Synthesis, electronic structure and reactivity of Rh(I)- and Ir(I)BIAN complexes

A range of new Rh(I)- and Ir(I)-BIAN complexes of 4- and 5-coordinate geometries were synthesised utilising archetypal BIAN ligands (i.e., Dipp- and MesBIAN) and ancillary ligands from across the spectrochemical series (low, mid and high field). The series of complexes are divided into four groups based on the ancillary ligands that were targeted in this study: (1) 1,5-cyclooctadiene (cod), (2) dicarbonyl, (3) triethylphosphine and carbonyl, as well as (4) cod and chloride. Using a multi-technique approach (NMR, IR, UV-Vis, SC-XRD, electrochemistry, and DFT computations), the electronic structure and catalytic reactivity of the series of BIAN complexes 1–4, featuring ancillary ligands with various electron-donating and withdrawing characteristics, were critically examined.

Experimental results, figures, and tables are presented in the following folders:

NMR Characterisation – NMR Characterisation Images.zip; Images are in Portable Network Graphics (.png) raster-graphics format.

Mass Spectrometry –  MS Spectrometry Images.zip; Images are in Portable Network Graphics (.png) raster-graphics format.

Infrared Spectroscopy – IR Absorption Images and Spectra.zip; Images are in Portable Network Graphics (.png) raster-graphics format, and spectra require the OriginLab Software package to view, open, or edit.

UV-Vis spectroscopy – UV-Vis Spectra and Images.zip; Images are in Portable Network Graphics (.png) raster-graphics format, and spectra require the OriginLab Software package to view, open, or edit.

Electrochemical analysis (CV and DPV) – Electrochemistry Images and Data.zip; Images are in Portable Network Graphics (.png) raster-graphics format, and spectra require the OriginLab Software package to view, open, or edit.

Single crystal X-ray Diffraction Data – SC-XRD Images and Data Tables.zip; XRD results from this study are presented in standardised file formats: ".cif", ".docx", ".tsv", ".png", and ".tif".

DFT Computational modelling was done on the series of BIAN complexes 1–4, and the free Dipp- and MesBIAN ligands. The compounds were modelled in both the gas phase {DFT b3lypD3 def2SVP (gas).zip} and dichloromethane solution {DFT b3lypD3 def2SVP (cPCM - CH2Cl2).zip}, in a variety of oxidation states. The results present include a selection of images of the optimised molecular geometries, frontier molecular orbitals, and charge distribution diagrams, as well as the ".Fchk" and ".log" files required to visualise the results using a software package such as GaussView5.

The results of the statistically-based Peak Characterisation Model (PCM) are presented in the folder Peak Characterisation Model - Images.zip. Images are in Portable Network Graphics (.png) and Joint Photographic Experts Group (.jpg) raster-graphics formats. The model was utilised to differentiate between voltammetric peaks (DPV) associated with the primary electrochemical reaction of the analyte and voltammetry peaks of impurities or secondary reactions in the electrolyte solution, as illustrated in Redox coupled DFT graphs.zip.

Results from the NMR-scale catalytic reactivity screening assays are presented in the Catalysis NMR Images, Data Tables.zip folder as data files in Microsoft Excel format, and images in Portable Network Graphics (.png) and/or Joint Photographic Experts Group (.jpg) raster-graphics formats.

The results for the electrocatalytic CO₂ reduction activity of the complex series 1–4 are reported in the folder Electrochemistry Images and Data.zip, sub-folder "CV + DPV (CO2)"; Images are in Portable Network Graphics (.png) raster-graphics format.