wtorek, 30 czerwca 2009

No H…H bonding in phenanthrene despite a bond path

 
 

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przez Computational Organic Chemistry autor: Steven Bachrach dnia 09-05-19

I blogged on Bickelhaput's examination of the stability of kinked vs. linear polycyclic aromatics1 in this post. Bickelhaupt argued against any H…H stabilization across the bay region, a stabilization that Matta and Bader2 argued is present based on the fact that there is a bond path linking the two hydrogens.

Grimme and Erker have now added to this story.3 They prepared the dideuterated phenanthrene 1 and obtained its IR and Raman spectra. The splitting of the symmetric (a1) and asymmetric (b1) vibrational frequencies is very small 9-12 cm-1. The computed splitting are in the same range, with very small variation with the computational methodology employed. The small splitting argues against any significant interaction between the two hydrogen (deuterium) atoms. Further, the sign of the coupling between the two vibrations indicates a repulsive interaction between the two atoms. These authors argue that the vibrational splitting is almost entirely due to conventional weak van der Waals interactions, and that there is no "bond" between the two atoms, despite the fact that a bond path connects them. This bond path results simply from two (electron density) basins forced to butt against each other by the geometry of the molecule as a whole.


1

References

(1) Poater, J.; Visser, R.; Sola, M.; Bickelhaupt, F. M., "Polycyclic Benzenoids: Why Kinked is More Stable than Straight," J. Org. Chem. 2007, 72, 1134-1142, DOI: 10.1021/jo061637p

(2) Matta, C. F.; Hernández-Trujillo, J.; Tang, T.-H.; Bader, R. F. W., "Hydrogen-Hydrogen Bonding: A Stabilizing Interaction in Molecules and Crystals," Chem. Eur. J. 2003, 9, 1940-1951, DOI: 10.1002/chem.200204626

(3) Grimme, S.; Mück-Lichtenfeld, C.; Erker, G.; Kehr, G.; Wang, H.; Beckers, H. W., H., "When Do Interacting Atoms Form a Chemical Bond? Spectroscopic Measurements and Theoretical Analyses of Dideuteriophenanthrene," Angew. Chem. Int. Ed. 2009, 48, 2592-2595, DOI: 10.1002/anie.200805751

InChIs

1: InChI=1/C14H10/c1-3-7-13-11(5-1)9-10-12-6-2-4-8-14(12)13/h1-10H/i7D,8D
InChIKey=YNPNZTXNASCQKK-QTQOOCSTEC


 
 

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Structure-reactivity relationships in a recognition mediated [3+2] dipolar c...

 
 

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przez RSC - Org. Biomol. Chem. latest articles autor: Douglas Philp dnia 09-06-23

Andrew J. Sinclair, Vicente del Amo, Douglas Philp
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środa, 24 czerwca 2009

Self-assembly and aggregation of melamine and melamine-uric/cyanuric acid investigated by STM and AFM on solid surfaces


Self-assembly and aggregation of melamine and melamine-uric/cyanuric acid investigated by STM and AFM on solid surfaces


Xu Zhang, Ting Chen, Qing Chen, Ling Wang, Li-Jun Wan

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Structure-reactivity relationships in a recognition mediated [3+2] dipolar cycloaddition reaction


Structure-reactivity relationships in a recognition mediated [3+2] dipolar cycloaddition reaction


Andrew J. Sinclair, Vicente del Amo, Douglas Philp

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Electron-Deficient Triphenylene and Trinaphthylene Carboximides


Electron-Deficient Triphenylene and Trinaphthylene Carboximides

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Controllable Columnar Organization of Positively Charged Polycyclic Aromatic Hydrocarbons by Choice of Counterions


Controllable Columnar Organization of Positively Charged Polycyclic Aromatic Hydrocarbons by Choice of Counterions

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Bias-Field and Pressure Effects on the One-Dimensional Dielectric Response i...

 
 

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czwartek, 18 czerwca 2009

Hydrogen-Bonding Recognition-Induced Color Change of Gold Nanoparticles for Visual Detection of Melamine in Raw Milk and Infant Formula


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Ruthenium-Based Olefin Metathesis Catalysts Bearing N-Heterocyclic Carbene Ligands


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niedziela, 14 czerwca 2009

Polysubstituted Pyridazinones from Sequential Nucleophilic Substitution Reactions of Tetrafluoropyridazine



Polysubstituted Pyridazinones from Sequential Nucleophilic Substitution Reactions of Tetrafluoropyridazine

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Influence of Bases and Ligands on the Outcome of the Cu(I)-Catalyzed Oxidative Homocoupling of Terminal Alkynes to 1,4-Disubstituted 1,3-Diynes Using Oxygen as an Oxidant



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Perspectives on Computational Organic Chemistry


Perspectives on Computational Organic Chemistry

The Journal of Organic Chemistry, Volume 74, Issue 12, Page 4433-4446, June 19, 2009.


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Detection of methylcytosine by DNA photoligation via hydrophobic interaction of the alkyl group


Detection of methylcytosine by DNA photoligation via hydrophobic interaction of the alkyl group


Masayuki Ogino, Yuuta Taya, Kenzo Fujimoto

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Planar chiral asymmetric naphthalenediimide cyclophanes: synthesis, characterization and tunable FRET properties


Planar chiral asymmetric naphthalenediimide cyclophanes: synthesis, characterization and tunable FRET properties


Sandro Gabutti, Silvia Schaffner, Markus Neuburger, Matthias Fischer, Gabriel Schafer, Marcel Mayor

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Recent highlights in the synthesis of highly functionalized pyrimidines


Recent highlights in the synthesis of highly functionalized pyrimidines


Marco Radi, Silvia Schenone, Maurizio Botta

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środa, 10 czerwca 2009

A Biomimetic Modular Polymer with Tough and Adaptive Properties

 
 

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Molecular recognition at the liquid-liquid interface of colloidal microcapsules

 
 

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przez RSC - Chem. Commun. latest articles autor: Vincent M. Rotello dnia 09-06-09

Debabrata Patra, Chiara Pagliuca, Chandramouleeswaran Subramani, Bappaditya Samanta, Sarit S. Agasti, Nada Zainalabdeen, Stuart T. Caldwell, Graeme Cooke, Vincent M. Rotello
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niedziela, 7 czerwca 2009

Przyspieszenie badań nad technologiami wodorowymi

 
 

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Naukowcy opracowali układ analityczny, która pozwala na jednoczesne badanie nawet 200 różnych związków chemicznych, pod kątem możliwości wykorzystania ich, jako katalizatorów produkcji wodoru z wody. Urządzenie to znacząco przyspieszy oraz obniży koszty badań nad nowymi katalizatorami stosowanymi, w przyszłej, masowej produkcji wodoru - informuje "Energy & Environmental Science".

 
 

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Optical explosives detection: from color changes to fluorescence turn-on

 
 

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via RSC - Chem. Soc. Rev. latest articles by Michael J. Knapp on 6/5/09

Meaghan E. Germain, Michael J. Knapp
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piątek, 5 czerwca 2009

The Tetracyanopyrazinide Dimer Dianion, [TCNP]22−. 2-Electron 8-Center Bonding

 
 

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Synthesis, Structure, and Reactions of NH-Bridged Calix[m]arene[n]pyridines

 
 

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środa, 3 czerwca 2009

Complementary Multiple Hydrogen-Bonding Interactions Increase the Glass Tran...

 
 

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A Novel Procedure for the Synthesis of Benzo[b][1,8]naphthyridine-3-carboxyl...

 
 

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via Synthesis by Weike Su, Weihui Zhong, Fuliang Lin, Ren’er Chen on 5/29/09

Synthesis
DOI: 10.1055/s-0029-1216853



Abstract

A novel procedure has been designed for the preparation of benzo[][1,8]naphthyridine-3-carboxylate derivatives from the reaction of Morita-Baylis-Hillman adduct acetates with primary amines, ammonium acetate or benzenesulfonamides. The approach, which involves readily available starting materials and mild reaction conditions, gives excellent yields after a convenient workup procedure.
[...]

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Development and Scope of the Phenolic Aldol Reaction of 2-Formylpyridines

 
 

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via Synlett by Matthew Whiting, Mark C. Wilkinson, Kathy Harwood on 6/2/09

Synlett
DOI: 10.1055/s-0029-1217325



Abstract

2-Formylpyridines have been shown to be suitable electrophiles for the magnesium-promoted phenolic aldol reaction. Exceptionally mild reaction conditions have been developed and a brief survey of the reaction scope has been conducted. This process gives straightforward access to a range of functionalised 2-hydroxy­phenyl-2-pyridylmethanols and 2-hydroxyphenyl-2-pyridylmethanes via their subsequent reduction.
[...]

© Georg Thieme Verlag Stuttgart ˙ New York

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wtorek, 2 czerwca 2009

One-Pot Iodination of Hydroxypyridines

 
 

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przez The Journal of Organic Chemistry: Latest Articles (ACS Publications) autor: Kevin M. Maloney et al dnia 09-06-01

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Cooperativity in multiply H-bonded complexes

 
 

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przez RSC - Chem. Commun. latest articles autor: Simon M. Turega dnia 09-06-02

Christopher A. Hunter, Ndidi Ihekwaba, Maria Cristina Misuraca, Maria Dolores Segarra-Maset, Simon M. Turega
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Christopher A. Hunter, Chem. Commun., 2009, DOI: 10.1039/b908010d
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poniedziałek, 1 czerwca 2009

Borylene-Based Direct Functionalization of Organic Substrates: Synthesis, Ch...

 
 

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przez Journal of the American Chemical Society: Latest Articles (ACS Publications) autor: Holger Braunschweig et al dnia 09-05-29

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A White-Light-Emitting Molecule: Frustrated Energy Transfer between Constitu...

 
 

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