Radiation Chemistry of Carbohydrates, X* γ-Radiolysis of Crystalline D-Glucose and D-Fructose

1977 ◽  
Vol 32 (2) ◽  
pp. 213-224 ◽  
Author(s):  
M. Dizdaroglu ◽  
D. Henneberg ◽  
K. Neuwald ◽  
G. Schomburg ◽  
C. Von Sonntag
Keyword(s):  
Aqueous Solution ◽  
Solid State ◽  
Dose Rate ◽  
Gluconic Acid ◽  
Room Temperature ◽  
Radiation Chemistry ◽  
Chain Reaction ◽  
A Chain ◽  
Reaction Schemes

α-D-Glucose and β-D-fructose were γ-irratiated in the solid (polycrystalline) state at room temperature at doses of 3.5 · 1020-4.2 · 1021 eV g-1 (dose rate 1.16 · 1018 eV g-1 min-1). Carbohydrate products containing ≤ 6 carbon atoms were identified and their G-values (in parentheses) measured.Glucose: Dihydroxyacetone (1) (0.05), 3-deoxy-tetrose (2) (0.015), 1,4-dideoxy-2-pentulose (3) (0.05), 2,4-dideoxy-pentose (4) (0.085), 2,4-dideoxy-pentonic acid (5), 2,3-dideoxypentos-4-ulose (6) (together 0.035), threose (7), erythrulose (8), erythrose (9), erythronic acid (10) (together 0.04), 1-deoxy-2-pentulose (11) (0.005), 2-deoxy-ribose (12) (0.25), 3-deoxy-pentosulose (18) (0.02), 3,5-dideoxy-hexonic acid (14) (0.02), 2,3-dideoxy-hexonic acid (15) (0.01), arabinose (16) (0.25), ribose (17), ribonic acid (18) (together 0.02), 2-deoxy-2-C-hydroxymethyl-pentonic acid (19) (0.06), 5-deoxy-gluconic acid (20), 2deoxy-5-keto-glucose (21), 2-deoxy-gluconic acid (22), 2-deoxy-3-keto-glucose (28), 3-deoxy-glucosone (24), 3-deoxy-gluconic acid (25), 3-deoxy-4-keto-glucose (26), 3-deoxymannonic acid (27) (together 0.4). Identified but nor measured quantitatively were glucosone (28), 3-keto-glucose (29), 4-keto-glucose (30), 5-keto-glucose (31) and gluconic acid (82). G(H2) = 5.75; G(CO2) = 0.7.Fructose: 7-9 (together 0.65), 3-deoxy-pentonic acids (37), 3-deoxy-pentosulose (88) (together 0.3), arabonic acid (89) (0.1), 18 (0.05), 6-deoxy-2,5-hexodiulose (40) (40). Identified but not measured quantitatively were glyceraldehyde (34), butanone-(3)-diol-(1,2) (35) and 2- and 3-deoxy-hexodiuloses. G(H2) = 4.75, G(CO2) = 0.05.Reaction schemes are proposed to account for the formation of the products. The scission of the hemiacetal bond and of the C-Η and C-C bonds next to it appears to be typical for solid state irradiations. The formation of deoxy-compounds is observed both in the solid state and in aqueous solution. The formation of dideoxy-compounds is only prominent in the solid state. In polycrystalline fructose a chain reaction is induced leading to 6-deoxy-2,5-hexodiulose (40).

Reactions of Thiyl Radicals. XI. Further Investigations of Thiol–Disulfide Photolyses in the Liquid Phase

1973 ◽  
Vol 51 (9) ◽  
pp. 1410-1415 ◽  
Author(s):  
Donna D. Carlson ◽  
Arthur R. Knight
Keyword(s):  
Liquid Phase ◽  
Room Temperature ◽  
Liquid Mixtures ◽  
Quantum Yields ◽  
Chain Reaction ◽  
Photochemical Process ◽  
High Quantum Efficiency ◽  
Thiyl Radicals ◽  
Exchange Processes ◽  
A Chain

The photolysis of C2H5SH liquid at 2537 Å has been shown to give H2 and C2H5SSC2H5 at equal rates with a quantum yield of 0.25. The photolysis of ethanethiol – methyl disulfide liquid mixtures leads, via a chain reaction involving propagation by attack of thiyl radicals on the disulfide S—S bond, to the formation with high quantum efficiency of CH3SH, C2H5SSC2H5 and, as an intermediate that is consumed after long exposures, CH3SSC2H5. The net result of the sequence of exchange processes is the essentially irreversible conversion of the methyl disulfide into methanethiol. The same overall reaction occurs thermally at room temperature, but the rate is appreciably less than that of the photochemical process. The quantum yields of formation of the unsymmetrical disulfides arising from the photochemically initiated exchange reaction in equimolar mixtures of CH3SSCH3 + n-C3H7SSC3H7 and C2H5SSC2H5 + n-C3H7SSC3H7 have been shown to be 6.9 and 4.4, compared to 355 for CH3-SSCH3 + C2H5SSC2H5 mixtures. In all three types of system examined in this investigation all thiyl radicals can be accounted for stoichiometrically on the basis of exchange and combination reactions alone, indicating negligible disproportionation of these species in condensed phase.

Radical-Induced Oxidation of Dithiothreitol in Acidic Oxygenated Aqueous Solution:  A Chain Reaction

1997 ◽  
Vol 119 (24) ◽  
pp. 5735-5739 ◽  
Author(s):  
Manohar Lal ◽  
Raghavendra Rao ◽  
Xingwang Fang ◽  
Heinz-Peter Schuchmann ◽  
Clemens von Sonntag
Keyword(s):  
Aqueous Solution ◽  
Chain Reaction ◽  
A Chain

Mixed Linker Strategy for the Construction of a Fluorescent 2D Network Based on [Ag2(COO)2] as Secondary Building Unit

2013 ◽  
Vol 68 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Di Sun ◽  
Shuai Yuan ◽  
Shan-Shan Liu ◽  
Ya-Qin Zhao ◽  
Lu-Lu Han ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Tetrahedral Coordination ◽  
Secondary Building Unit ◽  
Ultrasound Assisted ◽  
A Chain ◽  
2D Network ◽  
Distorted Tetrahedral Coordination

The ultrasound-assisted reaction of AgNO3, 2-amino-4,6-dimethylpyrimidine (dmapym) and 2,6-naphthalenedicarboxylic acid (H2npd) gave rise to a new 2D network of the formula [Ag2(dmapym)2(npd)]n (1). The atoms Ag1 and Ag2 in the complex show seesaw and distorted tetrahedral coordination geometries, respectively. The dmapym ligand acts as a bidentate bridge to bind paired Ag(I) ions into a chain. The chains are further connected by npd linkers to form the resultant 2D network reinforced by N-H···O hydrogen bonds between dmapym and npd. Weak C-H···p interactions are also found in the crystal structure. Complex 1 exhibits photoluminescence in the solid state at room temperature with an emission maximum at 418 nm upon excitation at 330 nm.

O2.cntdot.- Addition to ketomalonate leads to decarboxylation: a chain reaction in oxygenated aqueous solution

1991 ◽  
Vol 113 (18) ◽  
pp. 6934-6937 ◽  
Author(s):  
Man Nien Schuchmann ◽  
Heinz Peter Schuchmann ◽  
Martina Hess ◽  
Clemens Von Sonntag
Keyword(s):  
Aqueous Solution ◽  
Chain Reaction ◽  
A Chain

Radiation Chemistry of Carbohydrates, VI: γ-Radiolysis of Glucose in Deoxygenated N2O Saturated Aqueous Solution

1975 ◽  
Vol 30 (5-6) ◽  
pp. 416-425 ◽  
Author(s):  
Miral Dizdaroglu ◽  
Dieter Henneberg ◽  
Gerhard Schomburg ◽  
Clemens von Sonntag
Keyword(s):  
Aqueous Solution ◽  
Carbon Monoxide ◽  
Gluconic Acid ◽  
Radiation Chemistry ◽  
Oh Radicals ◽  
Minor Importance ◽  
Mechanism Of Formation ◽  
Hydrogen Atoms ◽  
Solvent Water ◽  
Water Elimination

In the γ-radiolysis of deoxygenated N2O-saturated aqueous solutions of D-glucose (10-2 M, 1 · 1019 - 4 · 1019 eV/g, dose rate 4.3 · 1018 eV/g · h at 25°C), the following products have been identified: Gluconic acid (1), 2-deoxy-gluconic acid (2), arabinose (3), 2-deoxy-ribose (4), 5-deoxy-gluconic acid (5), glucosone (6), 3-deoxy-glucosone (7), 3-keto-glucose (8), [2-deoxy-3-keto-glucose (9), 4-deoxy-3-keto-glucose (10)]3, 4-ketoglucose (11), 3-deoxy-4-keto-glucose (12), 5-deoxy-4-keto-glucose (13), 5-keto-glucose (14), 2-deoxy-5-keto-glucose (15), 4-deoxy-5-keto-glucose (16), 6-deoxy-5-keto-glucose (17), gluco-hexodialdose (18), 5-deoxy-xylo-hexodialdose (19), ribose (20), xylose (21), erythrose (22), threose (23), 3-deoxy-pentulose (24), 2-butanone-(1,4)-diol (25), and dihydroxyacetone (26). G-values were also determined.In the primary processes OH radicals and H atoms from the radiolysis of the solvent water abstract carbon bound hydrogen atoms from D-glucose to give all six possible primary glucosyl radicals. The observed products are formed in disproportionation reactions of the primary glucosyl radicals (1, 6, 8, 11, 14, 18) or of sugar radicals which originate from the primary glucosyl radicals by water elimination (2, 4, 7, 9, 10, 12, 13, 15, 16, 17, 19), rearrangements (5, 14, 15), or loss of carbon monoxide (3, 4, 20).Products 1-5 and probably 20 have primary glucosyl radicals with the odd electron at C-1 as precursors. Radicals with the free spin at C-2 give rise to the products 6 and 7. Attack at C-3 yield products 8-10, at C-4 products 11-13, at C-5 products 14-17, and an attack at C-6 products 18 and 19. Products 21-26 are formed in very low yields and hence are of minor importance. Their mechanism of formation has not been investigated.

Crystal structures and luminescence properties of two Cd(II) complexes based on 2-(1H-imidazol-1-methyl)-6-methyl-1H-benzimidazole

2015 ◽  
Vol 70 (8) ◽  
pp. 577-585 ◽  
Author(s):  
Yuhong Zhang ◽  
Qiuju Zhang ◽  
Yu Wen ◽  
Peng Li ◽  
Lin Ma ◽  
...  
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Room Temperature ◽  
Luminescent Properties ◽  
Chain Structure ◽  
Dimethyl Formamide ◽  
X Ray Diffraction ◽  
X Ray ◽  
2D Structure ◽  
A Chain

AbstractTwo new complexes, {[Cd(immb)I2]·DMF}n (1) and {[Cd3(immb)(btc)2]·H2O}n (2) (immb = 2-(1H-imidazol- 1-methyl)-6-methyl-1H-benzimidazole, btc = 1,2,3-benzenetricarboxylate, DMF = dimethyl formamide), have been synthesized and characterized. Single crystal X-ray diffraction shows that 1 exhibits a chain structure constructed by immb ligands bridging Cd(II) ions. In 2, Cd(II) ions are linked by immb ligands with bridging mode and btc3– anions with the μ2-η2:η1 bonding pattern leading to a 2D structure. Luminescent properties have been investigated in the solid state at room temperature.

Radiation Chemistry of DNA Model Compounds, IX. Carbohydrate Products in the γ-Radiolysis of Thymidine in Aqueous Solution. The Radical-Induced Scission of the N-Glycosidic Bond

1976 ◽  
Vol 31 (2) ◽  
pp. 227-233 ◽  
Author(s):  
Miral Dizdaroglu ◽  
Klaus Neuwald ◽  
Clemens Von Sonntag
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Room Temperature ◽  
Radiation Chemistry ◽  
Oh Radical ◽  
Glycosidic Linkage ◽  
Model Compounds ◽  
Sugar Moiety ◽  
G Value ◽  
Radical Attack

In the γ-radiolysis of deoxygenated N2O-saturated aqueous solutions of thymidine (10-3 M, room temperature, dose rate 4· 1018 eV/g.h., dose 6.7 1017-3.3 • 1018 eV/g) the following products (G-values in parentheses) have been identified : 2,5-dideoxy-pentos-4-ulose (1) (0.01), 2,4-dideoxy-pentodialdose (2) (0.02), 2,4-dideoxy-pentos-3-ulose (3) (0.03), 2,3-dideoxy-pentos-4-ulose (4) (0.01), 2-deoxy-pentos-4-ulose (5) (0.1), 2-deoxyribonic acid (6) (0.02) and thymine (8) ( ≤ 0.2). In the presence of oxygen (N2O/O2 80/20 v/v saturated) products 1-4 are absent, G (5) = 0.2, G (6) = 0.07 and G (8) ≤ 0.4. Furthermore, 2-deoxy-tetrodialdose (7) which is absent in deoxygenated solution is formed with a G-value of 0.03. Mechanisms are proposed to account for the scission of the N-glycosidic linkage. Product 6 is thought to be due to a primary OH radical attack at C-1′ of the sugar moiety, 8 arises from an attack at C-3′, 1, 4 and 5 from an attack at C-4′, and 2 and 7 from an attack at C-5′.

Radiation Chemistry of Carbohydrates, Vlll. γ-Radiolysis of Cellobiose in N2O-saturated Aqueous Solution. Part II. Quantitative Measurements. Mechanisms of the Radical-induced Scission of the Glycosidic Linkage

1976 ◽  
Vol 31 (6) ◽  
pp. 857-864 ◽  
Author(s):  
Clemens Von Sonntag ◽  
Miral Dizdaroglu ◽  
Dietrich Schulte-Frohlinde
Keyword(s):  
Aqueous Solution ◽  
Gluconic Acid ◽  
Major Part ◽  
Radiation Chemistry ◽  
Saturated Aqueous Solution ◽  
Second Step ◽  
Oh Radicals ◽  
Glycosidic Linkage ◽  
Reaction Sequence ◽  
Quantitative Measurements

The γ-radiolysis of cellobiose (10-2 M) in N2O saturated aqueous solution has been investigated and the G-values of the following 21 products containing six or less C-atoms have been measured (G-values in parentheses): glucose (2.1), gluconic acid (0.70), 4-ketoglucose (0.07), 5-keto-glucose (0.05), 4-deoxy-glucose (0.27), 5-deoxy-gluconic acid (0.18), 2-deoxy-gluconic acid (0.13), 3-deoxy-4-keto-glucose (0.23), 2-deoxy-5-keto-glucose (0.34), 4-deoxy-5-keto-glucose (0.14), 6-deoxy-5-keto-glucose (0.02), arabinose (0.07), ribose (0.015), 2-deoxy-ribose (0.17), 3-deoxy-pentulose (0.01), erythrose (0.015), threose (0.015), 2-deoxy-tetrose (0.01), butanone-(2)-diol(1.4) (0.01), dihydroxyacetone (0.01), carbon monoxide ( > 0.02).The formation of the major part (98%) of the measured products could be explained on the base of the following assumption: The first step of reaction sequence is abstraction of H atoms from C-Η bonds of the cellobiose by OH radicals. Radicals at C-1′, C-5′ and C-4 and their successors undergo in a second step four types of reactions: hydrolysis, rearrangement and H2O and CO elimination. In a third step the transformed radicals give rise to products by disproportionation reaction. Only two products out of 16 predicted under the above assumption are not observed. G-values for the attack at C-1′, C-5′ and C-4 are 1.4, 0.6 and 0.3 respectively.

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