Related Experiment Video
Updated: Jan 22, 2026
Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
Electron-Donating Ligand in Oxidorhenium(V) Chemistry: Consequences for Isomerism and Catalyst Properties
Cornelia Rom1, Christof Holzer2, Antoine Dupé1
1Institute of Chemistry, University of Graz, Schubertstr. 1, 8010 Graz, Austria.
Abstract:
The bidentate, monoanionic dimethyloxazoline-phenol ligand HL1 was used to synthesize the corresponding oxidorhenium(V) complex [ReOCl(L1)2] (2). Ligand HL1 is equipped with two electron-donating tert-butyl substituents. The HdmozR class of ligands has so far enabled the stereoselective synthesis of the so-called N,N-trans isomers of oxidorhenium(V) complexes. In contrast, when precursor complex [ReOCl3(OPPh3)(SMe2)] (P1) and HL1 are reacted, in addition to the expected N,N-trans isomer (trans-2), also the N,N-cis isomer (cis-2) is formed. So far, this isomerism has only been observed for the nonmethylated phenol-oxazoline ligand Hoz, resulting in mixtures of complexes N,N-cis/trans [ReOCl(oz)2] (cis/trans-1). For trans-2, the catalytic properties in oxyanion (perchlorate and nitrate) reduction were studied. Due to the slow kinetics in the latter, the two cationic complexes [ReO(L1)2]X (X = SO3CF3̅, 3a; X = O2CCF3̅, 3b) were synthesized. Cationic triflate complex 3a showed the highest conversion rates in perchlorate reduction compared to 3b and chlorido complex trans-2, corresponding to the weakness of the coordinating anion. A targeted synthesis of the dioxidorhenium(VI) complex [ReO2(L1)2] (4), the product of nitrite (NO2̅) reduction, allowed for mechanistic and electrochemical investigations. The solid-state structures of complexes cis-2, trans-2, 3b, and 4 were characterized by single-crystal X-ray diffraction.
Related Concept Videos
02:34Structural 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...
02:51Metal-Ligand Bonds
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...
01:22EDTA: Chemistry and Properties
02:43Isomerism
02:01Isomerism in Alkenes
An isomer is called cis-2-butene when the methyl groups are on the same side of the double bond, and the other stereoisomer, in which methyl groups are on the opposite side of the double bond, is called trans-2-butene. The cis and trans stereoisomers are not...
02:40Ligand Binding Sites
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...