Anion-Pai Interactions
The noncovalent interactions, such as H-bonding, electrostatic interactions, hydrophobic effects, coordination interactions to metal centres, cation-pai, anion-pai and pai-pai stacking, have become a extremely important way to generate functional materials via crystal orientation. Among these noncovalent interactions, the anion-pai interaction is still rare understood. Anions are intuitively thought to interact repulsively with aromatic rings which are taken as sources of electron. However, it has been theoretically and computationally proved that the negatively charged species can be attracted to the center of a charge neutral electron-deficient aromatic ring.[img]http://www.uib.es/depart/dqu/dquo/anion-pi.jpg[/img]
This type of unprecedented noncovalent bonding between anions and the aryl centroid of electron-deficient aromatic rings (1,3,5-triazine and the fluoride, chloride, and azide ion) has been demonstrated with an ab initio study by Mascal and Armstrong et al. [J. AM. CHEM. SOC. 2002, 124, 6274-6276]. They have realized the important of this work and declared that the association between the more synthetically versatile yet still ð-deficient 1,3,5-triazine ring (1) and the anions might possibly define a new noncovalent design principle for their recognition.As the important role in biochemical processes such as transporting and binding amino acids and nucleotides, the investigation of new anion binding motifs and their anion-pai interaction is becoming a challenging field which raises the research of supramolecular chemistry of anions.
Untill now, there have been a few evidence for the anion-pai interaction from theoretical studies (anion-pai interaction energies are computed to range from 10 to 20 kcal mol-1), but and the experimental support (X-ray structure) are rare. In these anion-pai stacking structures, the anion is located directly over the center of the arene ring. This kind of noncovalent interaction is dominated by two components: (1) attraction between the negative charge of the anion and the electric field of the arene and (2) anion-induced polarization.
However, on the basis of analysis of the Cambridge Structural Database, Johnson and Hey [J. AM. CHEM. SOC. 2007, 129, 48-58] reported in their paper that donor-acceptor charge-transfer binding motif is more common than the noncovalent one when halides interact with electron-deficient pai systems. That is the anions are more likely to reside over the periphery of the ring than over the center. They found three possible distinctly different types of complex. (A) strongly covalent sigma complexes, (B) weakly covalent donor pai-acceptor complexes and (C) noncovalent anion-pai complexes. (Qingjin Meng et al. also found recently novel CN-pai interactions in their stuies of quasi-1D magnets with spin transition [Inorg. Chem. 2007, 46, 8102-8104]). Therefore they suggested that molecular design strategies for incorporating electron-deficient pai systems within host architectures should consider the differing geometries attendant with CT versus noncovalent binding motifs.
Ref.
J. AM. CHEM. SOC. 2002, 124, 6274-6276
J. AM. CHEM. SOC. 2007, 129, 48-58
Inorg. Chem. 2007, 46, 8102-8104
[[i] 本帖最后由 niuniu123 于 2007-9-28 10:29 编辑 [/i]] a interesting topic, I downloaded the three refs with sups and cif files, and uploaded here, for guys interested in the topic.
[[i] 本帖最后由 cc136520 于 2007-9-28 09:20 编辑 [/i]] hi, friend
you must be a supramolecular chemistist
Have you any good experience in building architectures using these noncovalent interactions??
As an theoretical guy, i am very interesting in it. I think everyone will be interested in such kind of expericence changing. I am a tenderfoot in anion receptor, my work is design and investigate new receptors for kinds of anion. Sometimes the result cann't be explained easely by hydrogen bonding effect and others, so we guess there maybe Anion-Pai Interaction also exist between aryl-rings and anion in the system, but we have no experiment to justify this. as far as the theory can explain some experiment, it is good. The attractive interaction between anions and electron-deficient pai-system is understandable. Here is a latest JACS paper on this topic, which should be interesting for you guys.
[url]http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/asap/abs/ja073028k.html[/url]
J. Am. Chem. Soc., ASAP Article 10.1021/ja073028k S0002-7863(07)03028-4
Web Release Date: October 5, 2007
Copyright © 2007 American Chemical Society
Aromatic Molecules in Anion Recognition: Electrostatics versus H-Bonding
Holger Schneider, Kristen M. Vogelhuber, Florian Schinle, and J. Mathias Weber*
Contribution from the JILA, University of Colorado and NIST, and Department of Chemistry, University of Colorado, Boulder, Colorado 80309
[email]weberjm@jila.colorado.edu[/email]
Received April 30, 2007
Abstract:
Mass-selected complexes A-·C6FnH6-n (A = Cl, I, SF6; n = 0-5) were studied by infrared photodissociation spectroscopy and computational chemistry methods to investigate the interaction of negative ions and aromatic molecules, in which the charge distribution can be tuned by fluorination. Surprisingly, we find that, despite positive partial charges on the carbon atoms at high levels of fluorination, all anions under study prefer hydrogen bonding to the remaining H atoms in the ligand rather than binding to the positively charged ring. Moreover, bifurcated hydrogen bonds to two neighboring CH groups are energetically favored over linear hydrogen bonds to a single CH group.
[attach]3927[/attach]
[[i] 本帖最后由 niuniu123 于 2007-10-6 21:43 编辑 [/i]] It is interesting that the theoretical studies and experimetal studies leads to the similar conclusion at almost the same moment.
J. AM. CHEM. SOC. 2007, 129, 48-58 and this ASAP paper
new rsc paper
[b][i]Chem. Soc. Rev.[/i][/b], 2008, [b]37[/b], 68 - 83, [b]DOI:[/b] 10.1039/b614208g[size=150%][size=6][b][color=#9c0000]Anion-[img]http://www.rsc.org/images/entities/c_h2_char_03c0.gif[/img] interactions[/color][/b]
[/size][/size][b]Brandi L. Schottel, Helen T. Chifotides and Kim R. Dunbar[/b]
This [i]tutorial review[/i] provides an overview of the theoretical and experimental investigations that resulted in the recognition of anion-[img]http://www.rsc.org/images/entities/char_03c0.gif[/img] interactions, [i]i.e.[/i], non-covalent forces between electron deficient aromatic systems and anions. Several pioneering theoretical studies revealed that these interactions are energetically favorable ([img]http://www.rsc.org/images/entities/char_223c.gif[/img]20–50 kJ mol–1). Anion-[img]http://www.rsc.org/images/entities/char_03c0.gif[/img] interactions are gaining significant recognition, and their pivotal role in many key chemical and biological processes is being increasingly appreciated. The design of highly selective anion receptors and channels represent important advances in this nascent field of supramolecular chemistry.
[attach]4839[/attach]
[url=http://www.rsc.org/Publishing/Journals/CS/article.asp?doi=b614208g]http://www.rsc.org/Publishing/Journals/CS/article.asp?doi=b614208g[/url] [url=http://www3.interscience.wiley.com/cgi-bin/abstract/109746295/ABSTRACT]http://www3.interscience.wiley.com/cgi-bin/abstract/109746295/ABSTRACT[/url]
Angew. Chem. Int. Ed. 2004, 43, 5815 –5817, An Aromatic Anion Receptor Anion–p Interactions do Exist
[[i] 本帖最后由 cc136520 于 2007-12-20 07:37 编辑 [/i]]
Molecular Anions
[url]http://www.hec.utah.edu/anions/[/url]Quantitative Evaluation of Anion–Pi Interactions in Solution
Guzmán Gil-Ramírez 1, Eduardo C. Escudero-Adán 1, Jordi Benet-Buchholz 1, Pablo Ballester, Prof. 1 2 *1Institute of Chemical Research of Catalonia (ICIQ), Avda. Països Catalans 16, 43007 Tarragona, Spain, Fax: (+34) 977-920-221 [url=http://www.iciq.es/english/research/grups_eng/ballester/entrada.htm]http://www.iciq.es/english/resea ... llester/entrada.htm[/url]
2Catalan Institution for Research and Advanced Studies (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain
email: Pablo Ballester ([email=pballester@iciq.es]pballester@iciq.es[/email])
*Correspondence to Pablo Ballester, 1Institute of Chemical Research of Catalonia (ICIQ), Avda. Països Catalans 16, 43007 Tarragona, Spain, Fax: (+34) 977-920-221 [url=http://www.iciq.es/english/resea ... llester/entrada.htm]http://www.iciq.es/english/resea ... llester/entrada.htm[/url]
[url=http://www3.interscience.wiley.com/journal/118720873/abstract?CRETRY=1&SRETRY=0]http://www3.interscience.wiley.com/journal/118720873/abstract?CRETRY=1&SRETRY=0[/url] 看看热闹，不搞这个，不明白。
页:
[1]