%0 Journal Article %1 Dreher.2013 %A Dreher, Ameli %A Meyer, Sven %A Naether, Christian %A Westphal, Anne %A Broda, Henning %A Sarkar, Biprajit %A Kaim, Wolfgang %A Kurz, Philipp %A Tuczek, Felix. %D 2013 %J Inorganic Chemistry %K complex complex;molybdenum crystal diphosphine ethylimido imido model;spectroelectrochem molybdenum nitrogenase protonation redn structure %N 5 %P 2335--2352 %R 10.1021/ic301828e %T Reduction and Protonation of Mo(IV) Imido Complexes with depe Coligands: Generation and Reactivity of a S = 1/2 Mo(III) Alkylnitrene Intermediate %V 52 %X Redn. and protonation of Mo(IV) imido complexes with diphosphine coligands constitutes the second part of the Chatt cycle for biomimetic redn. of N2 to ammonia. To obtain insights into the corresponding elementary reactions the authors synthesized the Mo(IV) ethylimido complex Mo(MeCN)(NEt)(depe)2(OTf)2 (2-MeCN) from the Mo(IV)-NNH2 precursor Mo(NNH2)(OTf)(depe)2(OTf) (1). As shown by UV-visible and NMR spectroscopy, exchange of the acetonitrile ligand with one of the counterions in THF gave Mo(OTf)(NEt)(depe)2(OTf) (2-OTf). 2-MeCN and 2-OTf were studied by spectroscopy and x-ray crystallog. in conjunction with DFT calcns. Also, both complexes are investigated by cyclic voltammetry and spectroelectrochem. The complex 2-OTf undergoes a two-electron redn. in THF assocd. with loss of the trans ligand triflate. In contrast, 2-MeCN in acetonitrile is reduced to an unprecedented Mo(III) alkylnitrene complex Mo(NEt)(MeCN)(depe)2OTf (5) which abstrs. a proton from the parent Mo(IV) compd. 2-MeCN, forming the Mo(III) ethylamido complex 5H and a Mo(II) azavinylidene complex 6. Compd. 5 is also protonated to the Mo(III) ethylamido complex 5H in the presence of externally added acid and further reduced to the Mo(II) ethylamido complex 7. The results of this study provide further support to a central reaction paradigm of the Schrock and Chatt cycles: double redns. (and double protonations) lead to high-energy intermediates, and therefore, every single redn. has to be followed by a single protonation (and vice versa). Only in this way the biomimetic conversion of dinitrogen to ammonia proceeds on a min.-energy pathway. on SciFinder(R)

@article{Dreher.2013, abstract = {Redn. and protonation of Mo(IV) imido complexes with diphosphine coligands constitutes the second part of the Chatt cycle for biomimetic redn. of N2 to ammonia. To obtain insights into the corresponding elementary reactions the authors synthesized the Mo(IV) ethylimido complex [Mo(MeCN)(NEt)(depe)2](OTf)2 (2-MeCN) from the Mo(IV)-NNH2 precursor [Mo(NNH2)(OTf)(depe)2](OTf) (1). As shown by UV-visible and NMR spectroscopy, exchange of the acetonitrile ligand with one of the counterions in THF gave [Mo(OTf)(NEt)(depe)2](OTf) (2-OTf). 2-MeCN and 2-OTf were studied by spectroscopy and x-ray crystallog. in conjunction with DFT calcns. Also, both complexes are investigated by cyclic voltammetry and spectroelectrochem. The complex 2-OTf undergoes a two-electron redn. in THF assocd. with loss of the trans ligand triflate. In contrast, 2-MeCN in acetonitrile is reduced to an unprecedented Mo(III) alkylnitrene complex [Mo(NEt)(MeCN)(depe)2]OTf (5) which abstrs. a proton from the parent Mo(IV) compd. 2-MeCN, forming the Mo(III) ethylamido complex 5H and a Mo(II) azavinylidene complex 6. Compd. 5 is also protonated to the Mo(III) ethylamido complex 5H in the presence of externally added acid and further reduced to the Mo(II) ethylamido complex 7. The results of this study provide further support to a central reaction paradigm of the Schrock and Chatt cycles: double redns. (and double protonations) lead to high-energy intermediates, and therefore, every single redn. has to be followed by a single protonation (and vice versa). Only in this way the biomimetic conversion of dinitrogen to ammonia proceeds on a min.-energy pathway. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Dreher, Ameli and Meyer, Sven and Naether, Christian and Westphal, Anne and Broda, Henning and Sarkar, Biprajit and Kaim, Wolfgang and Kurz, Philipp and Tuczek, Felix.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/276d32d7ff3b06c5164cae95a027b4d9b/huebleriac}, doi = {10.1021/ic301828e}, interhash = {04a58021e7407ce5a432372adef1eab7}, intrahash = {76d32d7ff3b06c5164cae95a027b4d9b}, issn = {0020-1669}, journal = {Inorganic Chemistry}, keywords = {complex complex;molybdenum crystal diphosphine ethylimido imido model;spectroelectrochem molybdenum nitrogenase protonation redn structure}, number = 5, pages = {2335--2352}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Reduction and Protonation of Mo(IV) Imido Complexes with depe Coligands: Generation and Reactivity of a S = 1/2 Mo(III) Alkylnitrene Intermediate}, volume = 52, year = 2013 }