The First Examples of Organometallic Crown Ethers Containing Redox-Active Tetrahedral Mo₂Fe(μ₃-S) Cluster Cores via a Novel Self-Assembly Cyclization Reaction

Abstract

Three novel organometallic crown ethers with a general formula [Mo 2 Fe(µ 3 -S) (CO) . The crystal structure of 3 and one of the possible pathways for formation of 3-5 are briefly discussed.Since crown ethers were discovered in 1967, 1 a great variety of crown ethers, including those organometallic ones, have been synthesized and widely utilized in numerous fields, such as catalytic organic synthesis, molecular recognition, and chemical sensor technology. [2][3][4][5][6][7] However, although the first organometallic crown ether [η 5 -C 5 H 4 OCH 2 (CH 2 OCH 2 ) 3 CH 2 OC 5 H 4 -η 5 ]Fe appeared in 1986, 8 no organometallic crown ethers that contain metal cluster cores have been reported yet in the literature up to now. Fortunately, we recently found that the polyether chain-bridged dicyclopentadienylbis-(tricarbonylmolybdenumsodium) (1), 9 prepared from Mo(CO) 6 and NaC 5 H 4 CH 2 (CH 2 OCH 2 ) 3 CH 2 C 5 H 4 Na 9 in THF at reflux, reacted with the polyether chain-bridged dicyclopentadienyl double cluster [MoCoFe(µ 3 -S)(CO) 8 ] 2 -[η 5 -C 5 H 4 CH 2 (CH 2 OCH 2 ) 3 CH 2 C 5 H 4 -η 5 ] (2), 9 through an unexpected self-assembly cyclization reaction, to give three organometallic crown ethers containing a single, double, and triple tetrahedral [Mo 2 Fe(µ 3 -S)] cluster core with a general formula [Mo 2 Fe(µ 3 -S)(CO) 7 ] n [η 5 -C 5 H 4 -CH 2 (CH 2 OCH 2 ) 3 CH 2 C 5 H 4 -η 5 ] n in 53% total yield (3, n ) 1; 4, n ) 2; 5, n ) 3) (Scheme 1).The preparations of 3-5 were performed in a Schlenk flask under dry nitrogen. A mixture of Mo(CO) 6 (0.264

Synthesis and characterization of new acyclic polyethers and macrocyclic crown ethers containing double-butterfly Fe4S3 cluster cores. Crystal structures of {[Fe2(CO)6]2(μ4-S)}2[μ-SCH2(CH2OCH2)2CH2S-μ2] and {[Fe2(CO)6]2(μ4-S)}2[μ-SCH2(CH2OCH2)2CH2S-μ][μ-SCH2(CH2OCH2)3CH2S-μ]

“…Synthesis and spectroscopic characterization of {(l-RS)[Fe 2 (CO) 6 ] 2 (l 4 -S)} 2 (l-SZS-l) (1-5) and {[Fe 2 (CO) 6 ] 2 (l 4 -S)} 2 (l-SZS-l)(l-SYS-l) (6)(7)(8)(9)(10)(11) The [Et 3 NH] þ salts of dianions {[(l-CO)Fe 2 (CO) 6 ] 2 (l-SZS-l)} 2À (m) [Z ¼ CH 2 (CH 2 OCH 2 ) 2À4 CH 2 ] were prepared from Fe 3 (CO) 12 , dithiol HSZSH and Et 3 N, which showed an absorption band at ca. m ¼ 1744 cm À1 , characteristic of their l-CO ligands [10].…”

“…m ¼ 1744 cm À1 , characteristic of their l-CO ligands [10]. These salts reacted in situ with an equivalent of (l-S 2 )Fe 2 (CO) 6 to give the [Et 3 NH] þ salts of the S-centered dianions {(l-S À )[Fe 2 (CO) 6 ] 2 (l 4 -S)} 2 (l-SZS-l) (n) [10]. Further treatment of the [Et 3 NH] þ salts of dianions n with an equivalent or an excess of mono-and dihalides afforded a series of the corresponding acyclic polyether clusters 1-5 and macrocyclic crown ether clusters 6-11, respectively (Scheme 1).…”

“…Tetrahydrofuran (THF) was distilled from Na/benzophenone ketyl under nitrogen. (l-S 2 )Fe 2 (CO) 6 [12], Fe 3 (CO) 12 [14], HSCH 2 (CH 2 - [16], PhHgCl [17] and PhC (Cl)@NPh [18] were prepared according to the literature. Et 3 N and ClCH 2 CO 2 Et were of commercial origin and used without further purification.…”

“…Among such ethers we are particularly interested in those containing transition-metal cluster cores, since the affinity of the crown ether or its acyclic analog subunit toward metal complexation could be controlled by the oxidation state of the redox-active metal centers in the cluster cores. So far, we have reported some acyclic polyethers and macrocyclic crown ethers, such as those with the redox-active tetrahedral MCoFeS and M 2 FeS (M ¼ Mo, W) cluster cores [6][7][8][9]. Herein we describe the synthesis and structural characterization of some other new acyclic polyethers and macrocyclic crown ethers containing the double-butterfly Fe 4 S 3 cluster cores, which were prepared by reactions of the CO-bridged dianions {[(l-CO)Fe 2 (CO) 6 ] 2 (l-SZS-l)} 2À with a series of electrophiles, such as ClCH 2 CO 2 Et, PhHgCl, PhC(Cl)@ NPh and BrCH 2 (CH 2 OCH 2 ) n CH 2 Br (n ¼ 2-4).…”

Binding property and redox behaviour of nickel(II) macrocyclic complex containing crown ether toward alkaline earth metal ions

“…Crown ether linked with redox active center is interesting because it is a model compound of a redoxswitching material [1][2][3][4][5][6][7][8]. Transition metal ion in redox center can change the electric state of the binding crown ether making the selectivity against alkali metal ion increased.…”