Facile C?H Bond Formation by Reductive Elimination at a Dinuclear Metal Site

The electronically unsaturated dirhenium complex [Re₂(CO)₈(µ‐AuPPh₃)(µ‐Ph)] ( 1 ) was obtained from the reaction of [Re₂(CO)₈{µ‐η²‐C(H)C(H)nBu}(µ‐H)] with [Au(PPh₃)Ph]. The bridging {AuPPh₃} group was replaced by a bridging hydrido ligand to yield the unsaturated dirhenium complex [Re₂(CO)₈(µ‐H)(µ‐Ph)] ( 2 ) by reaction of 1 with HSnPh₃. Compound 2 reductively eliminates benzene upon addition of NCMe at 25 °C. The electronic structure of 2 and the mechanism of the reductive elimination of the benzene molecule in its reaction with NCMe were investigated by DFT computational analyses.     

Binuclear Aromatic C−H Bond Activation at a Dirhenium Site

The electronically unsaturated dirhenium complex [Re₂(CO)₈(μ‐H)(μ‐Ph)] ( 1 ) has been found to exhibit aromatic C?H activation upon reaction with N,N‐diethylaniline, naphthalene, and even [D₆]benzene to yield the compounds [Re₂(CO)₈(μ‐H)(μ‐η¹‐NEt₂C₆H₄)] ( 2 ), [Re₂(CO)₈(μ‐H)(μ‐η²‐1,2‐C₁₀H₇)] ( 3 ), and [D₆]‐ 1 , respectively, in good yields. The mechanism has been elucidated by using DFT computational analyses, and involves a binuclear C?H bond‐activation process.     

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.     

Synthese und Struktur chiraler Heterometallatetrahedrane des Typs [Re2(M1PPh3)(M2PPh3)(μ‐PCy2)(CO)7C≡CPh] (M1 = Ag,Au; M2 = Cu,Ag, Au)

Syntheses and Structure of Chiral Metallatetrahedron Complexes of the Type [Re₂(M¹PPh₃)(M²PPh₃)(μ‐PCy₂)(CO)₇C≡CPh] (M¹ = Ag, Au; M² = Cu, Ag, Au) From the reaction of Li[Re₂(μ‐H)(μ‐PCy₂)(CO)₇(C(Ph)O)] ( 1 ) with Ph₃AuC≡CPh both benzaldehyde and the trinuclear complex Li[Re₂(AuPPh₃)(μ‐PCy₂)(CO)₇C≡CPh] ( 2a ) were obtained in high yield. The complex anion was isolated as its PPh₄‐salt 2b . The latter reacts with coinage metal complexes PPh₃M²Cl [M² = Cu, Ag, Au] to give chiral heterometallatetrahedranes of the general formula [Re₂(AuPPh₃)(M²PPh₃)(μ‐PCy₂)(CO)₇C≡CPh] (M² = Cu 3a , Ag 3b , Au 3c ). The corresponding complex [Re₂(AgPPh₃)₂(μ‐PCy₂)(CO)₇C≡CPh] ( 3d ) is obtained from the reaction of [Re₂(AgPPh₃)₂(μ‐PCy₂)(CO)₇Cl] ( 4 ) with LiC≡CPh. 3d undergoes a metathesis reaction in the presence of PPh₃CuCl giving [Re₂(AgPPh₃)(CuPPh₃)(μ‐PCy₂)(CO)₇C≡CPh] ( 3e ) and PPh₃AgCl. Analogous metathesis reactions are observed when 3c is reacted with PPh₃AgCl or PPh₃CuCl giving 3a or 3b , respectively. The reaction of 1 with PPh₃AuCl gives benzaldehyde and Li[Re₂(AuPPh₃)(μ‐PCy₂)(CO)₇Cl] ( 5a ) which upon reaction with PhLi forms the trinuclear complex Li[Re₂(AuPPh₃)(μ‐PCy₂)(CO)₇Ph] ( 6a ). Again this complex was isolated as its PPh₄‐salt 6b . In contrast to 2b , 6b reacts with one equivalent of Ph₃PAuCl by transmetalation to give Ph₃PAuPh and PPh₄[Re₂(AuPPh₃)(μ‐PCy₂)(CO)₇Cl] ( 5b ). The X‐ray structures of the compounds 3a , 3b , 3e and 4 are reported.     

Deprotonierung von Mn2(μ-H)(μ-PR2)(CO)8 (R=Ph,Cy) zur Synthese von Heteronuklearen Mangan—Gold Clustern mit Mn2Aun-Kernen (n = 1 – 3)

Deprotonation of Mn₂(μ-H)(μ-PR₂)(CO)₈ (R = Ph Cy) for Synthesis of Heteronuclear Manganese-Gold Clusters with Mn₂Au_n Cores (n = 1–3) The dimanganese complexes Mn₂(μ-H)(μ-PR₂)(CO)₈ (R = Ph, Cy) have been deprotonated with 1,8-diazabicyclo[5.4.0]undec-7-en (DBU) in tetrahydrofuran solution at 20^°C to give the anions [Mn₂(μ-PR₂)(CO)₈]^?, which were isolated as tetraethylammonium salts. Both dimanganese complexes and the related anions were measured by cyclic voltammetry. The treatment of the aforementioned dimanganese complexes in thf solution with Lir' (R =Me, Ph) and subsequently with PPh₃AuCl gave at 20^°C three types of products: Mn₂(μ-PR₂(CO)₈(AuPPh₃),Mn₂(μ-PR₂)(μ-C(R′)O)(CO)₆-(AuPPh₃)₂ and Mn₂(μ-PR₂)(CO)₆(AuPPh₃)₃. The newly prepared substances were characterized by means of IR-, UV/VIS, ³¹P NMR data. The results of single X-ray analyses showed for the three-membered metal ring compound Mn₂(μ-PPh₂)(CO)₈(AuPPh₃) an uni-fold bridged σ(Mn? Mn) bond length of 306.7(3) pm, the metallatetrahedron complex Mn₂(μ-PPh₃)(μ-C(Ph)O(CO)₆(AuPPh₃)₂ a twofold bridged σ(Mn? Mn) bond length of 300.6(4) pm and the trigonal-bipyramidal cluster Mn₂(μ-Pph₂)(CO)₆(AuPPh₃)₃ an uni-fold bridged π(Mn? Mn) bond length of 274.7(3) pm. The Mn? Au bonds of these substances are accompanyied by semi-bridging CO ligands which are signified through short Au…C contact lengths in the range of 251 to 270 pm. In the substance with the Mn₂Au₂ metallatetrahedron core exists, additionally, such a contact with the acylic C atom of C(Ph)O bridging group of 263.4(18) pm. Such contact lengths were compared for corresponding dimanganese and dirhenium complexes.     

Zur Nucleophilie des sterisch anspruchsvollen Basenanions von Lithiumdiisopropylamid beim Protonenersatz gegen das isolobale AuPPh3-Kation in [(μ-H)(μ-PPh2) (CO)8Re2]

Nucleophilic Property of the Bulk Anion of the Base Lithium diisopropylamide at the Proton Exchange vs. the Isolobal AuPPh₃ Cation in [(μ-H) (μ-PPh₂) (CO)₈Re₂] The proton exchange in the starting material [(μ-H)(μ-PPh₂)(CO)₈Re₂] vs. the isolobal [AuPPh₃]⁺ cation when reacted with the steric expansive base LDA depending on reaction temperature leads to the three-membered metal ring substance [(μ-PPh₂)(CO)₈Re₂(AuPPh₃)] or the metallatetrahedron complex [(μ-C-(N i-Prop₂)O)(μ-PPh₂)(CO)₆Re₂(AuPPh₃)₂]. The tetrahedral cluster compound obtained through the nucleophilic property of LDA shows by means of cyclic voltammetry a reversible and a irreversible one-electron transfer redox step. The single crystal X-ray analysis of the compound with a tetrahedral Au₂Re₂ core gives following values of metal-metal bond lengths: Re? Re 312.2(2) pm, Au? Au 270.9(2) pm, and Au? Re 297.7(2) pm. The acyl diisopropylamido groups bridging the Re? Re bond is planar.     

Reaction of [Os3(CO)10(NCMe)2] with amides and aldehydes; X-ray crystal structure of [Os3(CO)10(μ-H)(COCH2Ph)]

Reaction of [OS₃(CO)₁₀(NCMe)₂] with amides and aldehydes has provided a high-yield route to clusters of the type [OS₃(CO)₁₀H(NHCOR)] (R  H, Me, Ph, Et, Pr) and [OS₃(CO)₁₀H(COR)] (R  Me, Ph, CH₂Ph, C₆H₁₃), respectively; the molecular structure of [OS₃(CO)₁₀H(COCH₂Ph)] has been established by a single-crystal X-ray analysis.     

Heterometallatom-Koordinationsverbindungen Re2(μ-PPh2)2[mer-(CO)3]2-trans-[InX2(H2O)]2 und neue halogenhaltige drei- und vierkernige Rheniumcluster aus Reaktionen zwischen Re2[μ-PPh2)2(CO)8] und InX3 (X = Cl,Br, I)

Heterometallic Coordination Compounds Re₂(μ-PPh₂)₂[mer-(CO)₃]₂-trans-[InX₂(H₂O)]₂ and New Halogene Containing Three- and Four-Nuclear Rhenium Clusters from Reactions between Re₂(μ-PPh₂)₂(CO)₈ and InX₃ (X = Cl, Br, I) In sealed glass tubes equimolar amounts of Re₂(μ-PPh₂)₂(CO)₈ and InX₃ (X = Cl, Br, I) were reacted in the presence of xylene at 220°C to two types of products. The first type comprised the heterometallic coordination compounds Re₂(μ-PPh₂)₂(CO)₆[InX₂(H₂O)]₂ (X = Cl, Br, I) (yield 60%), and the second halogene containing rhenium complexes Re₃(μ₃-H)(μ₃-X)(μ-PPh₂)₃(CO)₆ (unsaturated three-membered metal ring with 46 VE) and Re₄(μ-H)(μ-X)(μ-PPh₂)₄(μ₄-PPh)(CO)₈ and additionally those substances as cis-IRe(CO)₄(PPh₂H), Re₂(μ-PPh₂)(μ-X)(CO)₈ (X = Cl, Br), Re₂(μ-I)₂[μ-(PPh₂)₂O](CO)₆ and Re₄(μ-Cl)₂(μ-PPh₂)₄(μ₄-PPh)(CO)₈ (four-membered metal ring with 66 VE with three Re? Re bonds) which have been observed in one or two of the three reaction systems. A proposal of the reaction course is discussed. The single X-ray analysis of Re₂(μ-PPh₂)₂[mer(CO)₃]₂-trans[InI₂(H₂O)]₂ · 2 Me₂CO shows for the two fold phosphido bridged dirhenium molecular fragment with 34 VE a Re? Re bond of 294.6(1) pm. From two possible transpositions of both In? Re bond vectors, the one found advantageously has sterical reasons. The average In? Re single bond length is 271.1(1) pm. The corresponding determination of the unsaturated three-membered ring compound Re₃(μ₃-H) (μ₃-Cl)(μ-PPh₂)₃(CO)₆ showed three Re? Re bond lenghts of comparable size, of which the mean value of 281.9(1) pm was significantly shortened by π electron delocalization effect compared to that of a saturated phosphido bridged three-membered rhenium ring compound. As it was recognized by further comparison, the structural data of the common molecular fragments in the three examined three-membered rhenium ring clusters (X = Cl, Br, I) are not dependent on the different kind of halogeno ligand atoms. Finally, the crystal structure determination of the substance Re₄(μ-H)(μ-Br)(μ-PPh₂)₄(μ₄-PPh)(CO)₈ shows the presence of square-pyramidal Re₄(μ₄-P) atomic arrangement, of which the planar basic plane has a sequence of up- and downwards orientated four diphenylphosphido bridging groups. The four measured Re? Re single bond lengths (mean value 302.7(3) pm change with the different kind of bridging atoms. The structural features observed are compared with those of a corresponding iodine derivative.     

Darstellung von μ-Hydrido-μ-diphenylphosphido-bis(tetracarbonylrhenium) · 1/2 Xylol und Molekülstruktur des Derivates Re2(CO)6(PPh3)2(μ-H)(μ-PPh2) (Ph = C6H5)

Preparation of μ-Hydrido-μ-diphenylphosphido-bis(tetracarbonylrhenium) · 1/2 Xylene and Molecular Structure of the Derivative Re₂(CO)₆(PPh₃)₂(μ-H)(μ-PPh₂) (Ph = C₆H₅) The reaction of dirhenium decacarbonyl with diphenylphosphine in xylene solution gave at 190–200°C in a glas tube crystals of Re₂(CO)₈(μ-H)(μ-PPh₂) · 1/2 C₈H₁₀. The obtained adduct was reacted in the same solvent with an excess of triphenylphosphine to the derivative Re₂(CO)₆(PPh₃)₂(μ-H)(μ-PPh₂). Both diamagnetic dirhenium compounds with μ-H atom and μ-PPh₂ group were characterized by ¹H and ³¹P spectroscopic measurements. The molecular structure of the derivative was acertained by a single crystal X-ray analysis. Its result showed a three-membered Re₂(μ-P) ring as central molecular fragment. At these Re central atoms were attached two PPh₃ ligands in an unprefered cis-arrangement due to sterical reasons. A thermodynamic transinfluence of the (μ-P)? Re bond favoured the found positions of the PPh₃ ligands.     

Zur Selektivität des isolobalen Protonenaustausches im Hydrido/Phosphidoverbrückten Dirhenium-Komplex Re2(μ-H)(μ-PCyH)(CO)8

On the Selectivity of the Isolobal Proton Exchange in the Hydrido/Phsophido Bridged Dirhenium Complex Re₂(μ-H)(μ-PCyH)(CO)₈ H₂PCy and Re₂(CO)₁₀ in Xylene were heated in a sealed glass tube at 170°C for 18 h to afford Re₂(μ-H)(μ-PCyH)(CO)₈ in a yield of 30% and the cis/trans isomer pair Re₂(μ-PCyH)₂(CO)₈ in yields of 27% (trans) and 21% (cis). The isomer trans Re₂(μ-PCyH)₂(CO)₈ could be partially converted to the cis isomer by deprotonation with the non nucleophilic base DBU or by heating in xylene solution. The complex Re₂(μ-H)(μ-PCyH)(CO)₈ which is bifunctional relative to a proton abstraction was treated with equimolar amounts of DBU to generate [Re₂(μ-H)(μ-PCy)(CO)₈]^? under release of the more acidic proton from the PH group. Subsequently, this anion undergoes an isomerization to the thermodynamically more stable [Re₂(μ-PCyH)(CO)₈]^? by proton transfer. Such knowledge about the isomeric anions enabled us to synthesize selectively the monoaurated isomers Re₂(μ-AuPPh₃)(μ-PCyH)(CO)₈ and Re₂(μ-H)(μ₃-PCy(AuPPh₃))(CO)₈ in good yields by reaction with equimolar amounts of the electrophil ClAuPPh₃. In the presence of excess DBU and a twofold amount of ClAuPPh₃ the complex Re₂(μ-H)(μ-PCyH) · (CO)₈ formed the diaurated complex Re₂(μ-AuPPh₃)(μ₃-PCy(AuPPh₃))(CO)₈ (91%). Compared to the corresponding known dimanganese-gold isomers, each of the analogous dirhenium-gold complexes obtained showed no tendency for an isomerization process. Finally, the single crystal X-ray analyses of the three dirhenium-gold complexes led to the subsequent Re? Re bond lengths: 313,6(1) pm in Re₂(μ-H)(μ₃-PCy(AuPPh₃))(CO)₈, 316,8(2) pm in Re₂(μ-AuPPh₃)(μ₃PCy(AuPPh₃))(CO)₈ and 326,1(2) pm in Re₂(μ-AuPPh₃)(μ-PCyH)(CO)₈.     

Synthesis,Structure, and Reactivity of Hydridoiridium Complexes Bearing a Pincer‐Type PSiP Ligand

A series of iridium tetrahydride complexes [Ir(H)₄(PSiP‐R)] bearing a tridentate pincer‐type bis(phosphino)silyl ligand ([{2‐(R₂P)C₆H₄}₂MeSi]⁻, PSiP‐R, R=Cy, iPr, or tBu) were synthesized by the reduction of [IrCl(H)(PSiP‐R)] with Me₄N ⋅ BH₄ under argon. The same reaction under a nitrogen atmosphere afforded a rare example of thermally stable iridium(III)–dinitrogen complexes, [Ir(H)₂(N₂)(PSiP‐R)]. Two isomeric dinitrogen complexes were produced, in which the PSiP ligand coordinated to the iridium center in meridional and facial orientations, respectively. Attempted substitution of the dinitrogen ligand in [Ir(H)₂(N₂)(PSiP‐Cy)] with PMe₃ required heating at 150 °C to give the expected [Ir(H)₂(PMe₃)(PSiP‐Cy)] and a trigonal bipyramidal iridium(I)–dinitrogen complex, [Ir(N₂)(PMe₃)(PSiP‐Cy)]. The reaction of [Ir(H)₄(PSiP‐Cy)] with three equivalents of 2‐norbornene (nbe) in benzene afforded [Ir^I(nbe)(PSiP‐Cy)] in a high yield, while a similar reaction of [Ir(H)₄(PSiP‐R)] with an excess of 3,3‐dimethylbutene (tbe) in benzene gave the C H bond activation product, [Ir^III(H)(Ph)(PSiP‐R)], in high yield. The oxidative addition of benzene is reversible; heating [Ir^III(H)(Ph)(PSiP‐Cy)] in the presence of PPh₃ in benzene resulted in reductive elimination of benzene, coordination of PPh₃, and activation of the C H bond of one aromatic ring in PPh₃. [Ir^III(H)(Ph)(PSiP‐R)] catalyzed a direct borylation reaction of the benzene C H bond with bis(pinacolato)diboron. Molecular structures of most of the new complexes in this study were determined by a single‐crystal X‐ray analysis.     

Reactions of triosmium clusters with organic azides; x-ray crystal structures of [Os3(CO)10(NCMe)(N3COPh)], [Os3(μ-H)(CO)10(HN3Ph)], and [Os3(μ-H)2(CO)9(μ3-NPh)]

Organic azides [N₃R] react with [Os₃(CO)₁₁(NCMe)] and with [Os₃(μ-H)₂(CO)₁₀] to form [Os₃(CO)₁₀(NCMe)(N₃COR)] (R  Ph) and [Os₃(μ-H)(CO)₁₀(HN₃R)] (R  Ph, n-Bu, CH₂Ph, cyclo-C₆H₁₁), respectively; the latter may be converted to [Os₃(μ-H)₂(CO)₉(μ₃-NR)] by thermolysis; the molecular structure of the phenyl derivative of each class of compound has been confirmed by x-ray analysis.     

Reactions of the dirhenium(II) complexes Re2X4(dppm)2 (X= Cl,Br; dppm = Ph2PCH2PPh2) with isocyanides. Part IX. New isomeric forms of the mixed carbonyl-isocyanide dirhenium(II) Complexes Re2 Cl4(dppm)2(CO)(CNxyl) and [Re2Cl3(dppm)2(CO)(CNxyl)2]O3SCF3 The X-ray crystal structure of [(xyl NC)2ClRe(μ-dppm)2ReCl2(CO)] O3SCF3

The monocarbonyl complex Re₂Cl₄(µ-dppm)₂(CO) reacts with xylyl isocyanide in acetonitrile to afford the bioctahedral complex (CO)Cl₂Re(µ-dppm)₂ ReCl₂(CNxyl), 2b. This is a different structural isomer from the edge-sharing bioctahedral complex Cl₂Re(µ-Cl)(µ-dppm)₂ReCl(CNxyl) or this same stoichiometry which A formed when acetone is be reaction solvent. The complex2b reacts with a further equivalent of xylNC in the presence of TlO₃SCF₃ in dichloromethane to form a red complex of composition [Re₂Cl₃(µ-dppm)₂ (CO)(CNxyl)₂]O₃SCF₃. 3, which has the open bioctahedral structure [(xylNC)₂ClRe(µ-dppm)₂ReCl₂(CO)]O₃SCF₃. This is a third isomeric form of this dirhenium cation: the previously isolated green and yellow forms have edge-sharing bioctahedral structures. Crystal data for3 at 295 K: orthorhombic space group Pbca (No. 61) witha=22.654(5) Å,b=22.717(4) Å,c=27.324(4) A,V= 14061(7) ų, andZ = 8. The structure was refined to R = 0.059 (R, = 0.134 ) for 14164 data. The Re-Re distance is 2.3833(8) Å.     

New triosmium metal clusters derived from the reactions between [Os3(CO)10(NCMe)2] and amides

Triosmium clusters of the type [Os₃(CO)₁₀(μ-H)(NHCOR)] (1; R = H, Me, Ph, Et or Pr) are formed in high yields form the reaction of [Os₃(CO)₁₀(NCMe)₂] (2) with amides. The nature of the products formed from thermolysis of 1 depend on the group, R.     

Penta­chloro‐1,3,6‐tris­(diethyl­phenyl­phosphino)­dirhenium(II,III)

The title complex [systematic name: penta­chloro‐1κ³Cl,2κ²Cl‐tris(diethylphenylphosphino)‐1κP,2κ²P‐dirhenium(II,III)(Re—Re)], 1,3,6‐Re₂Cl₅(PEt₂Ph)₃ or [Re₂Cl₅(C₁₀H₁₅P)₃], consists of dirhenium mol­ecules with eclipsed structures similar to those of previously characterized 1,3,6‐Re₂Cl₅(PR₃)₃ compounds. The Re—Re bond distance is 2.2262 (3) Å and the metal–metal bond order is 3.5.     

New Mixed‐Metal Carbonyl Complexes Containing Bridging 2‐Mercapto‐1‐methylimidazole Ligand

Reaction of [Mn₂(CO)₁₀] with 2‐mercapto‐1‐methylimidazole in the presence of Me₃NO at 25 °C afforded two new dimanganese complexes [Mn₂(CO)₆(μ‐SN₂C₄H₅)₂] ( 1 ) and [Mn₂(CO)₇(μ‐SN₂C₄H₅)₂] ( 2 ). Compound 1 consists of two μ‐SN₂C₄H₅ ligands, each bound through the sulfur atom to two Mn atoms and through the nitrogen atom to one Mn atom forming a four‐membered chelate ring. Compound 2 was found to consist of one μ‐SN₂C₄H₅ ligand in a similar bonding mode to 1 but another μ‐SN₂C₄H₅ ligand coordinates through the sulfur atom to one Mn atom and through the nitrogen atom to another Mn atom. Compound 1 was also obtained as the only product from the reaction of [Mn₂(CO)₈(NCMe)₂] with 2‐mercapto‐1‐methylimidazole. In contrast, a similar reaction of [Re₂(CO)₈(NCMe)₂] with 2‐mercapto‐1‐methylimidazole led to the formation of the di‐, tri‐, and tetranuclear complexes [Re₃(CO)₈(μ‐CO)(μ₃‐SN₂C₄H₅)₂(μ‐H)] ( 3 ), [Re₄(CO)₁₂(μ‐SN₂C₄H₅)₄] ( 4 ), and [Re₂(CO)₆(μ‐SN₂C₄H₅)₂] ( 5 ). Compound 3 provides a unique example of a hydrido trirhenium compound. The reaction of [Cr(CO)₃(NCMe)₃] and [Mo(CO)₃(NCMe)₃] with 1 in refluxing THF afforded the mixed metal complexes [CrMn₂(CO)₈(μ‐CO)₂(μ₃‐SN₂C₄H₅)₂] ( 6 ) and [MoMn₂(CO)₈(μ‐CO)₂(μ₃‐SN₂C₄H₅)₂] ( 7 ), respectively, in which two Mn–M (M = Mo, Cr) bonds were formed. In contrast, a similar treatment of [W(CO)₃(NCMe)₃] with 1 yielded two W‐Mn complexes [Mn₂W(CO)₈(μ‐CO)₂(μ₃‐SN₂C₄H₅)₂] ( 8 ) and [Mn₂W(CO)₇(μ‐CO)₂(SN₂C₄H₅)(μ₃‐SN₂C₄H₅)₂] ( 9 ). Treatment of 1 with [Fe₃(CO)₁₂] at 70‐75 °C afforded the trinuclear mixed‐metal complex [FeMn₂(CO)₈(μ‐CO)(μ₃‐SN₂C₄H₅)₂] ( 10 ) and the diiron side product [Fe₂(CO)₆(μ‐S₂N₂C₄H₅)₂] ( 11 ). Compounds 6 ‐ 10 have a bent open structure of three metal atoms linked by two metal‐metal bonds and all, except 9 and 10 , contain a noncrystallographic two‐fold axis of symmetry. Compound 9 is structurally similar to 8 , but it contains a SN₂C₄H₆ ligand, mono coordinated through the exocyclic sulfur atom to the W atom and a Mn–Mn bond instead of a Mn–W bond. Compound 11 comprises two bridging S₂N₂C₄H₅ ligands, which arise from the coupling of 2‐mercapto‐1‐methylimidazole with sulfur.     

Synthesis of new heterometallic complexes by tin-sulfur bond cleavage of pySSnPh3 (pySH = pyridine-2-thiol) at triruthenium and triosmium centres

The ruthenium-tin complex, [Ru₂(CO)₄(SnPh₃)₂(μ-pyS)₂] (1), the main product of the oxidative-addition of pySSnPh₃ to Ru₃(CO)₁₂ in refluxing benzene, is [Ru(CO)₂(pyS)(SnPh₃)] synthon. It reacts with PPh₃ to give [Ru(CO)₂(SnPh₃)(PPh₃)(κ²-pyS)] (2) and further with Ru₃(CO)₁₂ or [Os₃(CO)₁₀(NCMe)₂] to afford the butterfly clusters [MRu₃(CO)₁₂(SnPh₃)(μ₃-pyS)] (3, M=Ru; 4, M=Os). Direct addition of pySSnPh₃ to [Os₃(CO)₁₀(NCMe)₂] at 70 °C gives [Os₃(CO)₉(SnPh₃)(μ₃-pyS)] (5) as the only bimetallic compound, while with unsaturated [Os₃(CO)₈{μ₃-PPh₂CH₂P(Ph)C₆H₄}(μ-H)] the previously reported [Os₃(CO)₈(μ-pyS)(μ-H)(μ-dppm)] (6) and the new bimetallic cluster [Os₃(CO)₇(SnPh₃){μ-Ph₂PCH₂P(Ph)C₆H₄}(μ-pyS)[(μ-H)] (7) are formed at 110 °C. Compounds 1, 2, 4, 5 and 7 have been characterized by X-ray diffraction studies.     

Syntheses of some mixed AuOs and PtOs clusters and the X-ray structure of [Os4H2(CO)12(AuPPh3)2]

Some reactions of [Os₄H₃(CO)₁₂AuPR₃] (R = Et, Ph) resulting in the formation of [Os₄H₂(CO)₁₂(AuPR₃)₂] are presented. A single-crystal X-ray structure of [Os₄H₂(CO)₁₂(AuPPh₃)₂] is reported and reveals a novel Ph₃PAuAuPPh₃ unit asymmetrically bridging one edge of an Os₄ tetrahedron, the first example of a mixed gold-metal carbonyl cluster with an AuAu bond.     

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.     

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.