N-Methyl-4-(4-nitrophenyl)-N-nitroso-1,3-thiazol-2-amine

The title compound, C10H8N4O3S, is almost planar [dihedral angle between the rings = 2.2 (2)°; r.m.s. deviation for the non-H atoms = 0.050 Å]. In the crystal, C—H...O and C—H...N hydrogen bonds link the molecules into (10-2) layers.

2,4-Di-tert-butyl-6-({[2-(di-methyl-amino)-eth-yl](2-hy-droxy-benz-yl)amino}-meth-yl)phenol.

The title compound, C26H40N2O2, has both its N atoms in trigonal-pyramidal geometries. The molecular structure is stabilized by O—H...N and C—H...O hydrogen bonds. In the crystal, C—H...π interactions lead to the formation of a supramolecular helical chain along theb-axis direction.

N-(3H-Thia­zol-2-yl­idene)­nitr­amine and N-methyl-N-(thia­zol-2-yl)­nitr­amine

The geometries of the thiazole ring and the nitramino groups in N-(3H-thiazol-2-ylidene)nitramine, C 3 H 3 N 3 O 2 S, (I), and N-methyl-N-(thiazol-2-yl)nitramine, C 4 H 5 N 3 O 2 S, (II), are very similar. The nitramine group in (II) is planar and twisted along the C-N bond with respect to the thiazole ring. In both structures, the asymmetric unit includes two practically equal molecules. In (I), the molecules are arranged in layers connected to each other by N-H...N and much weaker C-H...O hydrogen bonds. In the crystal structure of (II), the molecules are arranged in layers bound to each other by both weak C-H...O hydrogen bonds and S...O dipolar interactions.

Rearrangement of N-(3-pyridyl)nitramine

AbstractContrary to other N-(pyridyl)nitramines, the title compound cannot be rearranged to 3-amino-2-nitropyridine or other isomers. Hypothetical products of its transformation under influence of concentrated sulphuric acid, viz. 3-hydroxypyridine, 3,3′-azoxypyridine and 3,3′-azopyridine, were obtained from 3-nitro- and 3-aminopyridine in oxidation and reduction reactions. N-(3-Pyridyl)nitramine was prepared and rearranged in concentrated sulphuric acid. 3-Hydroxypyridine and 3,3′-azoxypyridine were isolated from the reaction mixture, other products were identified by the HPLC and GCMS methods. The results indicate that N-(3-pyridyl)hydroxylamine is an intermediate formed from N-(3-pyridyl…

Correction to Impact of organoaluminum compounds on phenoxyimine ligands in coordinative olefin polymerization. A theoretical study

Olefin polymerization and copolymerization by complexes bearing [ONNO]-Type salan ligands: Effect of ligand structure and metal type (titanium, zirconium, and vanadium)

A series of novel titanium(IV) complexes bearing tetradentate [ONNO] salan type ligands: [Ti{2,2′-(OC6H3-5-t-Bu)2-NHRNH}Cl2] (Lig1TiCl2: R = C2H4; Lig2TiCl2: R = C4H8; Lig3TiCl2: R = C6H12) and [Ti{2,2′-(OC6H2-3,5-di-t-Bu)2-NHC6H12NH}Cl2] (Lig4TiCl2) were synthesized and used in the (co)polymerization of olefins. Vanadium and zirconium complexes: [M{2,2′-(OC6H3-3,5-di-t-Bu)2-NHC6H12NH}Cl2] (Lig4VCl2: M = V; Lig4ZrCl2: M = Zr) were also synthesized for comparative investigations. All the complexes turned out active in 1-octene polymerization after activation by MAO and/or Al(i-Bu)3/[Ph3C][B(C6F5)4]. The catalytic performance of titanium complexes was strictly dependent on their structures an…

The substituent effect of π-electron delocalization in N-methylamino-nitropyridine derivatives: crystal structure and DFT calculations

AbstractThe crystal and molecular structures of 3-(N-methylamino)-2-nitropyridine, 5-(N-methylamino)-2-nitropyridine and 2-(N-methylamino)-5-nitropyridine have been characterized by X-ray diffraction. To perform conformational analysis, the geometries of the compounds as well as their conformers and rotamers were optimized at the B3LYP/6-311++G(3df,3pd) level. The resulting data were used to analyze the π-electron delocalization effect in relation to the methylamino group rotation in ortho-, meta- and para-substitution positions. Quantitative aromaticity indices were calculated based on which we estimated the electronic structures of the analyzed compounds. The substituent effect of the met…

Proton tautomerism in 2-nitramino-C-nitropyridine derivatives - Experimental and quantum chemical study

Abstract The structures of 2-nitramino-3-nitropyridine and 2-nitramino-5-nitropyridine have been characterized by X-ray diffraction and Density Functional Theory (DFT) studies. In the crystals, both compounds exist as the imino forms. The DFT calculations were performed in order to explore the amino-imino tautomerism of the studied compounds in the gas phase and the influence of solvent polarity on the tautomeric equilibrium. The Harmonic Oscillator Model of Aromaticity index (HOMA) and Nucleus Independent Chemical Shift (NICS) calculated for the pyridine rings of the studied systems, demonstrated a noticeable decrease in aromaticity of the imino forms. This study showed also that the highe…

Experimental and theoretical characterization of chelidonic acid structure

Abstract Chelidonic acid (4-oxo-4H-pyran-2,6-dicarboxylic acid) is present in plants of Papaveraceae family, especially in Chelidonium majus. Due to its anticancer, antibacterial, hepatoprotective, and antioxidant properties, it has been used in medical treatments. In this work, the X-ray structure of methanol solvate of chelidonic acid was determined. Layers of chelidonic acid are held by hydrogen bonds via COOH and C = O fragments and additionally bridged by methanol. The formed H-bond network between two acid units is different from typical –COOH dimers observed, e.g., in crystals of isophtalic acid. The molecular structure of 2,6-dimethyl-γ-pyrone (2Me4PN) and chelidonic acid, a 2,6-dic…

Ethylene homo- and copolymerization catalyzed by vanadium, zirconium, and titanium complexes having potentially tridentate Schiff base ligands

Abstract New potentially tridentate Schiff base ligands, 2-[({4-[(3-N,N-dimethylamino)propyl] phenyl}imino)methyl]-4,6-di-tert-butylphenol (L1H) and 2-[{2-(N-phenyl-N-methylaminomethyl)-phenylimino}-methyl]-4,6-di-tert-butylophenol (L2H) were prepared and after deprotonation they were reacted with VOCl3 or MCl4 (where M = Zr or Ti) to produce corresponding complexes (L1-V, L2-V, L1-Zr, L2-Ti) with good yields. All new compounds were characterized by the 1H and 13C NMR as well as FTIR spectroscopic methods. Upon activation with Et2AlCl or EtAlCl2, both the vanadium complexes exhibited exceptionally high catalytic activities in the ethylene polymerization (up to 69,000 kg/(molV⋅h) for L1-V an…

Synthesis and olefin homo- and copolymerization behavior of new vanadium complexes bearing [OSSO]-type ligands

Novel vanadium complexes bearing [OSSO]-type ligands having two phenolato units linked through the –CH2S(CH2)4SCH2– (1V) or –CH2S(CH2)2SCH2– (2V) bridge are synthesized with good yields by reacting a deprotonated ligand with VCl4. They are then used in ethylene (co)polymerization after activation with EtAlCl2 and Et2AlCl. In the presence of EtAlCl2, both complexes promote ethylene polymerization with very high activities, over 4 × 107 g/(mol h), leading to PEs with high molecular weight and narrow molecular weight distribution. The prepared complexes exhibit lower activity for ethylene/1-octene copolymerization. It is also revealed that the catalyst based on the –CH2S(CH2)4SCH2– bridged com…

Acidity and basicity of primaryN-phenylnitramines: catalytic effect of protons on the nitramine rearrangement

Para-substituted N-phenylnitramines were prepared either by oxidation of diazonium salts or by nitration under alkaline or acidic conditions. Isotopic [15N-NO2] labelling indicated that the bands characteristic of the N-nitro group appear in the 1318–1323 and 1585–1607 cm−1 regions. In the nitrogen NMR spectra, the nitramino group gives two resonances at −193 ± 3 (NH) and −32 ± 3 ppm (NO2). The chemical shifts in proton and carbon NMR spectra are predictable, based on increments and the additivity rule. The spectral data indicate the lack of conjugation between the nitramino group and another substituent bound to the ring. It seems to contradict the well-known fact that substituents strongl…

2-Amino-5-butyl-4-methyl-1,3-thia­zol-3-ium nitrate

The title compound, C8H15N3O3S, shows bond lengths and angles that are typical and are in accordance with expected values. The structure comprises a substituted thia­zolium ring that is connected to a nitrate ion via N-H...O hydrogen-bonding interactions.

Ring opening polymerization of ε-caprolactone initiated by titanium and vanadium complexes of ONO-type schiff base ligand

AbstractA phenoxy-imine proligand with the additional OH donor group, 4,6-tBu2-2-(2-CH2(OH)-C6H4N = CH)C6H3OH (LH2), was synthesized and used to prepare group 4 and 5 complexes by reacting with Ti(OiPr)4 (LTi) and VO(OiPr)3 (LV). All new compounds were characterized by the FTIR, 1H and 13C NMR spectroscopy and LTi by the single-crystal X-ray diffraction analysis. The complexes were used as catalysts in the ring opening polymerization of ε-caprolactone. The influence of monomer/transition metal molar ratio, reaction time, polymerization temperature as well as complex type was investigated in detail. The complexes showed high (LTi) and moderate (LV) activity in ε-caprolactone polymerization a…

Impact of Organoaluminum Compounds on Phenoxyimine Ligands in Coordinative Olefin Polymerization. A Theoretical Study

The reduction of the phenoxyimine moiety in three individual species—namely free ligand, aluminum complex, and titanium complex—with aluminum alkyls and aluminum hydride has been studied by means of DFT. It was demonstrated that the free phenoxyimine ligand in an equimolar mixture with trimethylaluminum does not undergo reduction. Instead, experimentally observed formation of the six-membered cyclic aluminum–phenoxyimine complex, useful in the ring-opening polymerization of lactones, takes place as the kinetically and thermodynamically favored process. However, it is anticipated that a 2-fold excess of the aluminum compound, especially aluminum hydride, acting on the resulting cyclic comple…

CCDC 1948113: Experimental Crystal Structure Determination

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CCDC 1895969: Experimental Crystal Structure Determination

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CCDC 1578498: Experimental Crystal Structure Determination

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CCDC 1877301: Experimental Crystal Structure Determination

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CCDC 1895970: Experimental Crystal Structure Determination

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CCDC 2144108: Experimental Crystal Structure Determination

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CCDC 1578497: Experimental Crystal Structure Determination

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