摘要
As opposed to the reversible redox reaction ({Fe(NO) 2 } 10 reduced-form DNIC [(NO) 2 Fe(S(CH 2 ) 3 S)] 2- (1)虠{Fe(NO) 2 } 9 oxidized-form [(NO) 2 Fe(S(CH 2 ) 3 S)] - ), the chemical oxidation of the {Fe(NO) 2 } 10 DNIC [(NO) 2 Fe(S(CH 2 ) 2 S)] 2- (2) generates the dinuclear {Fe(NO) 2 } 9 -{Fe(NO) 2 } 9 complex [(NO) 2 Fe(μ-SC 2 H 4 S) 2 Fe(NO) 2 ] 2- (3) bridged by two terminal [SC 2 H 4 S] 2- ligands. On the basis of the Fe K-edge pre-edge energy and S K-edge XAS, the oxidation of complex 1 yielding [(NO) 2 Fe(S(CH 2 ) 3 S)] - is predominantly a metal-based oxidation. The smaller S1-Fe1-S2 bond angle of 94.1(1)° observed in complex 1 (S1-Fe1-S2 88.6(1)° in complex 2), compared to the bigger bond angle of 100.9(1)° in the {Fe(NO) 2 } 9 DNIC [(NO) 2 Fe(S(CH 2 ) 3 S)] - , may be ascribed to the electron-rich {Fe(NO) 2 } 10 DNIC preferring a restricted bite angle to alleviate the electronic donation of the chelating thiolate to the electron-rich {Fe(NO) 2 } 10 core. The extended transition state and natural orbitals for chemical valence (ETS-NOCV) analysis on the edt-/pdt-chelated {Fe(NO) 2 } 9 and {Fe(NO) 2 } 10 DNICs demonstrates how two key bonding interactions, that is, a Fe-S covalent σ bond and thiolate to the Fe d z 2 charge donation, between the chelating thiolate ligand and the {Fe(NO) 2 } 9/10 core could be modulated by the backbone lengths of the chelating thiolate ligands to tune the electrochemical redox potential (E 1/2 =-1.64 V for complex 1 and E 1/2 =-1.33 V for complex 2) and to dictate structural rearrangement/chemical transformations (S-Fe-S bite angle and monomeric vs. dimeric DNICs).