Synthesis of [(μ-RS)Fe₂(CO)₆](μ₄-S)[(μ-R‘S)Fe₂(CO)₆] and [(μ-t-BuS)Fe₂(CO)₆](μ₄-Se)[(μ-PhSe)Fe₂(CO)₆] via Reactions of (μ-RS)(μ-p-MeC₆H₄SO₂S)Fe₂(CO)₆ with Nucleophiles. Crystal Structure of [(μ-t-BuS)Fe₂(CO)₆](μ₄-S)[(μ-PhC⋮CS)Fe₂(CO)₆]

Abstract

A new synthetic route to μ4-E (E = S, Se) twin clusters has been discovered, which involves reactions of (μ-RS)(μ-p-MeC6H4SO2S)Fe2(CO)6 with nucleophiles (μ-R‘S)(μ-XMgS)Fe2(CO)6 and (μ-PhSe)(μ-BrMgSe)Fe2(CO)6 to give the twin clusters [(μ-RS)Fe2(CO)6](μ4-S)[(μ-R‘S)Fe2(CO)6] (5a, R = R‘ = Et; 5b, R = Et, R‘ = PhC2; 5c, R = t-Bu, R‘ = Me; 5d, R = t-Bu, R‘ = Ph) and [(μ-t-BuS)Fe2(CO)6](μ4-Se)[(μ-PhSe)Fe2(CO)6] (6) characterized by combustion analysis, spectroscopy, and (for 5b) X-ray diffraction techniques.

Reactions of Monoanions [(μ-RE)(μ-E)Fe2(CO)6]− and Dianions [(μ-E)2Fe2(CO)6]2− (E = Se, S) with N-Substituted Benzimidoyl Chlorides, Leading to Novel Butterfly Fe/E Cluster Complexes

“…We found that monoanion [(μ-RSe)(μ-Se)Fe 2 (CO) 6 ] − ( A , R = Me, Et, m -MeC 6 H 4 ) (generated from (μ-Se 2 )Fe 2 (CO) 6 and Grignard reagents RMgX shown in Scheme ) reacted in situ with excess electrophile PhC(Cl)NPh in THF from −78 °C to room temperature (via nucleophilic attack of the Se-centered monoanion A at the leaving group (Cl − )-attached carbon atom of PhC(Cl)NPh) to give the expected butterfly Fe/Se cluster complexes 1 − 3 in 50−77% yields (Scheme ). However, in contrast to this, we found that monoanion [(μ-RS)(μ-S)Fe 2 (CO) 6 ] − ( B , R = Me, Et) (formed from (μ-S 2 )Fe 2 (CO) 6 and Grignard reagents RMgX shown in Scheme ) reacted in situ with PhC(Cl)NPh under similar conditions to afford unexpected butterfly Fe/S cluster complexes 4 and 5 in 51% and 77% yields, respectively (Scheme ).…”

“…Among such cluster complexes the butterfly monoanions [(μ-RE)(μ-E)Fe 2 (CO) 6 ] − ( A , E = Se; B , E = S) and dianions [(μ-E) 2 Fe 2 (CO) 6 ] 2− ( C , E = Se; D , E = S) are of great interest, since they are easily prepared and possess high nucleophilic reactivity toward various substrates. It is well known that the [MgX] + salts of monoanions A and B , and the dilithium salts of dianions C and D − can be prepared in nearly quantitative yields by reductive cleavage of the E−E bond of cluster (μ-E 2 )Fe 2 (CO) 6 with Grignard reagents and Super-Hydride (Et 3 BHLi), respectively, in THF at −78 °C (Scheme ). In addition, these anions have been also demonstrated to be versatile reagents for synthesis of a wide variety of novel butterfly Fe/E cluster complexes. − Recently, we published two papers that described the unexpected production of the butterfly Fe/S/P cluster complexes from reactions of the butterflyFe/S cluster anions B and D with a P-based electrophile, Ph 2 PCl. , Closely related to such studies, we further carried out a study on reactions of anions A − D with another type of electrophile, namely, the N-substituted benzimidoyl chlorides PhC(Cl)NR′, in order to find new reaction modes and to prepare the corresponding butterfly cluster complexes.…”

Novel Carbon Monochalcogenide Coordination Mode: [Rh2{μ-SeCMo(CO)2(Tp*)}2(η4-cod)2] (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate; cod =cyclo-octa-1,5-diene)

“…Other than for a single polymeric copper selenocyanate, no structural data are available for either of these ligands bridging transition metals. There is copious precedent for bridging thiocyanato ligands and limited data for bridging alkynylthiolato ligands ,, in particular within the area of cluster chemistry developed by Delgado …”

Synthetic and Structural Studies of Butterfly Fe/S/P Cluster Complexes Related to the Active Site of [FeFe]-Hydrogenases. Proton Reduction to H2 Catalyzed by (η1-Ph2PS-η1)2Fe2(CO)6

“…In addition, the Fe(1)−Fe(2) bond length (2.5889 Å) is slightly longer than the Fe(3)−Fe(4) bond length (2.5118 Å). It should be noted that complexes 14 − 18 are the first butterfly Fe/S/P complexes with two different subclusters, Fe 2 S 2 and Fe 2 SP, joined together through a common μ 4 -S atom, although numerous μ 4 -E (E = S, Se)-containing butterfly cluster complexes are known, such as [(μ-RS)Fe 2 (CO) 6 ] 2 (μ 4 -S) (R = Me, Et), [(μ-EtS)Fe 2 (CO) 6 ][(μ-PhCCS)Fe 2 (CO) 6 ](μ 4 -S), [(μ-EtS)Fe 2 (CO) 6 ] 2 (μ 4 -Se), and [(μ-EtTe)Fe 2 (CO) 6 ] 2 (μ 4 -S) …”