Silver complexes with 2-amino-4-methylpyrimidine: Synthesis, crystal structure, and luminescent properties

Reactions of AgReO₄ and AgCH₃SO₃ with L = 2-amino-4-methylpyrimidine (Ampym, C₅H₇N₃) in a ratio of 1: 2 in acetonitrile gave the complexes [AgL₂(ReO₄)] (I) and [AgL₂(CH₃SO₃)] (II). Their structures were determined. The crystals of complex I are monoclinic, space group C2/c, a = 5.985(1), b = 3.465(1), c = 19.071(1) Å, β = 96.52(1)°, V = 1527.0(3) ų, ρ_calcd = 2.507 g/cm³, Z = 4. The crystals of complex II are orthorhombic, space group Pbca, a = 14.784(1), b = 11.991(1), c = 17.711(1) Å, V = 3139.7(4) ų, ρ_calcd= 1.782 g/cm³, Z = 8. Structure I shows discrete cationic complexes [AgL₂]⁺. The silver atom is virtually linearly coordinated to two N atoms of crystallographically equivalent ligands L (Ag-N, 2.156(4) Å; the angle NAgN, 174.7(4)°). The complex cations are united into zigzag chains through the hydrogen bonds N-H...N. The resulting chains are linked by the hydrogen bonds N-H...O to uncoordinated perrhenate anions to form 2D supramolecular layers. In structure II, the Ag⁺ ion is coordinated by two crystallographically non-equivalent ligands L in a distorted linear fashion: Ag(1)-N(1), 2.166(7) Å;Ag(1)-N(4), 2.181(6) Å; the angle NAgN, 157.2(2)°. The anions CH₃SO₃ ^? are weakly linked to the Ag⁺ ions (Ag...O 2.72 Å) and are hydrogen-bonded to the complex cations [AgL₂]⁺, uniting them into supramolecular ribbons.     

Complexes of copper(II), nickel(II) and cobalt(II) with 2-fluoro,5-nitroaniline and 4-fluoro,2-nitroaniline

Preparation of new complexes of 2 - fluoro,5 - nitroaniline (2-F,5-NA) and 4 - fluoro,2 - nitroaniline (4-F,2-NA) of the type MLnX₂·mH₂O (where M = Cu(II), Ni(II), Co(II); L = 2-F,5-NA; 4-F,2-NA; n = 2,4,6; X = Cl⁻, Br⁻, SCN⁻, ClO₄⁻; m = 0–2) are described and their i.r., electronic spectra, and magnetic moments are reported. The ligands act always as monodentate O-bonded. The compounds are generally high spin, non electrolytes, and present square planar, tetrahedral and hexacoordinate structures.     

Parallel synthesis of 3-amino-4H-quinolizin-4-ones, fused 3-amino-4H-pyrimidin-4-ones, and fused 3-amino-2H-pyran-2-ones

On the basis of the enaminone methodology, libraries of 3-amino-4H-quinolizin-4-ones, fused 3-amino-4H-pyrimidin-4-ones, and fused 3-amino-2H-pyran-2-ones were synthesized by the solid-phase and by the solution-phase parallel synthesis. The solution-phase approach turned out to be advantageous over the solid-phase approach. The solution-phase synthesis afforded, in most cases, analytically pure products in high yields, whereas the solid-phase approach gave products in poor yields and in low purity.     

Electronic absorption spectra of 2-amino-6-nitro-, 4-amino-3-bromo-and 5-amino-2-bromotoluenes

A new technique—photoacoustic spectroscopy—has been used for the first time to record the u.v.-vis spectra of three substituted toluenes, namely 2-amino-6-nitrotoluene, 4-amino-3-bromotoluene and 5-amino-2-bromotoluene. The π-π* electronic transitions analogous to the benzene first primary and secondary transitions could be detected from the PAS spectra in comparison with the u.v. solution and vapour spectra recorded by conventional methods. Detection of singlet → triplet absorptions from the PAS spectra, with significant intensity, is considered to be an important feature which transitions are in general either not observed or observed with only very weak intensity, in solution or vapour, by conventional methods. The analysis shows that a few excited state combinations observed in the u.v. PAS spectra of the molecules presently studied are well comparable with such combinations in ground state observed in the near i.r. PAS spectra.     

Micellar effect on hydrolysis of 4-methyl-2-nitroaniline phosphate

The effect of anionic surfactant sodium dodecyl sulfate (SDS) on the hydrolysis of a substrate (mono-4-methyl-2-nitroaniline phosphate) by HCl was studied at 303 K. The reaction followed the first-order kinetics with respect to both HCl and the substrate. SDS effectively catalyzes this reaction, which rate increases with the concentration of SDS due to an increase of dielectric constant of the medium. The kinetic data were fitted to Menger-Portnoy, Piszkiewicz and Berezin kinetic models to explain the observed micellar effects. The various activation parameters both in the presence and absence of SDS were evaluated; a reasonable mechanism was proposed. The rate constant in micellar phase, binding constant and index of cooperativity were calculated accordingly.     

Synthesis and properties of 2-amino-1-thio-4-chromone derivatives

2-Amino-1-thio-4-chromone was synthesized and its substitution reactions at the N and C₃ atoms were studied. The mass spectrometric behavior of the synthesized 2-amino-1-thio-4-chromone derivatives was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 182–185, February, 1978.     

Thermodynamic properties of 4-amino-3-furazanecarboxamidoxime

4-Amino-3-furazanecarboxamidoxime (AAOF) is an important precursor for synthesizing new furazano (furoxano) energetic compounds. Its thermal behaviour was studied under a non-isothermal condition by DSC methods. The results of this study show that there are one melting process and two exothermic decomposition processes. Its kinetic parameters of the intense exothermic decomposition process are obtained from analysis of the DSC curves. The apparent activation energy (E_a), pre-exponential factor (A) and the mechanism function (f(α)) were (146 ± 18) kJ · mol⁻¹, (10^10.9±1.8) s⁻¹ and (1 − α)², respectively. The specific molar heat capacity (C_p,m) of AAOF was determined by a continuous C_p mode of micro-calorimeter. The self-accelerating decomposition temperature (T_SADT), thermal ignition temperature (T_TIT) and critical temperatures of thermal explosion (T_b) were obtained to evaluate its thermal safety.     

4-amino-2-phenylindole-based compounds with potential antibacterial activity

Primary condensation of 4-amino-2-phenylindole with ethyl acetoacetate and 4,4,4-trifluoroacetoacetate resulted in corresponding amides, which under acidic conditions were converted to pyrrolo[2,3-h]quinolones. Antibacterial activity of the amide obtained from aminoindole and ethyl 4,4,4-trifluoroacetylacetate was detected.     

On the lead tetraacetate oxidation of 4-amino-1,2,4-triazoles, 1-amino- and 2-amino-1,2,3-triazoles

Lead tetraacetate oxidation of 4-amino-1,2,4-triazoles, 1-amino- and 2-amino-1,2,3-triazoles affords mainly fragmentation to nitriles or acetylenes, even in the presence of intramolecularly attached double bonds.

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Über die Bleitetraacetatoxidation von 4-Amino-1,2,4-triazolen, 1-Amino- und 2-Amino-1,2,3-triazolen (Kurze Mitteilung)

Zusammenfassung Bei der Oxidation von 4-Amino-1,2,4-triazolen, 1-Amino- und 2-Amino-1,2,3-triazolen mit Bleitetraacetat entstanden hauptsächlich Nitrile bzw. Acetylene durch Fragmentierung — trotz der Gegenwart von intramolekularen Doppelbindungen.

     

2-Methyl-4-amino-5-aminomethylpyrimidin

Ohne Zusammenfassung