Maleic Anhydride – Triethylamine Complex

1973 ◽  
Vol 51 (21) ◽  
pp. 3539-3540 ◽  
Author(s):  
Mahmood F. Mayahi ◽  
M. F. El-Bermani
Keyword(s):  
Maleic Anhydride ◽  
Spectral Properties ◽  
Addition Product ◽  
Open Chain ◽  
Yellow Solution

Reaction of triethylamine with maleic anhydride (MA) forms first a yellow solution, which immediately turns into a dark brown product with a large increase in temperature. The addition product is a 1:1 open chain inner salt [Formula: see text]. The spectral properties of this salt are reported.

scholarly journals Sodium (1R)-D-glucit-1-ylsulfonate monohydrate

2012 ◽  
Vol 68 (4) ◽  
pp. m377-m378 ◽  
Author(s):  
Alan H. Haines ◽  
David L. Hughes
Keyword(s):  
Complex Cation ◽  
Three Dimensional ◽  
Addition Product ◽  
Chain Structure ◽  
Water Molecules ◽  
Open Chain ◽  
Carbon Chains ◽  
Molecular Anions ◽  
Dimensional Network ◽  
Cation Coordination

The title salt, Na+·C6H13O9S−·H2O, crystallizes with three independent cations, molecular anions and solvent water molecules in the asymmetric unit. This crystalline monohydrate addition product, formed by reaction of D-glucose and sodium hydrogen sulfite in water, forms a three-dimensional network through complex cation coordination and extensive intermolecular hydrogen bonding. Each of the independent molecules has an open-chain structure with the carbon chains adopting a sickle-like conformation, similar to that found in the potassium salt [Coleet al.(2001).Carbohydr. Res.335, 1–10], but there are significant differences in the patterns of complexation.

Intermolecular H-Abstraction of Thiyl Radicals from Thiols and the Intramolecular Complexing of the Thiyl Radical with the Thiol Group in 1,4-Dithiothreitol. A Pulse Radiolysis Study

1987 ◽  
Vol 42 (1-2) ◽  
pp. 134-140 ◽  
Author(s):  
M. Shahid Akhlaq ◽  
Clemens von Sonntag
Keyword(s):  
Hydroxyl Radicals ◽  
Spectral Properties ◽  
Radical Anion ◽  
Pulse Radiolysis ◽  
Thiol Group ◽  
Oh Radicals ◽  
Thiyl Radical ◽  
Solvated Electron ◽  
Open Chain ◽  
Thiyl Radicals

Abstract Hydroxyl radicals were generated by pulse radiolysis of N2O-saturated aqueous solutions. The OH radicals react with thiols such as 1,4-dithiothreitol by abstracting S-bound H-atoms (k = 1.5 × 1010 dm3 mol-1 s-1). The 1,4-dithiothreitol radical HSCH2(CHOH)2CH2S (2) closes the ring (k - 1.5 × 106 s-1) thereby forming the three-electron-bonded species (3) in equilibrium (2, 3: ε(380 nm) = 450 dm3 mol-1 cm-1) which has a reported pKa value of 5.2. At pH 7.2 3 deprotonates (k = 105 s-1) yielding the ring-closed radical anion 4 which is characterized by a strong absorption at 390 nm (ε = 5900 dm3 mol-1 cm-1). The deprotonation of 3 is catalyzed by HPO24 (k - 6 .8 × 107 dm3 mol-1 s-1). The ring-closed radical anion 4 has also been generated by reacting trans-4,5-dihydroxy- 1,2-dithian with the solvated electron and the H atom in Ar-saturated solution. Its protonation by protons yielding 3 occurs with k - 1.8 × 1010 dm3 mol-1 s-1, with H2PO-4 with k = 3.8 × 107 dm3 mol-1 s-1. In its reaction towards tetranitrom ethane 3 differs from its non-complexed analogue HOCH2-CH2S‘ (1) in that 3 is rapidly oxidized (k = 2 × 108 dm3 mol s-1) while 1 is not. Isoenergetic H transfer from 1,4-dithiothreitol to 1 occurs with a rate constant of k = 1.7 × 107 dm3 mol-1 s-1. 1,4-Dithiothreitol has pKa values at 9.12 and 10.15. At pH 9.1 thiolate ions com pete with ringclosure by complexing with 2 thereby forming an open-chain disulphide radical anion 6 which has very similar spectral properties as its ring-closed analogue 4.

Model of multicomponent narrow-band periodical non-stationary random signal

2020 ◽  
Vol 2020 (48) ◽  
pp. 17-24
Author(s):  
I.M. Javorskyj ◽  
◽  
R.M. Yuzefovych ◽  
P.R. Kurapov ◽  
◽  
...  
Keyword(s):  
Time Series ◽  
Real Time ◽  
Hilbert Transform ◽  
Spectral Properties ◽  
Narrow Band ◽  
Analytic Signal ◽  
Random Signal ◽  
Hilbert Transformation ◽  
The Hilbert Transform

The correlation and spectral properties of a multicomponent narrowband periodical non-stationary random signal (PNRS) and its Hilbert transformation are considered. It is shown that multicomponent narrowband PNRS differ from the monocomponent signal. This difference is caused by correlation of the quadratures for the different carrier harmonics. Such features of the analytic signal must be taken into account when we use the Hilbert transform for the analysis of real time series.

Structure and Spectral Properties of New Composites Based on Metal Alkanoates with Gold Nanoparticles

2015 ◽  
Vol 60 (04) ◽  
pp. 356-361 ◽  
Author(s):  
A. Tolochko ◽  
◽  
P. Teselko ◽  
A. Lyashchova ◽  
D. Fedorenko ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Spectral Properties
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