Pyrolyses of the anion dihydridotetracarbonylrhenate. Crystal and molecular structure of bis(tetraethylammonium) μ-hydrido-dodecacarbonyl-triangulo-trirhenate(2—)

The pyrolyses of [NEt₄][H₂Re(CO)₄] in boiling n-heptane, n-octane and n-nonane are described. Mixtures of polynuclear carbonyl- and hydridocarbonylrhenium species are obtained, the principal products being [Re₄(CO)₁₆]^2?, [H₂Re₃(CO)₁₂], [H₃Re₃(CO)₁₀]^2?, [H₃Re₃O(CO)₉]^2? and [H₆Re₄(CO)₁₂]^2?. A red-orange crystalline species was isolated from the reaction in n-heptane and shown by X-ray diffraction to be [Net₄]₂[HRe₃(CO)₁₂]. It gives orthorhombic crystals, space group Pbca, with cell constants a 16.07(1), b 23.39(2), c 19.49(1) Å. The structure was solved by Patterson and Fourier methods and refined by least-squares up to a final R value of 0.061, for 1303 independent counter data. The anion [HRe₃(CO)₁₂]^2? contains an isosceles metal atom triangle, with two short edges of 3.014(3) and 3.018(3) Å and a long hydrogen-bridged edge of 3.125(3) Å.     

Zur Reaktion des Rhenium(VII)-oxids mit 1,4-Dioxan – Kristallstruktur von Re2O7(OH2)2 · 2(1,4-Dioxan)

Reaction of Rhenium(VII) Oxide with 1,4-Dioxane – Crystal Structure of Re₂O₇(OH₂)₂ · 2(1,4-Dioxane) By solvolysis of polymeric Re₂O₇ with 1,4-dioxane in the presence of small amounts of H₂O two products of compositions Re₂O₆(OH)₂ · 3(1,4-dioxane) ( 1 ) and Re₂O₇ · 2H₂O · 2(1,4-dioxane) ( 2 ) are formed. From a complete X-ray single-crystal structure analysis 2 could now be characterized structurally (monoclinic, space group P2₁/c, a = 6.828(3) Å, b = 9.530(2) Å, c = 26.421(8) Å, β = 91.71(3)°, Z = 4). The compound is important as a convenient precursor for the preparation of pure rhenium trioxide. It is to be formulated as Re₂O₇(OH₂)₂ · 2(1,4-dioxane) and contains, contrary to 1 , no 1,4-dioxane coordinated to Re. The crystalline phase consists of a supramolecular arrangement of Re₂O₇(OH₂)₂ units as in “solid perrhenic acid” and of 1,4-dioxane molecules associated through O? H …? O hydrogen bridges. Analogous to dirhenium heptoxide and to solid perrhenic acid one of the rhenium atoms is in tetrahedral, the other is in distorted octahedral coordination.     

Studies on organometallic compounds with hetero multiple bridges : V. Crystal and molecular structure of the parent rhenium complex Re2Br2(CO)6(THF)2 and substituted products of tricarbonylrhenium(I) derived from it

Reactions of the tetrahydrofuran adduct Re₂Br₂(CO)₆(THF)₂ with some phosphorous- and nitrogen-containing donors under mild conditions are reported, which led to the formation of substituted products of tricarbonylrhenium(I). Bromide abstraction from the THF adduct by secondary amines and CS₂ produced the dithiocarbamato derivatives Re(S₂CNR₂)(CO)₃(HNR₂) whose behaviour in solution with CO was also investigated. Mass spectral data for some of the substituted products have been measured. The title compound crystallizes in the space group P2₁/n with cell constants a = 8.661(2), b = 11.251(3), c = 11.424(3) Å and β = 110.36(2)°, U = 1043.67 ų and D_calc = 2.686 g cm^?3, Z = 2. The molecule consists of a planar Re₂Br₂ moiety, as demanded by symmetry. The two THF groups are on opposite sides of this plane and the three CO groups around each rhenium atom are arranged in a fac arrangement. The unique ReBr distances are 2.642(5) and 2.644(4)Å, while the ReO distance is 2.129(31) Å. The ReBrRe and BrReBr angles are 97.3(2) and 82.7(1)°, respectively. The Re?Re nonbonding distance is 3.967(3) Å. The THF ligands consist of a nearly planar C₄ fragment (maximum deviation from planarity 0.06 Å), while the oxygen is 0.348 Å out of that plane, the angle defined by the C₄ plane and the COC fragment of the THF ligand being 24.99°. Final values of the discrepancy indices are R(F) = 0.074 and R_w(F) = 0.095.     

Platinum and rhenium phosphine carbonyl thiolate complexes

The heterometallic complex (CO)₃(PPh₃)Re(μ-SPr)Pt(PPh₃)(CO) (I) was formed in the reaction of Re₂(μ-SPr)₂(CO)₈ with (PPh₃)₂Pt(C₂Ph₂), together with (CO)₃(PPh₃)Re(μ-SPr)₂Re(CO)₄ (II), which was also prepared by an alternative synthesis. Compounds I and II were characterized by X-ray diffraction. In I, the Re-Pt single bond, 2.7414(5) Å, is supplemented by a thiolate bridge with shortened bonds: Pt-S (2.336(2) Å) and Re-S (2.449(2) Å). The Re-P (2.469(2) Å) and Pt-P (2.329(2) Å) bonds are also shortened. Complex II resulting from replacement of one CO group in the starting rhenium complex by triphenylphosphine has no M-M bond, and the Re-S and Re-P bond lengths (2.511(2)–2.527(2) and 2.517(3) Å) are close to the length of single bonds. It is assumed that the platinum atom in I is attached to the formally double bond Re ? SPr arising upon dissociation of Re₂(μ-SPr)₂(CO)₈.     

1H NMR Study of cis-trans Isomerization of Rhenium(III) Binuclear Complexes in Acetone Solutions

The behavior of rhenium(III) binuclear complexes K₂Re₂Hlg₈, Re₂(RCOO)₂Hlg₄ [Hlg = Cl and Br; R = CH₃, C₂H₅, (CH₃)₂CH, and (CH₃)₃C] in acetone solutions was studied by ¹H NMR. Reaction with neutral donor ligand (H₂O and hexamethylphosphoramide) induces transformation of trans-Re₂(RCOO)₂Hal₄ to solvated cis-Re₂(RCOO)₂Hal₄.     

Reaction of the unsaturated anion [Re3H4(CO)10]− with mercaptans. Synthesis and X-ray Characterization of the anion [ Re3H3 (CO)9(μ3-SBut)]−

The novel anion [Re₃H₃(CO)₉(μ₃-SBu^t)]^?, obtained by reaction of [Re₃H₄(CO)₁₀]^? with t-butyl mercaptan, has been characterized by IR, NMR and X-ray diffraction studies. It contains an equilateral Re₃ triangle (mean ReRe 3.091 Å), with nine terminal carbonyl groups, three for each metal atom, and a triply-bridging thiolate ligand (mean ReS 2.393 Å). The three hydrides are bridging on the edges of the triangle of metal atoms.     

Darstellung und Strukturen von (Et4N)2[Re(CO)3(NCS)3] und (Et4N)[Re(CO)2Br4]

Syntheses and Structures of (Et₄N)₂[Re(CO)₃(NCS)₃] and (Et₄N)[Re(CO)₂Br₄] Rhenium(I) and rhenium(III) carbonyl complexes can easily be prepared by ligand exchange reactions starting from (Et₄N)₂[Re(CO)₃Br₃]. Using nonoxidizing reagents the facial Re^I(CO)₃ unit remains and only the bromo ligands are exchanged. Following this procedure, (Et₄N)₂[Re(CO)₃(NCS)₃] can be obtained in high yield and purity using trimethylsilylisothiocyanate. The compound crystallizes in the monoclinic space group P2₁/n, a = 18.442(5), b = 17.724(3), c = 18.668(5) Å, β = 92.54(1)°, Z = 8. The NCS^? ligands are coordinated via nitrogen. The reaction of [Re(CO)₃Br₃]^2? with Br₂ yields the rhenium(III) anion [Re(CO)₂Br₄]^?. The tetraethylammonium salt of this complex crystallizes in the noncentrosymmetric, orthorhombic space group Cmc2₁, a = 8.311(1), b = 25.480(6), c = 8.624(1) Å, Z = 4. The carbonyl ligands are positioned in a cis arrangement. Their strong trans influence causes a lengthening of the Re? Br bond distances by at least 0.05 Å.     

A reactive and versatile trirhenium carbonyl cluster obtained by oxidation of [re3 (μ-H)4 (CO)10]−. Synthesis,x-ray characterization and reactivity of re3 (μ-H)3 (CO)10(NCMe)2

Oxidation of [Re₃(μ-H)₄(CO)₁₀]^? with CF₃SO₃H in acetonitrile gives the new complex Re₃(μ-H)₃(CO)₁₀(NCMe)₂. This contains a triangle of metal atoms with the edges bridged by the hydrides (mean ReRe 3.266 Å). The acetonitrile ligands, bound to two metals in a trans-diaxial manner, are easily replaced, giving a variety of derivatives.     

The Thermal Reaction of the Tris(μ-Hydrido)-Dodecacarbonyltrirhenium (o) Cluster with Triphenylphosphine and Triphenylphosphite

The thermal reaction between the tris(μ-hydrido)dodecacarbonyltrirhenium (o) cluster and triphenylphosphine or triphenylphosphite results in a trisubstituted rhenium cluster as the major product. The results of an X-ray structural analysis of H₃Re₂(CO)₉(PPh₃) are: Mr=1597.57, Monoclinic, P₂₁/n, a=15.598(1), b=9.530(2), c=41.685(3) Å, β=80.60(1)°, V=6113.(1) ų, Z=4, D_c=1.736 g/cm³, CuK_e, λ-1.54056 Å, μ-121.23 cm^?1, F(000)=3059.17, room temperature, R=0.049 for 7361 reflections with I≥2.5σ(I). The molecule has a triangular Re₂ core coordinated propellerwise by three PPh₃ ligands in the molecular plane with virtual C_3k symmetry.     

Reactions of the unsaturated anion [Re3H4(CO)10]− with car☐ylic acids and x-ray characterization of the anions [Re3H3(CO)10(μ-O2CR)]− (R = H,CF3)

The novel anions [Re₃H₃(CO)₁₀(μ-O₂CR)]^? (R = H, CH₃, CF₃), obtained by reaction of [Re₃H₄(CO)₁₀]^? with the corresponding car?ylic acids, have been characterized by IR and NMR spectra and by X-ray analysis of the formate and trifluoroacetate derivatives. They contain a triangle of rhenium atoms, with the car?ylate group diaxially bridging on the shorter ReRe edge.     

Crystal structure of the ionic bioctahedral cluster complex [Ni(NH3)6]2.5NH4[Re12CS17(CN)6]·8.5H2O

A rhenium cluster complex [Ni(NH₃)₆]_2.5·NH₄[Re₁₂CS₁₇(CN)₆]·8.5H₂O is obtained and structurally described. The compound crystallizes in the triclinic space group P-1 with the unit cell parameters: a = 11.0856(13) Å, b = 15.242(2) Å, c = 21.232(3) Å, α = 90.158(4)°, β = 97.439(4)°, γ = 90.051(4)°, V = 3557.3(8) ų, Z = 2, d _calc = 3.287 g/cm³. The crystal structure represents a packing of [Ni(NH₃)₆]²⁺ and NH₄ ⁺ cations, [Re₁₂CS₁₇(CN)₆]^6? cluster anions, and crystallization water molecules bound by a system of hydrogen bonds.     

Reactions of eq,eq-Re2(CO)8(MeCN)2 with phenylacetylene and α-ethynylestradiol. A new synthesis of acetylide complexes

The complex eq,,eq-Re₂(CO)₈(MeCN)₂ reacts with phenylacetylene and α-ethynylestradiol to give the acetylide complexes (μ-H)(μ-CCR)(Re₂(CO)₇(MeCN) [1, R = Ph; 2, R = α-ethynylestradiol] are not the expected compounds (μ-H)(μ-CCR)Re₂(CO)₈. The products were identified from their spectroscopic properties and by an X-ray structural determination in the case of 1. The α-ethynylestradiol complex exists in two diastereomeric forms.     

Strukturuntersuchungen an mono- und bis-alkoxy(triphenylsilyl)-carben-komplexen des rheniums

Steric and electronic influences on bond lengths and angles at the carbene carbon atoms of cis-Re₂(CO)₉C(OR)SiPh₃ (I: R = CH₃, II, R = C₂H₅) and cis,trans-Re₂(CO)₈[C(OEt)SiPh₃]₂ (III) are discussed based on their structural analyses. I (ReRe 305.2(1) pm; ReC(carbene) 209(2) pm) and II (two independent molecules; ReRe 305.0(3) and 305.2(4) pm; ReC (carbene) 208(5) and 210(5) pm) differ by the cis and trans positions of the alkyl groups at the partial C(carbene)O double bonds. The change in configuration affects the bond angles at the carbene carbon. In III the carbene ligands are bonded to different rhenium atoms; cis to one Re atom and trans to the other Re atom (ReRe bond 309.1(2) pm). The ReC(carbene length of the trans- carbene ligand is significantly shorter (185(3) pm) than that of the cis-carbene ligand (208(3) pm).     

[{Cu(trien)}<Subscript>2</Subscript>Re<Subscript>4</Subscript>Te<Subscript>4</Subscript>(CN)<Subscript>12</Subscript>]·3.5H<Subscript>2</Subscript>O: Synthesis and crystal structure

The crystals of a cluster complex of rhenium [{Cu(trien)}₂Re₄Te₄(CN)₁₂]· 3.5H₂O were synthesized by the reaction of aqueous K₄[Re₄Te₄(CN)₁₂] with an aqueous ammonia solution of copper chloride in the presence of a polydentate ligand triethylenetetraamine (trien). The structure of the compound was established by X-ray single crystal analysis (a = 14.2617(11) Å, b = 15.7220(7) Å, c = 21.8554(16) Å, β = 98.554(2)°, V = 4846.0(6) ų, Z = 4, space group P2₁/n, R = 0.0436). Two copper cations in the complex are coordinated to one cluster anion [Re₄Te₄(CN)₁₂]^4?. The copper atoms have typical five-coordinated surroundings formed by the nitrogen atom of the bridging cyanide ligand and four amino groups of the tetradentate trien.     

Vierkernige Clusterkomplexe vom Typ [MM′(AuPR3)2(μ‐H)(μ‐PCy2)(μ4‐PCy)(CO)6] (M,M′ = Mn,Re; R = Ph,Cy, Et): Synthese,Struktur und Topomerisierung

Tetranuclear Cluster Complexes of the Type [MM′(AuR₃)₂(μ‐H)(μ‐PCy₂)(μ₄‐PCy)(CO)₆] (M,M′ = Mn, Re; R = Ph, Cy, Et): Synthesis, Structure, and Topomerisation The dirhenium complex [Re₂(μ‐H)(μ‐PCy₂)(CO)₇(ax‐H₂PCy)] ( 1 ) reacts at room temperature in thf solution with each two equivalents of the base DBU and of ClAuPR₃ (R = Ph, Cy, Et) in a photochemical reaction process to afford the tetranuclear clusters [Re₂(AuPR₃)₂(μ‐H)(μ‐PCy₂)(μ₄‐PCy)(CO)₆] (R = Ph ( 2 ), Cy ( 3 ), Et ( 4 )) in yields of 35–48%. The homologue [Mn₂(μ‐H)(μ‐PCy₂)(CO)₇(ax‐H₂PCy)] ( 5 ) leads under the same reaction conditions to the corresponding products [Mn₂(AuPR₃)₂(μ‐H)(μ‐PCy₂)(μ₄‐PCy)(CO)₆] (R = Ph ( 6 ), Et ( 8 )). Also [MnRe(μ‐H)(μ‐PCy₂)(CO)₇(ax/eq‐H₂PCy)] ( 9 ) reacts under formation of [MnRe(AuPR₃)₂(μ‐H)(μ‐PCy₂)(μ₄‐PCy)(CO)₆] (R = Ph ( 10 ), Et ( 11 )). All new cluster complexes were identified by means of ¹H‐NMR, ³¹P‐NMR and ν(CO)‐IR spectroscopic measurements. 2 , 4 and 10 have also been characterized by single crystal X‐ray structure analyses with crystal parameters: 2 triclinic, space group P 1, a = 12.256(4) Å, b = 12.326(4) Å, c = 24.200(6) Å, α = 83.77(2)°, β = 78.43(2)°, γ = 68.76(2)°, Z = 2; 4 monoclinic, space group C2/c, a = 12.851(3) Å, b = 18.369(3) Å, c = 40.966(8) Å, β = 94.22(1)°, Z = 8; 10 triclinic, space group P 1, a = 12.083(1) Å, b = 12.185(2) Å, c = 24.017(6) Å, α = 83.49(29)°, β = 78.54(2)°, γ = 69.15(2)°, Z = 2. The trapezoid arrangement of the metal atoms in 2 and 4 show in the solid structure trans‐positioned an open and a closed Re…Au edge. In solution these edges are equivalent and, on the ³¹P NMR time scale, represent two fluxional Re–Au bonds in the course of a topomerization process. Corresponding dynamic properties were observed for the dimanganese compounds 6 and 8 but not for the related MnRe clusters 10 and 11 . 2 and 4 are the first examples of cluster compounds with a permanent Re–Au bond valence isomerization.     

Facile cleavage of a phenyl group from SbPh3 by dirhenium carbonyl complexes

The complex Re₂(CO)₈[μ-η²-C(H)C(H)Buⁿ](μ-H) (1) reacts with SbPh₃ at 68 °C to yield the new σ-phenyl dirhenium complex Re₂(CO)₈(SbPh₃)(Ph)(μ-SbPh₂) (4) in 72% yield. Compound 4 contains two rhenium atoms held together by a bridging SbPh₂ ligand. One rhenium atom contains a σ-phenyl group. The other rhenium atom contains a SbPh₃ ligand. Compound 4 was also obtained in 34% yield from the reaction of Re₂(CO)₁₀ with SbPh₃ in the presence of UV–Vis irradiation together with some monorhenium products: HRe(CO)₄SbPh₃ (5), Re(Ph)(CO)₄SbPh₃ (6) and fac-Re(Ph)(CO)₃(SbPh₃)₂ (7) in low yields. Complex 4 is split by reaction with an additional quantity of SbPh₃ to yield the monorhenium SbPh₃ complexes 6, 7 and mer-Re(Ph)(CO)₃(SbPh₃)₂ (8) that contain a σ-phenyl ligand. When 4 was treated with hydrogen, the phenyl ligand was eliminated as benzene and the dirhenium complexes Re₂(CO)₈(μ-SbPh₂)(μ-H) (10), and Re₂(CO)₇(SbPh₃)(μ-SbPh₂)(μ-H) (11), were formed that contain a bridging hydrido ligand. The doubly SbPh₂-bridged dirhenium complex Re₂(CO)₇(SbPh₃)(μ-SbPh₂)₂ (9) that has no metal–metal bond was also formed in these two reactions.     

Interpenetrating frameworks in the structure of the [(SnMe3)3Re6Se8(CN)6] cluster complex

Single-crystal X-ray diffraction is used to determine the structure of a new compound based on an octahedral cyanide anionic cluster complex of rhenium and a trimethyltin(IV) cation: {(SnMe₃)₃[Re₆Se₈(CN)₆]} (1). The crystallographic characteristics: space group C2/c, a = 13.9898(14) Å, b =15.334(2) Å, c = 20.761(2) Å, β = 97.75(0)°, V = 4412.91(90) ų, Z = 4, d _x = 3.607 g/cm³, and R = 0.0526. The compound has a framework structure; two porous frameworks with pcu topology interpenetrate each other.     

Synthese und Eigenschaften der heteronuklearen Metallatomcluster Re4(CO)12[μ3-GaRe(CO)5]4 und Re2(CO)3[μ-GaRe(CO)5]2

Synthesis and Properties of Heteronuclear Metal Atom Clusters Re₄(CO)₁₂[μ₃-GaRe(CO)₅]₄ and Re₂(CO)₈[μ-GaRe(CO)₅]₂ The title compounds were prepared by the reaction of gallium halides and dirhenium decacarbonyl. Crystals of the four-membered cluster Re₂(CO)₈[μ-GaRe(CO)₅]₂ gave at 300⁰C with aggregation of four Re atoms to an inner Re₄ tetrahedron the product Re₄(CO)₁₂(CO)[μ₃-GaRe(CO)₅]₄and with Ga₂I₃ shown by mass spectroscopic measurements the molecule ion Re₄(CO)₁₆+. In tetra-hydrofuran solution the cluster Re₄(CO)₁₂[μ₃-GaRe(CO)₅]₄ and the hydride Li[C₂H₅)₃BH] have formed the formyl complex Li₄{Re₄(CO)₁₂[μ₃ -GaRe(CO)₄(CHO)] ₄}, which was estimated by ¹H n. m. r. and i. r. spectroscopic data. Both synthesized gallium rhenium carbonyl clusters were characterized by i.r. spectroscopic measurements. The comparison of these results with those of the structurally known indium rhenium carbonyl clusters led to proposals of the molecule structure of the analogous gallium rhenium compounds.     

The crystal and molecular structure of the tetraethylammonium salt of tetrahydridopentadecacarbonyltetrarhenate(2−) in two crystallographic forms

The structure of the title compound, (NEt₄)₂[H₄Re₄(CO)₁₅], is reported in two crystallographic modifications, I and II. Both forms axe monoclinic and the cell constants are as follows: I, a 11.355(2), b 21.204(4), c 17.416(3) Å, β 94.15(2)°, space group P2₁/c; II, a 21.831(4), b 17.584(3), c 11.446(2) Å, β 96.02(2)°, space group P2₁,/n. Two sets of 3042 (I) and 2870 (II) independent diffraction intensities, collected by counter methods, were used for the solution and refinement of the two structures. The final conventional R factors have values 5.5% (I) and 6.3% (II), respectively. The crystal packings are compared, showing different conformations of the (NEt₄)⁺ cations. The anions contain a tetrametal cluster formed by an isosceles triangle plus an apically bound metal atom; the carbonyl groups are all terminally bonded to the rhenium atoms. Some differences, present both in the metal atom clusters and in the carbonyl dispositions, are discussed and compared with a third, previously reported, crystallographic modification of the same compound.     

Sulfido‐bridged rhenium–carbonyl complexes with planar and folded Re2S2 cores

The two sulfido‐bridged dirhenium complexes bis(μ‐4‐methoxy­phenyl­sulfido‐S)bis­(tetra­carbonyl­rhenium), [Re₂(C₇H₇­OS)₂­(CO)₈], and bis(μ‐naphthyl­sulfido‐S)bis[tricarbonyl(dicyclohexylphosphane)rhenium], [Re₂­(C₁₂­H₂₃P)₂(C₁₀H₇S)₂­(CO)₆], show different geometries of the common Re₂S₂ core. The 4‐methoxy­phenyl derivative has crystallographic symmetry and the naphthyl derivative has C² symmetry. This results from intramolecular repulsion due to different substitution patterns at the Re and S atoms.