Photochemical reactions of 1-ferrocenyl-4-phenyl-1,3-butadiyne with Fe(CO)5 and CO

Photolysis of a hexane solution containing ironpentacarbonyl, 1-ferrocenyl-4-phenyl-1,3-butadiyne at low temperature yields six new products: [Fe(CO)₂{η²:η²-PhCCCC(Fc)C(CCPh)C(Fc)Fe(CO)₃}-μ-CO] (1), [Fe₂(CO)₆{μ-η¹:η¹:η²:η²-PhCCCC(Fc)-C(O)-C(Fc)CCCPh}] (2), [Fe₂(CO)₆{μ-η¹:η¹:η²:η²-FcCC(CC Ph)-C(O)-C(Fc)CCCPh}] (3), [Fe₂(CO)₆{μ-η¹:η¹:η²:η²-FcCCCC(Fc)-C(O)-C(Fc)CCCPh}] (4), [Fe(CO)₃{μ-η²: η²-[FcCC(CCPh)C(CCPh)C(Fc)}CO] (5) and [Fe(CO)₃{μ-η²: η²-[FcCC(CCPh)C(CCPh)C(Fc)}CO] (6) formed by coupling of acetylenic moieties with CO insertion on metal carbonyl support. In presence of CO, formation of another new product 2,5-bis(ferrocenyl)-3,6-bis(tetracarbonylphenylmaleoyliron)quinone (7) was observed which on further reaction with ferrocenylacetyene gave the quinone, 2,5-bis(ferrocenyl)-3,6-bis(ethynylphenyl)quinone (8). Structures of 1-5 and 8 were established crystallographically.     

Intramolecular rearrangement of the bridging σ,π-acetylide ligand in the Os3H(CO)9(L)(μ-η2-CCPh) (L = CO,PMe2Ph) clusters and crystal structure of Os3H(CO)9(PMe2Ph)(μ-η2-CCPh)

Clusters Os₃H(Cl)(CO)₉(L) (L= CO, PMe₂Ph) react with lithium phenyl-acetylide to yield Os₃H(CO)₉(L)(μ-η²-CCPh),which has a bridging acetylide ligand. The Os₃H(CO)₁₀(μ-η²-CCPh) complex (II) is fluxional owing to rapid π → σ, σ → π interchange of acetylide ligand between the bridged osmium atoms, whereas the phosphine-substituted derivative, Os₃H(CO)₉(PM₂Ph)(μ-η²-CCPh) (III), is stereochemically rigid and exists at room temperature in two isomeric forms. These isomers have been isolated as solids and have been characterized by ¹H and ³¹P{¹H} NMR spectroscopy. According to the spectroscopic data, in the major (IIIa) and minor (IIIb) isomers the phosphine ligand is coordinated to the metal atom which is σ- or π-bonded to the bridging acetylide group, respectively. The isomerization of IIIb into IIIa occurs only at 80°C. The structure of IIIa has been confirmed by an X-ray diffraction study.     

Reactions of [Cp*Ru(H2O)(NBD)]+ with alkynes

Formal [2 + 2 + 2] addition reactions of [Cp*Ru(H₂O)(NBD)]BF₄ (NBD = norbornadiene) with PhC?CR (R = H, COOEt) give [Cp*Ru(η⁶‐C₆H₅? C₉H₈R)] BF₄ (1a, R = H; 2a, R = COOEt). Treatment of [Cp*Ru(H₂O)(NBD)]BF₄ with PhC?C? C?CPh does not give [2 + 2 + 2] addition product, but [Cp*Ru(η⁶‐C₆H₅? C?C? C?CPh)] BF₄(3a). Treatment of 1a, 2a, 3a with NaBPh₄ affords [Cp*Ru(η⁶‐C₆H₅? C₉H₈R)] BPh₄ (1b, R = H; 2b, R = COOEt) and [Cp*Ru(η⁶‐C₆H₅? C?C? C?CPh)] BPh₄(3b). The structures of 1b, 2b and 3b were determined by X‐ray crystallography. Copyright © 2007 John Wiley & Sons, Ltd.     

Cleavage of the Fe—Fe Bond of （Me2SiSiMe2） [η^5－C5H4Fe（CO）2]2 with Na／Hg and Molecular Structure of the Ring－Opened Complex

The reaction of the rifle cyclic complex (1) with sodium amalgam in THF resulted in the expected cleavage of the Fe-Fe bond to afford his-sodium salt ( Me2SiSiMe2 ) [η^5-C5H4Fe(CO)2]2 (4). The latter was not isolated and was used directly to react with MeI, PhCH2Cl, CH3C(O)Cl, PhC(O)Cl,Cy3SnCl (Cy= cyclohexyl) or Ph3SnCl to afford corresponding ring-opened derivatives (Me2SiSiMe2) [η^5-C5H4Fe(CO)2]2 [5, R=Me; 6, R=PhCH2; 7, R=CH3C(O); 8, R=PhC(O); 9, R = Cy3Sn or 10, R = Ph3Sn ]. The crystal and molecular structures of 10 were determined by X-ray diffraction analysis. The molecule took the desired ant/ conformation around the Si-Si bond. The length of the Si--Si bond is 0.2343(3)nm, which is essentially identical to that in the cyclic structure of 1[0.2346(4) tun]. This result unambiguously demonstrates that the Si--Si bond in the cyclic structure of 1 is not subject to obvious strain.     

Preparation of cis-bis-acetylene-bis(pentafluorophenyl)-palladium(II) and -platinum(II) complexes,crystal structure of cis-[Pt(C6F5)2 (PhCCPh)2]

Treatment of cis-[M(C₆F₅)₂(THF)₂] (M = Pd, Pt; THF = tetrahydrofuran) with PhCCPh has given the novel bis-acetylene-palladium(II) and -platinum(II) complexes cis-[M(C₆F₅)₂(PhCCPh)₂]; these are stable even though there seems to be no significant π-back bonding according to the X-ray structure of the platinum complex.     

Preparation and Characterization of an Unusual Di-Cobalt Complex; X-Ray Crystal Structure of Co(CO)2(μ-CO)(μ:η2,η4-C4Ph4)Co(CO)2(PPh3)

Reaction of [MoCo(CO)₅(PPh₃)₂(η⁵-C₅H₅)] (1) with diphenylacetylene in tetrahydrofuran at 50 °C yielded two heterobimetallic compounds, [MoCo(CO)₄.(PPh₃){μ-PhC ? CPh}(η⁵-C₅H₅)] (4) and [MoCo(CO)₅{μ-PhC ? CPh} (η⁵-C₅H₅)] (5). However, an unexpected product, Co(CO)₂(μ-CO)(μ:η₂,η⁴-C₄Ph₄)Co(CO)₂(PPh₃) (6), was observed while attempting to grow the crystals for structural determination of 4. The X-ray crystal structure of 6 was determined: triclinic, $ {\rm P}\bar 1 $, a = 11.654(2) Å, b = 12.864(2) Å, c = 13.854(2) Å, α = 89.67(2)°, β = 86.00(2)°, γ= 83.33(2)°, V = 2057.9(6) ų Z=2. In 6, two cobalt fragments are at apical and basal positions of the pseudo-pentagonal pyramidal structure, respectively. The electron count for the apical cobalt fragments is 20, which is rather unusual. It is believed that 6 was formed after the fragmentation and recombination of the fragmented species of 4.     

Unusual demetalation of iron from [2]ferrocenophane skeleton of di-nuclear ferracycle carbonyl complex

Photolysis of a hexane solution containing 1,1′- bis (trimethylsilylethynyl)ferrocene ( 1 ) and Fe (CO)₅, under argon at 0 °C led to the formation of dinuclear complexes [Fe (CO)₂{η²:η² – C (SiMe₃) = C(C₅H₄)FeC(C₅H₄) = C (SiMe₃)Fe (CO)₃}–μ–CO] ( 2 ) and [Fe (CO)₂{η²:η²–C (SiMe₃) = C(C₅H₅)–C(C₅H₅) = C (SiMe₃)Fe (CO)₃}–μ–CO] ( 3 ). DFT calculations support the experimentally observed demetalation of ferrocene unit of 2 to 3 in presence of water. These compounds were comprehensively characterized by IR and ¹H and ¹³C NMR spectroscopy and crystallographically ( 1 and 3 ).     

Hydrierung aromatischer Nitrile auf dem Fe3(CO)9-Cluster

Hydrogenation of Aromatic Nitriles on the Fe₃(CO)₉ Cluster The μ₃-nitrile bridged clusters Fe₃(CO)₉(μ₃-η²-N≡CR) ( 3 , R = phenyl, p-tolyl, p-anisyl) consume hydrogen upon heating in solution with formation of the acimidoyl- and the alkylideneimido-bridged clusters HFe₃(CO)₉(μ₃-η²-HN=CR) ( 1 ) and HFe₃(CO)₉(μ₃-η²-N=CHR) ( 2 ). These can be obtained in a better way by successive H⁺ and H^– addition with NaBH₄ and H₃PO₄. HFe₃(CO)₉(μ₃-η²-N=CHR) ( 2 ) adds P(OMe)₃ with concomitant hydrogen migration to form Fe₃(CO)₉P(OMe)₃(μ₃-η¹-N–CH₂R) ( 6 ). The phosphite-substituted cluster Fe₃(CO)₈P(OMe)₃(μ₃-η²-N≡CPh) ( 5 a ) on the other hand is converted by the H⁺/H^– addition to the products HFe₃(CO)₈P(OMe)₃(μ₃-η²-HN=CPh) ( 7 a ) and HFe₃(CO)₈P(OMe)₃(μ₃-η²-N=CHPh) ( 8 a ).     

Cationic arenechromium-nitrosyls and -hydrides

Complexes Cr(CO)₂L(C₆Me_6-nH_n), n = 0-3, L = CO and PPh₃, react with NOPF₆ in methanol/toluene to give [Cr(CO)L(NO)(C₆Me_6-nH_n)] PF₆, n = 0-3, L = CO; n = 0, L = PPh₃, and these react with nucleophiles (X^-) to give cyclohexadienyl derivatives Cr(CO)₂(NO)(C₆Me_6-nH_nX); the compounds Cr(CO)₂(PhCCPh)(C₆Me_6-nH_n) react with NOPF₆ to yield [Cr(H)(CO)₂(PhCCPh)(C₆Me_6-nH_n)] PF₆, n = 0 and 1.     

Komplexchemie P-reicher Phosphane und Silylphosphane. XI [1]. Bildung,Reaktionen und Strukturen von Chromcarbonylkomplexen aus Reaktionen von Li(THF)2[η2-(tBu2P)2P] mit Cr(CO)5 · THF und Cr(CO)4 · NBD

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. XI. Formation, Reactions, and Structures of Chromium Carbonyl Complexes from Reactions of Li(THF)₂[η₂-(^tBu₂P)₂P] with Cr(CO)₅ · THF and Cr(CO)₄ · NBD Reactions of Li(THF)₂[η²-(^tBu₂P)₂P] 1 with Cr(CO)₅ · THF yield Li(THF)₂Et₂O[Cr(CO)₄{η²-(^tBu₂P)₂P}η¹-Cr(CO)₅] 2 and the compounds [Cr(CO)₄{η²-(^tBu₂P)₂PH}] 3 , [Cr(CO)₅{η¹-(^tBu₂P)₂PH}] 4 , (^tBu₂P)₂PH 5 and ^tBu₂PH · Cr(CO)₅ 6 . The formation of 3, 4, 5 and 6 is due to byproducts coming from the synthesis of 1. 2 reacts with CH₃COOH under formation of 3 . After addition of 12-crown-4 1 with NBD · Cr(CO)₄ in THF forms Li(12-crown-4)₂[Cr(CO)₄-{η²-(^tBu₂P)₂P}] 7 (yellow crystals). 7 reacts with CH₃COOH to 3 – which regenerates 7 with LiBu – with Cr(CO)₅THF to compound 2 , with NBD · Cr(CO)₄ in THF to 2 and 3 (ratio 1 : 1). With EtBr, 7 forms [Cr(CO)₄{η²-(^tBu₂P)₂PEt}] 8 , and [Cr(CO)₄{η²-(^tBu₂P)₂PBr}] 9 with BrCH₂? CH₂Br. The compounds were characterized by means of ¹H, ¹³C, ³¹P, ⁷Li NMR spectroscopy, IR spectroscopy, elementary analysis, mass spectra, and 2, 3 and 4 additionally by means of X-ray diffraction analysis. 2 crystallizes in the space group P1 with 2 formula units in the elementary cell; a = 10.137(9), b = 15.295(12), c = 15.897(14) Å; α = 101.82(7), β = 91.65(7), γ = 98.99(7)°; 3 crystallizes in the space group P2_t/n with 4 molecules in the elementary unit; a = 11.914(6), b = 15.217(10), c = 14.534(10) Å; α = 90, β = 103.56(5), γ = 90°. 4 : space group P1 with 2 molecules in the elementary unit; a = 8.844(4), b = 12.291(6), c = 14.411(7) Å, α = 66.55(2), β = 89.27(2), γ = 71.44(2)°.     

Benzene ring assembly promoted by a camphor derived palladium complex

Trans-[PdCl₂L₂] (1, L=3-NNMe₂C₁₀H₁₄O), under mild reaction conditions, acts as a catalyst for the cyclic trimerization of alkynes. The best performance is achieved for the reaction with PhCCMe that affords 1,3,5-trimethyl-2,4,6-triphenyl benzene with high activity and selectivity (ca. 99%). As a general trend the catalytic activity is higher for internal (PhCCMe, PhCCPh) than for terminal alkynes (HCCPh, HCC^tBu, HCCCO₂Me). Under more drastic experimental conditions the reaction of 1 with PhCCPh yields trans-[PdCl₂(PhCCPh)₂] and no catalytic activity is observed. The molecular structure of 1,3,5-trimethyl-2,4,6-triphenyl benzene was confirmed by X-ray diffraction analysis. The molecules were characterized by ¹H- and ¹³C-NMR spectroscopies, FAB-MS and, in some cases, elemental analyses.     

Synthesis of a transition metal-dithionite complex, (η5-C5H5)(CO)2FeS(O)2S(O)2Fe(CO)2(η5-C5H5)

The reaction of Na[η⁵-C₅H₅Fe(CO)₂] with large excess of SO₂ in THF at ?78°C followed by warming to room temperature affords an iron—dithionite complex, (η⁵-C₅H₅)(CO)₂FeS(O)₂S(O)₂Fe(CO)₂(η⁵-C₅H₅).     

Konkurrierende bildung von heterometall-zweikern-komplexen mit μ-CCHPh und μ-ηPsu1,η3-CHCPhCO-brückenliganden bei der reaktion von C5H5Rh(PhCCH)PPri3 MIT Fe2(CO)9

The alkyne complex C₅H₅Rh(PhCCH)PPrⁱ₃ reacts wit Fe₂(CO)₉ to form two isomeric dinuclear products, C₅H₅(PPrⁱ₃)Rh(μ-CCHPh)(μ-CO)Fe(CO)₃ and C₅H₅(PPrⁱ₃)Rh(μ-η¹,η³-CHCPhCO)Fe(CO)₃. The X-ray crystal structure of the latter has been determined.     

Addition reactions to cyclopolyolefin transition metal π complexes

The non-coordinated double bonds of (η⁴-1,2,3,4-cycloheptatriene)Fe(CO)₃ and (η⁴-1,2,5,6-cyclooctatetraene)Co(η⁵-C₅H₅) add methylene generated from the Simmons-Smith reaction to yield (η⁴-2,3,4,5-bicyclo[5.1.0]octa-2,4-diene)Fe(CO)₃ and (η⁴-2,3,7,8-tricyclo[7.1.0.0^4,6]deca-2,7-diene)Co(η⁵-C₅H₅). An analogous reaction of (η⁴-1,2,3,4-cyclooctatetraene)Fe(CO)₃ yields (η⁴-6,7,8,9-tricyclo[8.1.0.0^3,5]undeca-6,8-diene)Fe(CO)₃, a product of the addition of three equivalents of methylene in which a cyclopropyl ring opening is proposed to occur. Dichlorocatbene, generated from C₆H₅HgCCl₂Br, would not react in a similar fashion. A BH₃ · THF solution would react with these starting materials but unusual products were produced.     

Synthesis of homo- and heterodinuclear metal complexes with dimethylsilylene bridged unsymmetrical bis(cyclopentadienyl) ligand

The reaction of the dilithium salt Li₂[Me₂Si(C₅H₄)(C₅Me₄)] (2) of Me₂Si(C₅H₅)(C₅HMe₄) (1) with [MCl(C₈H₁₂)]₂ (M=Rh, Ir) and [RhCl(CO)₂]₂ afforded homodinuclear metal complexes [{Me₂Si(η⁵-C₅H₄)(η⁵-C₅Me₄)}{M(C₈H₁₂)}₂] (M=Rh: 3; M=Ir: 4) and [{Me₂Si(η⁵-C₅H₄)(η⁵-C₅Me₄)}Rh₂(CO)₂(μ-CO)] (5), respectively. The reaction of 2 with RhCl(CO)(PPh₃)₂ afforded a mononuclear metal complex [{Me₂Si(C₅HMe₄)(η⁵-C₅H₄)}Rh(CO)PPh₃] (6) leaving the C₅HMe₄ moiety intact. Taking advantage of the difference in reactivity of the two cyclopentadienyl moieties of 2, heterodinuclear complexes were prepared in one pot. Thus, the reaction of 2 with RhCl(CO)(PPh₃)₂, followed by the treatment with [MCl(C₈H₁₂)]₂ (M=Rh, Ir) afforded a homodinuclear metal complex [Rh(CO)PPh₃{(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}Rh(C₈H₁₂)] (7) consisting of two rhodium centers with different ligands and a heterodinuclear metal complex [Rh(CO)(PPh₃){(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}Ir(C₈H₁₂)] (8). The successive treatment of 2 with [IrCl(C₈H₁₂)]₂ and [RhCl(C₈H₁₂)]₂ provided heterodinuclear metal complex [Ir(C₈H₁₂){(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}Rh(C₈H₁₂)] (9). The reaction of 2 with CoCl(PPh₃)₃ and then with PhCCPh gave a mononuclear cobaltacyclopentadiene complex [{Me₂Si(C₅Me₄H)(η⁵-C₅H₄)}Co(CPhCPhCPhCPh)(PPh₃)] (10). However, successive treatment of 2 with CoCl(PPh₃)₃, PhCCPh and [MCl(C₈H₁₂)]₂ in this order afforded heterodinuclear metal complexes [M(C₈H₁₂){(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}Co(η⁴-C₄Ph₄)] (M=Rh: 11; M=Ir: 12) in which the cobalt center was connected to the C₅Me₄ moiety. Although the heating of 10 afforded a tetraphenylcyclobutadiene complex [{Me₂Si(C₅Me₄H)(η⁵-C₅H₄)}Co(η⁴-C₄Ph₄)] (13), in which the cobalt center was connected to the C₅H₄ moiety, simple heating of the reaction mixture of 2, CoCl(PPh₃)₃ and PhCCPh resulted in the formation of a tetraphenylcyclobutadiene complex [{Me₂Si(C₅H₅)(η⁵-C₅Me₄)}Co(η⁴-C₄Ph₄)] (14), in which the cobalt center was connected to the C₅Me₄ moiety. The mechanism of the cobalt transfer was suggested based on the electrophilicity of the formal trivalent cobaltacyclopentadiene moiety. In the presence of 1,5-cyclooctadiene, the reaction of 2 with CoCl(PPh₃)₃ provided a mononuclear cobalt cyclooctadiene complex [{Me₂Si(C₅Me₄H)(η⁵-C₅H₄)}Co(C₈H₁₂)] (15). The reaction of 15 with n-BuLi followed by the treatment with [MCl(C₈H₁₂)]₂ (M=Rh, Ir) afforded the heterodinuclear metal complexes of [Co(C₈H₁₂){(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}M(C₈H₁₂)] (M=Rh: 16; M=Ir: 17). Treatment of 6 with Fe₂(CO)₉ at room temperature afforded a heterodinuclear metal complex [{Me₂Si(C₅HMe₄)(η⁵-C₅H₄)}{Rh(PPh₃)(μ-CO)₂Fe(CO)₃}] (18) in which the C₅HMe₄ moiety was kept intact. Treatment of dinuclear metal complex 5 with Fe₂(CO)₉ afforded a heterotrinuclear metal complex [{(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}{Rh(CO)Rh(μ-CO)₂Fe(CO)₃}] (19) having a triangular metal framework. The crystal and molecular structures of 3, 11, 12, 18 and 19 have been determined by single-crystal X-ray diffraction analysis.     

Preparation and reactions of the (dicarbonyl)(η5-cyclopentadienyl)(tetrahydrofuran)iron cation: A convenient route to (dicarbonyl)(η5-cyclopentadiemyl)(η2-olefin)iron cations and related complexes

The versatile reagent [η⁵-C₅H₅)Fe(CO)₂(THF)]BF₄ has been isolated from the reaction of (η₅-C₅H₅)Fe(CO)₂I and AgBF₄ in THF and shown to react in CH₂Cl₂ with olefins to yield [(η⁵-C₅H₅)Fe(CO)₂(η²-olefin)]BF₄ complexes. For most olefins the yields are high. The yield in these reactions can be increased by treating the CH₂Cl₂ solution of [(η⁵-C₅H₅)Fe(Co)₂(THF)]BF₄ and olefin with gaseous BF₃ in order to complex the THF as the BF₃-THF adduct. Most striking is the increase in yield for the cyclohexene complex from 17% to 92%.     

The kinetics and mechanism of diene exchange in (η4-enone) Fe(CO)2L complexes (L = phosphine,phosphite)

Kinetic data for the exchange of 1,3-cyclohexadiene with (η⁴-benzylideneacetone)Fe(CO)₂L complexes (L = CO, PPh_3-xMe_x (x = 0-2) or P(OPh)₃) to give (η⁴-1,3-cyclohexadiene)Fe(CO)₂L derivatives indicate a mechanism involving stepwise competing D and I_d opening of the ketonic M-CO π-bond. Rates increase in the order CO ? PPh₃ ≈ P(OPh)₃ > PPh₂Me ? PPhMe₂, and both steric and electronic factors appear to be important. (η⁴-1,3-cyclohexadiene)Fe(CO)₂L complexes of potential use in enantioselective synthesis (L=(+)-Ph₂P(menthyl) or (+)-Ph₂PCH₂CH(Me)Et) may be prepared via their (η⁴-benzylideneacetone)Fe(CO)₂L complexes.     

The photochemistry of (η-2-R-C3H4)Fe(CO)(NO)(X) (R = H or Cl; X = CO or PPh3) in room temperature solution or frozen gas matrixes

A photochemical study of allyl iron complexes of the type, (η³-2-R-C₃H₄)Fe(CO)(NO)(X) (R = H or Cl; X = CO or PPh₃) is presented. These compounds were studied in solid matrixes at 20 K, and at room temperature, by a combination of laser flash at 355 nm and steady-state photolysis. The predominant photochemical process for these compounds is loss of a CO ligand. In addition, exhaustive irradiation of (η³-2-R-C₃H₄)Fe(CO)(NO)(PPh₃) with λ_exc > 300 nm provided evidence for a haptotropic shift of the allyl group from η³ to η¹ coordination.     

Mechanisms of nucleophilic attack at coordinated carbon monoxide: II. Iodide addition to a carbon monoxide ligand in [Fe(CO3 (1–5-η-dienyl)]+ cations (dienyl = C6H7, C7H9, 2-MeOC6H6)

Nucleophilic addition to a carbonyl ligand has been shown to compete with attack at the metal or dienyl ring in the reactions of [Fe(CO)₃(1–5-η-dienyl)]⁺ cations with iodide ion. Thus, the novel acyl iodide complex [Fe(CO)₂(COI)(1–5-η-C₆H₇)] is found to be a major product from the reaction of [Fe(CO)₃(1–5-η-C₆H₇)]⁺ with I⁻ in nitromethane or acetone solvents. The other major initial product is the ring adduct [Fe(CO)₃(1–4-η-IC₆H₇)]. Exposure of the acyl iodide species to light causes its rapid decomposition. Analogous behaviour towards I⁻ is shown by the related [Fe(CO)₃(1–5-η-C₇H₉)]⁺ and [Fe(CO)₃(1–5-η-2-MeOC₆H₆)]⁺ cations.