Novel Single and Double Diiron Oxadithiolates as Models for the Active Site of [Fe]-Only Hydrogenases

Abstract

The series of diiron oxadithiolate model complexes for the active site of [Fe] 4), and [Fe 2 (µ-SCH 2 OCH 2 S-µ) (CO) 5 ] 2 [(η 5 -Ph 2 PC 5 H 4 ) 2 Fe] ( 5) have been synthesized and fully characterized by elemental analysis, spectroscopy, and X-ray diffraction analysis. The structural features for some of the model complexes are compared with the corresponding features for the active site of [Fe]-only hydrogenases.

Reactions of Selected Aromatic Thioketones with Dodecarbonyltriiron

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The Fe-S bond lengths are found to be within the same range observed for the hydrogenase model complexes. [10][11][12][13][14][15][16][17][18][24][25][26] The C-S average bond length (1.83 Å) is within the same range for a C-S single bond (1.80-1.85 Å) [40] and is significantly longer than the corresponding bond of Fe(PMe 3 ) 3 (Me)(κ,S,C-Ph 2 C=S) [1.675(4) Å] [38] , which contains a C=S bond. The bite angles of the butterfly shape are within the same ranges observed for the hydrogenase model complexes indicating a distorted octahedral geometry around each iron center.…”

Phenyl-functionalized diiron diselenolato complexes with intra- or inter-molecular bridging bidentate phosphine ligands

“…Just as in other diiron diselenolato complex [Fe 2 (l-SeC 3 H 6 Se-l)(CO) 4 ](l-dppm), the bond lengths and angles beyond the [2Fe2Se] core in complex 2 are very similar to their counterparts in the analogous diiron dithiolato complexes [(l-SCH 2 ) 2 CHC 6 H 5 ]Fe 2 (CO) 4 (ldppm) and [(l-SCH 2 ) 2 CH 2 ]Fe 2 (CO) 4 (l-dppm) [21,33]. Complex 3 contains two diiron propanediselenolato cores which are connected together by a dppf ligand, similar to the previously reported diiron diselenolato complex [Fe 2 (lSeC 3 H 5 CH 3 Se-l)(CO) 5 ] 2 (l-dppe) [32] and diiron dithiolato complexes [Fe 2 (l-SCH 2 OCH 2 S-l)(CO) 5 ] 2 [(g 5 -Ph 2 PC 5 H 4 ) 2 Fe] [34], [Fe 2 (l-SCH 2 OCH 2 S-l)(CO) 5 ] 2 [(g5-Ph 2 PC 5 H 4 ) 2 Ru] [35], [(l-SCH 2 ) 2 CHC 6 H 5 Fe 2 (CO) 5 ] 2 (l, j 1 , j 1 -dppf) [23] and [(l-SCH 2 ) 2 NPhFe 2 (CO) 5 ] 2 [(g 5 -Ph 2 PC 5-H 4 ) 2 Fe] [36]. Each phosphine of the dppf ligand occupies an axial position of the square pyramidal coordination spheres of Fe2 and Fe2A, in accord with diiron dithiolato complexes with an inter-molecular bridging diphosphine ligand, such as {[(l-SCH 2 ) 2 CH 2 ]Fe 2 (CO) 5 } 2 (dppe) [37] and {Fe 2 (CO) 5 [(l-SCH 2 ) 2 CH 2 ]} 2 [(l, j 1 , j 1 -Ph 2 PCH 2 N(nPr)CH 2 PPh 2 ] [38].…”

Synthesis and Characterization of [FeFe]‐Hydrogenase Models with Bridging Moieties Containing (S, Se) and (S, Te)

“…These data are in the typical range of such model complexes. [16,17,20,22,24,36,[47][48][49] For comparison, the carbonyl stretching frequencies of the all-sulfur PDT molecule 1 measured under the same conditions are in the range 2074-1990 cm -1 . The down-shifting of the CO absorption bands to lower frequencies from 1 through 2 to 3 is an indication of the increased π back-donation between the diiron center and the CO ligand caused by the rising donor ability of the chalcogen from S through Se to Te.…”