Cationic nickel porphyrinoids with unexpected reactivity

Wicht, Richard; Bahnmüller, Stefanie; Brandhorst, Kai; Schweyen, Peter; Bröring, Martin

doi:10.1039/c5sc03663a

Cited by 9 publications

(14 citation statements)

References 65 publications

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“…Chemical structures of the naturally occurring biotripyrrins a and b, and hexaethyltripyrrindione (H 3 Et 6 tpd, 1) with numbering system. phyrinoid systems [9] and has been shown lately to be of catalytic significance, [10] was unequivocally proven by EPR spectroscopy and supported by DFT calculations.…”

Section: Introductionmentioning

confidence: 99%

Hexaethyltripyrrindione (H₃Et₆tpd): A Non‐Innocent Ligand Forming Stable Radical Complexes with Divalent Transition‐Metal Ions

et al. 2016

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Nickel, palladium, and copper complexes of the tripyrrolic ligand hexaethyltripyrrindione (H 3 Et 6 tpd, 1) have been prepared and characterized by UV/Vis and EPR spectroscopy, as well as by single-crystal X-ray structure determination. In all cases the metal ion is coordinated in a distorted square-planar geometry carrying a water ligand at the fourth coordination site. The Et 6 tpd ligand acts as a radical dianion in all cases. In solution, monomeric species are present in which the open-

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Section: Introductionmentioning

confidence: 99%

Hexaethyltripyrrindione (H₃Et₆tpd): A Non‐Innocent Ligand Forming Stable Radical Complexes with Divalent Transition‐Metal Ions

et al. 2016

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“…23 37) Substituiert man eine meso-Position mit einer Diphenylmethangruppe, bildet sich Nickelkomplex (39). Wird dieser in einer doppelten Pd-katalysierten, intramolekularen C-H-Arylierung umgesetzt, entsteht das überraschend luftstabile, neutrale Radikal (40). 38) Binden stattdessen zwei Tripyrrine an den jeweiligen β-Positionen zum Palladiumkomplex (41), erhält man Farbstoffe mit drei Metallbindungstellen, die im nahen Infrarot absorbieren.…”

Section: Organische Farbstoffeunclassified

“…Nicht erwartet war dagegen, dass diese kationische Verbindung ein hervorragender Katalysator für C Ar -C Ar -Kupplungen ist. 40) Für natürliche Porphyrine gibt es neue Anwendungen und Konzepte. Hämproteine, die in der Natur nicht vorkommen, können C-H-Insertionsreaktionen katalysieren, wenn 44) Neue Methoden für die organische Synthese an der festen Phase (SPOS) sind die goldkatalysierte Synthese von Imidazolin-2-onen, 45) die Synthese von Phosphinen 46) und die On-resin-Makrocyclisierung von Peptiden via Ugi-Smiles-Multikomponentenreaktion 47) oder Alkinmetathese.…”

Section: Organische Farbstoffeunclassified

Message in a molecule

et al. 2016

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Since ancient times, steganography, the art of concealing information, has largely relied on secret inks as a tool for hiding messages. However, as the methods for detecting these inks improved, the use of simple and accessible chemicals as a means to secure communication was practically abolished. Here, we describe a method that enables one to conceal multiple different messages within the emission spectra of a unimolecular fluorescent sensor. Similar to secret inks, this molecular-scale messaging sensor (m-SMS) can be hidden on regular paper and the messages can be encoded or decoded within seconds using common chemicals, including commercial ingredients that can be obtained in grocery stores or pharmacies. Unlike with invisible inks, however, uncovering these messages by an unauthorized user is almost impossible because they are protected by three different defence mechanisms: steganography, cryptography and by entering a password, which are used to hide, encrypt or prevent access to the information, respectively.

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“…Metalloporphyrin π‐cation radicals have been involved as key intermediates in a large variety of enzymatic catalysis and photosynthesis . To unveil the key roles and fundamental molecular features that are important for relevant biochemical processes, π‐cation radicals of synthetic metalloporphyrin have been investigated continuously . We have been actively working on the structure‐function correlation of various diheme enzymes such as MauG[4a], [4b] and cytochrome c peroxidases (bCcP)[4c], [4d] using covalently linked porphyrin dimers .…”

Section: Introductionmentioning

confidence: 99%

Unusual Stabilization of Dication Diradical Intermediate of Dizinc(II) Porphyrin Dimer

Pandit

Shah

Rath

2018

Zeitschrift anorg allge chemie

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We have demonstrated here how the nature of a metal ion controls the reactivity of a metalloporphyrin π-cation radical. Oneelectron oxidations of diethylpyrrole-bridged dicopper(II) and dipalladium(II) porphyrin dimers using iodine as an oxidant result in the formation of strongly interacting cofacial mixed-valent π-cation radical dimers. The mixed-valent cation radical so generated being highly reactive drives a spontaneous and rapid transformation to form an indolizinium-fused chlorin-porphyrin heterodimer. In sharp contrast to this, similar addition of iodine leads to 1e-oxidation of dizinc(II) porphyrin dimer, which is followed by a second oxidation to produce a dication diradical complex. The axial coordination of iodine upon 1e-oxidation 856 of dizinc(II) porphyrin dimer lowers the overall oxidation potential of the system, and thereby, making the second oxidation easily accessible. This has resulted in the stabilization of a dication diradical complex, in which two porphyrin π-cation radicals undergo electronic communication through the bridging pyrrole group. Interestingly, despite being well-separated from each other, the two radical spins undergo strong antiferromagnetic coupling to form a diamagnetic compound. The conjugation also leads to a change in identity of the bridge, which further highlights the critical role played by the bridge in the electronic communication between the two rings. DFT calculations clearly support the experimental observations.

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Cationic nickel porphyrinoids with unexpected reactivity

Abstract: Nickel(II) complexes of ring-contracted 9-methylisocorroles were prepared by templated macrocyclisation and act as the first porphyrinoid catalysts for C–C cross-coupling.

Cited by 9 publications

References 65 publications

Hexaethyltripyrrindione (H₃Et₆tpd): A Non‐Innocent Ligand Forming Stable Radical Complexes with Divalent Transition‐Metal Ions

Hexaethyltripyrrindione (H₃Et₆tpd): A Non‐Innocent Ligand Forming Stable Radical Complexes with Divalent Transition‐Metal Ions

Message in a molecule

Unusual Stabilization of Dication Diradical Intermediate of Dizinc(II) Porphyrin Dimer

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Cationic nickel porphyrinoids with unexpected reactivity

Abstract: Nickel(II) complexes of ring-contracted 9-methylisocorroles were prepared by templated macrocyclisation and act as the first porphyrinoid catalysts for C–C cross-coupling.

Cited by 9 publications

References 65 publications

Hexaethyltripyrrindione (H3Et6tpd): A Non‐Innocent Ligand Forming Stable Radical Complexes with Divalent Transition‐Metal Ions

Hexaethyltripyrrindione (H3Et6tpd): A Non‐Innocent Ligand Forming Stable Radical Complexes with Divalent Transition‐Metal Ions

Message in a molecule

Unusual Stabilization of Dication Diradical Intermediate of Dizinc(II) Porphyrin Dimer

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Hexaethyltripyrrindione (H₃Et₆tpd): A Non‐Innocent Ligand Forming Stable Radical Complexes with Divalent Transition‐Metal Ions

Hexaethyltripyrrindione (H₃Et₆tpd): A Non‐Innocent Ligand Forming Stable Radical Complexes with Divalent Transition‐Metal Ions