An Aromatic Amine—1,3,5-Trinitrobenzene σ-Complex

1972 ◽  
Vol 50 (1) ◽  
pp. 129-131 ◽  
Author(s):  
E. Buncel ◽  
J. G. K. Webb
Keyword(s):  
Complex Formation ◽  
Aromatic Amine ◽  
Dmso Solution ◽  
Spectral Changes ◽  
Methoxide Ion

Interaction between aniline and the 1,3,5-trinitrobenzene–methoxide ion adduct 1 in DMSO solution results in spectral changes which are characteristic of σ-complex formation, the first such case involving an aromatic amine.

Structural Investigation of Sigma Complexes of Aromatic Amines with 1,3,5-Trinitrobenzene

1974 ◽  
Vol 52 (4) ◽  
pp. 630-639 ◽  
Author(s):  
Erwin Buncel ◽  
John G. K. Webb
Keyword(s):  
Dimethyl Sulfoxide ◽  
Aromatic Amine ◽  
Aromatic Amines ◽  
Structural Investigation ◽  
Structural Factors ◽  
Dmso Solution ◽  
Visible Spectroscopy ◽  
Sigma Complexes ◽  
Methoxide Ion ◽  
Characteristic Manner

Reaction of the 1,3,5-trinitrobenzene (TNB) – methoxide ion adduct 1 with a series of substituted arylamines in dimethyl sulfoxide (DMSO) solution yields new 1,3,5-trinitrobenzene – aromatic amine σ-complexes (2). The parent TNB–anilide complex is also obtained in the reaction of TNB with potassium anilide in DMSO. Identification of the complexes is effected by n.m.r. and visible spectroscopy. The n.m.r. parameters of the complexes are influenced in characteristic manner by substituents in the aryl-amine moiety. An analysis of electronic and structural factors in these systems is given, with emphasis on the following aspects: structural implications of NH–Hβ′ coupling; aromatic protons on the arylamine moiety; amino protons in free and complexed arylamines.

Note on the Influence of External Heavy-Atom Perturbers on the Phosphorescence Spectrum of Triphenylene

1984 ◽  
Vol 39 (11) ◽  
pp. 1145-1146 ◽  
Author(s):  
M. Zander
Keyword(s):  
Complex Formation ◽  
Methyl Iodide ◽  
Ground State ◽  
Chemical Nature ◽  
Heavy Atom ◽  
Phosphorescence Spectrum ◽  
Symmetry Reduction ◽  
Spectral Changes ◽  
Silver Perchlorate ◽  
Phosphorescence Spectra

Spectral changes in symmetry-forbidden phosphorescence spectra observed in the presence of external heavyatom perturbers may have quite different causes depending on the chemical nature of the perturber. This is exemplified using triphenylene as the phosphorescent compound and methyl iodide and silver Perchlorate respectively as the perturber. Intensification of the 0-0 band of the symmetry-forbidden phosphorescence spectrum of triphenylene by silver Perchlorate is assumed to result from symmetry-reduction of the hydrocarbon by ground-state complex formation with silver Perchlorate.

scholarly journals KINETIC STUDY ON ANIONIC σ-COMPLEX FORMATION BETWEEN 2,4,6-TRINITROANISOLE AND METHOXIDE ION BY HIGH PRESSURE STOPPED-FLOW METHOD

1979 ◽  
Vol 8 (6) ◽  
pp. 671-674 ◽  
Author(s):  
Noboru Takisawa ◽  
Muneo Sasaki ◽  
Fujitsugu Amita ◽  
Jiro Osugi
Keyword(s):  
High Pressure ◽  
Complex Formation ◽  
Kinetic Study ◽  
Stopped Flow ◽  
Flow Method ◽  
Methoxide Ion

Interaction of calmodulin and a calmodulin-binding peptide from myosin light chain kinase: major spectral changes in both occur as the result of complex formation

Biochemistry ◽  
1985 ◽  
Vol 24 (27) ◽  
pp. 8152-8157 ◽  
Author(s):  
Rachel E. Klevit ◽  
Donald K. Blumenthal ◽  
David E. Wemmer ◽  
Edwin G. Krebs
Keyword(s):  
Complex Formation ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Binding Peptide ◽  
Calmodulin Binding ◽  
Spectral Changes

N-Methylpicramide–methoxide ion interactions: proton abstraction versus σ-complex formation

1980 ◽  
Vol 58 (16) ◽  
pp. 1615-1620 ◽  
Author(s):  
Erwin Buncel ◽  
Masashi Hamaguchi ◽  
Albert R. Norris
Keyword(s):  
Complex Formation ◽  
Hydrogen Ion ◽  
Proton Abstraction ◽  
Ring Carbon ◽  
Bearing Ring ◽  
Ion Interactions ◽  
Methoxide Ion ◽  
First Time ◽  
Conjugate Base ◽  
Sole Product

The interactions of N-methylpicramide (NMP) with methoxide ion in dimethylsulfoxide–methanol media and with 1,4-diazabicyclooctane in dimethylsulfoxide have been investigated spectrophotometrically at 25.0 °C. Dimethylsulfoxide has been found to stabilize the conjugate base of NMP, formed via loss of hydrogen ion from the methylamino group, with respect to the anionic σ-complex generated via addition of methoxide ion to a ring carbon position. As a result, methanol–dimethylsulfoxide solutions rich in dimethylsulfoxide (i.e., 95/5, v/v, DMSO/MeOH) contain the conjugate base of NMP as the sole product of the 1:1 interaction of NMP and methoxide ion. At mole ratios of methoxide ion to NMP > 1 a second interaction results, yielding a dianion formed via addition of methoxide ion to one of the H-bearing ring carbon atoms of the conjugate base. Values of absorption maxima and molar absorptivities at the absorption maxima for the conjugate base of NMP and the dianion are reported here for the first time.

Meisenheimer complex formation between 4,6-dinitrobenzofurazan 1-oxide and primary, secondary and tertiary aromatic amines

1984 ◽  
Vol 37 (5) ◽  
pp. 985 ◽  
Author(s):  
RW Read ◽  
RJ Spear ◽  
WP Norris
Keyword(s):  
Complex Formation ◽  
Aromatic Amine ◽  
Aromatic Amines ◽  
Carbonate Solution ◽  
Complexation Reaction ◽  
Amino Group ◽  
Aromatic Carbon ◽  
Potassium Hydrogen Carbonate ◽  
Hydrogen Carbonate ◽  
Potassium Hydrogen

The uncatalysed formation of stable 1 : 1 Meisenheimer complexes between primary, secondary and tertiary aromatic amines and 4,6-dinitrobenzofurazan 1-oxide has been investigated. The thermodynamic product is derived from reaction through the aromatic carbon para or, if this position is substituted, ortho to the amino group of the aromatic amine. The complexes are stable to acid but react in aqueous potassium hydrogen carbonate solution or with aliphatic or aromatic amines to give crystalline salts of the complexes. In the presence of 1,4-diazabicyclo[2.2.2]octane, aniline reacts with 4,6-dinitrobenzofurazan 1-oxide to give an unstable nitrogen-bonded complex which is slowly converted into the carbon-bonded complex. The scope of the complexation reaction has been investigated and some of the mechanistic implications of the results are discussed.

N,N-Dimethylpicramide–methoxide ion interactions: 1:1 and 2:1 σ-complex formation

1980 ◽  
Vol 58 (16) ◽  
pp. 1609-1614 ◽  
Author(s):  
Erwin Buncel ◽  
Masashi Hamaguchi ◽  
Albert R. Norris
Keyword(s):  
Complex Formation ◽  
Reaction Conditions ◽  
Ion Interactions ◽  
Methanol Solutions ◽  
Methoxide Ion ◽  
First Time

The interactions of N,N-dimethylpicramide (DMP) with methoxide ion in dimethylsulfoxide–methanol media have been investigated spectrophotometrically at 25.0 °C. Both the 1:1 and 2:1 σ-complexes of DMP and methoxide ion have been observed under the various reaction conditions employed. However, dimethylsulfoxide has been found to preferentially stabilize the 1:1 σ-complex relative to the 2:1 σ-complex. As a consequence, at low base concentrations in dimethylsulfoxide–methanol solutions rich in dimethylsulfoxide (i.e. 95/5, v/v, DMSO/MeOH), the 1:1 σ-complex can be formed in the absence of any 2:1 σ-complex. This observation has been used to obtain, for the first time, values of the absorption maxima and molar absorptivities at the absorption maxima of both the 1:1 and 2:1 σ-complexes.

Nuclear magnetic resonance studies of the solvation of phosphorus(V) selenides, 1,2-bis(diphenylphosphino)ethane, and tris(dimethylamino)phosphine telluride by sulfur dioxide

1979 ◽  
Vol 57 (7) ◽  
pp. 754-761 ◽  
Author(s):  
Philip A. W. Dean
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Complex Formation ◽  
Nmr Spectra ◽  
Chemical Reactivity ◽  
Magnetic Resonance Studies ◽  
Spectral Changes ◽  
Thermodynamic Constants ◽  
Inert Solvent ◽  
Accompany Change

31P and 77Se nmr spectra have been measured for a range of phosphorus(V) selenides, diphosphorus(V) diselenides, and triphosphorus(V) triselenides in the inert solvent CH2Cl2 and in liquid SO2. Significant roughly-correlated reductions in |1J(PSe)| and deshielding of the 77Se resonance accompany change of solvent from CH2Cl2 to SO2. These changes are shown to arise from 1:1 phosphorus(V) selenide:SO2 donor:acceptor complex formation. Approximate thermodynamic constants for the formation of the complexes have been determined and possible structures for the 1:1 complexes with the diphosphorus(V) diselenides discussed. It is shown from 1H and 31P nmr spectral changes that Ph2P(CH2)2PPh2 forms a 1:1 complex with SO2, and approximate thermodynamic data for the SO2 complexation of the diphosphine have been established. Complexation is indicated by changes in both |1J(PTe)| and δP when (Me2N)3PTe is dissolved in SO2, but the chemical reactivity of this system precluded detailed study.

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