up to 96% yield via insertion of elemental sulfur into the Na-Csp bond of sodium acetylides (HC≡CNa, NaC≡CSNa) in liquid ammonia, followed by hydrolysis and spontaneous oligomerization of ethynethiols, ethynedithiols, and mono-and bis-(polysulfanyl)ethynes (HC≡CSH, HSC≡CSH, HC≡CSxH, HSxC≡CSyH). The resulting polyenic oligosulfides were isolated as brown powders melting in the temperature range from 122 to 203°C and containing up to 77% of sulfur; they are sparingly soluble in organic solvents and are high-resistance semiconductors (10−13–10−14 S cm−1) possessing paramagnetic (1017–1018 spin g−1) and redox properties. According to the data of IR and ESR spectroscopy and cyclic voltammetry, the oligomers obtained consist mainly of different oligosulfide units, including oligothienothiophene structures. They also ensure a high discharge capacity (345–720 mA h g−1) of lithium sulfur rechargeable batteries.

Conformational analysis of mono-and bis(dimethoxyphosphoryl)benzenes

Conformational analysis of mono-and bis(dimethoxyphosphoryl)benzenes with substituents in the benzene ring was performed by the method of dipole moments, IR spectroscopy, and quantum-chemical calculations (DFT B3LYP/6-31G*). Comparison of all calculated and experimental data shows that the compounds studied exist as equilibrium mixtures of conformers with preferred gg orientation of the phosphoryl and methoxy groups.

New substituted mono-and bis(imidazolyl)pyridines and their application in nitroaldolisation reaction

AbstractNew chiral nitrogen ligands based on the substituted mono-and bis(imidazolyl)pyridines have been prepared and characterised. Their complexes with cupric acetate were used as catalysts in the nitroaldolisation reaction. In the case of optically pure complexes of mono(imidazolyl)pyridine, the isolated products were 2-nitro-1-(2-nitrophenyl)ethanols or 2-nitro-1-(4-nitrophenyl)ethanols in overall yields of 49–93 % and with the maximum enantiomeric excess of 15.6 %. The complexes of bis(imidazolyl)pyridine also catalyse the nitroaldol reaction, the yields being 64–90 %, but with zero enantioselective excess.

Bis(Benzo-18-crown-6) Derivatives: Synthesis and Ion-Sensing Properties in Plasticized PVC Membranes

Several mono-and bis(benzo-18-crown-6) ethers comprising o-nitrophenyl urethanemoieties were synthesized and studied as ionophores in PVC membrane electrodes. Thebis(crown ether)s were found to exhibit good potentiometric Cs+ selectivity overmono and divalent cations as compared to the respective mono(crown ether)s.

Mono-and Bis(cyclopentadienyl)hafnium(IV) Derivatives with Higher Fatty Acids

Abstract The reactions of Cp2HfCl2 with some higher monocarboxylic acids having straight chains, caprylic (C8H16O2), lauric (C12H24O2), myristic (C14H28O2), palmitic (C16H32O2), stearic (C18H36O2), and behenic (C22H44O2) acid, have been studied in anhydrous tetrahydrofuran in 1:1 and 1:2 molar ratios, respectively. The reaction products isolated, of types Cp2Hf(L)Cl, CpHf(L)2Cl (LH represents different carboxylic acids), have been characterised by conductivity and magnetic susceptibility measurements and spectral (infrared, electronic, 1HNMR and 13C NMR) data. The bonding of the carboxylato ligand in these complexes has been discussed and plausible structures have been established.

Selective solvent extraction of tetrahedrally-coordinating transition metal ions from acidic aqueous media using benzimidazole–phosphinate ligands: specificity for zinc(II) over copper(II)

The synthesis, solution complexation behaviour and solvent extraction ability of related chelating mono-and bis-(benzimidazole)phosphinate ligands 8 and 9 has been assessed. 31P NMR, fluorescence and absorption spectroscopy and electrospray mass spectrometry revealed preferential formation of 1:1 complexes with the divalent ions Zn, Co and Ni, and ML2 complex formation with the bidentate ligand. Extraction studies showed that 9 extracted Zn>CoNi with no extraction of copper(II), but avid extraction of copper(I), generated insitu, consistent with the ligand's preference for the binding of tetrahedrally-coordinating metal ions.

Crystal and Molecular Structure of Methylpropylglyoxal Bis(amidinohydrazone) Sulphate Monohydrate

Abstract A single-crystal X-ray diffraction study was performed on methylpropylglyoxal bis(amidinohydrazone) (M PGBG) sulphate monohydrate. The bis(amidinohydrazone) dication was found to exist exclusively in the form of the anti-anti isomer, with an all-trans configuration of the glyoxal bis(amidinohydrazone) chain, just as do the free base, the monocation and the dication of glyoxal bis(amidinohydrazone) and the dications of all mono-and dialkylglyoxal bis(amidinohydrazones) so far studied. MPGBG sulphate monohydrate crystallizes in the triclinic space group Pl̅ with unit cell parameters a = 8.860(2), b = 9.195(2), c = 10.788(2) Å, α = 73.71(3), β = 77.59(3), γ = 65.28(3)° and with Z = 2. When the structure is compared with that of propylglyoxal bis(amidinohydrazone) (PGBG) sulphate, an analogous compound that is devoid of the methyl group of MPGBG, a distinct difference can be observed regard­ing the conformation of the propyl side chain. In the MPGBG dication, the propyl group is directed away from the glyoxal bis(amidinohydrazone) chain, whilst in the case of the PGBG dication it is tangled around the glyoxal bis(amidinohydrazone) moiety. Whether this difference results from packing effects and related factors, or whether it is a result of a more fundamental difference between MPGBG and PGBG, remains to be studied. The observed difference may contribute to the biochemical differences between the two compounds.

IR-Spectral Study of Solid State Complexes of Lanthanum with Mono-andbis-(2-Ethylhexyl) Phosphoric Acids

Abstract IR-spectra of the solid state lanthanum complexes with mono-and bis-(2-ethylhexyl) phosphoric acids (H2B, resp. HA) are studied. It is confirmed that La coordinates HA as LaO6-octahedra, connected through -La-O-P-O-La-bridging bonds. The so fixed polynucleous chains form the crystal structure of the complex. The obtained IR-spectral data as well as the results of the X-ray powder diffraction analysis show that La forms shorter polymeric chains than the other rare earth complexes of the same type. Certain methods for the synthesis of the solid state complexes of La with H2B (studied for the first time) are considered. It is shown that the structure of La-HB-complexes is consituted also by LaO6-octahedra, resp.-La-O-P-O-La-polymeric chains. However they are binded through crosswise PO—H., O(H)-P hydrogen bonds, owing to the non-deprotonized hydroxo-group presented in the complex. The so formed supramolecular structure has to be more disordered than the one in the case of the complexes with HA. This...

A direct15N NMR study of erbium(III)-nitrate complexation in aqueous solvent mixtures

The extent of inner-shell ion-pair formation of Er3+ with nitrate ion in aqueous mixtures has been studied by nitrogen-15 (15N) NMR spectroscopy. At low temperature, exchange is slow enough to permit the direct observation of15N signals for nitrate ions in the Er3+ solvation shell and in bulk medium. In water-acetone mixtures,15N NMR signals for the mono-and bis complexes are observed at low nitrate to Er3+ mole ratios, but only the bis complex is evident at higher anion concentrations. No spectral evidence for the tris complex was seen at any nitrate concentration. In water-methanol-acetone mixtures, signals for the mono and bis complexes persist even at higher nitrate concentrations, indicating a reduced tendency to ion-pair with increasing dielectric constant. Preliminary15N NMR results are presented for the nitrate complexes of other paramagnetic lanthanide ions.

Iridium(III) and rhodium(III) mono-and bis(1,10-phenanthroline) complexes and the optical isomers of iridium(III), rhodium(III), chromium(III), and cobalt(III) dihalobis(1-10-phenanthroline) complex cations

Iridium(III) and rhodium(III) mono-and bis(1,10-phenanthroline) complexes and the optical isomers of iridium(III), rhodium(III), chromium(III), and cobalt(III) dihalobis(1-10-phenanthroline) complex cations

2-Diethylamino-4,5-dimethyl-1,3,2-dioxaphospholenes

2-Diethylamino-4,5-dimethyl-l,3,2dioxaphospholenes are formed in the reactions of mono-and bis-(diethylamido) phosphites with biacetyl, the structure of which was confirmed by physical methods.

Organometallic compounds with metal-metal bonds. VII. Preparation and a study of the infrared spectra of mono-and bis(tetracarbonylcobalt) derivatives of germanium and tin

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganometallic compounds with metal-metal bonds. VII. Preparation and a study of the infrared spectra of mono-and bis(tetracarbonylcobalt) derivatives of germanium and tinD. J. Patmore and William A. G. GrahamCite this: Inorg. Chem. 1967, 6, 5, 981–988Publication Date (Print):May 1, 1967Publication History Published online1 May 2002Published inissue 1 May 1967https://doi.org/10.1021/ic50051a028RIGHTS & PERMISSIONSArticle Views162Altmetric-Citations88LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (934 KB) Get e-Alerts Get e-Alerts

Relationships Between the Surface Activity and Cholinesterase Inhibition of Carbamoylpiperidino-alkanes II: Variations in the Amide Function

The static surface tension of aqueous solutions of selected mono-and bis (carbamoylpiperidino)ethanes and -decanes has been determined and compared with the ability of these compounds to inhibit human plasma pseudo-cholinesterase. Parallels reported in a preceding communication were confirmed, and other relationships between surface-active properties and biochemical activity were explored.

Studies on Analytical Chemistry Related to Urea Resins. I

Since the determination of mono-and bis-(hydroxymethyl)-urea in an initial reaction product byuse of infrared absorption spectra was difficult when hexamethylenetetramine is used as a catalyst, hexamethylenetetramine was removed by extraction with chloroform and used for quantitative determination by use of infrared absorption spectra with the standard deviation of 2%. Quantitative determination of hexamethylenetetramine in various kinds of initial reaction products is made by this method and clarified that nearly all hexamethylenetetramine remain unchanged during the initialreaction period.