Aromatische Moleküle mit schalenförmiger Struktur: ein Ausflug in die molekulare Architektur

Die Chemie aromatischer Verbindungen geht zurück auf das Jahr 1825, in dem Faraday zum ersten Mal die Isolierung von Benzol aus Leuchtgas gelang. Mit der erst 40 Jahre später erfolgten Strukturzuordnung durch Kekulé setzte eine Entwicklung ein, die nicht nur zur Gründung und dem stürmischen Wachstum der deutschen chemischen Industrie führte, sondern auch der Wissenschaft immer wieder neue Impulse gegeben hat – bis auf den heutigen Tag

Evidence of the torsion of a polyene chain in a strongly hindered molecular environment: The ttbP4 crystal

In this work we provide experimental and theoretical evidence that in a molecular environment as restricted as the crystalline phase, the all-trans ttbP4 (1,1,8,8-tetrakis(tert-butyl)octa-1,3,5,7-tetraene) can undergo a conformational change, by rotating around the second single bond, when it is electronically excited to its 11Bu state. Undoubtedly, this is an interesting step to clarify the viability of the torsional mechanism of retinal pigments in the cavity of bacteriorhodopsin as proposed in the vision mechanism. We show that the fluorescence emission of ttbP4 in the crystalline phase is the combination of two bands corresponding to the emission from two different ttbP4 conformers. Theoretical simulations of absorption and emission spectra allowed us to identify the two conformers as: i) the most stable all-trans ttbP4, giving rise to a structured fluorescence band, and ii) the conformer generated by the torsion around the second single bond of ttbP4 polyene chain, giving rise to an emission band with hardly any structure. Interestingly, experimental data also show that the rotated structure, after deactivating to the ground state, takes a time to return to the all-trans configurationThankful to the Universidad Autonoma de Madrid for providing the facility to carry out this research. A.M.S. thanks the CCC-UAM for generous allocation of computing time and the Madrid Government (Comunidad de Madrid-Spain) under the Multiannual Agreement with UAM in the line Support to Young Researchers, in the context of the V PRICIT (SI3-PJI-2021-00463). We acknowledge Javier Cerezo for fruitful discussions and providing help with FCclases3 program to simulate the spectr

[2.2](4,7)Isobenzofuranophanes - Synthesis, Characterisation and Reactivity

The isomeric Diels-Alder adducts 3, obtained by cycloaddition of tetraphenylcyclopentadienone to the 4,5:12,13-bis-(oxanorbornadieno)[2.2]paracyclophanes syn,syn- and anti,-syn-2[Note ][The stereochemical descriptors syn and anti refer to the orientation of the oxygen bridge in the oxabicyclo[2.2.1]heptadiene subunits with respect to the [2.2]paracyclophaneskeleton.], yield the unstable isobenzofuranophane 4 by consecutive extrusion of carbon monoxide and tetraphenylbenzene when heated to 180°C. The molecular ion of 4 was observed in the EI mass spectrum. The stable tetraphenyl-substituted analogue 10 was synthesized independently from the previously unknown 4,5,12,13-tetrabenzoyl[2.2]paracyclophane (9). UV/Vis as well as fluorescence spectra and an X-ray crystal structure analysis of 9 are reported

A shared future:Chemistry's engagement is essential for resilience of people and planet

Strengthening resilience—elasticity or adaptive capacity—is essential in responding to the wide range of natural hazards and anthropogenic changes humanity faces. Chemistry's roles in resilience are explored for the first time, with its technical capacities set in the wider contexts of cross-disciplinary working and the intersecting worlds of science, society and policy. The roles are framed by chemistry's contributions to the sustainability of people and planet, examined via the human security framework's four material aspects of food, health, economic and environmental security. As the science of transformation of matter, chemistry is deeply involved in these material aspects and in their interfacing with human security's three societal and governance aspects of personal, community and political security. Ultimately, strengthening resilience requires making choices about the present use of resources as a hedge against future hazards and adverse events, with these choices being co-determined by technical capacities and social and political will. It is argued that, to intensify its contributions to resilience, chemistry needs to take action along at least three major lines: (i) taking an integrative approach to the field of ‘chemistry and resilience’; (ii) rethinking how the chemical industry operates; and (iii) engaging more with society and policy-makers

8-(Biphenyl-2-yl)-7,9-diphenyl-8H-cyclo­penta­[a]acenaphthylen-8-ol

In the title compound, C39H26O, the cyclo­penta­[a]acenaphthyl­ene skeleton displays the expected distortions, with formal sp 2 bond angles as high as C—C—C = 142.50 (10)°. The OH group forms inter­molecular hydrogen bonds via x-axis translation to the centroid (Cg) of the pendant phenyl ring of the biphenyl system, with H⋯Cg = 2.41 Å and O—H⋯Cg = 153°

En Route to European Journals of Inorganic and Organic Chemistry

In 1997 a new journal structure for the chemical literature in Europe will begin to evolve. Recueil des Travaux Chimiques des Pays-Bas will unite with Liebigs Annalen and Chemische Berichte; furthermore, Chemistry - A European Journal will become independent of Angewandte Chemie, its “carrier journal”. Recueil was founded in 1882 and is the journal of the Royal Netherlands Chemical Society (KNCV); Chemische Berichte (1865) and Liebigs Annalen (1832) are German Chemical Society (GDCh) journals. With these heritages in mind, we will apply the image of a “European House”, often used by politicians, to scientific publishing in Europe

Convenient diastereoselective synthesis of annulated 3-substituted-(5S*,6S*,Z)-2-(2-(2,4-dinitrophenyl)hydrazono)-5,6-diphenyl-1,3-thiazinan-4-ones

Racemic 2-(2,4-dinitrophenyl)hydrazono)-5,6-diphenyl-1,3-thiazinan-4-ones and (Z)-N '-(2,4-dinitrophenyl)-2,3-diphenylacrylohydrazide were formed during the diastereoselective reaction between 4-substituted 1-(2,4-dinitrophenyl)thiosemicarbazides and 2,3-diphenylcycloprop-2-enone under refluxing ethanol. The structures of the synthesized compounds were confirmed by single-crystal X-ray analyses. [GRAPHICS] .Peer reviewe

What is going to become of Chemische Berichte/Recueil and Liebigs Annalen/Receuil?

Although these two chemistry journals have a long tradition behind them, they have not shied away from changes! Did you know, for example, that “Berichte” and “Annalen” have published in English - no longer in German - since 1995? The two journals have also been allocated specific interest areas, and another big move took place at the beginning of this year: the merger with the Dutch “Recueil des Travaux Chimiques des Pays-Bas”. To accommodate all these changes, widescale reorganization had to take place. However, not only did the daily work continue, but another major and exciting development took place in the background: the changeover to electronic manuscript processing. (For an update see http://www.wiley-vch.de). The results of these efforts are concrete and can be seen on the pages of the journals every month