Effiziente Umwandlung von Licht in chemische Energie: Gerichtete, chirale Photoschalter mit sehr hohen Quantenausbeuten

Coordination-Induced Spin-State Switching with Nickel Chlorin and Nickel Isobacteriochlorin

We present the first coordination-induced spin-state switching with nickel chlorin and nickel isobacteriochlorin. The spin-state switching was monitored by UV-vis spectroscopy and NMR titration experiments. The association constants (K1 and K2) and thermodynamic parameters (ΔH and ΔS) of the coordination of pyridine were determined. The first X-ray analyses of a paramagnetic nickel chlorin and a nickel isobacteriochlorin provide further information about the structure of the octahedral complexes. Nickel chlorin and even more pronounced nickel isobacteriochlorin exhibit stronger coordination of axial ligands compared to the corresponding nickel porphyrin and thus provide the basis for more e…

Spin Switching with Triazolate-Strapped Ferrous Porphyrins

Fe(III) porphyrins bridged with 1,2,3-triazole ligands were synthesized. Upon deprotonation, the triazolate ion coordinates to the Fe(III) ion, forming an overall neutral high-spin Fe(III) porphyrin in which the triazolate serves both as an axial ligand and as the counterion. The second axial coordination site is activated for coordination and binds p-methoxypyridine, forming a six-coordinate low-spin complex. Upon addition of a phenylazopyridine as a photodissociable ligand, the spin state of the complex can be reversibly switched with ultraviolet and visible light. The system provides the basis for the development of switchable catalase- and peroxidase-type catalysts and molecular spin sw…

cis-Bromierung von Alkinen ohne kationische Zwischenstufen

Efficient Conversion of Light to Chemical Energy : Directional, Chiral Photoswitches with Very High Quantum Yields

Abstract Photochromic systems have been used to achieve a number of engineering functions such as light energy conversion, molecular motors, pumps, actuators, and sensors. Key to practical applications is a high efficiency in the conversion of light to chemical energy, a rigid structure for the transmission of force to the environment, and directed motion during isomerization. We present a novel type of photochromic system (diindane diazocines) that converts visible light with an efficiency of 18 % to chemical energy. Quantum yields are exceptionally high with >70 % for the cis–trans isomerization and 90 % for the back‐reaction and thus higher than the biochemical system rhodopsin (64 %). T…

Design and synthesis of the first triply twisted Möbius annulene.

As long as 50 years ago theoretical calculations predicted that Mobius annulenes with only one π surface and one edge would exhibit peculiar electronic properties and violate the Huckel rules. Numerous synthetic attempts notwithstanding, the first singly twisted Mobius annulene was not prepared until 2003. Here we present a general, rational strategy to synthesize triply or even more highly twisted cyclic π systems. We apply this strategy to the preparation of a triply twisted [24]dehydroannulene, the structure of which was confirmed by X-ray analysis. Our strategy is based on the topological transformation of 'twist' into 'writhe'. The advantage is twofold: the product exhibits a lower deg…

cis-bromination of alkynes without cationic intermediates

CCDC 1415585: Experimental Crystal Structure Determination

Related Article: Marcel Dommaschk, Vanessa Thoms, Christian Schütt, Christian Näther, Rakesh Puttreddy, Kari Rissanen, and Rainer Herges|2015|Inorg.Chem.|54|9390|doi:10.1021/acs.inorgchem.5b01756

CCDC 1885475: Experimental Crystal Structure Determination

Related Article: Morten K. Peters, Sebastian Hamer, Torben Jäkel, Fynn Röhricht, Frank D. Sönnichsen, Carolina von Essen, Manu Lahtinen, Christian Naether, Kari Rissanen, Rainer Herges|2019|Inorg.Chem.|58|5265|doi:10.1021/acs.inorgchem.9b00349

CCDC 1415586: Experimental Crystal Structure Determination

Related Article: Marcel Dommaschk, Vanessa Thoms, Christian Schütt, Christian Näther, Rakesh Puttreddy, Kari Rissanen, and Rainer Herges|2015|Inorg.Chem.|54|9390|doi:10.1021/acs.inorgchem.5b01756

CCDC 1884544: Experimental Crystal Structure Determination

Related Article: Morten K. Peters, Sebastian Hamer, Torben Jäkel, Fynn Röhricht, Frank D. Sönnichsen, Carolina von Essen, Manu Lahtinen, Christian Naether, Kari Rissanen, Rainer Herges|2019|Inorg.Chem.|58|5265|doi:10.1021/acs.inorgchem.9b00349

CCDC 1415587: Experimental Crystal Structure Determination

Related Article: Marcel Dommaschk, Vanessa Thoms, Christian Schütt, Christian Näther, Rakesh Puttreddy, Kari Rissanen, and Rainer Herges|2015|Inorg.Chem.|54|9390|doi:10.1021/acs.inorgchem.5b01756

CCDC 1407134: Experimental Crystal Structure Determination

Related Article: Marcel Dommaschk, Vanessa Thoms, Christian Schütt, Christian Näther, Rakesh Puttreddy, Kari Rissanen, and Rainer Herges|2015|Inorg.Chem.|54|9390|doi:10.1021/acs.inorgchem.5b01756

CCDC 1979407: Experimental Crystal Structure Determination

Related Article: Widukind Moormann, Tobias Tellkamp, Eduard Stadler, Fynn R��hricht, Christian N��ther, Rakesh Puttreddy, Kari Rissanen, Georg Gescheidt, Rainer Herges |2020|Angew.Chem.,Int.Ed.|59|15081|doi:10.1002/anie.202005361

CCDC 1979408: Experimental Crystal Structure Determination

Related Article: Widukind Moormann, Tobias Tellkamp, Eduard Stadler, Fynn R��hricht, Christian N��ther, Rakesh Puttreddy, Kari Rissanen, Georg Gescheidt, Rainer Herges |2020|Angew.Chem.,Int.Ed.|59|15081|doi:10.1002/anie.202005361

CCDC 1415588: Experimental Crystal Structure Determination

Related Article: Marcel Dommaschk, Vanessa Thoms, Christian Schütt, Christian Näther, Rakesh Puttreddy, Kari Rissanen, and Rainer Herges|2015|Inorg.Chem.|54|9390|doi:10.1021/acs.inorgchem.5b01756

CCDC 938919: Experimental Crystal Structure Determination

Related Article: Gaston R. Schaller, Filip Topić, Kari Rissanen, Yoshio Okamoto, Jun Shen, Rainer Herges|2014|Nature Chemistry|6|608|doi:10.1038/NCHEM.1955