Structure, reactivity, and spectroscopy of nitrogenase-related synthetic and biological clusters

Abstract

In this review, recent studies on nitrogenase-related synthetic molecular complexes and biological clusters are discussed, with a focus on their reactivity and spectroscopic characterization.

Electrocatalytic CO2Reduction with a Binuclear Bis‐Terpyridine Pyrazole‐Bridged Cobalt Complex**

“…[ 7 , 12 ] Along these lines, bimetallic electrocatalytic systems have been synthesized and studied aiming towards energy storage transformations,[ 13 , 14 ] such as water oxidation, [15] oxygen reduction,[ 16 , 17 ] hydrogen evolution reaction,[ 18 , 19 , 20 , 21 ] nitrogen reduction, [22] or carbon dioxide reduction [23] (Figure 1 ). Moreover, advances on the understanding of the structure and reactivity of metal‐based cofactors has caused the growth of bioinspired multimetallic molecular systems,[ 13 , 24 , 25 ] to exploit their cooperative‐reactivity potential. [26] A recent example of bioinspired bimetallic electrocatalysis for CO 2 transformation was recently published by Duboc et al., in which a NiFe‐hydrogenase model promoted the conversion of CO 2 to CH 4 in aqueous solutions at pH 4 with 16 % Faradaic efficiency (FE).…”

Superior Reactivity of Molybdenum–Sulfur Cluster Anions Mo5S2– and Mo5S3– toward Dinitrogen

“…Dinitrogen is an abundant and easily accessible resource, but it is regarded as an extremely stable molecule due to its strong N≡N triple bond (bond dissociation energy: 9.8 eV), leading to chemical inertness under ambient conditions. , In this regard, the fixation and activation of N 2 are recognized as a long-standing critical challenge. , Industrially, the Haber–Bosch synthesis which requires harsh conditions (temperature: 400 °C; pressure: 15–25 MPa) remains the most common large-scale process for N 2 fixation . In nature, the enzymatic reduction of gaseous nitrogen to ammonia at ambient conditions is mediated by nitrogenase enzymes (FeMo/FeV/FeFe-cofactor) with multinuclear metal–sulfur clusters working as key species. , Over the past decades, substantial efforts have been devoted to mimicking the structures and functions of the active centers in the cofactors. , Various transition metal sulfides including homonuclear and heteronuclear metal sulfide species have been synthesized to search for reactive species that can reduce N 2 and understand the mechanistic details of the reduction process. ,− Nevertheless, well-defined synthetic metal–sulfur clusters that are capable of converting N 2 are still limited due to the difficulties in precise synthesis and characterization of active centers in complicated heterogeneous catalysis. , Thus, it is still a major challenge to better comprehend the reduction of N 2 on metal–sulfur clusters at a molecular level and gain precious clues to design highly active catalysts in nitrogen fixation.…”

Revisiting the Fundamental Nature of Metal‐Ligand Bonding: An Impartial and Automated Fitting Procedure for Angular Overlap Model Parameters

“…Many examples in the literature have shown that the interplay of synthesis, spectroscopy and theory is essential for the targeted electronic structure design of transition metal complexes with improved properties. [1][2][3][4][5][6] An early and well-known example is the electronic structure analysis of vanadyl in terms of a molecular orbital picture. [7] This interplay rests on chemical concepts, which are often derived from quantum mechanics or accurate measurements, but are commonly applied and used in an intuitive manner.…”