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.     

Koordinativ ungesättigte Dirutheniumkomplexe: Synthese und Kristallstrukturen von [Ru2(CO)3L(μ‐η1 : η2‐C≡CPh)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] (L = CO,PnBu3)

Coordinatively Unsaturated Diruthenium Complexes: Synthesis and X‐ray Crystal Structures of [Ru₂(CO)₃L(μ‐η¹ : η²‐C≡CPh)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] (L = CO, PⁿBu₃) [Ru₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 1 ) reacts with several phosphines (L) in refluxing toluene under substitution of one carbonyl ligand and yields the compounds [Ru₂(CO)₃L(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] (L = PⁿBu₃, 2 a ; L = PCy₂H, 2 b ; L = dppm‐P, 2 c ; dppm = Ph₂PCH₂PPh₂). The reactivity of 1 as well as the activated complexes 2 a – c towards phenylethyne was studied. Thus 1 , 2 a and 2 b , respectively, react with PhC≡CH in refluxing toluene with elimination of dihydrogen to the acetylide‐bridged complexes [Ru₂(CO)₄(μ‐η¹ : η²‐C≡CPh)(μ‐P^tBu₂)(μ‐dppm)] ( 3 ) and [Ru₂(CO)₃L(μ‐η¹ : η²‐C≡CPh)(μ‐P^tBu₂)(μ‐dppm)] ( 4 a and 4 b ). The molecular structures of 3 and 4 a were determined by crystal structure analyses.     

Zur Darstellung phosphido‐chalkogenido‐verbrückter Dirheniumkomplexe vom Typ Re2(μ‐PCy2)(μ‐ER)(CO)8 (E = S,Se, Te; R = org. Rest)

Synthesis of Phosphido Chalcogenido Bridged Dirhenium Complexes of the Type Re₂(μ‐PCy₂)(μ‐ER)(CO)₈ (E = S, Se, Te; R = org. Residue) The reaction of Re₂(μ‐Br)(μ‐PCy₂)(CO)₈ with nucleophiles MER (M = Na, Li; E = S, Se, Te; R = org. residue) gives via substitution of the bromido bridge phosphido chalcogenido bridged dirhenium complexes of the general formula Re₂(μ‐PCy₂)(μ‐ER)(CO)₈. The new compounds were characterized by IR, ¹H and ¹³C NMR spectroscopic data and by elemental analyses. In addition the molecular structures for E = S, Se, Te and R = Ph as well as for E = S and R = H, n‐Bu, 2‐pyridyl have been established by single crystal X‐ray analysis. ¹³C NMR spectra of Re₂(μ‐PCy₂)(μ‐EPh)(CO)₈ (E = S, Se, Te) prove that the sulfur and selenium compounds are at room temperature dynamic molecules due to inversion of the pyramidal chalcogenido bridge. The tellurium compound, however, is rigid on the time scale of ¹³C NMR spectroscopy. Eventually the reactivity of the SH function of the novel complex Re₂(μ‐PCy₂)(μ‐SH)(CO)₈ was investigated by reaction with Re₂(CO)₈(MeCN)₂. In toluene at 90 °C the novel spirocyclic complex Re₂(μ‐PCy₂)(CO)₈(μ₄‐S)Re₂(μ‐H)(CO)₈ was formed by SH oxidative addition.     

Aktivierung von Schwefelkohlenstoff an Trirutheniumclustern: Synthese und Kristallstruktur von [Ru3(CO)5(μ‐H)2(μ‐PCy2)(μ‐Ph2PCH2PPh2){μ‐η2‐PCy2C(S)}(μ3‐S)] und [Ru3(CO)5(CS)(μ‐H)(μ‐PtBu2)(μ‐PCy2)2(μ3‐S)]

Activation of Carbon Disulfide on Triruthenium Clusters: Synthesis and X‐Ray Crystal Structure Analysis of [Ru₃(CO)₅(μ‐H)₂(μ‐PCy₂)(μ‐Ph₂PCH₂PPh₂){μ‐η²‐PCy₂C(S)}(μ₃‐S)] and [Ru₃(CO)₅(CS)(μ‐H)(μ‐P^tBu₂)(μ‐PCy₂)₂(μ₃‐S)] [Ru₃(CO)₆(μ‐H)₂(μ‐PCy₂)₂(μ‐dppm)] ( 1 ) (dppm = Ph₂PCH₂PPh₂) reacts under mild conditions with CS₂ and yields by oxidative decarbonylation and insertion of CS into one phosphido bridge the opened 50 VE‐cluster [Ru₃(CO)₅(μ‐H)₂(μ‐PCy₂)(μ‐dppm){μ‐η²‐PCy₂C(S)}(μ₃‐S)] ( 2 ) with only two M–M bonds. The compound 2 crystallizes in the triclinic space group P 1 with a = 19.093(3), b = 12.2883(12), c = 20.098(3) Å; α = 84.65(3), β = 77.21(3), γ = 81.87(3)° and V = 2790.7(11) ų. The reaction of [Ru₃(CO)₇(μ‐H)(μ‐P^tBu₂)(μ‐PCy₂)₂] ( 3 ) with CS₂ in refluxing toluene affords the 50 VE‐cluster [Ru₃(CO)₅(CS)(μ‐H)(μ‐P^tBu₂)(μ‐PCy₂)₂(μ₃‐S)] ( 4 ). The compound cristallizes in the monoclinic space group P 2₁/a with a = 19.093(3), b = 12.2883(12), c = 20.098(3) Å; β = 104.223(16)° and V = 4570.9(10) ų. Although in the solid state structure one elongated Ru–Ru bond has been found the complex 4 can be considered by means of the ³¹P‐NMR data as an electron‐rich metal cluster.     

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.     

Clusterkomplexe [M2Rh(μ‐PCy2)(μ‐CO)2(CO)8] mit triangularem Metallgerüst RhM2 (M = Mn,Re; M2 = MnRe): Synthese,Struktur, Ringöffnungen und Katalysatoreigenschaften für die Isomerisierung und Hydroformylierung von 1‐Hexen

Cluster Complexes [M₂Rh(μ‐PCy₂)(μ‐CO)₂(CO)₈] with Triangular Core of RhM₂ (M = Re, Mn; M₂ = MnRe): Synthesis, Structure, Ring Opening Reaction, and Properties as Catalysts for Hydroformylation and Isomerisation of 1‐Hexene The salts PPh₄[M₂(μ‐H)(μ‐PCy₂)(CO)₈] and Rh(COD)[ClO₄] were in equimolar amounts reacted at –40 to –15 °C in the presence of CO_(g) in CH₂Cl₂/methanol solution under release of PPh₄[ClO₄] to intermediates. Such species formed in a selective reaction the unifold unsaturated 46 valence electrons title compounds [M₂Rh(μ‐PCy₂)(μ‐CO)₂(CO)₈] (M = Re 1 , Mn 2 ; M₂ = MnRe 3 ) in yields of > 90%; analogeous the derivatives with the PPh₂ bridge could the obtained (M = Re 4 , Mn 5 ). From these clusters the molecular structure of 2 was determined by a single crystal X‐ray analysis. The exchange of the labil CO ligand attached at the rhodium ring atom in 1 – 3 against selected tertiary and secondary phosphanes in solution gave the substitution products [M₂RhL(μ‐PCy₂)(μ‐CO)₂(CO)₇] (M = Re: L = PMe₃ 6 , P(n‐Bu)₃ 7 , P(n‐C₆H₄SO₃Na)₃ 8 , HPCy₂ 9 , HPPh₂ 10 , HPMen₂ 11 , M₂ = MnRe: L = HPCy₂ 12 ) nearly quantitative. Such dimanganese rhodium intermediates ligated with secondary phosphanes were converted in a subsequent reaction to the ring‐opened complexes [MnRh(μ‐PCy₂)(μ‐H)(CO)₅Mn(μ‐PR₂)(CO)₄] (M = Mn: R = Cy 13 , Ph 14 , Mn 15 ). The molecular structure of 13 , which showed in the time scale of the ³¹P NMR method a fluxional behaviour, was determined by X‐ray structure analysis. All products obtained were always characterized by means of υ(CO)Ir, ¹H and ³¹P NMR measurements. From the reactants of hydroformylation process, CO_(g) 1 – 2 in different solvents afforded at 20 °C under a reversible ring opening reaction the valence‐saturated complexes [MRh(μ‐PCy₂)(CO)₇M(CO)₅] (M = Re 16 , Mn 17 ), whereas the reaction of CO_(g) and the ring‐opened 13 to [MnRh(μ‐PCy₂)(μ‐H)(CO)₆Mn(μ‐PCy₂)(CO)₄] ( 18 ) was as well reversible. The molecular structures of 17 and 18 were determined by X‐ray analysis. The υ(CO)IR, ¹H and ³¹P NMR measurements in pressure‐resistant reaction vessels at 20 °C ascertained the heterolytic splitting of hydrogen in the reaction of 1 – 2 dissolved in CDCl₃ or THF‐d₈ under formation of product monoanions [M₂Rh(μ‐CO)(μ‐H)(μ‐PCy₂)(CO)₉]^– (M = Re, Mn), which also were formed by the reaction of NaBH₄ and 1 – 2 . Finally, the substrate 1‐hexene and 1 and 3 gave under the release of the labil CO ligand an η²‐coordination pattern of hexene, which was weekened going from the Re to the Mn neighbor atoms. After the results of the catalytic experiments with 1 and 2 as catalysts, such change in the bonding property revealed an advantageous formation of hydroformylation products for the dirhenium rhodium catalyst 1 and that of isomerisation products of hexene for the dimanganese rhodium catalyst 2 . Par example, 1 generated n‐heptanal/2‐methylhexanal in TOF values of 246 [h^–1] (n/iso = 3.4) and the c,t‐hexenes in that of 241 [h^–1]. Opposotite to this, 2 achieved such values of 55 [h^–1] (n/iso = 3.6) and 473 [h^–1]. A triphenylphosphane substitution product of 1 increased the activity of the hydroformylation reaction about 20%, accompanied by an only gradually improved selectivity. The hydrogenation products like alcohols and saturated hydrocarbons known from industrial hydroformylation processes were not observed. The metals manganese and rhenium bound at the rhodium reaction center showed a cooperative effect.     

Dithiolene transfer from nickel to a dimolybdenum centre: the first dithiolene alkyne complex

Transfer of dithiolene ligands from [Ni(S₂C₂Ph₂)₂] to the dimolybdenum complex [Mo₂(μ-C₂R₂)(CO)₄Cp₂] (R=CO₂Me, Cp=η-C₅H₅) affords the first example of a dithiolene alkyne complex, [Mo₂(μ-C₂R₂)(μ-S₂C₂Ph₂)₂Cp₂], together with [Mo₂(μ-SCRCR)(μ-SCPhCPh)Cp₂] in which sulfur transfer from dithiolene to alkyne has occurred.     

Koordinativ ungesättigte Dirutheniumkomplexe: Synthese und Kristallstrukturen von [Ru2(CO)4(μ‐H)(μ‐S)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] und [Ru2(CO)4(μ‐X)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] (X = Cl,S2CH)

Coordinatively Unsaturated Diruthenium Complexes: Synthesis and X‐Ray Crystal Structures of [Ru₂(CO)₄(μ‐H)(μ‐S)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)], [Ru₂(CO)₄(μ‐X)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] (X = Cl, S₂CH) [Ru₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 1 ) reacts in benzene with elemental sulfur to the addition product [Ru₂(CO)₄(μ‐H)(μ‐S)(μ‐P^tBu₂)(μ‐dppm)] ( 2 ) (dppm = Ph₂PCH₂PPh₂). 2 is also obtained by reaction of 1 with ethylene sulfide. The reaction of 1 with carbon disulfide yields with insertion of the CS₂ into the Ru₂(μ‐H) bridge the dithioformato complex [Ru₂(CO)₄(μ‐S₂CH)(μ‐P^tBu₂)(μ‐dppm)] ( 3 ). Furthermore, 1 reacts with [NO][BF₄] to the complex salt [Ru₂(CO)₄(μ‐NO)(μ‐H)(μ‐P^tBu₂)(μ‐dppm)][BF₄] ( 4 ), and reaction of 1 with CCl₄ or CHCl₃ affords spontaneously [Ru₂(CO)₄(μ‐Cl)(μ‐P^tBu₂)(μ‐dppm)] ( 5 ) in nearly quantitative yield. The molecular structures of 2 , 3 and 5 were confirmed by crystal structure analyses.     

Koordinativ ungesättigte Dirutheniumkomplexe: Synthese und Kristallstrukturen von [Ru2(CO)n(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] (n = 4; 5) und [Ru2(CO)4(μ‐CH2)(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)]

Coordinatively Unsaturated Diruthenium Complexes: Synthesis and X‐ray Crystal Structures of [Ru₂(CO)_n(μ‐H)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] (n = 4; 5) and [Ru₂(CO)₄(μ‐CH₂)(μ‐H)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] The reaction of [Ru₂(μ‐CO)(CO)₅(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] ( 2 ) with dppm yields the dinuclear species [Ru₂(μ‐CO)(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 3 ) (dppm = Ph₂PCH₂PPh₂). Under thermal or photolytic conditions 3 loses very easily one carbonyl ligand and affords the corresponding electronically and coordinatively unsaturated complex [Ru₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 4 ). 4 is also obtainable by an one‐pot synthesis from [Ru₃(CO)₁₂], an excess of ^tBu₂PH and stoichiometric amounts of dppm via the formation of [Ru₂(CO)₄(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)₂] ( 1 ). 4 exhibits a Ru–Ru double bond which could be confirmed by addition of methylene to the dimetallacyclopropane [Ru₂(CO)₄(μ‐CH₂)(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 5 ). The molecular structures of 3 , 4 and 5 were determined by X‐ray crystal structure analyses.     

Molybdän‐ und Wolfram‐Komplexe mit MNS‐Sequenzen. Die Kristallstrukturen von [MoCl3(N3S2)(1,4‐Dioxan)2] und [Mo2Cl2(μ‐NSN)2(μ‐O)(NCMe3)(OCMe3)2]2

Molybdenum and Tungsten Complexes with MNS Sequences. Crystal Structures of [MoCl₃(N₃S₂)(1,4‐dioxane)₂] and [Mo₂Cl₂(μ‐NSN)₂(μ‐O)(NCMe₃)(OCMe₃)₂]₂ The cyclo‐thiazeno complexes [Cl₃MNSNSN]₂ of molybdenum and tungsten react with 1,4‐dioxane in dichloromethane suspension to give the binuclear donor‐acceptor complexes [μ‐(1,4‐dioxane){MCl₃(N₃S₂)}₂] which are characterized by IR spectroscopy. With excess 1,4‐dioxane the molybdenum compound forms the complex [MoCl₃(N₃S₂)(1,4‐dioxane)₂] in which, according to the crystal structure determination, one of the dioxane molecules coordinates at the molybdenum atom, the other one at one of the sulfur atoms of the cyclo‐thiazeno ring. The μ‐(NSN^2–) complex [Mo₂Cl₂(μ‐NSN)₂(μ‐O)(NCMe₃)(OCMe₃)₂]₂ has been obtained by the reaction of [MoN(OCMe₃)₃] with trithiazyle chloride in carbontetrachloride solution. According to the crystal structure determination this compound forms centrosymmetric dimeric molecules via two of the nitrogen atoms of two of the μ‐(NSN) groups to give a Mo₂N₂ fourmembered ring. [MoCl₃(N₃S₂)(1,4‐dioxane)₂]: Space group P2₁/c, Z = 4, lattice dimensions at –70 °C: a = 1522.9(2); b = 990.3(1); c = 1161.7(1) pm; β = 106.31(1)°, R₁ = 0.0317. [Mo₂Cl₂(μ‐NSN)₂(μ‐O)(NCMe₃)(OCMe₃)₂]₂ · 4 CCl₄: Space group P2₁/c, Z = 2, lattice dimensions at –83 °C: a = 1216.7(1); b = 2193.1(2); c = 1321.8(1) pm; β = 98.23(1)°; R₁ = 0.0507.     

Aktivierung von Schwefelkohlenstoff an Trirutheniumclustern: Synthese und Kristallstruktur von [Ru3(CO)4(μ‐PCy2)2(μ‐Ph2PCH2PPh2)(μ3‐S){μ3‐η2‐CSC(S)S}]

Activation of Carbon Disulfide on Triruthenium Clusters: Synthesis and X‐Ray Crystal Structure Analysis of [Ru₃(CO)₄(μ‐PCy₂)₂(μ‐Ph₂PCH₂PPh₂)(μ₃‐S){μ₃‐η²‐CSC(S)S}] [Ru₃(CO)₄(μ‐H)₃(μ‐PCy₂)₃(μ‐dppm)] ( 2 ) (dppm = Ph₂PCH₂PPh₂) reacts with CS₂ at room temperature and yields the open 50 valence electron cluster [Ru₃(CO)₄(μ‐PCy₂)₂(μ‐dppm)(μ₃‐S){μ₃‐η²‐CSC(S)S}] ( 3 ) containing the unusual μ₃‐η²‐C₂S₃ mercaptocarbyne ligand. Compound 3 was characterized by single crystal X‐ray structure analysis.     

[Fe2(μsb‐CO)(CO)3(NO)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)]: Synthese,Kristallstruktur und Koordinationsisomerie

[Fe₂(μ_sb‐CO)(CO)₃(NO)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)]: Synthesis, X‐ray Crystal Structure and Isomerization Na[Fe₂(μ‐CO)(CO)₆(μ‐P^tBu₂)] ( 1 ) reacts with [NO][BF₄] at —60 °C in THF to the nitrosyl complex [Fe₂(CO)₆(NO)(μ‐P^tBu₂)] ( 2 ). The subsequent reaction of 2 with phosphanes (L) under mild conditions affords the complexes [Fe₂(CO)₅(NO)L(μ‐P^tBu₂)], L = PPh₃, ( 3a ); η‐dppm (dppm = Ph₂PCH₂PPh₂), ( 3b ). In this case the phosphane substitutes one carbonyl ligand at the iron tetracarbonyl fragment in 2 , which was confirmed by the X‐ray crystal structure analysis of 3a . In solution 3b loses one CO ligand very easily to give dppm as bridging ligand on the Fe‐Fe bond. The thus formed compound [Fe₂(CO)₄(NO)(μ‐P^tBu₂)(μ‐dppm)] ( 4 ) occurs in solution in different solvents and over a wide temperature range as a mixture of the two isomers [Fe₂(μ_sb‐CO)(CO)₃(NO)(μ‐P^tBu₂)(μ‐dppm)] ( 4a ) and [Fe₂(CO)₄(μ‐NO)(μ‐P^tBu₂)(μ‐dppm)] ( 4b ). 4a was unambiguously characterized by single‐crystal X‐ray structure analysis while 4b was confirmed both by NMR investigations in solution as well as by means of DFT calculations. Furthermore, the spontaneous reaction of [Fe₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 5 ) with NO at —60 °C in toluene yields a complicated mixture of products containing [Fe₂(μ‐CO)(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 6 ) as main product beside the isomers 4a and 4b occuring in very low yields.     

Reduktive Dimerisierung von NO an Dirutheniumkomplexen und Bildung eines tridentaten 2, 2‐Bis(diphenylphosphanyl)ethanolato‐Liganden

The reaction of the trans‐hyponitrito complex [Ru₂(CO)₄(μ‐η²‐ONNO)(μ‐H)(μ‐PtBu₂)(μ‐dppen)] ( 1 , dppen = Ph₂PC(=CH₂)PPh₂) with tetrafluorido boric acid afforded the new complex salt [Ru₂(CO)₄(μ‐η²‐ONNOH)(μ‐H)(μ‐PtBu₂)(μ‐dppen)]BF₄ ( 2 ) containing the monoprotonate hyponitrous acid as the ligand in the cationic complex. Complex 1 showed a nucleophilic reactivity towards the trimethyloxonium cation resulting in the monoester derivative of the hyponitrous acid [Ru₂(CO)₄(μ‐η²‐ONNOMe)(μ‐H)(μ‐PtBu₂)(μ‐dppen)]BF₄ ( 3 ). During heating of compound 2 in ethanol under reflux for a short time nitrous oxide was liberated affording unexpectedly a new tridentate 2, 2‐bis(diphenylphosphanyl)ethanolato ligand formed by an intramolecular attack of an intermediate hydroxido ligand towards the unsaturated carbon carbon double bond in the bridging dppen ligand. Thus the complex salt [Ru₂(CO)₄{μ‐η³‐OCH₂CH(PPh₂)₂}(μ‐H)(μ‐PtBu₂)]BF₄ ( 4 ) was formed in good yields. The new compounds 2 , 3 , and 4 were characterized by spectroscopic means as well as their molecular structures were determined in the crystal.     

Koordinativ ungesättigte Dieisenkomplexe: Synthese und Kristallstrukturen von [Fe2(CO)4(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] und [Fe2(CO)4(μ‐CH2)(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)]

Coordinatively Unsaturated Diiron Complexes: Synthesis and Crystal Structures of [Fe₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] and [Fe₂(CO)₄(μ‐CH₂)(μ‐H)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] [Fe₂(μ‐CO)(CO)₆(μ‐H)(μ‐P^tBu₂)] ( 1 ) reacts spontaneously with dppm (dppm = Ph₂PCH₂PPh₂) to give [Fe₂(μ‐CO)(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 2 c ). By thermolysis or photolysis, 2 c loses very easily one carbonyl ligand and yields the corresponding electronically and coordinatively unsaturated complex [Fe₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 3 ). 3 exhibits a Fe–Fe double bond which could be confirmed by the addition of methylene to the corresponding dimetallacyclopropane [Fe₂(CO)₄(μ‐CH₂)(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 4 ). The reaction of 1 with dppe (Ph₂PC₂H₄PPh₂) affords [Fe₂(μ‐CO)(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppe)] ( 5 ). In contrast to the thermolysis of 2 c , yielding 3 , the heating of 5 in toluene leads rapidly to complete decomposition. The reaction of 1 with PPh₃ yields [Fe₂(CO)₆(H)(μ‐P^tBu₂)(PPh₃)] ( 6 a ), while with ^tBu₂PH the compound [Fe₂(μ‐CO)(CO)₅(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] ( 6 b ) is formed. The thermolysis of 6 b affords [Fe₂(CO)₅(μ‐P^tBu₂)₂] and the degradation products [Fe(CO)₃(^tBu₂PH)₂] and [Fe(CO)₄(^tBu₂PH)]. The molecular structures of 3 , 4 and 6 b were determined by X‐ray crystal structure analyses.     

Reactivity of the unsaturated dimolybdenum anion [Mo2(η-C5H5)2(μ-PCy2)(μ-CO)2] towards electrophiles based on p- and d-block elements

The 30-electron binuclear anion [Mo₂Cp₂(μ-PCy₂)(μ-CO)₂]⁻ reacts with the chlorophosphite ClP(OEt)₂ or the organotin chlorides Cl₂SnPh₂ or ClSnPh₃ to give compounds of the formula trans-[Mo₂Cp₂(μ-E)(μ-PCy₂)(CO)₂], (E = P(OEt)₂, SnPh₃, SnPh₂Cl). In contrast, this anion reacts with the organosilicon chlorides ClSiR₃ (R = Ph, Me) to give unstable silyloxycarbyne-bridged complexes [Mo₂Cp₂(μ-PCy₂)(μ-COSiR₃)(μ-CO)], which rapidly hydrolyze to give the known hydride [Mo₂Cp₂(μ-H)(μ-PCy₂)(CO)₂]. Two main types of products were also observed in the reactions of the title anion with different chlorocomplexes of the transition and post-transition metals. Thus, the reactions with [MCl₂Cp₂] (M = Ti, Zr) give moisture-sensitive isocarbonyl-bridged complexes of the type [Mo₂Cp₂(μ-COMClCp₂)(μ-PCy₂)(μ-CO)]. In contrast, softer metallic electrophiles such as [AuCl(PR₃)] (R = ⁱPr, ptol) react with the anion at the dimolybdenum site to form new trimetallic clusters of the formula [AuMo₂Cp₂(μ-PCy₂)(CO)₂(PR₃)], also retaining a Mo−Mo triple bond. Subsequent reactions of the latter products with the solvate complexes [Au(PR₃)(THF)][PF₆] give the tetranuclear clusters [Au₂Mo₂Cp₂(μ-PCy₂)(CO)₂(PR₃)₂][PF₆] (Mo−Mo = 2.5674(3) Å and Au−Au = 2.7832(2) Å when R = ⁱPr). Finally, the reaction of the title anion with HgI₂ gives the pentanuclear cluster [Hg{Mo₂Cp₂(μ-PCy₂)(CO)₂}₂] or the trinuclear cluster [Mo₂Cp₂(μ-HgI)(μ-PCy₂)(CO)₂] depending on the stoichiometry being actually used for the reaction. The trinuclear species is only stable in tetrahydrofuran (THF), and decomposes to give a mixture of the dimeric species [Mo₂Cp₂(μ-HgI)(μ-PCy₂)(CO)₂]₂ along with variable amounts of the known iodide-bridged complex [Mo₂Cp₂(μ-I)(μ-PCy₂)(CO)₂].     

Facile Carbon–Fluorine Bond Activation and Subsequent Functionalisation of 1,1‐Difluoroethylene and Tetrafluoroethylene Promoted by Adjacent Metal Centres

The bridging fluoroolefin ligands in the complexes [Ir₂(CH₃)(CO)₂(μ‐olefin)(dppm)₂][OTf] (olefin=tetrafluoroethylene, 1,1‐difluoroethylene; dppm=μ‐Ph₂PCH₂PPh₂; OTf^?=CF₃SO₃^?) are susceptible to facile fluoride ion abstraction. Both fluoroolefin complexes react with trimethylsilyltriflate (Me₃SiOTf) to give the corresponding fluorovinyl products by abstraction of a single fluoride ion. Although the trifluorovinyl ligand is bound to one metal, the monofluorovinyl group is bridging, bound to one metal through carbon and to the other metal through a dative bond from fluorine. Addition of two equivalents of Me₃SiOTf to the tetrafluoroethylene‐bridged species gives the difluorovinylidene‐bridged product [Ir₂(CH₃)(OTf)(CO)₂(μ‐OTf)(μ‐C?CF₂)(dppm)₂][OTf]. The 1,1‐difluoroethylene species is exceedingly reactive, reacting with water to give 2‐fluoropropene and [Ir₂(CO)₂(μ‐OH)(dppm)₂][OTf] and with carbon monoxide to give [Ir₂(CO)₃(μ‐κ¹:η²‐C?CCH₃)(dppm)₂][OTf] together with two equivalents of HF. The trifluorovinyl product [Ir₂(κ¹‐C₂F₃)(OTf)(CO)₂(μ‐H)(μ‐CH₂)(dppm)₂][OTf], obtained through single C? F bond activation of the tetrafluoroethylene‐bridged complex, reacts with H₂ to form trifluoroethylene, allowing the facile replacement of one fluorine in C₂F₄ with hydrogen.     

Heterodinukleare Komplexe: Synthese und Kristallstrukturen von [RuRh(μ‐CO)(CO)4(μ‐PtBu2)(tBu2PH)], [RuRh(μ‐CO)(CO)3(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] und [CoRh(CO)4(μ‐H)(μ‐PtBu2)(tBu2PH)]

Heterobinuclear Complexes: Synthesis and X‐ray Crystal Structures of [RuRh(μ‐CO)(CO)₄(μ‐P^tBu₂)(^tBu₂PH)], [RuRh(μ‐CO)(CO)₃(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)], and [CoRh(CO)₄(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] [Ru₃Rh(CO)₇(μ₃‐H)(μ‐P^tBu₂)₂(^tBu₂PH)(μ‐Cl)₂] ( 2 ) yields by cluster degradation under CO pressure as main product the heterobinuclear complex [RuRh(μ‐CO)(CO)₄(μ‐P^tBu₂)(^tBu₂PH)] ( 4 ). The compound crystallizes in the orthorhombic space group Pcab with a = 15.6802(15), b = 28.953(3), c = 11.8419(19) Å and V = 5376.2(11) ų. The reaction of 4 with dppm (Ph₂PCH₂PPh₂) in THF at room temperature affords in good yields [RuRh(μ‐CO)(CO)₃(μ‐P^tBu₂)(μ‐dppm)] ( 7 ). 7 crystallizes in the triclinic space group P 1 with a = 9.7503(19), b = 13.399(3), c = 15.823(3) Å and V = 1854.6 ų. Moreover single crystals of [CoRh(CO)₄(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] ( 9 ) could be obtained and the single‐crystal X‐ray structure analysis revealed that 9 crystallizes in the monoclinic space group P2₁/a with a = 11.611(2), b = 13.333(2), c = 18.186(3) Å and V = 2693.0(8) ų.     

Bi‐ and Polynuclear Transition‐Metal Carbon Tellurides

The first examples of bi‐ and polynuclear tellurocarbonyl complexes were obtained from the reactions of [W(≡CTe)(CO)₂(Tp*)]NEt₄ (Tp*=hydrotris(dimethylpyrazolyl)borate) with [MCl(PCy₃)]/TlPF₆ (M=Cu, Au) or [Au₂Cl₂(μ‐dppm)], which afford [WM(μ‐CTe)(PCy₃)(CO)₂(Tp*)] (M=Cu, Au) and [WAu₂(μ‐CTe)(μ‐dppm)(CO)₂(Tp*)]₃(PF₆)₃. In all cases it is specifically the tellurocarbonyl that assumes a bridging, but in each case distinct, role including examples of isotellurocarbonyl, semi‐bridging and σ–π coordination and combinations thereof. Tetrametallic complexes bridged by C₂Te and C₂Te₂ ligands are also described.     

Unprecedented Oxidative Addition and Metal‐Only Lewis Pair Chemistry of Antimony Trihalides

Reaction of the zero‐valent platinum complex [Pt(PCy₃)₂] with SbF₃ generates the cationic diplatinum stibenium complex [{(Cy₃P)₂Pt}₂(μ‐SbF₂)]⁺, the first unsupported metal‐only Lewis pair containing an antimony‐centered Lewis acid. In contrast, SbCl₃ undergoes oxidative addition to [Pt(PCy₃)₂], resulting in the dihalostibanyl complex trans‐[PtCl(SbCl₂)(PCy₃)₂], the first example of oxidative addition of an antimony–halide bond to a transition metal.     

The Nature of the UC Double Bond: Pushing the Stability of High‐Oxidation‐State Uranium Carbenes to the Limit

Treatment of [K(BIPM^MesH)] (BIPM^Mes={C(PPh₂NMes)₂}^2?; Mes=C₆H₂‐2,4,6‐Me₃) with [UCl₄(thf)₃] (1 equiv) afforded [U(BIPM^MesH)(Cl)₃(thf)] ( 1 ), which generated [U(BIPM^Mes)(Cl)₂(thf)₂] ( 2 ), following treatment with benzyl potassium. Attempts to oxidise 2 resulted in intractable mixtures, ligand scrambling to give [U(BIPM^Mes)₂] or the formation of [U(BIPM^MesH)(O)₂(Cl)(thf)] ( 3 ). The complex [U(BIPM^Dipp)(μ‐Cl)₄(Li)₂(OEt₂)(tmeda)] ( 4 ) (BIPM^Dipp={C(PPh₂NDipp)₂}^2?; Dipp=C₆H₃‐2,6‐iPr₂; tmeda=N,N,N′,N′‐tetramethylethylenediamine) was prepared from [Li₂(BIPM^Dipp)(tmeda)] and [UCl₄(thf)₃] and, following reflux in toluene, could be isolated as [U(BIPM^Dipp)(Cl)₂(thf)₂] ( 5 ). Treatment of 4 with iodine (0.5 equiv) afforded [U(BIPM^Dipp)(Cl)₂(μ‐Cl)₂(Li)(thf)₂] ( 6 ). Complex 6 resists oxidation, and treating 4 or 5 with N‐oxides gives [{U(BIPM^DippH)(O)₂‐ (μ‐Cl)₂Li(tmeda)] ( 7 ) and [{U(BIPM^DippH)(O)₂(μ‐Cl)}₂] ( 8 ). Treatment of 4 with tBuOLi (3 equiv) and I₂ (1 equiv) gives [U(BIPM^Dipp)(OtBu)₃(I)] ( 9 ), which represents an exceptionally rare example of a crystallographically authenticated uranium(VI)–carbon σ bond. Although 9 appears sterically saturated, it decomposes over time to give [U(BIPM^Dipp)(OtBu)₃]. Complex 4 reacts with PhCOtBu and Ph₂CO to form [U(BIPM^Dipp)(μ‐Cl)₄(Li)₂(tmeda)(OCPhtBu)] ( 10 ) and [U(BIPM^Dipp)(Cl)(μ‐Cl)₂(Li)(tmeda)(OCPh₂)] ( 11 ). In contrast, complex 5 does not react with PhCOtBu and Ph₂CO, which we attribute to steric blocking. However, complexes 5 and 6 react with PhCHO to afford (DippNPPh₂)₂C?C(H)Ph ( 12 ). Complex 9 does not react with PhCOtBu, Ph₂CO or PhCHO; this is attributed to steric blocking. Theoretical calculations have enabled a qualitative bracketing of the extent of covalency in early‐metal carbenes as a function of metal, oxidation state and the number of phosphanyl substituents, revealing modest covalent contributions to U?C double bonds.