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).     

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.     

Synthesis and 1H-, 13C-, and 57Fe-NMR spectra of mono- and bis[tricarbonyl(η4-diene)iron], and (η3-allyl)tetracarbonyliron trifluoroborate complexes

A variety of mono- and bis[Fe(CO)₃(η⁴-diene)] complex with alky, CH₂OH, CHO, COCH₃, COOR, and CN substituents on the 1,3-diene system have been synthesized. Dienes with a (Z)-configuration terminal Me group show steric inhibition of metal complexation resulting in lower yields and formation of tetracarbonyl(η²-diene) and tricarbonyl(η⁴-heterodiene) complexes as additional products. Regioselective attack by C-nucleophiles at the carbonyl C-atoms of the functional group with or without concomitant 1,3 mogration of the Fe(CO)₃ group was used to synthesize polyenes and isoprenoid building blocks as mono- or dinucliar Fe(CO)₃ complexes. Wittig-Horner-type reactions of Fe(co)₃-complexed synthons result in sterospecific formation of (E)-configurated olefins. The ¹H-, ¹³C- and ⁵⁷Fe-NMR spectra of olefinic and allylic organoiron complexes are reported, H,H,C,H, and C,C coupling constants have been evaluated and are analyzed in terms of the geometry of the coordinated diene. The results are corroborated by the crystal structure of tricarbonyl[3–6-η-((E)-6-methyl-3,5-heptadiene-2-one)]iron( 34 ) which shows an unusual distortion of the (CH₃)₂C = group, The ⁵⁷Fe-NMR chemical shifts extend over the ranges of 0–600 ppm for [Fe(CO)₃(η⁴-diene)] complexes, 780–1710 ppm for [Fe(CO)₄(η³-allyl)] [BF₄] and [FeX(CO)₃(η⁴-allyl)] complexes, and 1270–1690 ppm for [Fe(CO)₃(η⁴-enone)] complexes, relative to Fe(CO)₅.