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Structural Mimics of Acetylene Hydratase: Tungsten Complexes Capable of Intramolecular Nucleophilic Attack on Acetylene
Author(s) -
Vidovič Carina,
Peschel Lydia M.,
Buchsteiner Michael,
Belaj Ferdinand,
MöschZanetti Nadia C.
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201903264
Subject(s) - acetylene , chemistry , intramolecular force , nucleophile , pyridine , ligand (biochemistry) , stereochemistry , nucleophilic addition , medicinal chemistry , organic chemistry , catalysis , receptor , biochemistry
Bioinspired complexes employing the ligands 6‐ tert ‐butylpyridazine‐3‐thione (SPn) and pyridine‐2‐thione (SPy) were synthesized and fully characterized to mimic the tungstoenzyme acetylene hydratase (AH). The complexes [W(CO)(C 2 H 2 )(CHCH‐SPy)(SPy)] ( 4 ) and [W(CO)(C 2 H 2 )(CHCH‐SPn)(SPn)] ( 5 ) were formed by intramolecular nucleophilic attack of the nitrogen donors of the ligand on the coordinated C 2 H 2 molecule. Labelling experiments using C 2 D 2 with the SPy system revealed the insertion reaction proceeding via a bis‐acetylene intermediate. The starting complex [W(CO)(C 2 H 2 )(SPy) 2 ] ( 6 ) for these studies was accessed by the new acetylene precursor mixture [W(CO)(C 2 H 2 ) n (MeCN) 3− n Br 2 ] ( n =1 and 2; 7 ). All complexes represent rare examples in the field of W−C 2 H 2 chemistry with 4 and 5 being the first of their kind. In the ongoing debate on the enzymatic mechanism, the findings support activation of acetylene by the tungsten center.