Rhodium Complexes of a New-Generation Sapphyrin: Unique Structures, Axial Chirality, and Catalysis

Qiu-Cheng Chen; Irena Saltsman; Alexander Kaushansky; Zi-Ye Xiao; Natalia Fridman; Xuan Zhan; Zeev Gross

doi:10.1002/chem.201804138

Rhodium Complexes of a New-Generation Sapphyrin: Unique Structures, Axial Chirality, and Catalysis

Chemistry. 2018 Nov 22;24(65):17255-17261. doi: 10.1002/chem.201804138. Epub 2018 Oct 30.

Authors

Qiu-Cheng Chen¹, Irena Saltsman¹, Alexander Kaushansky¹, Zi-Ye Xiao¹, Natalia Fridman¹, Xuan Zhan¹, Zeev Gross¹

Affiliation

¹ Schulich Faculty of Chemistry, Technion-Israel Institution of Technology, Haifa, 32000, Israel.

PMID: 30138537
DOI: 10.1002/chem.201804138

Abstract

Rhodium insertion into the new 5,10,15,20-tetrakis(trifluoromethyl)sapphyrin was found to be much more facile than for other analogues, owing to NH⋅⋅⋅F hydrogen-bonding interactions that stabilise the pyrrole-inverted structure characteristic of the metallated product. The thus-obtained rhodium(I) complexes have axial chirality, and the enantiomers were resolved. The latter were found to interconvert quite rapidly in a process that involves a tautomerisation-like movement of the metal fragment between the five N atoms. The rhodium sapphyrins were investigated as catalysts for organic synthesis, by studying their carbene-transfer activity in the cyclopropanation of styrene with ethyl diazoacetate and comparing it to that of rhodium corroles.

Keywords: chirality; fluorinated ligands; macrocyclic ligands; porphyrinoids; rhodium.