Related Experiment Video
Updated: Sep 24, 2025

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
Published on: July 30, 2017
Syn and Anti Metal Complexes of 24π Antiaromatic Bis(Dicarbonylrhodium(I))Dithiaamethyrin
Yoshihiro Ishimaru1, Fumiya Takahashi1, Samu Mochizuki1
1Division of Material Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, 338-8570, Saitama City, Saitama, Japan.
Abstract:
From the reaction of sterically less hindered tetrapropyl[24]dithiaamethyrin(1.0.0.1.0.0) 5, with [Rh(CO)2 Cl]2 , a unique anti form of the bis(dicarbonylrhodium(I)) complex (6-anti), where two rhodium ions are on the opposite faces of the macrocyclic ligand, was isolated for the first time in 12% yield along with the corresponding syn isomer (6-syn, 61% yield). These structures were characterized in detail by single-crystal X-ray structure analysis. Compound 6-syn exhibited a bowl-shaped structure with the two rhodium atoms separated by a distance of ∼4.5 Å. In contrast, 6-anti contained a wave-shaped macrocycle with a distance of ∼5.3 Å between the two rhodium atoms. Furthermore, the 1 H nuclear magnetic resonance spectra and density functional theory calculation results revealed that 6-anti had a stronger paratropic ring current and a more planar structure than 6-syn. The isolation of both 6-anti and 6-syn enabled detailed discussion of the structure-property relationship.
Related Concept Videos
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Valence Bond Theory
Aromatic Hydrocarbon Anions: Structural Overview
Due to the absence of continuous...
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo,...
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
Aryldiazonium Salts to Azo Dyes: Diazo Coupling

