Achiral inorganic material

The influence of a surface on an adsorbed species is well-accepted. The TA/Ni(l 10) system demonstrates how much the molecule can influence the behaviour of the surface. How far can an adsorbate like tartaric acid induce such effects Work by Switzer and co-workers on the electrodeposition of CuO films in the presence of tartaric acid showed that chirality could be induced in a normally achiral inorganic material [25]. In a standard electrochemical cell, a Au(OOl) crystal is placed in a solution containing Cu(II) ions, tartrate ions and NaOH. At a certain potential, CuO will deposit, as a thin-film on the Au Surface. Characterization by diffraction revealed that the deposited CuO film has no mirror or inversion elements, i.e. it is chiral. The chirality of the film is controlled by the chirality of the tartrate ions in the solution (/ ,/ )-tartrate yielding a chiral CuO(-lll) fihn while presence of (S,S )-tartrate produces the mirror Cu(l-l-l) enantiomorph. Switzer et al, by catalyzing the oxidation of tartaric acid, demonstrate that not only the bulk, but also the surface of the CuO film is chiral the CuO electrode surface grown in the presence of (/ ,/ )-tartrate is more effective at oxidizing (/ ,/ )-TA, while the surface deposited in the presence of (S,S )-tartrate is more effective at oxidizing (S,S )-TA. 

Abstract Enantioselective heterogeneous catalysis requires surfaces with structures that are chiral at the atomic level. It is possible to obtain naturally chiral surfaces from crystalline inorganic materials with chiral bulk structures. It is also possible to create naturally chiral surfaces from achiral materials by exposing surfaces that have atomic stractures with no mirror symmetry planes oriented perpendicular to the surface. Over the past decade there have been a number of experimental and theoretical demonstrations of the enantiospecific physical phenomena and surface chemistry that arise from the adsorption of chiral organic compounds on the naturally chiral, high Miller index places of metals. 

TABLE 3. Asymmetric autocatalysis in reaction of 87 initiated by chiral inorganic crystals, inorganic-organic hybrid materials and chiral cocrystals of achiral compounds... 

Our findings showed a new way to transcribe the supramolec-ular chirality of a dynamic supramolecular architecture the transfer of the supramolecular chirality of G-quadmplex at the nanometric and micrometric scale is reported, thereby creating nanosized hybrid structures or microsized inorganic superstructures, respectively. Moreover, we obtain chiral materials by using a starting achiral guaninesiloxane Gsi as precursor of achiral G-quartet and of chiral supramolecular G-quadruplex. Figures 7 and 8 represent the first pictures of the dynamic G-quadruplex transcribed at the nanometric level. 

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