Komplexchemie P-reicher Phosphane und Silylphosphane. IV. Bildung und Struktur der Chromcarbonylkomplexe des Tris(di-tert-butylphospha)heptaphosphanortricyclans, (t-Bu2P)3P7

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. IV. Formation and Structure of the Chromium Carbonyl Complexes of Tris(di-tert-butylphospha)heptaphosphanortricyclane (t-Bu₂P)₃P₇ The reaction of (t-Bu₂P)₃P₇ 1 with Cr(CO)₅ · THF in a molar ratio of 1:1 yields yellow crystals of (t-Bu₂P)₃P₇[Cr(CO)₅] 2 having the Cr(CO)₅ group coordinated to a P^b atom (basal) of the three membered ring. With a molar ratio of 1:2 compounds 2 , (t-Bu₂P)₃P₇[Cr(CO)₅]₂ 3 , (t-Bu₂P)₃P₇[Cr(CO)₅][Cr(CO)₄] 4 and (t-Bu₂P)₃P₇[Cr(CO)₄]₂ 5 were obtained. In 3 (yellow crystals) one Cr(CO)₅ group is linked to a P^b atom, the other one to an exocyclic P^exo atom. On irradiation 3 loosing one CO group generates 4 (orange red crystals) with an unchanged Cr(CO)₅ group linked to the Pb atom and a five membered chelate-like ring containing an apical Pa atom, two equatorial P^a atoms, one P^exo atom and the Cr atom of the carbonyl group. Compound 5 (orange red crystals) contains two such five membered rings. (t-Bu₂P)₃P₇[Cr(CO)₄]₃ 6 (red needles) is formed with Cr(CO)₅ · THF in a molar ratio of 1 : 1. However, even with higher amounts of Cr(CO)₅ · THF and after extended reaction times, only 6 is formed; no further Cr carbonyl group could be attached to the P skeleton. With Cr(CO)₅ · NBD in a molar ratio of 1 : 1, (t-Bu₂P)₃P₇[Cr(CO)₄] 7 is produced from 1, and 5 with a molar ratio of 2 : 1. As in 4, the Cr(CO)₄ group in 7 (orange crystals) participates in a five membered chelate-like ring. It was not possible to generate 6 from 5 with an excess of Cr(CO)₄ · NBD and with extended reaction times. The molecular structures of the compounds were identified by investigating the ³¹P[¹H] NMR spec-tra and considering especially the coordination shift, and by crystal structure determinations of 2 and 4. Compound 2 crystallizes in the space group PI (no.2) with a = 1566.2(4) pm, b = 2304.1(5) pm, c = 1563.3(4) pm,α = 95.57(3)°, β = 108.79(3)°, γ = 109.82(4)° and Z = 4 formula units in the elementary cell. Compound 4 crystallizes in the space group P 2₁ /n (no. 14) with a = 1416.6(5) pm, b = 2573.6(5) pm, c = 1352.9(4) pm,β = 99.17(5)° and Z = 4 formula units in the elementary cell.     

Synthese und spektroskopische Eigenschaften neuer komplexierter Triphosphane

Synthesis and Spectroscopy of new Triphosphine Complexes The reaction of PCl₃ with [HPPh₂W(CO)₅] in the presence of NEt₃ affords stepwise the diand triphosphine complexes [Cl₂PPPh₂W(CO)₅] and ClP[PPh₂W(CO)₅]. Triphosphine complexes of the type [{M′(CO)₅}(H)P{PPh₂M(CO)₅}] (M = M′ = Cr or Mo) are not formed from the reaction of HP[PPh₂M(CO)₅] with [M′(CO)₅thf]. However they were prepared by reaction of [M′(CO)₅PCl₃] with Li[PPh₂M(CO)₅]. The products were characterized by NMR, IR spectroscopy, and mass spectrometry.     

Gallium-, Indium-Mangan- und Thallium-Rhenium-Carbonylverbindungen

Gallium-, Indium-Manganese-, and Thallium-Rhenium Carbonyl Compounds Compounds of type Na{Cl_4?nM[Mn(CO)₅]_n} (M ? Ga, In; n = 1, 2, 3) were prepared by reaction of the Lewis acids MCl₃ and NaMn(CO)₅. Instead of the sodium salts were obtained the compounds (C₃H₇CO₂)₂InMn(CO)₄L (Indium atom with the coordination number 5) from Indium(III) butyrate with two carboxylate groups bonded as chelate ligands and NaMn(CO)₄L [L ? CO, P(C₆H₅)₃] in the molar ratio 1:1. By reacting TlCl with NaRe(CO)₅ i.r. spectroscopic measurements of the solution pointed out the intermediate product TlRe(CO)₅, which was unstable against a disproportionation reaction into Tl and Tl[Re(CO)₅]₃. The last named compound delivered as a thermal decomposition product Re₂(CO)₈[μ-TlRe(CO)₅]₂. I.r. bands of the new compounds were assigned.     

Reaction of Pentelidene Complexes with Diazoalkanes: Stabilization of Parent 2,3‐Dipnictabutadienes

The reaction of the phosphinidene complex [Cp*P{W(CO)₅}₂] ( 1 a ) with diphenyldiazomethane leads to [{W(CO)₅}Cp*P=NN{W(CO)₅}=CPh₂] ( 2 ). Compound 2 is a rare example of a phosphadiazadiene ligand (R‐P=N?N=CR′R′′) complex. At temperatures above 0 °C, 2 decomposes into the complex [{W(CO)₅}PCp*{N(H)N=CPh₂)₂] ( 3 ), among other species. The reaction of the pentelidene complexes [Cp*E{W(CO)₅}₂] (E=P, As) with diazomethane (CH₂NN) proceeds differently. For the arsinidene complex ( 1 b ), only the arsaalkene complex 4 b [{W(CO)₅}₂{η^1:2‐(Cp*)As=CH₂}] is formed. The reaction with the phosphinidene complex ( 1 a ) results in three products, the two phosphaalkene complexes [{W(CO)₅}₂{η^1:2‐(R)P=CH₂}] ( 4 a : R=Cp*, 5 : R=H) and the triazaphosphole derivative [{W(CO)₅}P(Cp*)‐CH₂‐N{W(CO)₅}=N‐N(N=CH₂)] ( 6 a ). The phosphaalkene complex ( 4 a ) and the arsaalkene complex ( 4 b ) are not stable at room temperature and decompose to the complexes [{W(CO)₅}₄(CH₂=E?E=CH₂)] ( 7 a : E=P, 7 b : E=As), which are the first examples of complexes with parent 2,3‐diphospha‐1,3‐butadiene and 2,3‐diarsa‐1,3‐butadiene ligands.     

Synthesis,Structure, Bonding,and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)2}2{μ‐η2:η2‐B2H4}] and [{Cp*M(CO)2}2B2H2M(CO)4], M=Mo,W

The reaction of [(Cp*Mo)₂(μ‐Cl)₂B₂H₆] ( 1 ) with CO at room temperature led to the formation of the highly fluxional species [{Cp*Mo(CO)₂}₂{μ‐η²:η²‐B₂H₄}] ( 2 ). Compound 2, to the best of our knowledge, is the first example of a bimetallic diborane(4) conforming to a singly bridged C_s structure. Theoretical studies show that 2 mimics the Cotton dimolybdenum–alkyne complex [{CpMo(CO)₂}₂C₂H₂]. In an attempt to replace two hydrogen atoms of diborane(4) in 2 with a 2e [W(CO)₄] fragment, [{Cp*Mo(CO)₂}₂ B₂H₂W(CO)₄] ( 3 ) was isolated upon treatment with [W(CO)₅?thf]. Compound 3 shows the intriguing presence of [B₂H₂] with a short B?B length of 1.624(4) Å. We isolated the tungsten analogues of 3 , [{Cp*W(CO)₂}₂B₂H₂W(CO)₄] ( 4 ) and [{Cp*W(CO)₂}₂B₂H₂Mo(CO)₄] ( 5 ), which provided direct proof of the existence of the tungsten analogue of 2 .     

Synthesis,Structure, Bonding,and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)2}2{μ‐η2:η2‐B2H4}] and [{Cp*M(CO)2}2B2H2M(CO)4], M=Mo,W

The reaction of [(Cp*Mo)₂(μ‐Cl)₂B₂H₆] ( 1 ) with CO at room temperature led to the formation of the highly fluxional species [{Cp*Mo(CO)₂}₂{μ‐η²:η²‐B₂H₄}] ( 2 ). Compound 2, to the best of our knowledge, is the first example of a bimetallic diborane(4) conforming to a singly bridged C_s structure. Theoretical studies show that 2 mimics the Cotton dimolybdenum–alkyne complex [{CpMo(CO)₂}₂C₂H₂]. In an attempt to replace two hydrogen atoms of diborane(4) in 2 with a 2e [W(CO)₄] fragment, [{Cp*Mo(CO)₂}₂ B₂H₂W(CO)₄] ( 3 ) was isolated upon treatment with [W(CO)₅⋅thf]. Compound 3 shows the intriguing presence of [B₂H₂] with a short B−B length of 1.624(4) Å. We isolated the tungsten analogues of 3 , [{Cp*W(CO)₂}₂B₂H₂W(CO)₄] ( 4 ) and [{Cp*W(CO)₂}₂B₂H₂Mo(CO)₄] ( 5 ), which provided direct proof of the existence of the tungsten analogue of 2 .     

Niob- und Tantalkomplexe mit P2- und P4-Liganden

Niobium and Tantalum Complexes with P₂ and P₄ Ligands The photolysis of [Cp″Ta(CO)₄] 1 (Cp″ = C₅H₃^tBu₂?1,3) and P₄ affords Cp″(CO)₂Ta(η⁴?P₄) 2 , [{Cp″(CO)Ta}₂(m??η^2:2?P₂)₂] 3 and [Cp₃″(CO)₃Ta₃(P₂)₂] 4 . In a photochemical reaction 2 and [Cp*Nb(CO)₄] 5 form [{Cp*(CO)Nb}{Cp″(CO)Ta}(m??η^2:2?P₂)₂] 6 and [{Cp*(CO)₂Nb} {Cp*Nb}{Cp″(CO)Ta}(m?₃?η^2:1:1?P₂)₂] 7 , a compound with the novel m?₃?η^2:2:1?P₂-coordination mode. The reaction of 2 and [Cp*Co(C₂H₄)₂] 8 leads to [{Cp*Co} {Cp″(CO)Ta}(m??η^2:2?P₂)₂] 9 , a heteronuclear complex with an ?early”? and a ?late”? transition metal. Complexes 2, 3, 7 and 9 have been further characterized by X-ray structure analyses.     

Umsetzungen einiger Schwefel-Fluor-Verbindungen mit Verbindungen von übergangsmetallen; Darstellung und spektroskopische Untersuchung von Sulfito-Komplexen mit MnII,Mo0 und W0

Reactions of some Sulfur-Fluorine Compounds with Compounds of Transition Metals; Synthesis and Spectroscopic Investigation of Sulfito Complexes, involving Mn^II, Mo⁰, and W⁰ In the oxidative addition reactions of sulfuryl fluoride ( 1 ) and of methanesulphonic acid fluoride ( 2 ) with η²-ethylene-bis(triphenylphosphine)platinum(0) the novel ionic binuclear tetrakis(triphenylphosphine)-(μ-fluoro)-(μ-peroxo)-platinum(II)-fluorosulfonate and -methylsulfonate complexes 3 a and 3 b were formed. O,O-Sulfito-manganese(II) tricarbonyl 5 a and the binuclear μ-disulfito-dimanganese decacarbonyl complex 6 a were obtained in the reaction of disulfuryl difluoride ( 4 ) with the carbonyl metalate complex, Na⁺[Mn(CO)₅]^?. In this redox reaction several further products (e.g., CO, SO₂F₂ ( 1 ) and Mn₂(CO)₁₀) were formed and were determined quantitatively. In the presence of acetonitrile the acetonitrile-O,O-sulfito-manganese(II) tricarbonyl complex 5 b was isolated. The new binuclear complexes, bis(η⁵-cyclopentadienyl)-μ-disulfito-dimetalhexacarbonyls ( 6 b : metal = Mo⁰ and 6 c : metal = W⁰) were obtained in the reaction of 4 with the carbonyl metalates Na⁺[CpM(CO)₃]^? (M?Mo¹, W¹; Cp = cyclopentadienyl). Further products (e.g., CO, SO₂F₂ ( 1 ) and [CpM(CO)₃]₂, M?Mo, W) were formed and were determined quantitatively. The validity of the concept of hard and soft acids and bases (HSAB-concept) and of the 18-valence-electron rule (18-VE-rule) could not be confirmed in all cases. The characterization of 3a, 3b, Sb, 6b and 6c was based on their IR and NMR spectra, and in one case, on the mass spectra ( 5b ). For 3a and 3b the dynamic behaviour at room temperature in CD₂Cl₂ and CD₃OD was studied by ³¹P-NMR spectroscopy. The results are interpreted in terms of exchange processes in solution between the coordinated μ-fluoride and the solvent ligand or the uncoordinated anion. 5a and 6a and the by-products (e.g., CO and SO₂F₂ ( l )), which were formed in the redox reactions, were identified by their infrared spectra.     

Komplexchemie P-reicher Phosphane und Silylphosphane. VII. Carbonylkomplexe des Heptaphosphans(3) iPr2(Me3Si)P7

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. VII Carbonyl Complexes of the Heptaphosphane(3) iPr₂(Me₃Si)P₇ From the reaction of iPr₂(Me₃Si)P₇ 1 with one equivalent of Cr(CO)₅THF the yellow products iPr₂(H)P₇[Cr(CO)₅] 2 and iPr₂(Me₃Si)P₇[Cr(CO)₅] 3 were isolated by column chromatography on silicagel. The P? H group in 2 results from a cleavage of the P? SiMe₃ bond during chromatography. The Cr(CO)₅ group in 2 is linked to an iPr? P^e atom, in 3 to the Me₃Si? P^e atom of the P₇ skeleton. The substituents do not force the formation of a single isomer; nevertheless 3 ist considerably favoured as compared to 2 . From the reaction of 1 with 2 equivalents of Cr(CO)₅THF the yellow iPr₂(H)P₇[Cr(CO)₅]₂ 4 was isolated bearing one Cr(CO)₅ group at an iPr? P^e atom, the other one at a P^b atom of the P₇ skeleton. Compound 3 yields with Cr(CO)₄NBD the red iPr₂(Me₃Si)P₇[Cr(CO)₅][Cr(CO)₄] 5 . Three isomers of 5 appear. Two P^e atoms of 5 are bridged by the Cr(CO)₄ group, the third P^e atom is linked to the Cr(CO)₅ ligand. iPr₂(H)P₇[Fe(CO)₄] was isolated from the reaction of 1 with Fe₂(CO)₉. ³¹P NMR and MS data are reported.     

Reaction of Tungsten–Phosphinidene and –Arsinidene Complexes with Carbodiimides and Alkyl Azides: A Straightforward Way to Four‐Membered Heterocycles

The reaction of the phosphinidene and arsinidene complexes [Cp*E{W(CO)₅}₂] (E=P ( 1 a ), As ( 1 b ); Cp*=C₅Me₅) with carbodiimides leads to the new four‐membered heterocycles of the type [Cp*C(NR)₂E{W(CO)₅}₂] (E=P: R=iPr ( 2 a ), Cy ( 3 a ); E=As: R=iPr ( 2 b ), Cy ( 3 b )). The reaction of phosphinidene complex 1 a with alkyl azides yields the triazaphosphete derivatives [Cp*P{W(CO)₅}N(R)NN{W(CO)₅}] (R=Hex, Cy) ( 4 ). These unprecedented N₃P four‐membered triazaphosphete complexes can be regarded as stabilized intermediates of the Staudinger reaction, which have not been previously isolated. All of the isolated products were characterized by NMR, IR spectroscopy, mass spectrometry, and by single‐crystal X‐ray diffraction analysis.     

Untersuchungen zur Darstellung von [CpxSb{M(CO)5}2] (Cpx = Cp,Cp*; M = Cr,W)

Investigations of the Synthesis of [Cp^xSb{M(CO)₅}₂] (Cp^x = Cp, Cp*; M = Cr, W) The reaction of CpSbCl₂ with [Na₂{Cr₂(CO)₁₀}] leads to the chlorostibinidene complex [ClSb{Cr(CO)₅}₂(thf)] ( 1 ), whereas the reaction of CpSbCl₂ with [Na₂{W₂(CO)₁₀}] results in the formation of the complexes [ClSb{W(CO)₅}₃] ( 2 ), [Na(thf)][Cl₂Sb{W(CO)₅}₂] ( 3 ), [ClSb{W(CO)₅}₂(thf)] ( 4 ) and [Sb₂{W(CO)₅}₃] ( 5 ). The stibinidene complex [CpSb{Cr(CO)₅}₂] ( 6 ) is obtained by the reaction of [ClSb{Cr(CO)₅}₂] with NaCp, while its Cp* analogue [Cp*Sb{Cr(CO)₅}₂] ( 7 ) is formed via the metathesis of Cp*SbCl₂ with [Na₂{Cr₂(CO)₁₀}]. The products 2 , 3 , 4 and 7 are additionally characterised by X‐ray structure analyses.     

1-Alkoxy-2-azaallenyl-komplexe von chrom und wolfram

The successive reaction of (CO)₆M with Na[NCR₂¹] and [Et₃O]BF₄ yields (CO)₅M[C(NCR₂¹)OEt] (II: M = Cr; III: M = W; CR₂¹ = C(C₆H₄Br-p)₂ (a), CPh₂ (b), C(C₆H₄OMe-p)₂ (c), C(C₆H₄)₂O (d), CBu₂^tt (e)). Hexacarbonyltungsten, (CO)₆W, reacts with Na[NCPh₂] and MeOSO₂F to give (CO)₅W[C(NCPh₂) OMe] (IV). X-Ray analysis of IIe shows that: (1) the CNC fragment is almost linear (171.7°); (2) the two NC bond lengths are equal within experimental error; and (3) the O,C,Cr,N plane is perpendicular to the C(Me₃),C,N,C(Me₃) plane (90.0°). Therefore compounds II–IV are best described as 1-alkoxy-2-azaallenyl complexes.     

Metallkomplexe mit anionischen Liganden von Elementen der 4. Hauptgruppe. VIII. Pentacarbonyl-trihalogenstannido-metallat(O)-Komplexe von chrom,molybdän und wolfram mit fluor- und jodhaltigen stannidliganden

Metal Complexes with Anionic Ligands of Elements of the Main Group IV. VIII Pentacarbonyltrihalogenostannidometalate(O) Complexes of Chromium, Molybdenum, and Tungsten with Fluorine and Iodine Containing Trihalogenostannido Ligands In methylenechloride [As(C₆H₅)₄][SnF₃] readily reacts with the metalhexacarbonyls forming the arsoniumsalts of the pentacarbonyltrifluorostannidometalate(O) complexes, [M(CO)₅SnF₃]^? (M ? Cr, Mo, W). Exclusively by the reaction of the intermediately formed complex Cr(CO)₅THF only one pure triiodostannidometalate(O) Complex, [N(C₂H₅)₄][Cr(CO)₅SnJ₃], could be isolated. The trihalogenostannidometalate(O) complexes [M(CO)₅SnClX₂]^? (X ? F: M ? Cr, Mo, W; X ? J: M ? Cr) could be prepared by SnX₂-insertion reactions of the [M(CO)₅Cl]^? complexes. The bonding properties of the halogenostannide ions are discussed on the bases of the IR spectra of their metalate(O) complexes.     

Oxidative Addition of Diphenyl Disulfide/Thiophenol to [Mn(CO)5]−: Crystal Structure of cis-[Mn(CO)4(SPh)2]−

Oxidative addition of diphenyl disulfide to the coordinatively unsaturated [Mn(CO)₅]^? led to the formation of low-spin, six-coordinate cis-[Mn(CO)₄(SPh)₂]^?. The complex cis-[PPN][Mn(CO)₄(SPh)₂] crystallized in monoclinic space group P2₁/c with a = 9.965(2) Å, b = 24.604(5) Å, c = 19.291(4) Å, β = 100.05(2)°, V = 4657(2)ų, and Z = 4; final R = 0.036 and R_w = 0.039. Thermal transformation of cis-[Mn(CO)₄(SPh)₂]^? to [(CO)₃Mn(μ-SPh)₃Mn(CO)₃]^? was completed overnight in THF at room temperature. Additionally, reaction of [Mn(CO)₅]^? and PhSH in 1:2 mole ratio also led to cis-[PPN](Mn(CO)₄(SPh)₂]. Presumably, oxidative addition of PhSH to [Mn(CO)₄]^? was followed by a Lewis acid-base reaction to form cis-[Mn(CO)₄(SPh)₂]^? with evolution of H₂.     

Komplexe mit Antimon‐Liganden: [tBu2(Cl)SbW(CO)5], [tBu2(OH)SbW(CO)5], O[SbPh2W(CO)5]2, E[SbMe2W(CO)5]2 (E = Se,Te), cis‐[(Me2SbSeSbMe2)2Cr(CO)4]

Complexes Containing Antimony Ligands: [^tBu₂(Cl)SbW(CO)₅], [^tBu₂(OH)SbW(CO)₅], O[SbPh₂W(CO)₅]₂, E[SbMe₂W(CO)₅]₂ (E = Se, Te), cis‐[(Me₂SbSeSbMe₂)₂Cr(CO)₄] Syntheses of [^tBu₂(Cl)SbW(CO)₅] ( 1 ), [^tBu₂(OH)SbW(CO)₅] ( 2 ), O[SbPh₂W(CO)₅]₂ ( 3 ), Se[SbMe₂W(CO)₅]₂ ( 4 ), cis‐[(Me₂SbSeSbMe₂)₂Cr(CO)₄] ( 5 ) Te[SbMe₂W(CO)₅]₂ ( 6 ) and crystal structures of 1 – 5 are reported.     

Bifunktionalisierte 1 H‐Phosphiren‐ und g1‐1‐Phosphaallen‐Wolframkomplexe

Bifunctionalized 1 H‐Phosphirene and g¹‐1‐Phosphaallene Tungsten Complexes The tungsten(0) complex [{(Me₃Si)₂HCPC(Ph)=N}W(CO)₅] 1 reacts upon heating with acetylene derivatives 2 a–d in toluene to form benzonitrile and the complexes [{(Me₃Si)₂HCPC(R)=COEt} · W(CO)₅] 5 a–d ( 5 a : R = SiMe₃; 5 b : R = SiPh₃; 5 c : R = SnMe₃; 5 d : R = SnPh₃) and [{(Me₃Si)₂HCP=C=C(OEt)R} · W(CO)₅] 6 a, b ( 6 a : R = SnMe₃; 6 b : R = SnPh₃), which have been isolated by chromatography; complexes 5 c and 6 a have been characterized as mixtures. Spectroscopic and mass spectrometric data are discussed. The crystal structure of the compound 5 a was determined by X‐ray single crystal structure analysis ( 5 a : space group P2₁/n, Z = 4, a = 977.6(2) pm, b = 1814.6(4) pm, c = 1628.0(4) pm, β = 93.95(2)°).     

Ring Expansions of Nonpolar Polyphosphorus Rings

The reaction of the phosphinidene complex [Cp*P{W(CO)₅}₂] ( 1 a ) (Cp*=C₅Me₅) with the anionic cyclo-P_n ligand complex [(η³-P₃)Nb(ODipp)₃]⁻ ( 2 , Dipp=2,6-diisopropylphenyl) resulted in the formation of [{W(CO)₅}₂{μ₃,η^3:1:1-P₄Cp*}Nb(ODipp)₃]⁻ ( 3 ), which represents an unprecedented example of a ring expansion of a polyphosphorus-ligand complex initiated by a phosphinidene complex. Furthermore, the reaction of the pnictinidene complexes [Cp*E{W(CO)₅}₂] (E=P: 1 a , As: 1 b ) with the neutral complex [Cp′′′Co(η⁴-P₄)] (Cp′′′=1,2,4-tBu₃C₅H₂) led to a cyclo-P₄E ring (E=P, As) through the insertion of the pentel atom into the cyclo-P₄ ligand. Starting from 1 a , the two isomers [Cp′′′Co(μ₃,η^4:1:1-P₅Cp*){W(CO)₅}₂] ( 5 a , b ), and from 1 b , the three isomers [Cp′′′Co(μ₃,η^4:1:1-AsP₄Cp*){W(CO)₅}₂] ( 6 a – c ) with unprecedented cyclo-P₄E ligands (E=P, As) were isolated. The complexes 6 a – c represent unique examples of ring expansions which lead to new mixed five-membered cyclo-P₄As ligands. The possible reaction pathways for the formation of 5 a , b and 6 a – c were investigated by a combination of temperature-dependent ³¹P{¹H} NMR studies and DFT calculations.     

About the Reaction of C(PPh3)2 with [M(CO)6] (M = Cr,Mo): Unusual Formation of μ-Carbonato Complexes of Mo under Participation of THF

Attempts to synthesize complexes of group 6 carbonyl compounds [M(CO)₆] (M = Cr, Mo, W) with the carbone C(PPh₃)₂ ( 1 ) via the photo chemically created adducts [(CO)₅M(THF)] lead to quantitative formation of the salts [HC(PPh₃)₂]₂[M₂(CO)₁₀] ( 2 , Cr; 3 , Mo; 4 , W). Alternatively, a long-time thermal reaction of [Mo(CO)₆] performed with 1 in THF generates a series of products initiated by a Wittig-type reaction. In addition to 3 , minor amounts of [(CO)₅MoCCPPh₃] ( 8 ), [(CO)₅MoO₂CC{PPh₃}₂] ( 5 ), and the carbonate complexes [HC(PPh₃)₂]₂[(CO)₅Mo(CO₃)Mo(CO)₄] ( 6 ) and [HC(PPh₃)₂]₂[(CO)₄Mo(CO₃)Mo(CO)₄] ( 7 ) were found. Compounds 2 , 3 , 5 , 6 , and 7 were characterized by X-ray analyses, ³¹P NMR, and IR spectroscopy. The water, necessary for the formation of the carbonate, stems from decomposition of THF.     

Eisen- und Nickelcarbonylkomplexe mit substituierten Distiban- und Antimonido-Liganden

Iron and Nickel Carbonyl Complexes with Substituted Distibane and Antimonido Ligands The reactions of enneacarbonyldiiron with substituted distibanes yield mononuclear complexes [Fe(CO)₄SbR₂SbR₂] (R = C₂H₅, t-C₄H₉), a dinuclear complex [(CO)₄FeSbPh₂SbPh₂Fe(CO)₄] and antimonido-bridged compounds [(CO)₃Fe(SbR₂)₂-Fe(CO)₃] (R = C₂H₅, C₆H₅). Product of the reaction of tetramethyldistibane with tetracarbonylnickel is the binuclear complex [(CO)₃NiSbMe₂SbMe₂Ni(CO)₃]. The ¹H-n.m.r., i.r., and mass spectra of the new compounds are reported.     

Zweifach arsenverbrückte CrFe-, MoFe- und WFe-bindungen

The reaction of K₂Fe(CO)₄ with (CO)₄ M(AsMe₂Cl)₂ (M  Cr, Mo, W) gives low yields of the new heterodinuclear complexes (CO)₄M-[μ-AsMe₂]₂-Fe(CO)₃ with CrFe, MoFe and WFe bonds.