Dithiolate diiron

Very recently, Hammarstrom, Ott, and coworkers found that the catalytic activity was significantly increased (up to 200 TON based on the iron complex) when a diiron complex having a 3,6-dichlorobenzene-1,2-dithiolate ligand (Fig. 10) instead of a benzylazadithiolate ligand was used as a WRC (see ref. [64] in [232]). 

Fig. 10 Diiron complex having a 3,6-dichlorobenzene- 1,2-dithiolate ligand as a catalyst for the hydrogen generation...

Deprotonated bridging dithiolate ligands in diiron carbonyl complexes of type 101 (R = H, Ph) rearrange intramolecularly by nucleophilic attack on an iron atom while an electron pair is displaced onto a sulfur atom with formation of an Fe—C bond in 102 (76). Neutral derivatives can be formed upon further alkylation, leading to type Ij complexes (Table 1). The bridg-... 

The complex in Figure 11.18 successfully induces photoinduced proton reduction, hut with very low activities. Provide two reasons why using naphthalene monoimide dithiolates as the linker between the photosensitizer and the active site for proton reduction was considered desirable. What spectral argument was used to reason that the ground state zinc porphyrin moiety does not interact electronically with the diiron portion of this complex ... 

The first three-component hydrogen production systems, i.e., catalyst, photosensitizer, and sacrificial electron donor, employing a diiron dithiolate-type catalyst were reported by Song and coworkers [129, 130]. Drawing from the extensive... 

Justice AK, Rauchfuss TB, Wilson SR (2007) Unsaturated, mixed-valence diiron dithiolate model for the H-ox state of the [FeFe]-hydrogenase. Angew Chem Int Ed 46(32) 6152-6154. doi 10.1002/anie.200702224... 

Olsen MT, Bruschi M, De Gioia L, Rauchfuss TB, Wilson SR (2008) Nitrosyl derivatives of diiron(I) dithiolates mimic the structure and Lewis acidity of the [FeFe]-hydrogenase active site. J Am Chem Soc 130(36) 12021-12030. doi 10.1021/ja802268p... 

Following the first syntheses of biomimetic models of the [FeFe]-hydrogenase active site covalently linked to a ruthenium photosensitizer by Akermark, Sun, and their coworkers in 2003 [90,91], various diiron dithiolate mimics have been combined to a photosensitizing unit [92-100]. 

In a different approach, the diiron center has been connected to a rhenium photosensitizer by covalent attachment to the organic dithiolate bridge (14 in Figure 9.13) allowing performing up to 12 TON under optimized conditions of photocatalysis [122]. 

In a second approach to preparing clusters with multiple diiron centres. Song et al. have utilized the diiron-bridged complexes 145, prepared from the reactions of Fe3(GO)i2 with the appropriate dithiol in the presence of Et3N, as a building block to synthesize a range of chains and macrocycles containing up to four diiron centers. 

More recently, diiron dithiolates (DIT, Fig. 17) have been explored as model complexes mimicking the active site of [FeFe]-hydrogenases, whose structure was... 

Hou, J. Peng, X. J. Zhou, Z. Y. Sim, S. G. Zhao, X. Gao, S. Tris(N-pyrrolidinyljphosphine substituted diiron dithiolate related to iron-only hydrogenase... 

Grain P-Y, Capon J-F, Kervarec N, Gloaguen F, PetiUon F, Pichon R, SchoUhammer P, Talarmin J. Use of 1,10-phenanthroline in diiron dithiolate derivatives related to the [Fe-Fe] hydrogenase active site. Dalton Trans 2007 34 3754-3756. 

Li P, Wang M, Chen L, Liu J, Zhao Z, Sun L. Structures, protonation, and electrochemical properties of diiron dithiolate complexes containing pyridyl-phosphine ligands. Dalton Trans 2009 11 1919-1926. 

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