Cation/jt interaction

Zacharias, N. and Dougherty, D.A. Cation-JT interactions in ligand recognition and catalysis. Trends Pharm. Sci. 2002, 23, 281-287. 

Cation-JT interactions have been primarily invoked as the major reason which dictates the site selectivity for the ene pathway. DFT calculations at the B3LYP/6-31G level of theory revealed that the binding site of Na+ to the substrates of Table 23 is controlled significantly by the presence of substituents capable of interacting with the cation via non-bonded electron pairs (e.g. fluorine or oxygen atoms). The Na+ -F interaction, for example, is highly exothermic and is the driving force for the facile adsorption of fluorinated compounds within Na-Y. ... 

Gallivan JP, Dougherty DA. Cation-Jt interactions in structural biology. Proc Natl Acad Sci USA 1999 96 9459-64. 

It is indisputable that ILs can be widely applied to functionalize CNTs due to their excellent dispersing power. Recently, liquid-phase exfoliation of CNTs has been reviewed by Coleman [61] however, the dispersion mechanism for CNTs in ILs is still controversial. A cation-jt interaction between nanotubes and imidazolium ions was first proposed by Fukushima and Aida [55,57] to account for the exfoliation of entangled SWCNTs into smaller bundles, even individuals. On the basis of combined results of differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrum, and X-ray diffraction (XRD) analysis, Gilman et al. [81] provided the evidence for a cation-Ti interaction in the imidazolium-treated MWCNTs. Some researchers also cited this interpretation to support their cases [82]. 

Figure 1.19 Schematic drawing of the cation-jt interaction showing the contact between the two. The quadrupole moment of benzene, along with its representation as two opposing dipoles, is also shown.

Gokel, G. W., Barbour, L. J., Ferdani, R., Hu, J. X., Lariat ether receptor systems show experimental evidence for alkali metal cation-Jt interactions , Acc. Chem. Res. 2002, 35, 878-886. 

Lenthall, J. T. and Steed, J. W., Organometallic cavitands Cation-Jt interactions and anion binding via Jt-metallation , Coord. Chem. Rev. 2007, 251, 1747-1760. 

Weakly polar interactions in proteins and protein-ligand complexes are frequently phenomenologically analyzed and classified in terms of the interacting partners [29]. This especially includes interactions with Jt-systems, such as the NH-jt, OH-jt, or CH-Jt interaction [30, 31], aromatic-aromatic interactions (parallel jt-jt stacking versus edge-to-face interaction), and the cation-jt interaction [32]. All of these can... 

Salonen, L.M., Bucher, C., Banner, D.W., Haap, W, Mary, J.-L., Benz, f., Kuster, O., Seiler, P., Schweizer, W.B., and Diederich, F. (2009) Cation-Jt interactions at the active site of factor Xa dramatic enhancement upon stepwise N-alkylation of ammonium ions. Angewandte Chemie - International Edition in English, 48, 811-814. 

Cation-Jt-interactions are noncovalent binding forces with great importance in many systems. Ab initio calculations were performed on complexes between cations and j-triazine, which has a small and positive quadrupole moment. Minimum-energy Jt-complexes were found between j-triazine and cations (Figure 2). A likely explanation of this duality is the stabilization obtained from the ion-induced polarization <2003OL2227>. 

R 734 O. Nakamura, Asymmetric Synthesis with Cation-jt Interaction ,... 

Cation-JT interactions are also prominent at the active sites of enzymes involving cationic substrates. Key examples include the blood coagulation serine proteases Factor Xa and thrombin, and a number of enzymes that use S-adenosyhnethionine. a sulfonium ion that serves as nature s ubiquitous methyl transfer agent. A spectacular series of examples is the array of enzymes that catalyze the cationic cyclizations of polyenes in a key step of terpene and steroid biosynthesis. It is now clear that... 

Becher, J. A pyiTolo-tetrathiafulvalene cage Synthesis and X-ray crystal structure. Org. Lett. 2802. 4. 4189-4192. Bartoli, S. Roelens. S. Binding acetylcholine and tetra-methylammonium to a cyclophane receptor Anion s contribution to the cation-jt interaction. J. Am. Chem. Soc. 2002. 124. 8307-8315. 

---