Molybdenum and Tungsten Oxidoreductase Models

Abstract

This microreview gives an overview about advances in bioinorganic model chemistry for molybdenum‐ and tungsten‐dependent oxidoreductases with respect to specific aspects of the evolution, structure or function of distinct active‐site properties. The approaches to evaluate catalytic properties fine‐tuned by the ligand sphere, interpret and assign enzyme spectra and to understand why two different metals are used for the same task but in distinct habitats and respective evolutionary aspects are discussed on the basis of exemplary case studies. This short review provides a personal perspective and appreciation of the complex problems associated with the respective foremost synthetic and analytical model chemistry and their solutions partly accompanied and supported by theoretical results.

An Update on WII and MoII Carbonyl Precursors and Their Application in the Synthesis of Potentially Bio‐Inspired Thiophenolate‐Oxazoline Complexes

“…Moreover, in subsequent reactions the coordinated PPh 3 has to be removed leading to additional steps in the work-up protocol. Therefore our focus was moved towards the phosphine and chlorine-free species [W(CO) 4 Br 2 ], which is obtainable by a straightforward oxidation reaction of [W(CO) 6 ] with Br 2 in CH 2 Cl 2 . [14,16] Compared to 2a, by using bromine the stoichiometry of the reagents can be controlled much easier and therefore the risk of over-oxidation can be minimized (cp.…”

“…Furthermore the novel tetranuclear Mo-precursor [Mo 4 (CO) 7 Br 10 ] (4a) was synthesized. The symmetric and asymmetric IR stretching frequencies of its seven carbonyl ligands were calculated using DFT and related to the experimental values.…”

“…Two possible precursors of the general type [M II (CO) n X 2 ] (M = Mo, W; n = 2, 3, 4, X = Cl, Br, I) have been described in literature. The phosphinestabilized, 18-electron species [M(CO) 3 (PPh 3 ) 2 X 2 ] (M = Mo, W; X = Cl, Br, I) [8][9][10][11][12][13] and the less stable 16-electron species [M(CO) 4 X 2 ] (M = Mo, W; X = Cl, Br, I). [10,[12][13][14][15][16][17] (2a) [8][9][10] [19,21] …”

Dioxomolybdenum(VI) and -Tungsten(VI) Amino Bisphenolates as Epoxidation Catalysts

“…In such reactions, an oxygen atom is transferred from an oxygen donor to a biologically relevant acceptor molecule or vice versa [1][2][3][4][5]. Considering these important biological functions, many examples of molybdenum-and tungsten-containing model compounds for OAT have been studied [6][7][8][9][10]. Similarly, a number of artificial dioxomolybdenum(VI) and -tungsten(VI) complexes have been prepared for catalytic applications in important industrial processes, for example olefin epoxidation [11][12][13].…”

Electronic Fine‐Tuning of Oxygen Atom Transfer Reactivity of cis‐Dioxomolybdenum(VI) Complexes with Thiosemicarbazone Ligands

“…[2][3][4][5][6] Whereas bidentate dithiolene ligands model the S,S donor set found in the molybdopterin cofactor of the enzymes, [7,8] bidentate ligands with N,S, N,N and N,O donor have also been found to catalyze OAT. Examples include pyridine thiolates, [9] iminopyrrolato, [10,11] diketiminate (NacNac), [12] and β-ketiminato [13] ligands.…”