Structural studies and electrochemical catalysis investigation of [FeFe]-hydrogenase H-cluster mimics mediated by monophosphane ligands

Electrochemical Behavior of Mono‐Substituted [FeFe]‐Hydrogenase H‐Cluster Mimic Mediated by Stannylated Dithiolato Ligand

“…33 cm −1 ) compared to the parent complex 1 , [39] which reflects a better electron‐donor character of the phosphite ligand than that of the carbonyl. These CO stretching vibrations of complex 2 are consistent with those of monophosphane‐substituted analogues [44–54] . The 1 H NMR spectrum of 2 shows a multiplet in the region of 7.32–7.47 ppm, which is attributed to the Ph‐protons, while the methyl protons of the mono‐phosphite ligand show a doublet at 3.70 ppm ( 3 J { 31 P− 1 H}=12.0 Hz).…”

“…This has been confirmed by cooling the sample to 223 K, which results in splitting of the broad signal into two singlets at 181.6 and 170.2 ppm as shown in Figure 2. This suggests that the dynamic site exchange processes at low temperature are suitably slow on the NMR timescale to allow the detection of the isomers (apical and basal coordination modes) expected for 2 [49,54,57,58] …”

“…This suggests that the dynamic site exchange processes at low temperature are suitably slow on the NMR timescale to allow the detection of the isomers (apical and basal coordination modes) expected for 2. [49,54,57,58]…”

“…[42,43] Another tactic to improve the electronic/steric properties of the synthetic approaches is by replacing one of the CO ligands at the diiron core with a stronger σ-donor one, such as phosphines or phosphites ligands . [44][45][46][47][48][49][50][51][52][53][54] The key objective of this alteration is to enhance the electron richness at the [Fe 2 S 2 ] core of the synthetic models.…”

Di-, tri- and tetraphosphine-substituted Fe/Se carbonyls: synthesis, characterization and electrochemical properties

“…In comparison with the phosphine-substituted Fe/Se carbonyls reported in the literature, the E pc1 of compound 4 (−2.14 V) occurs at more negative potential than those of the monophosphine-substituted models Fe 2 {μ-(SeCH 2 ) 2 CHMe}(CO) 5 PPh 3 (−1.97 V), Fe 2 {μ-(SeCH 2 ) 2 CHMe} (CO) 5 P(OMe) 3 (−2.01 V), 73 Fe 2 (μ-Se 2 C 3 H 5 CH 3 )(CO) 5 (PPh 3 ) (−2.0 V), 40 Fe 2 {(μ-SeCH 2 ) 2 O} (CO) 5 (Ph 2 PNMe 2 ) (−1.79 V) and Fe 2 {(μ-SeCH 2 ) 2 O}(CO) 5 {Ph 2 PP(O)Ph 2 } (−1.67 V), 74 but is slightly positive relative to the dppbz substituted model Fe 2 {μ-SeCH 2 CH(Me)CH 2 Se-μ}(CO) 4 (dppbz) (−2.24 V) (dppbz = 1,2-bis(diphenylphosphino)benzene). 75 Furthermore, it is noteworthy that the E pc1 of compound 4 presents a slightly positive potential than those of phosphine disubstituted PDT-bridged diiron compounds Fe 2 (μ-PDT)(CO) 4 (PMe 2 Ph) 2 (−2.22 V) and Fe 2 (μ-PDT)(CO) 4 (PMe 3 )(Ph 2 PCH 2 Py) (−2.20 V).…”