Synthesis of Double and Quadruple Butterfly Fe/S Cluster Complexes via a Novel Type of Reaction of Anions (μ-RS)(μ-S-)[Fe2(CO)6]2(μ4-S) with Succinyl Chloride
Abstract:The bridging sulfido anions (μ-RS)(μ-S-
)[Fe2(CO)6]2(μ4-S) (4a) react with succinyl chloride in THF
to give double and quadruple butterfly Fe/S clusters (μ-RS)(μ-RSS)[Fe2(CO)6]2(μ4-S) (5a, R = Et; 6a, R = t-Bu)
and [(μ-RS)Fe2(CO)6(μ4-S)Fe2(CO)6]2(μ-S−S-μ) (5b, R =
Et; 6b, R = t-Bu), unexpectedly. Crystal structrues of 6a
and 6b are described.
“…Although single butterfly Fe/S cluster salt m 5 reacts with succinyl chloride to give the expected succinylbridged double butterfly cluster complex 4 [17] , treatment of double butterfly cluster salt m 3 (E = S) with succinyl chloride results in formation of the oxidative coupling product, namely quadruple butterfly Fe/S cluster complexes 5 with a S-S bond unexpectedly (Scheme 6) [18] .…”
Section: Methodsmentioning
confidence: 99%
“…It can be seen that 5 has a S1-S1 * bond, and the whole molecule is symmetric with respect to a mirror plane through the midpoint of the S1-S1 * bond. The S1-S1 * , C13-S3 and C13 * -S3 * are all equatorial bonds, which is presumably necessary in order to reduce the strong steric repulsions between the bulky groups attached to these bonding atoms [18][19][20] . …”
This article describes recent developments in chemical study on a series of butterfly-shaped μ-CO-containing Fe/E (E = S, Se, Te) cluster salts. These salts include eleven novel cluster anions, which are the single butterfly one μ-CO-containing [(μ-RE)(μ-CO)Fe 2 (CO) 6 ] − (A), the double butterfly two μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 2 (μ-EZE-μ)} 2− (B, E = S; C, E = Se), the triple butterfly three μ-CO-
containing {[(μ-CO)Fe 2 (CO) 6 ] 3 [(μ-SCH 2 CH 2 ) 3 N]} 3− (D), {[(μ-CO)Fe 2 (CO) 6 ] 3 [1,3,5-(μ-SCH 2 ) 3 C 6 H 3 ]} 3− (E), {[(μ-CO)Fe 2 (CO) 6 ] 3 [(μ-SCH 2 ) 3 CMe]} 3− (F), the double butterfly one μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] [Fe 2 (CO) 6 ][(μ-SCH 2 ) 3 CMe]} − (G) derived in situ from F, the quadruple butterfly four μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 4 [1,2,4,5-(μ-SCH 2 ) 4 C 6 H 2 ]} 4− (H), the triple butterfly two μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 2 [Fe 2 (CO) 6 ][1,2,4,5-(μ-SCH 2 ) 4 C 6 H 2 ]} 2− (I) derived in situ from H, the quadruple butterfly four μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 4 [(μ-SCH 2 ) 4 C]} 4− (J), and the triple butterfly two μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 2 [Fe 2 (CO) 6 ][(μ-SCH 2 ) 4 C]} 2− (K) derivedin situ from J. This article describes not only the synthetic methods for formation of such anionic cluster (A-K) salts, but also their novel reactions leading to various new types of butterfly Fe/E cluster complexes. All these findings described in this article are important both theoretically and practically.
“…Although single butterfly Fe/S cluster salt m 5 reacts with succinyl chloride to give the expected succinylbridged double butterfly cluster complex 4 [17] , treatment of double butterfly cluster salt m 3 (E = S) with succinyl chloride results in formation of the oxidative coupling product, namely quadruple butterfly Fe/S cluster complexes 5 with a S-S bond unexpectedly (Scheme 6) [18] .…”
Section: Methodsmentioning
confidence: 99%
“…It can be seen that 5 has a S1-S1 * bond, and the whole molecule is symmetric with respect to a mirror plane through the midpoint of the S1-S1 * bond. The S1-S1 * , C13-S3 and C13 * -S3 * are all equatorial bonds, which is presumably necessary in order to reduce the strong steric repulsions between the bulky groups attached to these bonding atoms [18][19][20] . …”
This article describes recent developments in chemical study on a series of butterfly-shaped μ-CO-containing Fe/E (E = S, Se, Te) cluster salts. These salts include eleven novel cluster anions, which are the single butterfly one μ-CO-containing [(μ-RE)(μ-CO)Fe 2 (CO) 6 ] − (A), the double butterfly two μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 2 (μ-EZE-μ)} 2− (B, E = S; C, E = Se), the triple butterfly three μ-CO-
containing {[(μ-CO)Fe 2 (CO) 6 ] 3 [(μ-SCH 2 CH 2 ) 3 N]} 3− (D), {[(μ-CO)Fe 2 (CO) 6 ] 3 [1,3,5-(μ-SCH 2 ) 3 C 6 H 3 ]} 3− (E), {[(μ-CO)Fe 2 (CO) 6 ] 3 [(μ-SCH 2 ) 3 CMe]} 3− (F), the double butterfly one μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] [Fe 2 (CO) 6 ][(μ-SCH 2 ) 3 CMe]} − (G) derived in situ from F, the quadruple butterfly four μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 4 [1,2,4,5-(μ-SCH 2 ) 4 C 6 H 2 ]} 4− (H), the triple butterfly two μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 2 [Fe 2 (CO) 6 ][1,2,4,5-(μ-SCH 2 ) 4 C 6 H 2 ]} 2− (I) derived in situ from H, the quadruple butterfly four μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 4 [(μ-SCH 2 ) 4 C]} 4− (J), and the triple butterfly two μ-CO-containing {[(μ-CO)Fe 2 (CO) 6 ] 2 [Fe 2 (CO) 6 ][(μ-SCH 2 ) 4 C]} 2− (K) derivedin situ from J. This article describes not only the synthetic methods for formation of such anionic cluster (A-K) salts, but also their novel reactions leading to various new types of butterfly Fe/E cluster complexes. All these findings described in this article are important both theoretically and practically.
“…Although Reihlen prepared the first dinuclear Fe/S cluster complex (μ-RS) 2 Fe 2 (CO) 6 (R = Et) as early as 1928, the butterfly-shaped Fe 2 S 2 structures of such complexes were confirmed only in 1963 by means of X-ray crystal diffraction techniques . In view of their unique structures and the potentially novel reactivities, Seyferth and co-workers began in the 1970s to systematically study the chemistry of such butterfly Fe/S cluster complexes, which was then thought to be nearly mature at the end of the 1990s. , However, just around this period of time research interest in butterfly Fe/S cluster complexes was extensively revived. This is due to the realization that the active site of [FeFe]-hydrogenases (so-called H-clusters) resembles the archetypal (μ-RS) 2 Fe 2 (CO) 6 derivatives, which consist of a butterfly Fe 2 S 2 cluster core and four unusual ligands: CO, CN − , [Fe 4 S 4 (SCys) 4 ], and a dithiolate (Figure ) .…”
The butterfly Fe/S cluster anions (µ-RS)(µ-S -)Fe 2 (CO) 6 (A, R ) Et, p-MeC 6 H 4 ), (µ-S -) 2 Fe 2 (CO) 6 (C), [(µ-S -)Fe 2 (CO) 6 ] 2 (4-µ-SC 6 H 4 C 6 H 4 S-µ-4′) (D), and [(µ-S -)Fe 2 (CO) 6 ] 2 [4-µ-SC 6 H 4 OCH 2 CH 2 OC 6 H 4 Sµ-4′] (E) (generated in situ via reactions of (µ-S 2 )Fe 2 (CO) 6 with RMgBr, Et 3 BHLi, 4-LiC 6 H 4 C 6 H 4 Li-4′, and 4-LiC 6 H 4 OCH 2 CH 2 OC 6 H 4 Li-4′) were found to react with Ph 2 PCl to give a series of novel butterfly Fe/S/P cluster complexes. Treatment of monoanions A (R ) Et, p-MeC 6 H 4 ) with 1 equiv of Ph 2 PCl in THF from -78 °C to room temperature gave the single-butterfly Fe 2 S 2, whereas dianions C, D, and E reacted with 2 equiv of Ph 2 PCl to give single-butterfly Fe 2 S 2 P 2 complex (η 1 -Ph 2 PS-η 1 ) 2 Fe 2 (CO) 6 ( 11) and double-butterfly Fe 4 S 4 P 2 complexes [(η 1 -Ph 2 PS-η 1 )Fe 2 (CO) 6 ] 2 (4-µ-SC 6 H 4 C 6 H 4 S-µ-4′) ( 12) and [(η 1 -Ph 2 PS-η 1 )Fe 2 (CO) 6 ] 2 [4-µ-SC 6 H 4 OCH 2 CH 2 OC 6 H 4 S-µ-4′] (13), respectively. More interestingly, the novel µ 4 -S-containing doublebutterfly Fe 4 S 2 P complexes [(µ-RS)Fe 2 (CO) 6 ](µ 4 -S)[(µ-Ph 2 P)Fe 2 (CO) 6 ] (14, R ) Me; 15, R ) Ph; 16, R ) Et) could be prepared by reactions of single-butterfly complexes (µ-RS)(η 1 -Ph 2 PS-η 1 )Fe 2 (CO) 6 (1, R ) Me; 3, R ) Ph; 7 R ) Et) with excess Fe 2 (CO) 9 in THF at room temperature, whereas the quadruplebutterfly Fe 8 S 4 P 2 complexes [(µ-Ph 2 P)Fe 2 (CO) 6 (µ 4 -S)Fe 2 (CO) 6 ] 2 (4-µ-SC 6 H 4 C 6 H 4 S-µ-4′) ( 17) and [(µ-Ph 2 P)Fe 2 (CO) 6 (µ 4 -S)Fe 2 (CO) 6 ] 2 [4-µ-SC 6 H 4 OCH 2 CH 2 OC 6 H 4 S-µ-4′] (18) were similarly prepared by reactions of the corresponding double-butterfly complexes 12 and 13 with excess Fe 2 (CO) 9 , respectively. All the new complexes 7-18 have been characterized by elemental analysis, by spectroscopy, and for 9, 11, and 14 by X-ray crystallography. In view of the structural similarity of these Fe/S/P complexes to the [FeFe]-hydrogenase active site, they might be regarded as H-cluster models. As a representative, model complex 11 was found to be able to catalyze proton reduction to hydrogen under CV conditions.
“…The μ -CO-bridged anions of type [( μ -RE)( μ -CO)Fe 2 (CO) 6 ] - ( 1 , E = S, Se, Te) are rich in chemical reactivities and have been extensively used as an important class of synthon to synthesize a variety of novel cluster complexes. − In previous papers 18-20 we reported that anions 1 reacted with ( μ -S 2 )Fe 2 (CO) 6 in THF at room temperature (for E = S) or from −78 °C to room temperature (for E = Se, Te) to give a new type of butterfly Fe/E cluster sulfur-centered anions ( μ -RE)( μ -S - )[Fe 2 (CO) 6 ] 2 ( μ 4 -S) ( 2 ) (Scheme ). 1 …”
The [Et3NH]+ or [MgBr]+ salts of anions [(μ-RE)(μ-CO)Fe2(CO)6]- (1, E = S, Se, Te) reacted
with (μ-Se2)Fe2(CO)6 followed by treatment of the [Et3NH]+ or [MgBr]+ salts of the
intermediate selenium-centered anions (μ-RE)(μ-Se-)[Fe2(CO)6]2(μ
4-Se) (3) with monohalide
PhCH2Br or MeI to give a series of double butterfly Fe/E cluster complexes (μ-RE)(μ-R1Se)[Fe2(CO)6]2(μ
4-Se) (4, RE = EtS, R1 = PhCH2; 5, t-BuS, PhCH2; 6, p-MeC6H4Se, PhCH2; 7,
p-MeC6H4Se, Me; 8, p-MeC6H4Te, PhCH2; 9, p-MeC6H4Te, Me). Similarly, reaction of the in
situ prepared [Et3NH]+ salt of the intermediate selenium-centered anion (μ-t-BuS)(μ-Se-)[Fe2(CO)6]2(μ
4-Se) with dihalide 1,2-(BrCH2)2C6H4 or 1,3-(BrCH2)2-5-MeC6H3 afforded quadruple butterfly Fe/E cluster {(μ-t-BuS)[Fe2(CO)6]2(μ
4-Se)}2(μ-1-SeCH2C6H4CH2Se-2-μ) (10)
or double butterfly Fe/E cluster (μ-t-BuS)[(μ-1-SeCH2-3-BrCH2-5-MeC6H3)[Fe2(CO)6]2 (μ
4-Se) (11) and quadruple butterfly Fe/E cluster {(μ-t-BuS)[Fe2(CO)6]2(μ
4-Se)}2(μ-1-SeCH2-5-MeC6H3CH2Se-3-μ) (12), respectively. All the new products 4−11 have been characterized
by elemental analysis, IR, 1H and 77Se NMR spectroscopy, and for 4, 7, and 9 single-crystal
X-ray diffraction techniques.
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