“…The Fe 3 (CO) 9 fragment is quite basic The p K a , for instance, of HFe 3 (CO) 9 Scy (cy = cyclohexyl) in MeCN is 16 . Reactions of [ I ] 2- with both protic and Lewis acids such as Hg 2+ , (Ph 3 P)Au + , or Cu + all occur on the Fe 3 unit rather than the chalcogenide. − On the other hand, the reaction between [ Ib ] 2- and Re(CO) 5 (O 3 SCF 3 ) yields the stable [Fe 3 (CO) 9 (SRe(CO) 5 )] - , probably as a result of steric inhibition of the access to the iron centers.…”
Section: Resultsmentioning
confidence: 99%
“…Previous work using superheated MeOH for the synthesis of chalcogen−iron carbonylates indicated that the MeOH solvent could alkylate the chalcogen atom, as evidenced by the structural characterization of the [M 4 (Te 2 ) 2 (TeMe) 2 (CO) 8 ] 2- (M = Ru, Fe) prepared under those conditions. On the other hand, reactivity studies using Lewis and protic acids − as well as Fenske Hall calculations 16 showed that the main nucleophility of the [EFe 3 (CO) 9 ] 2- ([ Ia ] 2- , E = O; [ Ib ] 2- , E = S; [ Ic ] 2- , E = Se; [ Id ] 2- , E = Te) lies in the Fe 3 base ( II - and III ). This makes this series of compounds an excellent choice for probing the site specificity of various electrophiles as a function of E. …”
Section: Introductionmentioning
confidence: 99%
“…Previous work using superheated MeOH for the synthesis of chalcogen-iron carbonylates indicated that the MeOH solvent could alkylate the chalcogen atom, 8 as evidenced by the structural characterization of the [M 4 (Te 2 ) 2 (TeMe) 2 (CO) 8 ] 2-(M ) Ru, Fe) prepared under those conditions. On the other hand, reactivity studies using Lewis and protic acids [9][10][11][12][13][14][15] as well as Fenske Hall calculations 16 showed that the main nucleophility of the [EFe 3 (CO) 9 ] 2-([Ia] 2-, E ) O;…”
The compounds [PPN]2[EFe3(CO)9] (E = S ([PPN]2[Ib], E = Se ([PPN]2[Ic]), and E = Te
([PPN]2[Id])) (PPN = [(Ph3P)2N]+) were alkylated using methyl triflate or methyl iodide.
[PPN]2[Ib] reacted with methyl triflate at the sulfur atom to form [PPN][Fe3(CO)9SMe] ([PPN][IVb]). In contrast, alkylation of [PPN]2[Ic] and [PPN]2[Id] occurred at the metal framework
giving [PPN][MeFe3(CO)9E] (E = Se, [PPN][Vc], Te = [PPN][Vd]), of which [PPN][Vc] was
characterized by X-ray crystallography. Compounds [PPN][Vc] and [PPN][Vd] represent
new examples of the uncommon class of cluster compounds having alkyl groups terminally
bound to a metal carbonyl cluster compound. The crystal structure of [PPN][Vc] shows a
long Fe−Me distance of 2.226(9) Å. The removal of electron density from the parent clusters
[Ic]2- and [Id]2- could be seen in the trends of the 77Se or 125Te chemical shifts for [Vc]-,
[Vd]-, and some structurally related compounds.
“…The Fe 3 (CO) 9 fragment is quite basic The p K a , for instance, of HFe 3 (CO) 9 Scy (cy = cyclohexyl) in MeCN is 16 . Reactions of [ I ] 2- with both protic and Lewis acids such as Hg 2+ , (Ph 3 P)Au + , or Cu + all occur on the Fe 3 unit rather than the chalcogenide. − On the other hand, the reaction between [ Ib ] 2- and Re(CO) 5 (O 3 SCF 3 ) yields the stable [Fe 3 (CO) 9 (SRe(CO) 5 )] - , probably as a result of steric inhibition of the access to the iron centers.…”
Section: Resultsmentioning
confidence: 99%
“…Previous work using superheated MeOH for the synthesis of chalcogen−iron carbonylates indicated that the MeOH solvent could alkylate the chalcogen atom, as evidenced by the structural characterization of the [M 4 (Te 2 ) 2 (TeMe) 2 (CO) 8 ] 2- (M = Ru, Fe) prepared under those conditions. On the other hand, reactivity studies using Lewis and protic acids − as well as Fenske Hall calculations 16 showed that the main nucleophility of the [EFe 3 (CO) 9 ] 2- ([ Ia ] 2- , E = O; [ Ib ] 2- , E = S; [ Ic ] 2- , E = Se; [ Id ] 2- , E = Te) lies in the Fe 3 base ( II - and III ). This makes this series of compounds an excellent choice for probing the site specificity of various electrophiles as a function of E. …”
Section: Introductionmentioning
confidence: 99%
“…Previous work using superheated MeOH for the synthesis of chalcogen-iron carbonylates indicated that the MeOH solvent could alkylate the chalcogen atom, 8 as evidenced by the structural characterization of the [M 4 (Te 2 ) 2 (TeMe) 2 (CO) 8 ] 2-(M ) Ru, Fe) prepared under those conditions. On the other hand, reactivity studies using Lewis and protic acids [9][10][11][12][13][14][15] as well as Fenske Hall calculations 16 showed that the main nucleophility of the [EFe 3 (CO) 9 ] 2-([Ia] 2-, E ) O;…”
The compounds [PPN]2[EFe3(CO)9] (E = S ([PPN]2[Ib], E = Se ([PPN]2[Ic]), and E = Te
([PPN]2[Id])) (PPN = [(Ph3P)2N]+) were alkylated using methyl triflate or methyl iodide.
[PPN]2[Ib] reacted with methyl triflate at the sulfur atom to form [PPN][Fe3(CO)9SMe] ([PPN][IVb]). In contrast, alkylation of [PPN]2[Ic] and [PPN]2[Id] occurred at the metal framework
giving [PPN][MeFe3(CO)9E] (E = Se, [PPN][Vc], Te = [PPN][Vd]), of which [PPN][Vc] was
characterized by X-ray crystallography. Compounds [PPN][Vc] and [PPN][Vd] represent
new examples of the uncommon class of cluster compounds having alkyl groups terminally
bound to a metal carbonyl cluster compound. The crystal structure of [PPN][Vc] shows a
long Fe−Me distance of 2.226(9) Å. The removal of electron density from the parent clusters
[Ic]2- and [Id]2- could be seen in the trends of the 77Se or 125Te chemical shifts for [Vc]-,
[Vd]-, and some structurally related compounds.
“…We were interested in comparing the chemical behavior of [Fe 3 (μ 3 -O)(CO) 9 ] 2- and [Fe 3 (μ 3 -S)(CO) 9 ] 2- , − because of their possible relationships with oxygen and sulfur atoms chemisorbed on metal surfaces. Only very few data regarding their chemical behavior are presently known and these are essentially limited to their protonation and alkylation, − or their condensation reactions to give heterometallic clusters. , The only other available information is a report on the limited redox propensity of the [Fe 3 (μ 3 -S)(CO) 9 ] 2- dianion; this was found to undergo a quasi-reversible one-electron anodic oxidation in dichloroethane, whose diagnostic parameters were indicative of the relative instability of the electrogenerated [Fe 3 S(CO) 9 ] - species …”
A reinvestigation of the redox behavior of the [Fe(3)(&mgr;(3)-S)(CO)(9)](2)(-) dianion led to the isolation and characterization of the new [Fe(5)S(2)(CO)(14)](2)(-), as well as the known [Fe(6)S(6)(CO)(12)](2)(-) dianion. As a corollary, new syntheses of the [Fe(3)S(CO)(9)](2)(-) dianion are also reported. The [Fe(5)S(2)(CO)(14)](2)(-) dianion has been obtained by oxidative condensation of [Fe(3)S(CO)(9)](2)(-) induced by tropylium and Ag(I) salts or SCl(2), or more straightforwardly through the reaction of [Fe(4)(CO)(13)](2)(-) with SCl(2). The [Fe(6)S(6)(CO)(12)](2)(-) dianion has been isolated as a byproduct of the synthesis of [Fe(3)S(CO)(9)](2)(-) and [Fe(5)S(2)(CO)(14)](2)(-) or by reaction of [Fe(4)(CO)(13)](2)(-) with elemental sulfur. The structures of [N(PPh(3))(2)](2)[Fe(5)S(2)(CO)(14)] and [N(PPh(3))(2)](2)[Fe(6)S(6)(CO)(12)] were determined by single-crystal X-ray diffraction analyses. Crystal data: for [N(PPh(3))(2)](2)[Fe(5)S(2)(CO)(14)], monoclinic, space group P2(1)/c (No. 14), a = 24.060(5), b = 14.355(6), c = 23.898(13) Å, beta = 90.42(3) degrees, Z = 4; for [N(PPh(3))(2)](2)[Fe(6)S(6)(CO)(12)], monoclinic, space group C2/c (No. 15), a = 34.424(4), b = 14.081(2), c = 19.674(2) Å, beta = 115.72(1) degrees, Z = 4. The new [Fe(5)S(2)(CO)(14)](2)(-) dianion shows a "bow tie" arrangement of the five metal atoms. The two Fe(3) triangles sharing the central Fe atom are not coplanar and show a dihedral angle of 55.08(3) degrees. Each Fe(3) moiety is capped by a triply bridging sulfide ligand. The 14 carbonyl groups are all terminal; two are bonded to the unique central atom and three to each peripheral iron atom. Protonation of the [Fe(5)S(2)(CO)(14)](2)(-) dianion gives reversibly rise to the corresponding [HFe(5)S(2)(CO)(14)](-) monohydride derivative, which shows an (1)H-NMR signal at delta -21.7 ppm. Its further protonation results in decomposition to mixtures of Fe(2)S(2)(CO)(6) and Fe(3)S(2)(CO)(9), rather than formation of the expected H(2)Fe(5)S(2)(CO)(14) dihydride. Exhaustive reduction of [Fe(5)S(2)(CO)(14)](2)(-) with sodium diphenyl ketyl progressively leads to fragmentation into [Fe(3)S(CO)(9)](2)(-) and [Fe(CO)(4)](2)(-), whereas electrochemical, as well as chemical oxidation with silver or tropylium tetrafluoroborate, in dichloromethane, generates the corresponding [Fe(5)S(2)(CO)(14)](-) radical anion which exhibits an ESR signal at g = 2.067 at 200 K. The electrochemical studies also indicated the existence of a subsequent one-electron anodic oxidation which possesses features of chemical reversibility in dichloromethane but not in acetonitrile solution. A reexamination of the electrochemical behavior of the [Fe(3)S(CO)(9)](2)(-) dianion coupled with ESR monitoring enabled the spectroscopic characterization of the [Fe(3)S(CO)(9)](-) radical monoanion and demonstrated its direct involvement in the generation of the [Fe(5)S(2)(CO)(14)](n)()(-) (n = 0, 1, 2) system.
“…The preparation and purification of SCo3(CO)9,2f SFeCo2(CO)9,3 SHFe2Co(CO)9,18 SH2Fe3(C09,19 S2Fe3(CO)9,20 (9) (a) Oxton, I. A.; Powell, D. B.; Skinner, P.; Marko, L.;Werner, H. Inorg. Chim.…”
drhein-Westfalen. The computer time was generously provided by the Rechenzentrum der Universitát Bielefeld and by the Rechenzentrum der Universitát Koln. Some of the calculations were also carried out at the Interdata 8/32 minicomputer (Universitát Bochum), sponsored by the Deutsche Forschungsgemeinschaft. We also thank Professor V. Staemmler for interesting discussions and valuable suggestions and the reviewers for useful comments.
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