INTEC   05402
INSTITUTO DE DESARROLLO TECNOLOGICO PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
artículos
Título:
Chromium(0) and Molydenum(0) Complexes with a Pyridyl-Mesoionic Carbene Ligand: Structural, (Spectro)electrochemical, Photochemical, and Theoretical Investigations
Autor/es:
DI MARTINO-FUMO, PATRICK; BODEN, PIT; SOBOTTKA, SEBASTIAN; ALBOLD, UTA; SARKAR, BIPRAJIT; GERHARDS, MARKUS; BENS, TOBIAS; BEERHUES, JULIA; NEUMAN, NICOLÁS I.
Revista:
INORGANIC CHEMISTRY
Editorial:
AMER CHEMICAL SOC
Referencias:
Año: 2020
ISSN:
0020-1669
Resumen:
This work reports on the synthesis and in-depthelectrochemical and photochemical characterization of twochromium(0) and molydenum(0) metal complexes with bidentatepyridyl-mesoionic carbene (MIC) ligands of the 1,2,3-triazol-5-ylidene type and carbonyl coligands. Metal complexes with MICligands have turned out to have very promising electrocatalytic andphotochemical properties, but examples of MIC-containingcomplexes with early-transition-metal centers remain extremelyrare. The electrochemistry of these new MIC complexes was studiedby cyclic voltammetry and especially spectroelectrochemistry in theIR region consistent with a mainly metal-centered oxidation, whichis fully reversible in the case of the chromium(0) complex. At thesame time, the two reduction steps are predominantly ligand-centered according to the observed near-IR absorbance, with thefirst reduction step being reversible for both systems. The results ofthe electron paramagnetic resonance studies on the oxidized and reduced species confirm the IR spectroelectrochemistryexperiments. The photochemical reactivity of the complexes with a series of organic ligands was investigated by time-resolved (step-scan) Fourier transform infrared (FTIR) spectroscopy. Interestingly, the photoreactions in pyridine and acetonitrile are fullyreversible with a slow dark reverse reaction back to the educt species over minutes and even hours, depending on the metal centerand reagent. This reversible behavior is in contrast to the expected loss of one or several CO ligands known from related homolepticas well as heteroleptic M(CO)4L2α-diimine transition-metal complexes.