From an {Fe4S4}-cluster to {Fe2S2}- and {Fe3S}-carbonyls. Crystal structure of [Fe3S(CO)9]2−

We report the electrochemical and chemical synthesis of the first isolable iron carbonyls obtained directly from an {Fe₄S₄}-cluster and carbon monoxide: the structure of one product of chemical reduction, [Fe₃S(CO)₉]²⁻, had been determined by X-ray crystallography.     

Synthesis and chemical characterization of some InFe heteronuclear carbonyl compounds; crystal structure of [NMe3CH2Ph]3[In{Fe(CO)4}3] and [NEt4]2[In2Br4{η-Fe(CO)4}2]

The reaction in THF of Na₂[Fe(CO)₄·xTHF with InBr₃ in an approximate 3.5:1 molar ratio affords the new [In{Fe(CO)₄}₃]³⁻ trianion, which has been isolated as its trimethylbenzylammonium salt and structurally characterized by single-crystal X-ray diffraction studies. On oxidation with two equivalents of AgBF₄ it stepwise affords the anions [In₂Fe₆(CO)₂₄]^x− with x = 4 and 2, respectively. Its reaction with InBr₃ gives species of the composition [InBr_3−x{Fe(CO)_4x}]^x− (x = 1,2), and the anion with the composition [InBr₂{Fe(CO)₄}]⁻ has been structurally characterized as the dimeric species [InBr₂Br₄{η-Fe(CO)₄}₂]²⁻.     

Electronic structure and spectra of [Fe(CN)6SO3]4−

The complex ion [Fe(CN)₆SO₃]⁴⁻ has been prepared in aqueous solution and as the zinc salt in the solid state. The electronic and IR spectra of the complex ion (I) have been recorded. MO calculations have been performed to understand the electronic structure of complex I. The electronic spectra of I and hexacyanoferrate(II) [HCF(II)] have been calculated and compared with the experimental results for I, HCF(II) and HCF(III). The experimental and theoretical results suggest that the oxidation state of Fe in I is + 3 and not +2 and the SO₃ moiety is bonded to one of the nitrogen atoms of the cyano group.     

Synthesis,chemical, and electrochemical characterization of the [Ag13{μ3-Fe(CO)4}] n− (n = 3, 4, 5) cluster anions: X-Ray structural determination of [N(PPh3)2]3 [Ag12(μ12-Ag){μ3Fe(CO)4}8]1

The oxidation of the [Fe(CO)₄]^2– dianion with Ag⁺ salts occurs through a particularinner-sphere mechanism, which involves an intermediate cascade of silver clusters stabilized by Fe(CO)₄ ligands. The last detectable Ag-Fe cluster of the sequence is the [Ag₁₃{-Fe(CO)₄}₈]^3– trianion, which has been selectively obtained by using ca. 1.7 equivalents of Ag⁺ per mole of [Fe(CO)₄]^2–. The [Ag₁₃{-Fe(CO)₄}₈]^3–- trianion has been isolated in a crystalline state with several quaternary cations, and has been characterized by X-ray diffraction studies of its bis(triphenylphosphine)iminium salt. [N(PPh₃)₂]₃ [Ag₁₃{ ₃-Fe(CO)₄}₈]·2(CH₃)₂CO, monoclinic, space group P2₁ (No.4),a = 16.284(2) Å,b =18.767(5) Å,c = 25.905(4) Å, = 90.46(1)°,V = 7916(3) ų,Z = 2,R = 0.0324. The molecular structure of the anion consists of a centered cuboctahedron of silver atoms with the triangular faces capped by Fe(CO)₄ units. Chemical reduction of ( Ag₁₃{ ₃-Fe(CO)₄}₈]^3– affords the corresponding [Ag₁₃{ ₃-Fe(CO)₄)₈]^4–, which in turn gives [Ag₁₃{ ₃-Fe(CO)₄)₈]^5– and [Ag₆{ ₃-Fe(CO)₄}₄]^– upon further reduction. Electrochemical investigations confirm the reversibility of the [Ag₁₃{ ₃-Fe(CO)₄}₈]^3–/4– redox change. Furthermore, in spite of some electrode poisoning effects, evidence of the existence of the [Ag₁₃{ ₃-Fe(CO)₄}₈]^5– pentaanion was obtained. The yet structurally uncharacterized [Ag₆{ ₃-Fe(CO)₄)₄]^2– dianion is quantitatively obtained by reaction of [Fe(CO)₄]^2– with ca. 1.5 equivalents of Ag⁺ or by addition of one equivalent of Ag⁺ to solutions of the [Ag₅{Fe(CO)₄}₄]^3– trianion. All attempts to isolate its quaternary salts as crystalline materials failed owing to formation of amorphous insoluble precipitates. The above series of ₃-Fe(CO)₄ octa-capped cuboctahedral Ag₁₃ clusters can be envisioned as the Ag⁺ . Ag and Ag^– cryptates of the [Ag₁₂{}₃-Fe(CO)₄}₈]^4– cryptand. respectively.Dedicated to Prof L. F. Dahl on his 65th birthday.     

Tris(pyrazolyl)borate half-sandwich complexes of trivalent uranium incorporating the [C8H6{SiiPr3-1,4}2]2− and [C8H4{SiiPr3-1,4}2]2− ligands

The reaction of UI₃ in THF with KTp^Me2 and the subsequent addition of [K₂(C₈H₆{SiⁱPr₃-1,4}₂)] or [K₂(C₈H₄{SiⁱPr₃-1,4}₂)] yields dark red [U(κ³-Tp^Me2)(C₈H₆{SiⁱPr₃-1,4}₂)] 1 and purple [U(κ³-Tp^Me2)(C₈H₄{SiⁱPr₃-1,4}₂)] 2, respectively. The ¹H NMR of 1 at room temperature suggests a rigid structure, whereas 2 is fluxional in solution on the NMR timescale. 1 is unreactive towards CO, CO₂ and MeNC under mild conditions; density functional calculations were used to compare the electronic and steric effects of the Tp^Me2 vs. Cp* ligands in mixed sandwich complexes of the type [U(L)(C₈H₆{SiH₃-1,4}₂)] (L = Cp* or (κ³-Tp^Me2)). On heating at 80 °C, 1 reacts with excess MeNC to yield [U(C₈H₆{SiⁱPr₃-1,4}₂)(κ²-dmpz)₂(η¹-CNMe)] 3. The structures of 1–3 have been determined by single crystal X-ray diffraction.     

Thermodynamic Model for BiPO4(cr) and Bi(OH)3(am) Solubility in the Aqueous Na+–H+–\mathrm{H}_{2}\mathrm{PO}_{4}^{-}–\mathrm{HPO}_{4}^{2-}–\mathrm{PO}_{4}^{3-}–OH−–Cl−–H2O System

Prior to this study no data for the solubility product of BiPO₄(cr) or the complexation constants of Bi with phosphate were available. The solubility of BiPO₄(cr) was studied at 23±2?°C from both the over- and under-saturation directions as functions of a wide range in time (6–309 days), pH values (0–15), and phosphate concentrations (reaching as high as 1.0 mol?kg^?1). HCl or NaOH were used to obtain a range in pH values. Steady state concentrations and equilibrium were reached in <6 days. The data were interpreted using the SIT model. These extensive data provided a solubility product value for BiPO₄(cr) and an upper limit value for the formation of BiPO₄(aq). Because the aqueous system in this study involved relatively high concentrations of chloride, reliable values for the complexation constants of Bi with chloride were required to accurately interpret the solubility data. Therefore as a part of this investigation, existing Bi–Cl data were critically reviewed and used to obtain values of equilibrium constants for various Bi–Cl complexes at zero ionic strength along with the values for various SIT ion interaction parameters. Predictions based on these thermodynamic quantities agreed closely with our experimental data, the chloride concentrations of which ranged as high as 0.7 mol?kg^?1. The study showed that BiPO₄(cr) is stable at pH values <9.0. At pH values >9.0, Bi(OH)₃(am) is the solubility controlling phase. Reliable values for the Bi(OH)₃(am) solubility reactions involving Bi(OH)₃(aq) and $\mathrm{Bi}(\mathrm{OH})_{4}^{-}$ and the formation constants of these aqueous species are also reported.     

Synthesis, Electrochemistry and Crystal Structure of the [Ni36Pt4(CO)45]6− and [Ni37Pt4(CO)46]6− Hexaanions

The [Ni₃₆Pt₄(CO)₄₅]^6- and [Ni₃₇Pt₄(CO)₄₆]^6- clusters have been obtained in mixture upon reaction in acetonitrile of [Ni₆(CO)₁₂]^2- salts with K₂PtCl₄ in a 2.5:1 molar ratio. The two hexaanions were indistinguishable by spectroscopic techniques. Crystallization of their trimethylbenzylammonium salts led to crystals of composition 0.5[NMe₃CH₂Ph]₆[Ni₃₆Pt₄(CO)₄₅]-0.5[NMe₃CH₂Ph]₆[Ni₃₇Pt₄(CO)₄₆]·C₃H₈O, hexagonal,space group P6₃ (No. 173), a=17.853(9), c=27.127(13) Å, Z=2; final R=0.057. The metal core of the [Ni₃₆Pt₄(CO)₄₅]^6- anion consists of a Pt₄ tetrahedron fully encapsulated in a shell of 36 Ni atoms belonging to a very distorted and incomplete ₅ tetrahedron. The [Ni₃₇Pt₄(CO)₄₆]^6- hexaanion derives from the former by capping the unique triangular face of the metal polyhedron with an additional Ni(CO) fragment. The [Ni₃₆Pt₄(CO)₄₅]^6--[Ni₃₇Pt₄(CO)₄₆]^6- mixture is rapidly degraded to the known [Ni₉Pt₃(CO)₂₁]^4- cluster by exposure to carbon monoxide. Its reaction with protic acids initially affords the corresponding [H_6-nNi₃₆Pt₄(CO)₄₅]^n--[H_6-nNi₃₇Pt₄(CO)₄₆]^n- (n=5, 4) derivatives, and eventually leads to rearrangement to the known [H_6-n Ni₃₈Pt₆(CO)₄₈]^n- species. Both [Ni₃₆Pt₄(CO)₄₅]^6--[Ni₃₇Pt₄(CO)₄₆]^6- and [HNi₃₆Pt₄(CO)₄₅]^5--[HNi₃₇Pt₄(CO)₄₆]^5- mixtures have been chemically and electrochemically reduced to their corresponding [Ni₃₆Pt₄(CO)₄₅]^n--[Ni₃₇Pt₄(CO)₄₆]^n- (n=7–9) and [HNi₃₆Pt₄(CO)₄₅]^n--[HNi₃₇Pt₄(CO)₄₆]^n- (n=6–8) mixtures.     

[Fe2S2(CO)6]2− as a cluster precursor: synthesis and structure of [MoFe3S6(CO)6]2− and oxidative decarbonylation to a persulfide-bridged MoFe3S4 double cubane

Reactions of [Fe₂S₂(CO)₆]²⁻ (3) with [Cl₂FeS₂MS₂]²⁻ [M = Mo (4) or W (6)] and [Cl₂FeS₂VS₂FeCl₂]³⁻ (8) in acetonitrile-THF solutions afford the new clusters [MFe₃S₆(CO)₆]²⁻ (M = Mo (5) or W (7)] and [VFe₆S₈(CO)₁₂]³⁻ (9). (Et₄N)₂ (5) crystallizes in orthorhombic space group Pbcn with a = 15.314(7) Å, b = 16.627(6) Å, c = 29.971(13) Å, and Z = 8. Cluster 5 is formed by displacement of chloride from 4 by 3 to yield a species with the [Fe₂(μ₃-S)₂Fe(μ₂-S)₂MoS₂]²⁻ core arrangement containing one Fe(II) and Mo(VI) in distorted tetrahedral sites. Similar structures are proposed for 7 and 9, with the latter containing two 3 ligands bound to the [VFe₂S₄]¹⁺ core of 8. Treatment of 5 with RSSR results in oxidative decarbonylation and formation of [Mo₂Fe₆S₈(S₂)₂(SR)₆]⁴⁻ (10) (R = p-C₆H₄Cl or p-C₆H₄Br), which consists of two [MoFe₃(μ₃-S)₄]³⁺ cubane-type subclusters bridged by two μ₂-η³-S₂²⁻ groups. Cluster 10 was also obtained in a direct-assembly system consisting of [MoS₄]²⁻ + 3FeCl₃+ S₂²⁻ + 7RS⁻ in methanol. Evidence is presented that the solid-state structure of 10 is maintained in solution. The redox change [MoFe₃(μ₂-S)₂(μ₃-S) ₂S₂]²⁻ (5) → [MoFe₃(μ₃-S)₄(S₂)]¹⁺ (10) is described as an oxidatively induced core internal conversion in which there is net Fe and S oxidation and Mo reduction. It is argued that the reduction of tetrahedral Mo(VI) to or near Mo(III), stabilized in a six-coordinate site, is a significant factor in the formation of the cubane structure. The formation of the cubane cluster [VFe₃S₄Cl₃(DMF)₃]¹⁻ from 8 and FeCl₂ is similarly promoted by the reduction of tetrahedral V(V) to or near V(III). The syntheses of 5, 7, 9 and 10 illustrate the utility of 3 as a cluster precursor.     

Synthesis and structures of mercury and cadmium complexes: [Ph4Sb] 2 + [Hg2I6]2−·Ph2Hg, [Ph4Sb] 2 + [E2I6]2− (E = Hg, Cd), and [Ph4Sb] 2 + [Hg4I10]2−

The reaction of pentaphenylantimony with mercury iodide affords the ionic complex [Ph₄Sb] ₂ ⁺ [Hg₂I₆]^2?·Ph₂Hg (I). The [Ph₄Sb] ₂ ⁺ [Hg₂I₆]^2? (II) and [Ph₄Sb] ₂ ⁺ [Cd₂I₆]^2? (III) complexes are synthesized from tetraphenylantimony iodide and mercury and cadmium iodides. The [Ph₄Sb] ₂ ⁺ [Hg₄I₁₀]^2? complex (IV) is prepared from tetraphenylantimony 2,4-dimethylbenzenesulfonate and mercury iodide. According to the X-ray diffraction data, the Sb atom in the [Ph₄Sb]⁺ cations of complex I has virtually ideal tetrahedral coordination (the CSbC angles are 108.09°–109.64°). In the central square fragment Hg₂I₂ of the [Hg₂I₆]^2? anion, the Hg-I_br bond lengths are 2.825 and 3.075 Å, and the terminal iodine atoms are more strongly bonded to the mercury atoms (Hg-I_term 2.691 and 2.700 Å). The [Cd₂I₆]^2? anion in complex III has a similar structure (the Cd-I_bridg and Cd-I_term distances are 2.865, 2.872 and 2.723, 2.748 Å, respectively). The anions in complex IV are joined by I…Hg (3.651 Å) and I…I (4.058 Å) interactions into an infinite dimeric network.     

Synthesis and Crystal Structure of a Novel Heptanuclear Ruthenium- and Sodium-containing Polyoxomolybdate [ {Na(H2O)3}2{Ru(dmso)3}2(MoO4)3]·3H2O

The title compound, [{Na(H2O)3}2{Ru(dmso)3}2(MoO4)3]·3H2O, has been obstructure was determined by single-crystal X-ray diffraction method. The crystal crystallizes in the triclinic system, space group P1 with a = 12.3333(3), b = 12.6289(3), c = 32.0284(14)(A), α =79.873(7), β = 87.549(9), y = 64.500(4)°, V = 4429.5(2) (A)3, Z = 4, Mr = 1358.85, Dc = 2.038g/cm3, F(000) = 2696 and μ = 1.874 mm-1. The compound contains a novel pentanuclear triangle bipyramidal core, [{ Ru(dmso)3 } 2(MoO4)3]2-, which consists of two { Ru(dmso)3 } 2+ fragments and three {μ2-MoO4}2- units. Furthermore, the dmso ligands bridge the pentanuclear [Ru2Mo3] core and two [Na(H2O)3]+ fragments together, forming a neutral heptanuclear ruthenium- and sodiumcontaining polyoxomolybdate.     

Finally Stable and Homoleptic: Isolation and Characterization of {Cu[Fe(CO)5]2}+ Stabilized with Perfluoroalkoxyaluminate Anion, [Al(OC(CF3)3)4]−

Developments in the chemistry of weakly coordinating anions enabled isolation of numerous unique metal complexes with unusual ligands. An important example is the family of metal-Fe(CO)₅ complexes. In the current paper we present synthesis and thorough characterization of the first truly homoleptic {Cu[Fe(CO)₅]₂}⁺ cation obtained as a salt of weakly coordinating [Al(OR^F)₄]⁻ (R^F=C(CF₃)₃) anion. TGA/DSC/MS study show that its decomposition becomes noticeable only above 110 °C, thus it can be stored as powder in air-free conditions for months. The crystal structure of {Cu[Fe(CO)₅]₂}⁺ shows strong asymmetry of the cation and very short Cu-CO bonds in comparison to analogous {M[Fe(CO)₅]₂}⁺ where M=Ag or Au. Characterization is complemented with analysis of vibrational spectra and extensive DFT calculations which give insight into the energetics of Cu⁺-Fe(CO)₅ systems. Our results show that {Cu[Fe(CO)₅]₂}⁺ is homoleptic only as salt of [Al(OR^F)₄]⁻. Furthermore, in the presence of additional, even weakly basic ligands, the Cu⁺-Fe(CO)₅ bond strength decreases what may contribute to the complex's instability in liquid SO₂ or in the presence of [SbF₆]⁻. These conclusions point at the key role of selection of proper anion and solvent in stabilization of these types of complexes.     

The unusual electrochemical behaviour of [Co8(CO)18C]2− compared to [M6(CO)15C]2− (M = Co,Rh) and [Fe6(CO)16C]2− carbido clusters

A variety of electrochemical reactions has been observed for the carbido-carbonyl clusters [Co₈(CO)₁₈C](NMe₃CH₂C₆H₅)₂, [Co₆(CO)₁₅C](NMe₃CH₂C₆H₅)₂, [Rh₆(CO)₁₅C](Et₄N)₂ and [Fe₆(CO)₁₆C](Et₄N)₂. The hexanuclear clusters undergo irreversible electrochemical oxidation and reduction steps, whereas the octacobalt species exhibits three electrochemically reversible one-electron steps. The relation between the redox properties and the structure of these clusters is discussed.     

Synthesis and structure of antimony iodide complexes: [Ph3MeP] + 2 [SbI5]2−, [Ph3MeP] + 3 [Sb3I12]3−·Me2C=O, [Ph3MeP] + 3 [Sb3I12]3−, and [Ph3MeP] + 3 [Sb2I9]3−

Complexes with antimony-containing anions, [Ph₃MeP] ₊ ² [SbI₅]^2? (I), [Ph₃MeP] ₊ ² [Sb₃I₁₂]^3? (II), [Ph₃MeP] ₊ ³ [Sb₃I₁₂]^3? · Me₂C=O (III), and [Ph₃MeP] ₊ ³ [Sb₂I₉]^3? (IV), were synthesized by reacting triphenylmethylphosphonium iodide with antimony iodide. The central atom in the cations of the complexes has a distorted tetrahedral coordination. In the trinuclear anions of complexes II and III, each of the terminal SbI₃ groups is bound to the central Sb atom through two μ₂- and one μ₃ iodine bridges (SbSbSb angles are 103.0° and 102.2°, respectively). In the binuclear anion of complex IV, antimony atoms are linked with each other via three bridging iodine atoms.     

Interpretation der Absorptionsspektren der Komplexionen [Mo(CN)8]4−, [Mo(CN)8]3−, [W(CN)8]4− und [W(CN)8]3−

Zusammenfassung Die Absorptions- und Reflexionsspektren der Oktocyanokomplexe desMo(IV) undW(IV) sowie die Absorptionsspektren der Oktocyanotomplexe desMo(V) undW(V) werden mitgeteilt. Die Spektren werden unter Zugrundelegung der durch Raman- und IR-spektroskopische Untersuchungen gefordertenD _4d-Symmetrie dieser Verbindungen interpretiert. Die beobachteten Banden niedriger Intensität (log<3) werden Übergängen in einem Termsystem zugeordnet, das für die Konfigurationend ² undd ₁ und die SymmetrieD _4d berechnet worden ist. Banden hoher Intensität (log>3) werden auf Übergänge in antibindende Zustände zurückgeführt, an denen höherep-Zustände des Zentralions sowie Ligandenzustände beteiligt sind. Die erhaltenen Werte des Feldparameters stimmen mit ligandenfeldtheoretischen Erwartungen überein.

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Absorption and reflection spectra of the octacyanides ofMo(IV) andW(IV) and the absorption spectra of the octacyanides ofMo(V) andW(V) are presented. The spectra are interpreted in terms of theD _4d symmetry of the compounds supported by investigations of Raman and infrared spectra. Bands of low intensity (log<3) correspond to transitions between levels obtained in the case of the configurationsd ² andd ¹ respectively, in a field ofD _4d symmetry. Bands of high intensity (log>3) are attributed to transitions into antibonding levels in which p-orbitals of the central ion and ligand orbitals participate. The values of the field parameter obtained are in accord with ligand field theory.

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Résumé Les spectres d'absorption et de réflexion des complexes octocyanurés duMo(IV) et duW(IV) ainsi que les spectres d'absorption des mêmes complexes deMo(V) et de W(V) sont présentés. Les spectres sont interprétés en supposant la symétrieD _4d des molécules indiquée par des analyses des spectres Raman et infrarouges. Les bandes de faible intensité (log<3) sont attribuées à des transitions dans un système de niveaux, calculé pour les configurationsd ² etd ¹, respectivement, en symétrieD _4d. Des bandes de forte intensité (log>3) sont attribuées à des transitions vers des niveaux antiliants auxquels participent des fonctions élevéesp de l'ion central et des fonctions des groupes liés. Les valeurs obtenues pour le paramètre de champ sont en accord avec les prévisions de la théorie.

     

Phosphine-centred resolution of (η4-diene)Fe(CO)3 complexes: (η4-tropone)Fe(CO)2L and (η4-isoprene)Fe(CO)2L [L = (+)-(neomenthyl)PPh2]

(η⁴-Tropone)Fe(CO)₃ and (η⁴-isoprene)Fe(CO)₃ form separable diastereoisomers on substitution of CO by (+)-(neomenthyl)PPh₂. In the tropone complex, diastereoisomer interconversion occurs by a 1,3-metal shift. The absolute configuration of the isoprene complex has been determined crystallographically.     

Synthesis and structure of antimony complexes [Ph3AmP] 2 + [Sb2I8 · 2DMSO]2−, [Ph3PrP] 2 + [Sb2I8 · C4H8O2]2−, and [(HOCH2CH2)3NH] 4 + [Sb4I16]4−

The reaction of equimolar amounts of triphenylamyl- and triphenylpropylphosphonium iodides and triethanolammonium iodide with antimony iodide in dimethyl sulfoxide, dioxane, or acetone gave complexes [Ph₃AmP] ₂ ⁺ [Sb₂I₈ · 2DMSO]^2?, [Ph₃PrP] ₂ ⁺ [Sb₂I₈ · C₄H₈O₂]^2?, and [(HOCH₂CH₂)₃NH] ₄ ⁺ [Sb₄I₁₆]^4?, the structure of which was established by X-ray diffraction analysis. The cations of all complexes have slightly distorted tetrahedral structure, and the antimony atoms in the anions are hexacoordinated. The crystals of the complexes have intra- and intermolecular contacts, which form the structure.     

The reaction of [Ru10C(CO)24][ppn]2 with carbon monoxide to yield [Ru3(CO)12] and [Ru6C(CO)16]2−

The dianion [Ru₁₀C(CO)₂₄]²⁻ in CH₂Cl₂ reacts with CO under ambient conditions to produce quantitative amounts of the species [Ru₃(CO)₁₂] and [Ru₆C(CO)₁₆]²⁻; the hydrido-anion [HRu₁₀C(CO)₂₄]⁻ reacts similarly to form [Ru₆C(CO)₁₆]⁻.     

Synthesis and structure of tetra-p-tolylantimony complexes [(4-MeC6H4)4Sb] 2 + [Hg2I6]2−, [(4-MeC6H4)4Sb] 2 + [HgI4]2−, [(4-MeC6H4)4Sb] 3 + [Sb3I12]2−, and [(4-MeC6H4)4Sb]+[ReO4]−

Complexes [(4-MeC₆H₄)₄Sb] ₂ ⁺ [Hg₂I₆]^2? (I), [(4-MeC₆H₄)₄Sb] ₂ ⁺ [HgI₄]^2? (II), [(4-MeC₆H₄)₄Sb] ₃ ⁺ [Sb₃I₁₂]^2? (III), were synthesized by reactions of tetra-p-tolylantimony iodide with mercury iodide and antimony iodide, respectively. Tetra-p-tolylantimony perrhenate [(4-MeC₆H₄)₄Sb]⁺[ReO₄]^? (IV) was prepared from tetra-p-tolylantimony chloride and sodium perrhenate in acetone. Crystal structures of complexes I, II, and IV were determined by X-ray crystallography. Mercury and rhenium atoms have tetrahedral coordinations in these complexes. The Hg-I and Re-O distances in the structures of I, II, and IV vary within 2.7719(13)–2.7908(12)Å, 2.7028(3)–2.9163(3) Å, and 1.693(3)–1.744(3) Å, respectively. Antimony atoms in two crystallographically independent trinuclear centrosymmetric [Sb₃I₁₂]^2? anions of complex III have an octahedral environment. Each terminal SbI₃ fragment (Sb-I_t, 2.8265(9)–2.8333(10)Å) is bound to the central atom through tree bridging iodine atoms (Sb(2)-I_br, 3.2275(9)–3.3620(10)Å). The distances between the central Sb atom and bridging iodine atoms are much shorter (Sb(1)-I_br, 3.0153(6)–3.0316(6) Å; Sb(3)-I_br, 2.9926(6)–3.0074(6) Å).