Markus Neuburger

An element of surprise - efficient copper-functionalized dye-sensitized solar cells

Dye-sensitized solar cells with carboxylate-derivatized {Cu(I)L(2)} complexes are surprisingly efficient and offer a long-term alternative approach to ruthenium-functionalized systems.

A supramolecularly-caged ionic iridium (III) complex yielding bright and very stable solid-state light-emitting electrochemical cells

A new iridium(III) complex showing intramolecular interligand pi-stacking has been synthesized and used to improve the stability of single-component, solid-state light-emitting electrochemical cell (LEC) devices. The pi-stacking results in the formation of a very stable supramolecularly caged complex. LECs using this complex show extraordinary stabilities (estimated lifetime of 600 h) and luminance values (average luminance of 230 cd m-2) indicating the path toward stable ionic complexes for use in LECs reaching stabilities required for practical applications.

Tripeptides of the type H-D-Pro-Pro-Xaa-NH2 as catalysts for asymmetric 1,4-addition reactions : structural requirements for high catalytic efficiency

Analysis of the structural and functional requirements within the asymmetric peptidic catalyst H-D-Pro-Pro-Asp-NH(2) led to the development of the closely related peptide H-D-Pro-Pro-Glu-NH(2) as an even more efficient catalyst for asymmetric conjugate addition reactions of aldehydes to nitroolefins. In the presence of as little as 1 mol % of H-D-Pro-Pro-Glu-NH(2), a broad range of aldehydes and nitroolefins react readily with each other. The resulting gamma-nitroaldehydes were obtained in excellent yields and stereoselectivities at room temperature. Within the structure of the peptidic catalysts, the D-Pro-Pro motif is the major contributor to the high stereoselectivities. The C-terminal amide and the spacer to the carboxylic acid in the side-chain of the C-terminal amino acid are responsible for the fine-tuning of the stereoselectivity. The peptidic catalysts not only allow for highly effective asymmetric catalysis under mild conditions, but also function in the absence of additives.

Large Work Function Shift of Gold Induced by a Novel Perfluorinated Azobenzene-Based Self-Assembled Monolayer

Tune it with light! Self-assembled monolayers on gold based on a chemisorbed novel azobenzene derivative with a perfluorinated terminal phenyl ring are prepared. The modified substrate shows a significant work function increase compared to the bare metal. The photo-conversion between trans and cis isomers chemisorbed on the surface shows great perspectives for being an accessible route to tune the gold properties by means of light.

Memory of Chirality in Photochemistry

The helical-chiral character of the diradical intermediate 2, which cyclizes quicker than it equilibrates, explains the memory effect of chirality that occurs during the enantioselective photocyclization of alanine derivative 1 to give the proline derivative 3. Ts=H(3)CC(6)H(4)SO(2).

In search of enantioselective catalysts for the Henry reaction: are two metal centres better than one?

Catalysts for the asymmetric Henry reaction involving copper(II) complexes of the chiral Schiff bases N,N′-(1R,2R)-(−)-1,2-cyclohexylenebis(3-hydroxysalicylideneamine) (H21) and N,N′-(1R,2R)-(−)-1,2-cyclohexylenebis(3-ethoxysalicylideneamine) (H22), and H23, which is the reduced analogue of H21, have been studied. Whereas [Cu(1)] and [Cu(2)] give poor yields and enantioselectivity, [Cu(3)] produced moderate to high yields and enantioselectivities were optimal when reactions were carried out in toluene rather than a polar solvent. A significant finding is that both yield and enantioselectivity are enhanced when a second equivalent of Cu(OAc)2 is added to the catalyst. The single-crystal structures of [Cu(3)] and [Cu(1)(H2O)] are presented, and the host–guest interactions and molecular packing in the latter are compared with those in [Cu(2)(H2O)].

Total Synthesis of Cyrneine A

Keywords: cross-coupling ; natural products ; neurochemistry ; stereoselective synthesis ; total synthesis ; Ring Enlargement Reaction ; Asymmetric-Synthesis ; Tricyclic Core ; Cyathin Diterpenoids ; Heck Reaction ; Intermediate ; Cyclization Reference EPFL-ARTICLE-177265doi:10.1002/anie.201200515View record in Web of Science Record created on 2012-05-18, modified on 2017-05-12

Optically active sulfoximines in enantioselective palladium catalysis

Abstract Chiral sulfoximine/Pd-complexes catalyze enantioselective allylic alkylations. The corresponding products have been obtained in good yields with moderate enantioselectivities (up to 73% ee . The crystal structure of an allyl/Pd(II)-complex bearing a chelating sulfoximine is reported.

A one-dimensional copper(II) coordination polymer containing [Fe(pytpy)2]2+ (pytpy = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine) as an expanded 4,4′-bipyridine ligand : a hydrogen-bonded network penetrated by rod-like polymers

The one-dimensional coordination polymer [{(H2O)(NO3)2CuFe(1)2}2(NO3)4·2.15MeCN·5.85H2O]n assembles when the pendant pyridine donors in [Fe(1)2]2+ (1 = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine) are treated with Cu(NO3)2·3H2O, exemplifying [Fe(1)2]2+ as an expanded 4,4′-bipyridine ligand. In the solid state, the polymer chains are threaded through hydrogen-bonded macrocycles comprising coordinated and non-coordinated water molecules and nitrate ions, the macrocycles being motifs within interconnected sheets in the structure.

Synthesis of Substituted [8]Cycloparaphenylenes by [2 + 2 + 2] Cycloaddition

A new modular approach to the smallest substituted cycloparaphenylenes (CPPs) is presented. This versatile method permits access to substituted CPPs, choosing the substituent at a late stage of the synthesis. Variously substituted [8]CPPs have been synthesized, and their properties analyzed. The structural characteristics of substituted CPPs are close to those of unsubstituted CPPs. However, their optoelectronic behavior differs remarkably due to the larger torsion angle between the phenyl units.