Complexation of [2.2]paracyclophane with an (η5-cyclopentadienyl)iron+ moity: mono- and di-cations

The reaction of [2.2]paracyclophane with ferrocene in the presence of AlCl₃ and Al/powder gives the new compounds [1-6-η-[2.2]paracyclophane- (η⁵-cyclopentadienyl)iron]⁺[PF₆] and [1-6-η; 9-14-η-[2.2]paracyclophane- [(η⁵-cyclopentadienyl)iron]₂]²⁺[PF₆]₂ in high yields. The species have been characterized by elemental analysis, and by ¹H and ¹³C NMR spectroscopy.     

Effects on Coordination of Thioether Sites. 4. Structural Analysis of η3-Tripodal Ligand Manganese(I) Complexes

Crystal structures of a series of manganese(I) complexes containing tripodal ligands were determined. For [η³-{CH₃C(CH₂PPh₂)₂(CH₂SPh)-P,P′,S}Mn(CO)₃]PF₆ ( 1 ): a = 10.856(3) Å, b = 19.698(3) Å, c = 17.596(5) Å, β = 96.17(2)°, monoclinic, Z = 4, P2₁/c, R(F_o) = 0.068, R_w(F_o) = 0.055 for 3617 reflections with I_o > 2σ(I_o). For [η³-{CH₃C(CH₂PPh₂)(CH₂SPh)₂-P,P′,S}Mn(CO)₃]PF₆ ( 2 ): a = 9.890(2) Å, b = 20.403(4) Å, c = 10.269(3) Å, β = 117.44(2)°, monoclinic, Z = 2, P2_l, R(F_o) = 0.050, R_w(F_o) = 0.037 for 1760 reflections with I_o > 2σ(I_o). For [η³-{CH₃C(CH₂PPh₂)₂(CH₂S)-P,P′,S}Mn(CO)₃] ( 4 ): a = 8.191(7) Å, b = 10.495(3) Å, c = 19.858(6) Å, α = 99.61(2)°, β = 96.17(2)°, γ = 92.70(4)°, triclinic, Z = 2, P-I, R(F_o) = 0.048, R_w(F_o) = 0.039 for 2973 reflections with I_o > 2σ(I_o). There is no significant difference in the bond lengths of Mn-S bonds among three species in their crystal structures [2.325(2) Å in 1; 2.358(4) in 2; 2.380(2) in 4], but the better donating ability of thiolate in complex 4 appears on the lower frequencies of its carbonyl stretching absorptions.     

Chiral arene ruthenium complexes: Part 3. [Ruthenium(η6-arene)(η4-1,5-cyclooctadiene)] complexes with N or O donor functions in the arene side chain

Arene ruthenium(0) complexes with carbonyl side chain functionalities like [Ru(η⁶-C₆H₅COR)(η⁴-COD)] or [Ru(η⁶-o-C₆H₄{R¹}COR)(η⁴-COD)] (COD=1,5-cyclooctadiene; R=H, CH₃; R¹=H, CH₃, OCH₃) are easily accessible by replacing the naphthalene ligand of [Ru(η⁶-naphthalene)(η⁴-COD)] (1) through an arene exchange reaction. These carbonyl species are susceptible to standard organic reactions of the carbonyl function, thus allowing the introduction of dangling side chains bearing highly polar functions like hydroxyl or amino groups. Aldol reaction of [Ru(o-C₆H₄{CH₃}COCH₃)(COD)] (3) with (−)-menthylchloroformate in the presence of LDA (LDA=lithium diisopropylamide) leads to a diastereomeric mixture of [Ru(menthyl-{3-oxo-3-η⁶-o-tolyl}propionate)(COD)] (10). However, treatment of 3 with LDA and o-tolylaldehyde or benzaldehyde affords the unexpected products [Ru(1-η⁶-o-tolyl-3-o-tolylpropan-1-one)(COD)] (11) and [Ru(1-η⁶-o-tolyl-1-phenylpropan-1-one)(COD)] (12). A diastereoselective addition (88% de) of deprotonated menthylacetate to [Ru(o-tolylaldehyde)(COD)] (4) results in the formation of [Ru(menthyl 3-η⁶-o-tolyl-3-hydroxypropionate)(COD)] (13). Racemic planar-chiral aldehyde complexes 2 and 4 react with amines giving the imination products in good yield. In case of reaction between 2 and (R)-N-amino-2-(methoxymethyl)-pyrrolidine (RAMP), diastereomeric [Ru(N-[[η⁶-(2-methylphenyl]methylene]-(R)-2-(methoxymethyl)-1-pyrrolidinamine)(COD)] (17) is formed. The diastereomers (R,R)-17 and (S,R)-17 have been separated by fractional crystallisation. Asymmetric arene ruthenium complexes with a defined planar-chiral configuration are thus accessible. Reduction of [Ru(3-η⁶-phenyl-(R)-methylbutyrate)(COD)] (7) with LiAlH₄ yields the chiral γ-alcohol [Ru(3-η⁶-phenyl-(R)-1-butanol)(COD)] (18). A Wittig olefination converts the aldehyde complex 4 into a mixture of E- and Z-isomeric [Ru(1-η⁶-o-tolyl-2-phenylethylene)(COD)] 21a and 21b, which were separated again by fractional crystallisation.     

Synthesis of some heterocyclic skeletons via organoiron complexes. Crystal and molecular structure of (5a,6,7,8,9,9a-η6-1,4-benzoxathiino[3,2-b]pyridine)(η5-cyclopentadienyl)iron hexafluorophosphate

Synthesis of the heterocyclic skeletons of some biologically active compounds from (η⁶-o-dichlorobenzene)(η⁵-cyclopentadienyrl)iron hexafluorophosphate in a two step procedure is described. Cyclopentadienyliron hexafluorophosphate complexes of 1,4-benzodioxino[2,3-b]pyridine, 1,4-benzoxathiino[3,2-b]pyridine, 10H-pyrido[3,2-b]benzoxazine, benzo[b]naphtho[2,3-e][1,4]dioxin, 4-methylbenzo[b]benzopyran-2-one[7,6-e][1,4]dioxin and benzo[b]anthracen-9,10-diono[1,2-e][1,4]dioxin were isolated and characterized. Upon pyrolytic sublimation of these complexes the free heterocycles were obtained and characterized. (η⁶-1,4-Benzoxathiino[3,2-b]pyridine)(η⁵-cyclopentadienyl)iron hexafluorophosphate crystalizes in the orthothombic system, space group Pbca; the dihedral angle between the planes of outer rings was found to be 176.8 (1).     

Syndioselective propylene polymerization catalyzed by rac-2,2-dimethylpropylidene (1-η5-cyclopentadienyl) (1-η5-fluorenyl) dichlorozirconium

Syndioselective propylene polymerization has been promoted by rac-2,2-dimethylpropylidene (1-η⁵-cyclopentadienyl) (1-η⁵-fluorenyl) dichlorozirconium ( 1 ). The active catalytic species were generated using either triphenylcarbenium tetrakis (pentafluorophenyl) borate ( 2 ) (Zr⁺ method) or methylaluminoxane (MAO method). The former exhibited much higher activity than the latter, especially at low polymerization temperatures (T_p). Syndiotactic poly (propylene) (s-PP) obtained at T_p = ?20°C has T_m approaching 160°C, [rrrr] pentad fraction of 0.92 to 0.95, and 45% crystallinity (X_c). It crystallized in two antichiral unit cells B and C. The C structure is favored by low temperature of polymerization, slow crystallization from melt, and annealing. The s-PP has M?_w/M?_n ranging from 3.6 to 4.4, which can be separated into stereoregular fractions soluble in heptane and hexane and stereoirregular fractions soluble in pentane, ether, and acetone. Therefore, this system cannot be considered to be a single-site catalyst. A parallel study was made on the isopropylidene (1-η⁵-cyclopentadienyl) (1-η⁵-fluorenyl) dichlorozirconium ( 3 )/MAO catalyst. Molecular mechanics calculations were performed for all combinations of the configuration of asymmetric centers. The steric energy favors syndiotactic enchainment for both catalysts 1 and 3 , with 1 forming the more syndioselective catalyst. © 1994 John Wiley & Sons, Inc.     

Crystal and Molecular Structure of Carbonyl (1,1,4,4-Tetrafluoro-2-tert-Butyl-1,4-Disilabut-2-Ene) (η5-Cyclopentadienyl) Cobalt (II)

(C₃H₅)Co(CO)(Si₂F₄C₄H₁₀) was synthesized by the photochemical reaction between dicarbonyl (η⁵-cyclopentadienyl) cobalt and 1,1,2,2-tetrafluoro-1,2,-disilacyclobutene. Its structure was identified by IR, NMR and mass spectrometry. The single crystal structure was studied for confirmation. The compound crystalized in a monoclinic space group P2₁/n with unit cell a=7.120 (6), b=20.334. (3), c=10.682(1) Å, β=90.97(8)°, Z=4 final R=0.050 for 3667 observed reflections. The molecule has a mirror plane symmetry about the Co atom coordination sphere. The reaction between the cobalt carbonyl and the 1,2-disilacyclobutene produces only silicon-cobalt σ bonds.     

[η6‐1‐Chloro‐2‐(pyrrolidin‐1‐yl)benzene](η5‐cyclopentadienyl)iron(II) hexafluoridophosphate and (η5‐cyclopentadienyl){2‐[η6‐2‐(pyrrolidin‐1‐yl)phenyl]phenol}iron(II) hexafluoridophosphate

In the complex salt [η⁶‐1‐chloro‐2‐(pyrrolidin‐1‐yl)benzene](η⁵‐cyclopentadienyl)iron(II) hexafluoridophosphate, [Fe(C₅H₅)(C₁₀H₁₂ClN)]PF₆, (I), the complexed cyclopentadienyl and benzene rings are almost parallel, with a dihedral angle between their planes of 2.3 (3)°. In a related complex salt, (η⁵‐cyclopentadienyl){2‐[η⁶‐2‐(pyrrolidin‐1‐yl)phenyl]phenol}iron(II) hexafluoridophosphate, [Fe(C₅H₅)(C₁₆H₁₇NO)]PF₆, (II), the analogous angle is 5.4 (1)°. In both complexes, the aromatic C atom bound to the pyrrolidine N atom is located out of the plane defined by the remaining five ring C atoms. The dihedral angles between the plane of these five ring atoms and a plane defined by the N‐bound aromatic C atom and two neighboring C atoms are 9.7 (8) and 5.6 (2)° for (I) and (II), respectively.     

Thermische disproportionierung von (η5-C5H5)2V2(CO)5. Tetrakis[carbonyl(η5-cyclopentadienyl)vanadium], (η5-C5H5)4V4(CO)4

The novel vanadium cluster tetrakis[carbonyl(η⁵-cyclopentadienyl)- vanadium has been prepared in 32% yield by thermal disproportionation of μ-dicarbonyltricarbonylbis(η⁵-cyclopentadienylvanadium) (V-V) in boiling tetrahydrofuran.     

Reactions of Dienes with a Mo(0) Complex with Tetraphosphine Coligand [Mo(P4)(Ph2PCH2CH2PPh2)] (P4 = Meso‐o‐C6H4(PPhCH2CH2PPh2)2)

Reaction of tetraphosphine complex [Mo(κ⁴‐P4)(Ph₂PCH₂CH₂PPh₂)] (1; P4 = meso‐o‐C₆H₄‐(PPhCH₂CH₂PPh₂)₂) with E‐1,3‐pentadiene in toluene at 60 °C gave the η⁴‐diene complex [Mo(η⁴‐E‐1,3‐pentadiene)(κ⁴‐P4)] (2), which is present as a mixture of two isomers due to the orientation of the Me group in the diene ligand. Treatment of 1 with Z‐1,3‐pentadien also resulted in the formation of 2 as the sole product after heating the reaction mixture at 90 °C. Whereas the reaction of 1 with 1,3‐cyclohexadiene at 60 °C afforded the η⁴‐diene complex [Mo(η⁴‐cyclohexadiene)(κ⁴‐P4)] (6), that with cyclopentadiene led to the C‐H bond scission product [η⁵‐C₅H₅)MoH(κ³‐P4)] (7). Detailed structures were determined by X‐ray crystallography for 2, 6,and 7, and fluxional feature of 6 in solution was clarified based on the VT‐NMR studies.     

Darstellung und Struktur von Tetrafluoro(η5-pentamethylcyclopentadienyl)niob und Tetrafluoro(η5-cyclopentadienyl)niob

Preparation and Structure of Tetrafluoro(η⁵-pentamethylcyclopentadienyl) Niobium and Tetrafluoro(η⁵-cyclopentadienyl) Niobium A facile preparation method for (η⁵-C₅Me₅)NbF₄ 3 and (η⁵-C₅H₅)NbF₄ 4 is reported by using AsF₃ as a fluorinating agent. Single crystals obtained from AsF₃ contain the solvent molecule as well as HF. The composition of the crystal is [(η⁵-C₅Me₅)NbF₄(AsF₃)₂]₂ · [(η⁵-C₅Me₅)NbF₄(HF)AsF₃]₂ 5 . The X-ray crystal structure of 5 will be reported. 5 crystallizes triclinic with one furmula in the space group P1 and lattice constants a = 843.1(4), b = 1154.9(6), c = 1910.2(10) pm, α = 91.68(3)°, β = 99.30(3)°, γ = 104.44(2)°.     

Photochemische Reaktionen von Cyclopentadienylbis(ethen)rhodium mit Phenanthren,Acenaphthylen und Triphenylen,sowie ungewöhnlicher H-Austausch zwischen η2-koordinierten Phenanthren- bzw. Acenaphthylen- und η5-Cyclopentadienyl-Liganden

Photochemical Reactions of Cyclopentadienylbis(ethene)rhodium with Phenanthrene, Acenaphthylene, and Triphenylene, and Unusual H Exchange between η²-Coordinated Phenanthrene or Acenaphthylene and η⁵-Cyclopentadienyl Ligands During UV irradiation of [CpRh(C₂H₄)₂] (Cp = η⁵-C₅H₅) in hexane/ether in the presence of phenanthrene one ethene ligand is displaced by coordination of the 9,10 double bond of phenanthrene, and (η⁵-cyclopentadienyl) (η²-ethene)(η²-9,10-phenanthrene)rhodium ( 1 ) is formed. The analogous reaction in hexane in the presence of acenaphthylene occurs with formation of the complexes (η²-1,2-acenaphthylene)(η⁵-cyclopentadienyl)(²-ethene)rhodium 2 and bis(η²-1,2-acenaphthylene)(η⁵-cyclopentadienyl)rhodium 3 in which one and two ethene molecules of [CpRh(C₂H₄)₂], respectively, are substituted by η²-1,2-acenaphthylene. The irradiation of [CpRh(C₂H₄)₂] with triphenylene in hexane yields the compounds [CpRh(η⁴-1,2,3,4-triphenylene)] ( 4 ), [(CpRh)₂(μ-η³: η³-triphenylene)] ( 5 ), and [(CpRh)₃(μ₃-η²: η²: η²-triphenylene)] ( 6 ). Despite the partially very low yields the new complexes could be unequivocally characterized spectroscopically and in the case of 1 and 3 by X-ray structural analysis. The compounds 1 and 2 in solution reveal a novel dynamic behaviour; via an intramolecular C? H activation, exchange occurs between the protons of the η²-coordinated arene and the Cp ligand. The complex 4 in solution is fluxional, too.     

Studies on the reactions of (η5cyclopentadienyl)dicarbonylcobalt with phenyl-1-naphthylacetylene and with phenyl-2-naphthylacetylene,and an X-ray crystallographic determination of one of the products: (η5cyclopentadienyl)-[η4-3,3-di-(1-naphthyl)-2,4diphenylcyclobutadiene]cobalt

The reactions of (η⁵-C₅H₅)Co(CO)₂ with both phenyl-1-naphthylacetylene and phenyl-2-naphthylacetylene have been shown to produce all four possible η⁵-cyclobutadiene-cobalt complexes and all six possible η⁴-cyclopentadienone-cobalt derivatives. The structures of the η⁴-cyclobutadiene-cobalt complexes have been assigned on the basis of proton NMR and mass spectral studies, and unequivocally established by means of an X-ray diffraction investigation for one of the isomers as (η⁵-cyclopentadienyl)[η⁴-1,3-di(1-naphthyl)-2,4-diphenylcyclobutadiene]cobalt. This compound is triclinic, a = 10.88(2), b = 15.710(6), c = 8.728(4) Å, α = 95.09(4)°, β = 101.94(2)°, γ = 86.93(3)°. The space group is P$\text{1}$ with Z = 2. The structure was solved by Patterson and Fourier methods and refined by full-matrix least squares methods (4128 reflections above 3σ) to a final R = 0.036. Bond distances and angles are normal but the cyclobutadiene ring is not quite planar. One of the atoms is 0.047 Å out of the plane of the other three apparently to relieve steric stress. The two phenyl rings are almost coplanar with the cyclobutadiene ring (torsion angles 3.9 and 20.4°) while the naphthyl rings are almost perpendicular to it (torsion angles 63.8, 64°).     

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.     

Synthesis,structure and electrochemical properties of a zinc(II) coordination polymer based on ferrocenyl-substituted carboxylate and bis (benzimidazolyl)pentane ligands

By reaction of two ligands, Na(o-OOCC₆H₄COFc) (Fc?=?(η⁵–C₅H₅)Fe(η⁵–C₅H₄)) and 1,1′–(1,5–pentamethylene)bis-1H-benzimidazole (pbbm), with Zn(OAc)₂?·?2H₂O in methanol solution, we have synthesized a zinc(II) coordination polymer [Zn(o-OOCC₆H₄COFc)₂(pbbm)] _n . The polymer was characterized by X-ray single crystal diffraction, IR spectroscopy, and elemental analysis. Each Zn atom was connected by two pbbm ligands, leading to an infinite one-dimensional chain. Two monodentate o-FcCOC₆H₄COO^? anions completed the coordination sphere of the central Zn(II) ion. The polymer's electrochemical properties were investigated in DMF solution.     

Molecular and crystal structure of Bis(η5-cyclopentadienyl)titanium(IV) Dibromide,Ti(η5-C5H5)2Br2

The crystal and molecular structure of Bis(η⁵-cyclopentadienyl)titanium(IV) dibromide, Ti(η⁵?C₅H₅)₂Br₂, has been investigated by an X-ray structure determination. Crystal data: triclinic, a = 7.872(5), b = 11.807(5), c = 12.310(3) Å, α = 107.62(3), β = 100.83(4), γ = 90.69(4)°, V = 1 068(14) ų, T = 293, space group P1 , Z = 4 (there are two crystallographically independent molecules in the asymmetric unit cell and their conformations are similar). Final R and R_w values are 0.068 and 0.073, respectively. The structural results are compared to those for similar type molecules.     

Multilayered iron complexes of metacyclophanes. 1H NMR behavior

Syntheses are described for a series of (η⁶-cyclophane)(η⁵cyclopentadienyl)iron(II) complexes, where the cyclophane moiety is anti-[2.2]metacyclophane, anti-4,12-dimethyl[2.2]metacyclophane, anti-4,12-dimethyl-7,15-dimethoxy[2.2]metacyclophane, and [2.2](2,5)thiophenophane. The triple-layered complexes η⁶,η⁶-anti-[2.2]metacyclophane)bis[(η⁵-cyclopentadienyl)iron(II)] bis(hexafluorophosphate) and (η⁶,η⁶-anti-4,12-dimethyl[2.2]metacyclophane)bis[(η⁵-cyclopentadienyl)iron(II)] bis(hexafluorophosphate) were also prepared. The NMR spectra of these compounds provide a useful insight into the nature of the iron-cyclophane bonding.     

Über die Temperaturabhängigkeit der 13C-NMR.-Spektren von Tetracarbonyl (η-(Z)-cycloocten)eisen und (Z)-cycloocten

On the Temperature Dependence of the ¹³C-NMR.-Spectra of Tetracarbonyl (η-( Z )-cyclooctene)iron and of ( Z )-Cyclooctene Reaction of (Z)-cyclooctene (1) with Fe₂(CO)₉ in pentane at 0° yielded tetracarbonyl(η-(Z)-cyclooctene)iron (2) as a yellow oil which can be stored over a longer period only at ?78°. It is shown that the title compounds ( 1 and 2 , respectively) are fluxional. The activation parameters for the conformational C-atom site exchange of (Z)-cyclooctene (1) and tetracarbonyl (η-(Z)-cyclooctene)iron (2) (in CCl₂F₂) have been determined between 113 K and 151 K for 1 and between 151 K and 205 K for 2 , respectively, by a complete line shape analysis of the temperature dependent proton noise-decoupled ¹³C-NMR. signals of the olefinic C-atom. The kinetic data and activation parameters are given in Tables 1 and 2.     

Reaktionen des [η2-{P–PtBu2}Pt(PPh3)2] und [η2-{P–PtBu2}Pt(dppe)] mit Metallcarbonylen. Bildung von [η2-{(CO)5M · PPtBu2}Pt(PPh3)2] (M = Cr,W) und [η2-{(CO)5Cr · PPtBu2}Pt(dppe)]

Coordination Chemistry of P-rich Phosphanes and Silylphosphanes. XVI [1] Reactions of [g²-{P–P^tBu₂}Pt(PPh₃)₂] and [g²-{P–P^tBu₂}Pt(dppe)] with Metal Carbonyls. Formation of [g²-{(CO)₅M · PP^tBu₂}Pt(PPh₃)₂] (M = Cr, W) and [g²-{(CO)₅Cr · PP^tBu₂}Pt(dppe)] [η²-{P–P^tBu₂}Pt(PPh₃)₂] 4 reacts with M(CO)₅ · THF (M = Cr, W) by adding the M(CO)₅ group to the phosphinophosphinidene ligand yielding [η²-{(CO)₅Cr · PP^tBu₂}Pt(PPh₃)₂] 1 , or [η²-{(CO)₅W · PP^tBu₂}Pt(PPh₃)₂] 2 , respectively. Similarly, [η²-{P–P^tBu₂}Pt(dppe)] 5 yields [η²-{(CO)₅Cr · PP^tBu₂}Pt(dppe)] 3 . Compounds 1 , 2 and 3 are characterized by their ¹H- and ³¹P-NMR spectra, for 2 and 3 also crystal structure determinations were performed. 2 crystallizes in the monoclinic space group P2₁/n (no. 14) with a = 1422.7(1) pm, b = 1509.3(1) pm, c = 2262.4(2) pm, β = 103.669(9)°. 3 crystallizes in the triclinic space group P1 (no. 2) with a = 1064.55(9) pm, b = 1149.9(1) pm, c = 1693.2(1) pm, α = 88.020(8)°, β = 72.524(7)°, γ = 85.850(8)°.     

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.     

[μ‐1κ2O,O′:2(η5)‐Cyclopentadienylcarboxylato][2(η5)‐diphenylphosphinocyclopentadienyl]bis[1,1(η5)‐tetramethylcyclopentadienyl]iron(II)titanium(III)

Reacting stoichiometric amounts of 1‐(diphenylphosphino)ferrocene­carboxylic acid and [Ti(η⁵‐C₅HMe₄)₂(η²‐Me₃SiC[triple‐bond]CSiMe₃)] produced the title carboxyl­atotitanocene complex, [{μ‐1κ²O,O′:2(η⁵)‐C₅H₄CO₂}{2(η⁵)‐C₅H₄P(C₆H₅)₂}{1(η⁵)‐C₅H(CH₃)₄}₂Fe^IITi^III] or [FeTi(C₉H₁₃)₂(C₆H₄O₂)(C₁₇H₁₄P)]. The angle subtended by the Ti/O/O′ plane, where O and O′ are the donor atoms of the κ²‐carboxy­late group, and the plane of the carboxyl‐substituted ferrocene cyclo­penta­dienyl is 24.93 (6)°.