Direct STM evidence of a surface interaction between chiral modifier and pro-chiral reagent: Methylacetoacetate on R,R-tartaric acid modified Ni

Jones, T.E.; Baddeley, Christopher J.

doi:10.1016/s0039-6028(02)02219-7

Cited by 73 publications

(109 citation statements)

References 18 publications

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…Intermolecular diastereoisomerism is in particular present in heterogeneous enantioselective catalysis, where the chiral modifier selectively interacts with the prochiral reactant. Tartaric acid, the modifier for enantioselective hydrogenation of b-ketoesters, has been studied in coadsorption with the prochiral methylacetoacetate (MAA) on Ni(111) [148]. At intermediate coverage (R,R)-tartrate indeed steers MAA into a homochiral alignment, so that hydrogenation directly from the surface would only create the (R)-hydroxy enantiomer.…”

Section: Diastereomers and Diastereomeric Recognitionmentioning

confidence: 99%

Molecular chirality at surfaces

Ernst

2012

Physica Status Solidi (b)

221

264

View full text Add to dashboard Cite

With the adsorption of larger molecules being increasingly tackled by surface scientists, the aspect of chirality often plays a role. This paper gives a topical review of molecular chirality at surfaces and gives a phenomenological overview of different aspects of adsorption and self‐assembly of chiral and prochiral molecules and the principles of mirror‐symmetry breaking at a surface. After a brief introduction into the history of molecular chirality and the important role it played for understanding the spatial structure of molecules, definitions of chirality are presented. Topics treated here are principle ways to create single chiral adsorbates, chiral ensembles, and monolayers by achiral molecules, adsorption of intrinsically chiral molecules at achiral and chiral surfaces, long‐range symmetry breaking in two‐dimensional (2D) crystals due to additional chiral bias, chiral restructuring of solid surfaces under the influence of chiral molecules, switching the handedness of adsorbates, and chirality at the liquid/air interface. An outlook onto further potential research directions and recommendations for further reading, including nonsurface‐related sources of chiral topics completes this paper.

show abstract

Section: Diastereomers and Diastereomeric Recognitionmentioning

confidence: 99%

Molecular chirality at surfaces

Ernst

2012

Physica Status Solidi (b)

221

264

View full text Add to dashboard Cite

show abstract

“…51 demonstrated that the identity of the reactant tautomer actually present under reaction conditions 254 depends critically on the modification procedure used for catalyst preparation. For example, it was found 255 that at on Ni(111) at ~ 300 K, at saturation coverage of the chiral modifiers tartaric acid 52 and glutamic12 acid both species completely blocked adsorption of the reactant. The significance of this is that both 257 modifiers, when present on their own, can form ordered arrays only at high coverages, when the surface 258 is fully passivated to reaction.…”

mentioning

confidence: 99%

Aspects of Heterogeneous Enantioselective Catalysis by Metals

2011

View full text Add to dashboard Cite

Publisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Langmuir, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://pubs.acs.org/doi/abs/10.1021/la200009w. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Some aspects of metal-catalyzed heterogeneous enantioselective reactions are reviewed with specific 23 reference to four different systems where the phenomena that control enantioselection appear to be very 24 different. In the case of glucose electro-oxidation it is clear that any intrinsic chirality present at the 25 metal surface plays a vital role. With -keto hydrogenation, achiral surfaces modified by the adsorption 26 of chiral agents become effective enantioselective catalysts and formation of extended arrays of chiral 27 species appears not to be of importance: instead a 1:1 docking interaction controlled by hydrogen 28 bonding between the adsorbed chiral modifier and the prochiral reactant determines the outcome. 29Hydrogen bonding also plays a central role in -ketoester hydrogenation, but here fundamental studies 30indicate that the formation of ordered arrays involving the reactant and chiral ligand is of importance. 31Asymmetric C=C hydrogenation, though relatively little studied, has the potential for major impact in 32 synthetic organic chemistry both at the laboratory scale and in the manufacture of fine chemicals and 33 pharmaceuticals. The structural attributes that determine whether or not a given chiral ligand is effective 34 have been identified; the ability to form strong covalent bonds with the metal surface while also 35 resisting hydrogenation and displacement by the strongly-adsorbing reactant under reaction conditions 36 are essential necessary conditions. Beyond these, ligand rigidity in the vicinity of the chirality center 37 coupled with resistance to SAM formation are critically important factors whose absence results in 38 racemic chemistry.

show abstract

“…A few features involving just the fragment species are also observed, such as two three-pronged stars joined together or a six-pronged chiral propeller displaying both R-and S-organisational chiralities. We note that all of these structures can also be found in small 15 percentages on the room temperature high coverage sample, indicating that Au(111) still has residual catalytic activity although significantly lower than that of Cu(110). Also for Au(111) the nature of the fragments was investigated by a comparative room temperature deposition of the 20 biphenylcarboxylic acid molecule.…”

mentioning

confidence: 84%

“…[19][20][21][22] A similar species, biphenyl carboxylate, is also one of the possible fragments of the NEP if its cleavage occurred at the RCH(CH 3 )-OC(O)R bond. The cationic species resulting from this fragmentation is actually observed in the positive mode 15 electrospray mass spectrum of NEP (figure ESI.1). This secondary cation is particularly stable in the case of NEP because it is situated next to the aromatic naphthalene group.…”

mentioning

confidence: 85%

“…The dissociative pathway has been identified by comparing with possible fragment species, demonstrating that the ester cleavage occurs along the RCH(CH 3 )-OC(O)R bond. 15 Scanning tunnelling microscopy (STM) has developed into a useful tool for molecular characterisation over recent years. Specifically, there have been many instances where the chirality of molecules has been inferred from molecular packing 1-3 or has been imaged unambiguously with the STM.…”

mentioning

confidence: 99%

See 1 more Smart Citation