scholarly journals Preparation and structure of silver complexes with 4-nitroimidazole

1992 ◽  
Vol 70 (3) ◽  
pp. 943-951 ◽  
Author(s):  
Isabelle Ségalas ◽  
André L. Beauchamp
Keyword(s):  
Nitro Group ◽  
Nmr Spectra ◽  
Acidic Solution ◽  
Aqueous Media ◽  
Polymeric Chain ◽  
Silver Complexes ◽  
Endocyclic Nitrogen Atom ◽  
Neutral Ligands ◽  
Coordination Patterns ◽  
C Nmr

The reaction of 4-nitroimidazole (NO2ImH) with AgNO3 and AgBF4 in neutral or weakly acidic aqueous media yielded the insoluble [Ag(NO2Im)] compound, whose infrared and 13C NMR spectra are consistent with a polymeric chain of deprotonated ligands bridging silver atoms via the endocyclic nitrogen atoms. In strongly acidic solution, [Ag(NO2ImH)2]X salts (X = NO3, BF4) were obtained and their crystal structures were determined. [Ag(NO2ImH)2]NO3: monoclinic, P2/n, a = 14.214(1), b = 12.571(2), c = 14.222(1) Å, β = 111.38(7)°, Z = 8, R = 0.021, 3443 observed reflections; [Ag(NO2ImH)2]BF4; monoclinic, P21/c, a = 9.543(4), b = 6.478(2), c = 20.869(9) Å, β = 90.84(3)°, Z = 4, R = 0.027, 1646 observed reflections. In both compounds, the two-coordinated metal forms roughly collinear bonds to two neutral ligands via the endocyclic nitrogen atom adjacent to the nitro group. One oxygen of each nitro group makes a secondary Ag—O bond near the equatorial plane. The anions are hydrogen bonded to the ligand N—H groups and do not directly interact with the metal. Solution 1H and 13C NMR spectra show that the cationic complexes dissociate in DMSO. The infrared and CP-MAS 13C NMR spectra are discussed in connection with the coordination patterns observed. Keywords: silver, imidazole, crystal structure, infrared spectroscopy, nuclear magnetic resonance.

Article

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1057-1065
Author(s):  
John T Edward ◽  
Francis L Chubb ◽  
Denis FR Gilson ◽  
Rosemary C Hynes ◽  
Françoise Sauriol ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Acidic Solution ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Cage Compounds ◽  
Amine Nitrogen ◽  
X Ray ◽  
Bridgehead Nitrogen ◽  
C Nmr

Three new cage peroxides, 1,6-diaza-3,4,8,9-tetraoxabicyclo[4.4.2]dodecane (3a),1,6-diaza-3,4,8,9-tetraoxa-11-methylbicyclo[4.4.2]dodecane (3b), and 1,6-diaza-3,4,8,9-tetraoxatricyclo[4.4.2.411,12]hexadecane (4), have been prepared by reaction of 1,2-diaminoethane, 1,2-diaminopropane, and trans-1,2-diaminocyclohexane, respectively, with formaldehyde and hydrogen peroxide in aqueous acidic solution. Their structures have been established by X-ray diffraction, and show the bridgehead nitrogen atoms to be predominantly sp2 hybridized. The structures accord with 1H and 13C NMR spectra. Variable temperature NMR studies show that the diperoxide 3a begins to undergo rapid inversion (on the NMR time scale) at about 303 K; up to 370 K the diperoxides 3b and 4 show no conformational change.Key words: cage compounds, formaldehyde, peroxides, amine nitrogen, hybridization.

An intermediate of reaction of 2-naphthol with activated sludge

1988 ◽  
Vol 53 (7) ◽  
pp. 1574-1578 ◽  
Author(s):  
Karel Komers ◽  
Antonín Lyčka ◽  
Josef Jirman ◽  
Ivan Kolb
Keyword(s):  
Activated Sludge ◽  
Nmr Spectra ◽  
Dissociation Constants ◽  
Aqueous Media ◽  
Standard State ◽  
Acid Base ◽  
C Nmr

A redbrown intermediate has been isolated from a reaction mixture of 2-naphthol and the activated sludge, and its structure has been determined on the basis of its IR, MS, and especially 2D 1H and 13C NMR spectra. It corresponds to 4-(2-hydroxy-1-naphthyl)-6-hydroxy-1,2-naphthoquinone (I). In aqueous media I behaves as an acid-base indicator with the colour transition from yellow to redbrown. The concentration dissociation constants of I have been determined spectrophotometrically: K1 = 3·47 . 10-7, K2 = 3·80 . 10-10 for the standard state c0 = 1 mol dm-3, 298 K, 105 Pa.

Preparation and NMR Spectra of Substituted 2-(4-Nitrophenyl)imidazolinones

1996 ◽  
Vol 61 (6) ◽  
pp. 910-920 ◽  
Author(s):  
Miloš Sedlák ◽  
Aleš Halama ◽  
Jaromír Kaválek ◽  
Vladimír Macháček ◽  
Petr Mitaš ◽  
...  
Keyword(s):  
Nitro Group ◽  
Nmr Spectra ◽  
C Nmr

A series of 11 substituted 2-(4-nitrophenyl)imidazolinones have been prepared by base catalyzed cyclizations of substituted 2-(4-nitrobenzoylamino)alkanamides. At higher methoxide concentrations the cyclization can be accompanied by reduction of nitro group to azoxy group. All the substances prepared have been identified by 1H and 13C NMR spectra.

scholarly journals Boric Acid Catalyzed Convenient Synthesis of Benzimidazoles in Aqueous Media

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Mohammad Reza Poor Heravi ◽  
Marjan Ashori
Keyword(s):  
Boric Acid ◽  
Nmr Spectra ◽  
Aqueous Media ◽  
Reaction Conditions ◽  
Efficient Catalyst ◽  
H Nmr ◽  
Convenient Synthesis ◽  
Ft Ir ◽  
Acid Catalyzed ◽  
C Nmr

Synthesis of benzimidazoles has been developed by theo-phenylenediamine with aldehydes using boric acid an efficient catalyst under mild reaction conditions in aqueous media. The product is applicable to aryl and heteroaryl aldehydes. This reaction led to the formation of benzimidazoles new derivatives in good yields. The FT-IR,19F-NMR,1H-NMR,13C-NMR spectra and elemental analysis confirm the structure of compounds.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

13C NMR spectra of 1-aryl-ferrocenylethylenes

1986 ◽  
Vol 51 (3) ◽  
pp. 670-676 ◽  
Author(s):  
Eva Solčániová ◽  
Štefan Toma ◽  
Tibor Liptaj
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Substituent Effects ◽  
13C Nmr Spectra ◽  
Bridge Group ◽  
C Nmr ◽  
Electron Effects

13C NMR spectra of 18 ferrocene analogues of trans stilbenes (1-aryl-2-ferrocenylethylenes) were measured. It was found that bridge group weakens the transfer of the substituent electron effects into ferrocene nucleus, especially distinctly into 3',4'positions of cyclopentadienyl ring. The transfer of substituent effects into β-position of the bridge -CH=CH- is greater in derivatives studied by us than in stilbenes. Synthesis of 1-(4-dimethylaminophenyl)-2-ferrocenylethylene is described.

The synthesis and stereochemistry of the ternary cobalt(III) complex with a stereospecific ligand derived from (S)-leucine

1986 ◽  
Vol 51 (2) ◽  
pp. 318-326 ◽  
Author(s):  
Milan Strašák ◽  
Pavol Novomeský
Keyword(s):  
Ir Spectroscopy ◽  
Aqueous Medium ◽  
Absorption Spectroscopy ◽  
Absolute Configuration ◽  
Nmr Spectra ◽  
Methyl Groups ◽  
Electron Absorption Spectroscopy ◽  
Electron Absorption ◽  
C Nmr

A new stereospecific ligand, ethylenediamine-N,N'-di(S)-α-isocapronic acid, was synthesized by condensation of (S)-leucine with 1,2-dibromoethane in alkaline aqueous medium. It follows from the 1H and 13C NMR spectra that the terminal methyl groups are chemically and magnetically nonequivalent. Of the four theoretically possible isomers of the ternary cobalt (III) complex with ethylenediamine, separation on catex yielded only one, whose absolute configuration was determined by a combination of 1H and 13C NMR, electron absorption spectroscopy and CD and IR spectroscopy.

17O and 13C NMR spectra of some geminal diacetates

1988 ◽  
Vol 53 (3) ◽  
pp. 588-592 ◽  
Author(s):  
Antonín Lyčka ◽  
Josef Jirman ◽  
Jaroslav Holeček
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
The Other ◽  
13C Nmr Spectra ◽  
Other Hand ◽  
Carboxylic Esters ◽  
C Nmr ◽  
Oxygen Atoms

The 17O and 13C NMR spectra of eight geminal diacetates RCH(O(CO)CH3)2 derived from simple aldehydes have been measured. In contrast to the dicarboxylates R1R2E(O(CO)R3)2, where E = Si, Ge, or Sn, whose 17O NMR spectra only contain a single signal, and, on the other hand, in accordance with organic carboxylic esters, the 17O NMR spectra of the compound group studied always exhibit two well-resolved signals with the chemical shifts δ(17O) in the regions of 183-219 ppm and 369-381 ppm for the oxygen atoms in the groups C-O and C=O, respectively.

Carbon-13 and nitrogen-14 NMR spectra of 1-(substituted phenyl)pyridinium salts

1980 ◽  
Vol 45 (10) ◽  
pp. 2766-2771 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Heavy Water ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Pyridinium Salts ◽  
Nmr Signals ◽  
C Nmr

The 13C and 14N NMR spectra of 1M solutions of 1-(substituted phenyl)pyridinium salts (4-CH3, 4-OCH3, H, 4-Cl, 4-Br, 4-I, 3-NO2, 4-NO2, 2,4-(NO2)2 (the 13C NMR only)) have been measured in heavy water at 30 °C. The 13C and 14N chemical shifts, the 1J(CH) coupling constants, some 3J(CH) coupling constants, and values of half-widths Δ 1/2 of the 14N NMR signals are given. The 13C chemical shifts of C(4) correlate with the σ0 constants (δC(4) = (1.79 ± 0.097) σ0 + (147.67 ± 0.041)), whereas no correlation of the nitrogen chemical shifts with the σ constants has been found. The half-widths Δ 1/2 correlate with the σ0 constants (Δ 1/2 = (76.2 ± 4.9) σ0 + (106.4 ± 2.2)) except for 1-phenylpyridinium chloride.

Synthesis of the six isomeric thieno[c]-fused 1,5- and 1,6-naphthyridines

1991 ◽  
Vol 56 (11) ◽  
pp. 2340-2351 ◽  
Author(s):  
Salo Gronowitz ◽  
Johan Malm ◽  
Anna-Britta Hörnfeldt
Keyword(s):  
Nmr Spectra ◽  
Coupling Reaction ◽  
One Pot ◽  
C Nmr

trough the use of Pd(0)-catalyzed coupling between 2- and 4-formyl-3-thiopheneboronic acids and 3-amino-2-bromopyridine and 4-acetamido-3-bromopyridine, convenient one-pot procedures for the preparation of thieno[2,3-c]-1,5-naphthyridine, thieno[3,4-c]-1,5-naphthyridine, thieno-[2,3-c]-1,6-naphthyridine, and thieno[3,4-c]-1,6-naphthyridine have been developed. In order to obtain thieno[3,2-c]-1,6-naphthyridine 2-(tributylstannyl)-3-thiophene aldehyde had to be used, since the organometallic partner in the coupling reaction, 3-formyl-2-thipheneboronic acid, is too easily deboronated. The effect of silver(I) oxide and thallium(I) carbonate on the coupling was studied. 1H and 13C NMR spectra of the six isomeric thieno{c]-fused 1,5- and 1,6-naphthyridines are discussed.

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