Related Experiment Video
Updated: Jun 19, 2026

Preparation of SNS Cobalt(II) Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
Oxygenated N-Confused Porphyrins: Structural Elucidation and Distinct Vanadium(IV) Coordination Motifs
Bhakyaraj Kasi1,2,3, Tanmoy Pain1, Kai-Chun Hsu1,4,5
1Institute of Chemistry, Academia Sinica, Nangang, Taipei 115201, Taiwan.
None:
N-Confused porphyrinoids exhibit unusual structural and electronic properties arising from pyrrole inversion, yet the controlled oxygenation of these macrocycles remains underdeveloped because competing pathways often generate complex mixtures. Here, we identify a stepwise oxygenation sequence associated with vanadium metalation of an N-confused porphyrin (NCP) framework, providing access to structurally defined oxygenated NCP derivatives and their vanadium complexes. The lactam-containing NCP 3-oxo-H2PFNCP (3) was isolated as a minor coproduct in Lindsey's N-confused porphyrin synthesis protocol using CF3SO3H as the acid catalyst. Subsequent reaction with vanadyl acetylacetonate afforded the free-base 3,21-dioxygenated NCP 3,21-dioxo-H3PFNCP (4) together with two distinct vanadium(IV) complexes, V(═O)(OH)(3-oxo-PFNCP) (5) and [n-Bu4N][V(OH)(3,21-dioxo-PFNCP)]- (6). Single-crystal X-ray diffraction established that 6 adopts an unusual intramolecular V-O-C chelation motif arising directly from macrocycle oxygenation. UV-vis, NMR, HRMS, EPR, and electrochemical studies further revealed clear differences between 5 and 6 in their electronic structures and coordination environments. Both complexes mediate hydrogen peroxide-driven oxidation of cyclohexene and thioanisole, with 6 giving higher yields of the quantified cyclohexene oxidation products and higher selectivity for sulfone formation in thioanisole oxidation. These results demonstrate that controlled oxygenation of N-confused porphyrins can generate unusual vanadium coordination motifs with differentiated oxygen-transfer reactivity.
Related Concept Videos
Valence Bond Theory
Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group with both...
Coordination Number and Geometry
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
Aromatic Hydrocarbon Anions: Structural Overview
Due to the absence of continuous overlap of p...

