TowardsoperandoIR‐ and UV‐vis‐Spectro‐Electrochemistry: A Comprehensive Matrix Factorisation Study on Sensitive and Transient Molybdenum and Tungsten Mono‐Dithiolene Complexes**

Abstract

The redox sequences of sensitive aliphatic mono-dithiolene complexes [M II (CO) 2 (cydt)(dppe)] (M = Mo, W) were studied with extensive cyclic voltammetrical and spectro-electrochemical (SEC) investigations using UV-vis and IR spectroscopy. With a newly developed matrix factorisation technique, the pure component spectra and temporal evolution of the developed species were ascertained, including sensitive and transient ones. The concentration of all involved compounds at the working electrode as dependent on the respective applied potential was derived with very high accuracy. The assignment of the species' geometries and electronic structures was further verified by quantum chemical calculations. Overall, the combined electrochemical, spectroscopic, quantum chemical and mathematical approach facilitates a comprehensive understanding of the underlying electrochemical transformations and equilibria. Since only a single CV run is needed to obtain all data required to identify the individual species, the method presented here is expected to be applicable to a wide range of complicated electrochemically responsive systems and thus opens a path towards developing a deeper mechanistic understanding of the underlying chemistry.

Beginner's Guide to Raman Spectroelectrochemistry for Electrocatalysis Study

“…[10] One family of the in situ technologies with particular interest is spectroelectrochemistry, which combines electrochemical studies with spectroscopic methods, such as UV-vis and infrared. [11][12] The general technical principle involves light being introduced onto the electrode/electrolyte interface to interact with local species, and the photons can be reflected, absorbed, scattered, and emitted. Examining the energy of these photons during electrochemical processes can reveal the dynamic structural details of the interface on a temporal and spatial scale.…”

“…For example, surface probe microscopies, such as atomic force microscopy (AFM) and scanning tunneling microscopy (STM), can provide real‐time morphological details on the electrode surface; [5–6] X‐ray related technologies (X‐ray diffraction: XRD; X‐ray absorption spectroscopy: XAS; X‐ray photoelectron spectroscopy: XPS) can reveal the structure and surface electronic properties; [7–9] mass spectroscopy can detect the electrochemically generated intermediates and products [10] . One family of the in situ technologies with particular interest is spectroelectrochemistry, which combines electrochemical studies with spectroscopic methods, such as UV‐vis and infrared [11–12] . The general technical principle involves light being introduced onto the electrode/electrolyte interface to interact with local species, and the photons can be reflected, absorbed, scattered, and emitted.…”

Feinabstimmung der Redoxeigenschaften von heteroleptischen Molybdän‐Komplexen mittels Ligand‐Ligand‐Kooperativität

“…Unabhängig davon findet sich für jeden der vier Komplexe die typische 2 e − ‐Oxidation im Bereich von ca. 0 V. Wie bereits zuvor beschrieben, [13e] folgt auf die elektrochemische Oxidation eine chemische Reaktion (EC‐Mechanismus), bei der CO freigesetzt wird und ein lösungsmittelkoordinierter Komplex entsteht. Belegt wird dies durch die XRD‐Molekülstruktur von [Mo(CH 3 CN) 3 (cydt)(P 2 p ‐tol N 2 t Bu )] 2+ ( 6 ) (Abbildung S4) [16]…”

“…Mit einer kürzlich veröffentlichten Methode zur spektralen Zerlegung von spektroelektrochemischen UV/Vis‐Daten wurden die zeitabhängigen Konzentrationen (Abbildung S17) und die Reinkomponentenspektren aller vier untersuchten Monodithiolenkomplexe extrahiert, einschließlich der Spektren ihrer in situ erzeugten, reduzierten Zustände (Abbildungen S18–S21) [13e, 26] . Die erhaltenen Spektren konnten verwendet werden, um die Stapelung der Liganden weiter zu validieren.…”

On properties of EFA plots

“…The experimental details on this experiment involving five molybdenum monodithiolene complexes are reported in previous studies. 7,8 The complete sequence of 948 spectra and the first 150 spectra are shown in Figure 2 (upper row). The rows of the spectral data matrix D are normalized so that each spectrum has the Euclidean norm 1.…”