Charge-assisted hydrogen bonding as a cohesive force in soil organic matter: water solubility enhancement by addition of simple carboxylic acids

The influence of soil organic matter on the initial and residual phytotoxicity of thirteens-triazine herbicides was investigated in greenhouse experiments using three Horotiu sandy loam soils with organic matter levels of 9.8, 15.5, and 20.6%. The amount of herbicide required to reduce the growth of oats (Avena sativaL. ‘Mapua’) by 50% (GR50) when compared with the control was determined for each herbicide and each organic matter level. Results showed that the GR50values for all herbicides were highly and positively correlated with the soil organic matter. In general, the phytotoxicity of compounds of high water solubility was less influenced by soil organic matter than those having low water solubility. The chloro-triazines persisted longer in soil than did the methoxy- or methylthio-triazines. Simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] and atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] were the most persistent of the chloro-triazines.

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Aliphatic carboxylic acids in buried Ah horizons in Alberta, Canada as paleoenvironmental indicators

Canadian Journal of Earth Sciences ◽

10.1139/e83-075 ◽

1983 ◽

Vol 20 (5) ◽

pp. 859-866 ◽

Cited By ~ 4

Author(s):

J. F. Dormaar

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Carboxylic Acids ◽

Soil Formation ◽

Aliphatic Acids ◽

Southern Alberta ◽

Aliphatic Carboxylic Acids ◽

Paleoenvironmental Indicators

In southern Alberta, a buried Ah horizon is frequently present beneath Mazama tephra (ca. 6600 years BP). Drainage conditions during the formation of such buried Ah horizons may determine the quality of the aliphatic carboxylic acids in the soil organic matter. The spectrum of aliphatic acids extracted from a number of buried Ah horizons indeed suggests either well drained or poorly drained conditions during soil formation regardless of the mode of deposition of materials before or after the soil-forming interval. The climate required for development of the well drained paleosols was inferred to be similar to the climate under which surficial Black Chernozemic Ah horizons were formed.

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The use of β-cyclodextrins to enhance the aqueous solubility of trichloroethylene and perchloroethylene and their removal from soil organic matter: Effect of substituents

Canadian Journal of Chemistry ◽

10.1139/v02-205 ◽

2003 ◽

Vol 81 (1) ◽

pp. 45-52 ◽

Cited By ~ 13

Author(s):

Salma Shirin ◽

Erwin Buncel ◽

Gary W vanLoon

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Binding Constant ◽

Binding Constants ◽

Aqueous Solubility ◽

Solubility Enhancement ◽

Degree Of Substitution ◽

Water Remediation ◽

Effective Removal ◽

Matter Effect

This paper describes a systematic study for the evaluation of different substituted β-cyclodextrins (β-CDs), as agents for the enhancement of the aqueous solubility of two major organic pollutants, trichloroethylene (TCE) and perchloroethylene (PCE). The aqueous solubility enhancement occurs through the formation of hostguest inclusion complexes between the CD molecule (host) and the polychloroethylene (guest) and is driven primarily by hydrophobic forces. The CDs evaluated are: methyl-β-CD (Mβ-CD), hydroxypropyl-β-CD (HPβ-CD), carboxymethyl-β-CD (CMβ-CD1, CMβ-CD2), and sulfated-β-CD (Sβ-CD1, Sβ-CD2); the degree of substitution was also varied. Using a 5% (w/v) aqueous CD solution, solubility enhancement factors (St/So) up to 5.5 and 14 were determined for TCE and PCE, respectively. Binding constants (K11) for TCE with the substituted CDs were evaluated using an 1H NMR technique; these were found to range from 3 to 120 M1. It was shown that solubility enhancement, as well as the binding constant, is dependent on the type and degree of substitution of the β-CD molecule; the determining factors are discussed. The CDs are also capable of effective removal of PCE and TCE retained by soil organic matter. Thus, a suitably substituted β-CD may be a valuable additive in pump-and-treat protocols for site remediation of polychlorinated organics. Key words: Cyclodextrin, trichloroethylene, perchloroethylene, solubility enhancement, binding constant, soil and water remediation.

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Characterization of porous microaggregates and soil organic matter sequestered in allophanic paleosols on Holocene tephras using synchrotron-based X-ray microscopy and spectroscopy

10.21203/rs.3.rs-513069/v1 ◽

2021 ◽

Author(s):

Doreen Yu-Tuan Huang ◽

David J. Lowe ◽

G. Jock Churchman ◽

Louis A. Schipper ◽

Alan Cooper ◽

...

Keyword(s):

Organic Matter ◽

Fine Structure ◽

Soil Organic Matter ◽

Porous Structure ◽

Functional Groups ◽

Science Studies ◽

Organic Chemical ◽

X Ray ◽

Nexafs Spectroscopy ◽

Allophanic Soil

Abstract Allophanic tephra-derived soils can sequester sizable quantities of soil organic matter (SOM). However, no studies have visualized the fine internal porous structure of allophanic soil microaggregates, nor studied the carbon structure preserved in such soils or paleosols. We used synchrotron radiation-based transmission X-ray microscopy (TXM) to perform 3D-tomography of the internal porous structure of allophanic soil microaggregates, and carbon near-edge X-ray absorption fine-structure (C NEXAFS) spectroscopy to characterize SOM in ≤12,000-yr-old tephra-derived allophanic paleosols. The TXM tomography showed a vast network of internal, tortuous nano-pores within an allophanic microaggregate comprising nanoaggregates. SOM in the allophanic paleosols at four sites was dominated by carboxylic/carbonyl functional groups with subordinate quinonic, aromatic, and aliphatic groups. All samples exhibited similar compositions despite differences between the sites. That the SOM does not comprise specific types of functional groups through time implies that the functional groups are relict. The SOM originated at the land/soil surface: ongoing tephra deposition (intermittently or abruptly) then caused the land-surface to rise so that the once-surface horizons were buried more deeply and hence became increasingly isolated from inputs by the surficial/modern organic cycle. The presence of quinonic carbon, from biological processes but vulnerable to oxygen and light, indicates the exceptional protection of SOM and bio-signals in allophanic paleosols, attributable both to the porous allophane aggregates that occlude the relict SOM from degradation, and to rapid burial by successive tephra-fallout, as well as strong Al-organic chemical bonding. TXM and C NEXAFS spectroscopy unravel the fine structure of soils and SOM and are of great potential for soil science studies.

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Characterizing porous microaggregates and soil organic matter sequestered in allophanic paleosols on Holocene tephras using synchrotron-based X-ray microscopy and spectroscopy

Scientific Reports ◽

10.1038/s41598-021-00109-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Doreen Yu-Tuan Huang ◽

David J. Lowe ◽

G. Jock Churchman ◽

Louis A. Schipper ◽

Alan Cooper ◽

...

Keyword(s):

Organic Matter ◽

Fine Structure ◽

Soil Organic Matter ◽

Porous Structure ◽

Functional Groups ◽

Science Studies ◽

Organic Chemical ◽

X Ray ◽

Nexafs Spectroscopy ◽

Allophanic Soil

AbstractAllophanic tephra-derived soils can sequester sizable quantities of soil organic matter (SOM). However, no studies have visualized the fine internal porous structure of allophanic soil microaggregates, nor studied the carbon structure preserved in such soils or paleosols. We used synchrotron radiation-based transmission X-ray microscopy (TXM) to perform 3D-tomography of the internal porous structure of dominantly allophanic soil microaggregates, and carbon near-edge X-ray absorption fine-structure (C NEXAFS) spectroscopy to characterize SOM in ≤ 12,000-year-old tephra-derived allophane-rich (with minor ferrihydrite) paleosols. The TXM tomography showed a vast network of internal, tortuous nano-pores within an allophanic microaggregate comprising nanoaggregates. SOM in the allophanic paleosols at four sites was dominated by carboxylic/carbonyl functional groups with subordinate quinonic, aromatic, and aliphatic groups. All samples exhibited similar compositions despite differences between the sites. That the SOM does not comprise specific types of functional groups through time implies that the functional groups are relict. The SOM originated at the land/soil surface: ongoing tephra deposition (intermittently or abruptly) then caused the land-surface to rise so that the once-surface horizons were buried more deeply and hence became increasingly isolated from inputs by the surficial/modern organic cycle. The presence of quinonic carbon, from biological processes but vulnerable to oxygen and light, indicates the exceptional protection of SOM and bio-signals in allophanic paleosols, attributable both to the porous allophane (with ferrihydrite) aggregates that occlude the relict SOM from degradation, and to rapid burial by successive tephra-fallout, as well as strong Al-organic chemical bonding. TXM and C NEXAFS spectroscopy help to unravel the fine structure of soils and SOM and are of great potential for soil science studies.

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Study of Hydrogen Bonding in Carboxylic Acids by the MNDO/M Method

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19941251 ◽

1994 ◽

Vol 59 (6) ◽

pp. 1251-1260 ◽

Cited By ~ 4

Author(s):

Michal Bureš ◽

Jaroslav Bezus

Keyword(s):

Experimental Data ◽

Hydrogen Bond ◽

Hydrogen Bonding ◽

Hydrogen Bonds ◽

Carboxylic Acids ◽

Promising Method ◽

Semiempirical Methods ◽

Am1 Method ◽

Bond Lengths ◽

Pm3 Method

The semiempirical methods MNDO/M, AM1 and PM3 were applied to the study of hydrogen bonds in carboxylic acids. The calculated hydrogen bond lengths and enthalpies of dimerization were compared with experimental data. The AM1 method fails to properly describe systems with strong hydrogen bonds. The PM3 method predicts the hydrogen bond lengths correctly but underestimates systematically the enthalpies of dimerization. MNDO/M appears to be a promising method for the treatment of association of carboxylic acids.

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The hydrogen-bonded complex bis(tert-butylammonium) 2,6-dichlorophenolate 2,4-dichlorophenol–2,4-dichlorophenolate tetrahydrofuran disolvate containing a chiralR53(10) hydrogen-bonded ring as a supramolecular synthon

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229616013577 ◽

2016 ◽

Vol 72 (10) ◽

pp. 720-723 ◽

Cited By ~ 1

Author(s):

Xiao-Qing Cai ◽

Bei Tian ◽

Jian-Nan Zhang ◽

Zhi-Min Jin

Keyword(s):

Hydrogen Bonding ◽

Hydrogen Bonds ◽

Crystal Structures ◽

Functional Groups ◽

High Probability ◽

Internal Symmetry ◽

Supramolecular Synthon ◽

Π Interactions ◽

Graph Set ◽

Hydrogen Bonded

A fixed hydrogen-bonding motif with a high probability of occurring when appropriate functional groups are involved is described as a `supramolecular hydrogen-bonding synthon'. The identification of these synthons may enable the prediction of accurate crystal structures. The rare chiral hydrogen-bonding motifR53(10) was observed previously in a cocrystal of 2,4,6-trichlorophenol, 2,4-dichlorophenol and dicyclohexylamine. In the title solvated salt, 2C4H12N+·C6H3Cl2O−·(C6H3Cl2O−·C6H4Cl2O)·2C4H8O, five components, namely twotert-butylammonium cations, one 2,4-dichlorophenol molecule, one 2,4-dichlorophenolate anion and one 2,6-dichlorophenolate anion, are bound by N—H...O and O—H...O hydrogen bonds to form a hydrogen-bonded ring, with the graph-set motifR53(10), which is further associated with two pendant tetrahydrofuran molecules by N—H...O hydrogen bonds. The hydrogen-bonded ring has internal symmetry, with a twofold axis running through the centre of the 2,6-dichlorophenolate anion, and is isostructural with a previous and related structure formed from 2,4-dichlorophenol, dicyclohexylamine and 2,4,6-trichlorophenol. In the title crystal, helical columns are built by the alignment and twisting of the chiral hydrogen-bonded rings, along and across thecaxis, and successive pairs of rings are associated with each other through C—H...π interactions. Neighbouring helical columns are inversely related and, therefore, no chirality is sustained, in contrast to the previous case.

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Water Solubility Enhancement of DDT by Humic Acid and Extracellular Organic Matter of Aquatic Algae

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.565 ◽

2012 ◽

Vol 518-523 ◽

pp. 565-568 ◽

Cited By ~ 2

Author(s):

Hua Ma ◽

Fu Yi Cui ◽

Zhi Wei Zhao ◽

Zhi Quan Liu ◽

Dong Mei Liu

Keyword(s):

Organic Matter ◽

Humic Acid ◽

Water Body ◽

Sampling Method ◽

Water Solubility ◽

Solubility Enhancement ◽

Absorption Coefficients ◽

Solution Ph ◽

Eutrophic Water ◽

Extracellular Organic Matter

The water solubility enhancement of 2,4´-DDT and 4,4´-DDT by humic acid and extracellular organic matter released from Microcystis aeruginosa was investigated by a ingenious sampling method and increasing apparent solute solubilities. Water solubility enhancements of the two DDT isomerizes by both humic acid and extracellular organic matter at the solution pH 7-11, and their solubilities increased with the increase of pH. Absorption coefficients Ciw (2,4´-DDT and 4,4´-DDT) increased with the increase of pH for HA and EOM, but Ciw for EOM are about two times than for HA at same TOC concentrations. The results suggested that more attentions should be paid to the enhancement of organic chemicals by EOM, especially in eutrophic water body where an increasing algae population usually appears, and the enhancement of DDT solubility by EOM may increase the risk of pesticide residues to organisms.

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Clusters of Hydroxyl-Functionalized Cations Stabilized by Cooperative Hydrogen Bonds: The Role of Polarizability and Alkyl Chain Length

Molecules ◽

10.3390/molecules25214972 ◽

2020 ◽

Vol 25 (21) ◽

pp. 4972

Author(s):

Jule Philipp ◽

Ralf Ludwig

Keyword(s):

Hydrogen Bonding ◽

Ionic Liquids ◽

Hydrogen Bonds ◽

Functional Groups ◽

Chain Length ◽

Alkyl Chain ◽

Kinetic Stability ◽

Alkyl Chain Length ◽

Coupling Constants ◽

Imidazolium Cations

We explore quantum chemical calculations for studying clusters of hydroxyl-functionalized cations kinetically stabilized by hydrogen bonding despite strongly repulsive electrostatic forces. In a comprehensive study, we calculate clusters of ammonium, piperidinium, pyrrolidinium, imidazolium, pyridinium, and imidazolium cations, which are prominent constituents of ionic liquids. All cations are decorated with hydroxy-alkyl chains allowing H-bond formation between ions of like charge. The cluster topologies comprise linear and cyclic clusters up to the size of hexamers. The ring structures exhibit cooperative hydrogen bonds opposing the repulsive Coulomb forces and leading to kinetic stability of the clusters. We discuss the importance of hydrogen bonding and dispersion forces for the stability of the differently sized clusters. We find the largest clusters when hydrogen bonding is maximized in cyclic topologies and dispersion interaction is properly taken into account. The kinetic stability of the clusters with short-chained cations is studied for the different types of cations ranging from hard to polarizable or exhibiting additional functional groups such as the acidic C(2)-H position in the imidazolium-based cation. Increasing the alkyl chain length, the cation effect diminishes and the kinetic stability is exclusively governed by the alkyl chain tether increasing the distance between the positively charged rings of the cations. With adding the counterion tetrafluoroborate (BF4−) to the cationic clusters, the binding energies immediately switch from strongly positive to strongly negative. In the neutral clusters, the OH functional groups of the cations can interact either with other cations or with the anions. The hexamer cluster with the cyclic H-bond motive and “released” anions is almost as stable as the hexamer built by H-bonded ion pairs exclusively, which is in accord with recent IR spectra of similar ionic liquids detecting both types of hydrogen bonding. For the cationic and neutral clusters, we discuss geometric and spectroscopic properties as sensitive probes of opposite- and like-charge interaction. Finally, we show that NMR proton chemical shifts and deuteron quadrupole coupling constants can be related to each other, allowing to predict properties which are not easily accessible by experiment.

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