2,2′‐Bis(indolyl)methane, 8. Mitt. Darstellung und NMR‐spektroskopische Charakterisierung von 2,2′ ‐Bis(methylindolyl)‐aryl‐methanen

Abstract

In der Reaktion von 3‐Methyl‐ bzw. 1,3‐Dimethylindol (1a,1b) sind mit den Arylaldehyden 2 unter salzsaurer Katalyse die Methane 6 und 7 in glatter Reaktion zugänglich. Zwischenprodukte des Reaktionsweges zu 6 und 7 sind nur an einem Beispiel über eine Solvolyse‐Reaktion isolierbar. Die Struktureigenschaften der Methane 6 und 7 werden erstmals NMR‐spektroskopisch beschrieben.

Deprotonated diindolylmethanes as dianionic analogues of scorpionate bis(pyrazolyl)borate ligands: synthesis and structural characterization of representative titanocene and zirconocene complexes

“…Chemical shifts are reported relative to tetramethylsilane. Tentative 13 C NMR assignments are based on previously reported NMR assignments for polyindolylmethanes [11,12] as well as on NMR assignments of indole derivatives reported by Park et al [13]. In the reporting of NMR data, indole carbons are labeled C2-C7 with C3a and C7a indicating ring fusion positions.…”

A Synthetic Analogue of Rieske‐Type [2Fe‐2S] Clusters

“…[6] Herein we report the synthesis as well as spectroscopic and crystallographic characterization of the first accurate synthetic model compound 4 for Rieske type [2Fe-2S] clusters.A stepwise ligand exchange strategy starting from [NEt 4 ] 2 -[Fe 2 S 2 Cl 4 ] [7] (1) was discovered to be a suitable synthetic approach affording the first asymmetrically coordinated [2Fe-2S] clusters. After extensive ligand screening, a backbone phenyl substituted chelating diskatylmethane [8] {N 2 } capping ligand, which serves as a mimic for the natural histidine residues, was found to suppress the usually preferred formation of the homoleptic N-and S-coordinate cluster compounds. Addition of the deprotonated {N 2 } ligand to a cooled solution of 1 led to the isolation of the partially substituted intermediate [NEt 4 ] 2 [{N 2 }Fe 2 S 2 Cl 2 ] (2, Scheme 1).…”

“…A stepwise ligand exchange strategy starting from [NEt 4 ] 2 -[Fe 2 S 2 Cl 4 ] [7] (1) was discovered to be a suitable synthetic approach affording the first asymmetrically coordinated [2Fe-2S] clusters. After extensive ligand screening, a backbone phenyl substituted chelating diskatylmethane [8] {N 2 } capping ligand, which serves as a mimic for the natural histidine residues, was found to suppress the usually preferred formation of the homoleptic N-and S-coordinate cluster compounds. (3) were formed as a byproduct and identified by X-ray diffraction ( Figure S38 in the Supporting Information).…”

Ein synthetisches Analogon für [2Fe‐2S]‐Cluster des Rieske‐Typs

“…ein chelatisierender Diskatylmethan-Ligand [8] [9] Eisenzentren in 3 und 5 auf (Tabelle 1 und Tabelle S6 in den Hintergrundinformationen). Ein Vergleich mit den Rieske-Proteinen zeigt, dass sich 4 lediglich in den Fe-N-Abständen und den N-Fe-N-Winkeln vom natürlichen Vorbild unterscheidet (Tabelle S7 in den Hintergrundinformationen); [2c] ursächlich für diese Diskrepanz ist wahrscheinlich die unterschiedliche Ladung der Liganden: Der {N 2 }-Ligand im vorliegenden Modellkomplex ist dianionisch, während die Imidazolgruppen im oxidierten Zustand des Proteins am e-N-Atom protoniert und damit neutral sind.…”