Hand in Hand: Experimental and Theoretical Investigations into the Reactions of Copper(I) Mono‐ and Bis(guanidine) Complexes with Dioxygen

Autor: Matthias Witte, Roxana Haase, Siegfried Schindler, Jörg Glatthaar, Miriam Wern, Tobias Hoppe, Sonja Herres-Pawlis, Patricia Liebhäuser, Alexander Hoffmann
Rok vydání: 2016
Předmět:
Zdroj: European Journal of Inorganic Chemistry. 2016:4744-4751
ISSN: 1099-0682
1434-1948
DOI: 10.1002/ejic.201600906
Popis: Mono- and bis(guanidine) ligands stabilise bis-µ-oxido dicopper(III) complexes. Here, the formation of this complex has been investigated in detail using low temperature stopped-flow techniques for the monoguanidine 2-(3-(dimethylamino)propyl)-1,1,3,3-tetramethylguanidine (TMGdmap) and the related bis(guanidine) 1,3-bis(N,N,N',N'-tetramethylguanidino)propane (btmgp). Low temperature IR studies in solution support the formation of a bis-µ-oxido complex. For both systems, no intermediates could be detected on their way to the bis-µ-oxido complexes which is rationalised by extensive DFT calculations. In a first step, the oxygen reduction during the binding to the copper(I) complex to form a superoxido species is studied. In the second step, the full path from superoxido over trans-µ-peroxido to side-on-peroxido and finally bis-µ-oxido is modelled for singlet and triplet states. Hereby, a clear picture about the detailed reaction mechanism is gained which directly correlates with the observed activation enthalpies and reaction orders. The superoxido formation is rate-determining as pseudo-first order in copper(I) although the bis-µ-oxido formation is observed. The results illustrate the strength of density functional theory for the prediction of the reactivity of real-life systems.
Databáze: OpenAIRE
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