Premium
Structural and Electronic Responses to the Three Redox Levels of Fe(NO)N 2 S 2 ‐Fe(NO) 2
Author(s) -
Ghosh Pokhraj,
Ding Shengda,
Quiroz Manuel,
Bhuvanesh Nattamai,
Hsieh ChungHung,
Palacios Philip M.,
Pierce Brad S.,
Darensbourg Marcetta Y.,
Hall Michael B.
Publication year - 2018
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.201804168
Subject(s) - diamagnetism , bimetallic strip , electron paramagnetic resonance , chemistry , ligand (biochemistry) , crystallography , redox , spin states , cationic polymerization , ligand field theory , oxidation state , magnetic susceptibility , electronic structure , stereochemistry , nuclear magnetic resonance , ion , computational chemistry , inorganic chemistry , magnetic field , physics , quantum mechanics , biochemistry , receptor , organic chemistry , metal , catalysis
The nitrosylated diiron complexes, Fe 2 (NO) 3 , of this study are interpreted as a mono‐nitrosyl Fe(NO) unit, MNIU, within an N 2 S 2 ligand field that serves as a metallodithiolate ligand to a dinitrosyl iron unit, DNIU. The cationic Fe(NO)N 2 S 2 ⋅Fe(NO) 2 + complex, 1 + , of Enemark–Feltham electronic notation {Fe(NO)} 7 ‐{Fe(NO) 2 } 9 , is readily obtained via myriad synthetic routes, and shown to be spin coupled and diamagnetic. Its singly and doubly reduced forms, {Fe(NO)} 7 ‐{Fe(NO) 2 } 10 , 1 0 , and {Fe(NO)} 8 ‐{Fe(NO) 2 } 10 , 1 − , were isolated and characterized. While structural parameters of the DNIU are largely unaffected by redox levels, the MNIU readily responds; the neutral, S= 1 / 2 , complex, 1 0 , finds the extra electron density added into the DNIU affects the adjacent MNIU as seen by the decrease its Fe‐ N ‐O angle (from 171° to 149°). In contrast, addition of the second electron, now into the MNIU, returns the Fe‐ N ‐O angle to 171° in 1 − . Compensating shifts in Fe MNIU distances from the N 2 S 2 plane (from 0.518 to 0.551 to 0.851 Å) contribute to the stability of the bimetallic complex. These features are addressed by computational studies which indicate that the MNIU in 1 − is a triplet‐state {Fe(NO)} 8 with strong spin polarization in the more linear FeNO unit. Magnetic susceptibility and parallel mode EPR results are consistent with the triplet state assignment.