A survey of structural effects on formation constants in C-H hydrogen bonding

Slasinski, Floyd M.; Tustin, J. M.; Sweeney, Francis J.; Armstrong, Alan M.; Ahmed, Qadeer; Lorand, John P.

doi:10.1021/jo00878a007

Cited by 19 publications

(15 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a recent paper [17], polychlorobiphenyls, which are structurally quite similar, are stated to exhibit a noticeable B value. In a paper by Slasinski et al [18], hydrogen‐bond formation between polychlorobenzenes and hexamethylphosphoramide was observed when cyclohexane, but not carbon tetrachloride, is used as a solvent. Thus, we consider the possibility of the polychlorobenzenes exhibiting weak hydrogen bond as still an open issue and worthy of further investigation.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of a predictive model for air/surface adsorption equilibrium constants and enthalpies

Arp¹,

Goss²,

Schwarzenbach³

2006

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

A model used to predict equilibrium adsorption to surfaces using a poly-parameter linear free-energy relationship as well as an empirical model used to predict enthalpies of adsorption of volatile compounds were evaluated with new experimental data to cover semivolatile compounds and a larger variability of compound classes. Equilibrium adsorption constants on a quartz surface ranging over seven orders of magnitude were measured for 142 compounds, and enthalpies of adsorption on a quartz surface from -33.7 to -99.8 kJ/mol were measured for 76 compounds. Agreement between experimental and predicted data was within a factor of two (82.1%) or three (100.0%) for the equilibrium adsorption constants and within 20% for the enthalpy of adsorption values. Thus, the scatter in the validation data sets reported here were practically the same as that for the calibration data sets used to derive the models. The few outliers that we identified in the prediction of equilibrium adsorption constants likely are caused by either shortcomings of the reported sorbate parameters or the occurrence of chemical speciation in the water layer on the surface of the quartz.

show abstract

Section: Discussionmentioning

confidence: 99%

Evaluation of a predictive model for air/surface adsorption equilibrium constants and enthalpies

Arp¹,

Goss²,

Schwarzenbach³

2006

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

show abstract

“…HMPA was stored over molecular sieves. The procedure for preparation of solutions has been reported 9–10. Pmr spectra were obtained using a Varian 300 MHz instrument with an Oxford magnet.…”

Section: Methodsmentioning

confidence: 99%

“…To begin an experiment, the field was optimized using 10–20% acetone‐d 6 in CCl 4 , and the lock then turned off. Values of K and δ c – δ a were extracted from δ obs and concentrations via the iterative computer program previously used,9–10 based on the Higuchi equation12 ( vide infra ).…”

Section: Methodsmentioning

confidence: 99%

“…H‐bonds are both inter‐ and intramolecular, biochemical as well as chemical, and involve not only OH and NH bonds, but also CH and SH, among others. CH H‐bonds are found in crystals,4, 5, 6 modify physical properties (CHCl 3 and acetone mix exothermically, Eqn (1)), and a common anesthetic, Halothane, 1,1,1‐trifluoro‐2‐bromo‐2‐chloroethane, exemplifies a series of compounds known to form CH H‐bonds 9…”

Section: Introductionmentioning

confidence: 99%

“…To evaluate the relative strengths of CH H‐bonds, equilibrium constants, Ks, for H‐bonding in a variety of molecules with HMPA in CCl 4 and in cyclohexane, e.g., Eqn (3), were measured some time ago using a pmr technique 9–10. We noticed that substituting the para‐H atom by a nitro group on α , α ‐dibromotoluene increased by eightfold K for H‐bonding of the α ‐hydrogen.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

CH hydrogen bonding: 3. Hammett correlations for phenylacetonitriles and tetrafluorobenzenes with HMPA

Lorand¹

2011

J of Physical Organic Chem

Self Cite

View full text Add to dashboard Cite

Understanding the hydrogen bond, or H‐bond, arguably the strongest known intermolecular attractive force, is of great importance. Models of H‐bonding hold that both electrostatic and covalent components are at work. H‐bonding of CH bonds, and thus presumably other AH bonds, is greatly facilitated by polar substituents. We have found that equilibrium constants, K, for CH H‐bonding in series of phenylacetonitriles and tetrafluorobenzenes with HMPA are closely correlated by the Hammett equation. That is, K values vary as substituents of different polarities are introduced at positions remote from the donor CH bond. This result is consistent with a significant electrostatic component in these examples of H‐bonding. It may, however, also be explained by interaction with the σ* orbital of the CH bond, which is involved in the covalent component of the H‐bond. Theoretical models need to be applied to this and other cases. Copyright © 2010 John Wiley & Sons, Ltd.

show abstract

Aromatische Diazoniumsalze, VII. Die Reduktion aromatischer Diazoniumsalze durch Hexamethylphosphorsäuretriamid (HMPT)

Tröndlin

Rüchardt

1977

Chem. Ber.

View full text Add to dashboard Cite

Die Reduktion aromatischer Diazoniumsalze mit HMPT verlluft nach kinetischen Versuchen als sehr schnelle und lange Radikalkettenreaktion, vermutlich iiber die Kettenschritte 1 -3. Uber Versuche zum Nachweis des Kettenstarts und zur praparativen Anwendung der Reaktion wird berichtet. Aromatic Diazonium Salts, V11" The Reduction of Aromatic Diazonium Salts by Heramethylphosphoric Triamide (HMPT)From kinetic evidence it is concluded, that a long radical chain probably composed of the chain steps 1 -3 is responsible for the fast and eflicient reduction of aromatic diazonium salts by HMPT. Results concerning the chain start and the synthetic usefulness of the reaction are reported.Der Tur die Synthese wichtige Austausch einer aromatischen Diazoniumgruppe gegen Wasser-stoB wurde bereits durch Griess mit Alkohol als Reduktionsmittel beschrieben z). Seitdem sind zahlreiche, teilweise in hervorragender Ausbeute verlaufende Reduktionsverfahren bekannt geworden ').

show abstract

A survey of structural effects on formation constants in C-H hydrogen bonding

Abstract: and in that of aldehydes by the aprotic donors. Anyway, the relative strength of the coordinating power of hydrogen donors and hydrogen acceptors is one of the important factors to control the reaction mechanisms of transfer hydrogenations.

Cited by 19 publications

References 3 publications

Evaluation of a predictive model for air/surface adsorption equilibrium constants and enthalpies

Evaluation of a predictive model for air/surface adsorption equilibrium constants and enthalpies

CH hydrogen bonding: 3. Hammett correlations for phenylacetonitriles and tetrafluorobenzenes with HMPA

Aromatische Diazoniumsalze, VII. Die Reduktion aromatischer Diazoniumsalze durch Hexamethylphosphorsäuretriamid (HMPT)

Contact Info

Product

Resources

About