Related Experiment Video

Updated: Feb 17, 2026

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

Published on: March 20, 2017

Highly Electrophilic, Catalytically Active and Redox-Responsive Cobaltoceniumyl and Ferrocenyl Triazolylidene Coinage

Stefan Vanicek¹, Maren Podewitz¹, Jessica Stubbe²

¹Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Center for Chemistry and Biomedicine, Innrain 80-82, 6020, Innsbruck, Austria.

Chemistry (Weinheim an Der Bergstrasse, Germany)

|December 8, 2017

Abstract:

A convenient access to a triad of triazoles with ferrocenyl and cobaltoceniumyl substituents is reported. N-Alkylation, deprotonation and metalation with Cu^I /Ag^I /Au^I synthons affords the heteroleptic triazolylidene complexes. Due to the combination of neutral, electron-donating ferrocenyl substituents and cationic, strongly electron-withdrawing cobaltocenium substituents, the mesoionic carbene (MIC) ligands of these complexes are electronically interesting "push-pull", "pull-push" and "pull-pull" metalloligands with further switchable redox states based on their fully reversible Fe^II /Fe^III , (ferrocene/ferrocenium) and Co^III /Co^II , (cobaltocenium/cobaltocene) redox couples. These are the first examples of metal complexes of (di)cationic NHC ligands based on cobaltoceniumyl substituents. DFT calculated Tolman electronic parameter (TEP) of the new MIC ligands, show these metalloligands to be extremely electron-poor NHCs with properties unmatched in other carbene chemistry. Utilization of these multimetallic electronically tunable compounds in catalytic oxazoline synthesis and in antitumor studies are presented. Remarkably, 1 mol % of the Au^I complex with the dicationic MIC ligand displays full catalytic conversion, without the need for any other additives, in less than 2 hours at ambient temperatures. These results thus firmly establish these new classes of cobaltoceniumyl based (di)cationic MIC ligands as prominent players in several branches of chemistry.

Keywords:

catalysis cytotoxicity density functional calculations mesoionic carbenes sandwich complexes

More Related Videos

Preparation of SNS CobaltII Pincer Model Complexes of Liver Alcohol Dehydrogenase

Preparation of SNS CobaltII Pincer Model Complexes of Liver Alcohol Dehydrogenase

Published on: March 19, 2020

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Published on: April 19, 2019

Related Concept Videos

Colors and Magnetism

Colors and Magnetism

Color in Coordination Complexes
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...

Metal-Ligand Bonds

Metal-Ligand Bonds

The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...

Valence Bond Theory

Valence Bond Theory

Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...

Formation of Complex Ions

Formation of Complex Ions

A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...

Complexation Equilibria: Factors Influencing Stability of Complexes

Complexation Equilibria: Factors Influencing Stability of Complexes

In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...

Complexation Equilibria: The Chelate Effect

Complexation Equilibria: The Chelate Effect

In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...

Articles linked to this work by shared authors, journal, and citation graph.

Iron Complexes Supported by a Rigid Macrocyclic PNPN Ligand.

Inorganic chemistry·2026

Introducing Diradicaloid Thiele's Hydrocarbon Derivatives as Ligand in Transition Metal Chemistry.

Angewandte Chemie (International ed. in English)·2026

Identification of novel functional sites in the Cav1.3 calcium channel α1-subunit using evolutionary modeling.

Proceedings of the National Academy of Sciences of the United States of America·2026

Vibrational spectra of formic acid and its dimer: I. Spectroscopic accuracy through matrix-isolation IR spectroscopy and anharmonic computations.

Physical chemistry chemical physics : PCCP·2026

Vibrational spectra of formic acid and its dimer: II. Towards identifying structural motifs in atmospheric organic clustering.

Physical chemistry chemical physics : PCCP·2026

Bulkiness Makes the Difference: Modulating Solid-State Emission of Anticoronavirus Active Pt(tpy)C(O)NHCH2R Complexes Featuring Adamantyl vs Propargyl R Groups.

Inorganic chemistry·2026

See all related articles