University of Oulu

Louw, W. J., Radhakrishnan, S. G., Malan, F. P., & Bezuidenhout, D. I. (2023). Synthesis, electronic structure and interaction of rhodium(I) and iridium(I) bisimine-acenaphthalene complexes with CO2. Polyhedron, 235, 116350.

Synthesis, electronic structure and interaction of rhodium(I) and iridium(I) bisimine-acenaphthalene complexes with CO₂

Saved in:
Author: Louw, Wynand J.1; Radhakrishnan, Shankara G.1; Malan, Frederick P.1;
Organizations: 1Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa
2Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, University of Oulu, P.O. BOX 3000, FI-90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.5 MB)
Persistent link:
Language: English
Published: Elsevier, 2023
Publish Date: 2023-03-17


The bis(arylimino)acenaphthalene (BIAN) group of α-diimine compounds has shown promising electron sink behaviour and redox non-innocent activity as ligands to main group and transition metals. Here we present a series of rhodium(I) and iridium(I) complexes of BIAN derivatives with 2,6-diisopropylphenyl (DippBIAN, DB) and 2,4,6-trimethylphenyl (MesBIAN, MB), featuring various electron withdrawing and donating ancillary ligands. The crystal structures of square planar complexes 1b [RhMB(cod)]PF₆, 1d [IrMB(cod)]PF₆, 2a [RhDB(CO)₂]PF₆, 2b [RhMB(CO)₂]PF₆, 2c [IrDB(CO)₂]PF₆ and 3a [RhDB(CO)(PEt₃)]PF₆ are reported, as well as the square pyramidal structure of 4c [IrDB(cod)Cl]. The C-N and C-C bond lengths within the bisimine moiety for the structures of 2a and 4c suggest that the DippBIAN ligands are present in a reduced state, however, all other data from our multi-technique analyses correspond to results for neutral BIAN ligands. These contrasting results are indicative of the DippBIAN’s non-innocent behaviour, accepting additional electron density from the metal centre due to push–pull mechanism between the ancillary and BIAN ligands. The electrochemical study in non-coordinating solvent CH₂Cl₂ revealed that all complexes featured at least one reversible, ligand-centred reduction event at less negative potentials (above –1.0 V vs Ag/Ag⁺). In addition, preliminary results from our electrocatalytic CO₂ reduction study has shown a promising interaction between CO₂ and complex 3a, paving the way for exploring heterogeneous catalysis on these class of compounds.

see all

Series: Polyhedron. The international journal for research in inorganic chemistry
ISSN: 0277-5387
ISSN-E: 1873-3719
ISSN-L: 0277-5387
Volume: 235
Article number: 116350
DOI: 10.1016/j.poly.2023.116350
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
Funding: The authors gratefully acknowledge the University of Pretoria, the National Research Foundation, South Africa (Renewable and Sustainable Energy Masters and Doctoral Scholarship), and Sasol Technology R&D Pty. Ltd. (South Africa) for financial support; the Centre for High Performance Computing (CHPC Cape Town, South Africa, for access to utilise their computational resources; and Dr M. Wooding for her assistance in conducting the mass spectrometry analyses. SGR thanks the South African National Research Foundation (NRF) for research support via the CSUR funding element, UID: 116317.
Copyright information: © 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (