The structure and formation of niobocene carbonyl heteronuclear derivatives. The molecular structures of Cp2Nb(CO)(μ-CO)Mn(CO)4, Cp2Nb(CO)(μ-H)Ni(CO)3 and [Cp2Nb(CO)(μ-H)]2Mo(CO)4

The heteronuclear Cp₂Nb(CO)(μ-CO)Mn(CO)₄ (I), Cp₂Nb(CO)(μ-H)Ni(CO)₃ (II) and [Cp₂Nb(CO)(μ-H)]₂M(CO)₄ (III, M = Mo;IV, M = W) complexes were prepared by reaction of Cp₂NbBH₄/Et₃N with Mn₂(CO)₁₀ in refluxing toluene, direct reaction of Cp₂NbBH₄ with Ni(CO)₄ in ether, and reaction of Cp₂NbBH₄/Et₃N with M(CO)₅. THF complexes (M = Mo or W) in THF/benzene mixture. An X-ray investigation of compounds I–III was performed. It is established that in I the bonding between Mn(CO)₅ and Cp₂Nb(CO) (with the angle (α) between the ring planes being 44.2(5)°) fragments takes place via a direct NbMn bond (3.176(1) Å) and a highly asymmetric carbonyl bridge (MnC_co 1.837(5) Å, NbC_co 2.781(5) Å). On the other hand, in complex II the sandwich Cp₂Nb(CO)H molecule (angle α = 37.8°) is combined with the Ni(CO)₃ group generally via a hydride bridge (NbH 1.83 Å, NiH 1.68 Å, NbHNi angle 132.7°) whereas the large Nb?Ni distance, 3.218(1) Å, shows the weakening or even absence of the direct NbNi bond. Similarly, in complex III two Cp₂Nb(CO)H molecules (with α angles equal to 41.4 and 43.0°, respectively) are joined to the Mo(CO)₄ group via the hydride bridges (NbH 1.83 and 1.75 Å and MoH 2.04 and 2.06 Å) producing a cis-form. The direct NbMo bonds are probably absent, since the Nb?Mo distances are rather long (3.579 and 3.565 Å). The effect of electronic and steric factors on the structure of heteronuclear niobocene carbonyl derivatives is discussed.     

Antiferromagnetic complexes with a metal-metal bond: XV. Antiferromagnetic heterometallospirane clusters [(CH3C5H4)2Cr2(μ-SCMe3)(μ3-S)2]2M (M = MnII,FeII): Synthesis and molecular structures

The reaction of (CH₃C₅H₄CrSCMe₃)₂S (Ia) with Cp₂Mn in boiling toluene (containing some THF) has been used to prepare a pentanuclear cluster, [(CH₃C₅H₄)₂Cr₂(SCMe₃)(μ₃-S)₂]Mn (II), which is antiferromagnetic and crystallizes into the monoclinic crystal system: space group Cc, a 26.540(10), b 9.208(3), c 21.595(9) Å; β 135.30(2)°, V = 3712.1 ų, Z = 4. According to X-ray analysis, cluster II contains a metallospirane core, Cr₄Mn, which appears to be strongly distorted, compared to its earlier studied cyclopentadienyl analogue [Cp₂Cr₂SCMe₃(μ₃-S)₂]₂Mn, due to the short intramolecular contacts CH₃…S (2.9–3.1 Å). The angle between the metal triangle planes of Cr₂Mn is 109.60°. Here, the two long CrMn bonds (3.019(3) and 3.104(4) Å) are combined with the shorter Cr Cr bond (2.651(6) Å) in one triangle and, vice versa, the less extended CrMn bonds (2.839(4) and 2.967(3) Å) are combined with a longer CrCr bond (2.726(6) Å) in the other triangle of Cr₂Mn. By the reaction of Ia with [CpFe(CO)₂]₂ (taken in the ratio of $\text{2}\text{1}$) in boiling toluene, the antiferromagnetic cluster [(CH₃C₅H₄)₂Cr₂(SCMe₃)(μ₃-S)₂]₂Fe (III) has been synthesized in which the same distortions as in cluster II are present, as revealed by X-ray analysis. In the metallospirane core of the molecule of III, the Cr₂Fe triangles make an angle of 113.84° with each other. In this cluster, the CrCr distances in the peripheral binuclear fragments (CH₃C₅H₄)₂Cr₂(μ-SCMe₃)(μ₃-S)₂ are practically equal (2.688(3) and 2.661(3) Å), whereas the FeCr bond lengths are markedly different (2.749(2) and 2.827(2) Å in on triangle and 2.910(2) and 2.969(2) Å in the other). The dependence of the geometries of clusters II and III on the steric effects of the methyl substituents in the cyclopentadienyl ligands and on the electronic effect of the central metal atom (Mn^II or Fe^II) is discussed.     

Small ring metallocycles : V. Crystal and molecular structure of hydrido-1,3-(1,1,3,3-tetramethyldisiloxanediyl)carbonylbis(triphenylphosphine)iridium(III), Me2SiOSiMe2Ir(H)(CO)(PPh3)2 · EtOH

The structure of the cyclo-metalladisiloxane, Me₂SiOSiMe₂Ir(H)(CO)(PPh₃)₂, has been determined by single crystal X-ray diffraction using Mo-K_α radiation. Data were collected to 20 = 45 ° giving 6060 unique reflections,of which 4582 had I ?3σ(I). The latter were used in the full-matrix refinement. Crystallographic data: space group, P$\text{1}$; cell constants: 12.604(7),12.470(4), 15.821(6) Å, 66.93(6)°, 105.34(7)°, 112.41(8)°;V 2095(3) ų; p(obs) 1.45 g/cm³; p(calc) 1.46g/cm³ (Z=2). The asymmetric unit consists of one iridium complex and one molecule of ethanol of salvation. The structure was solved by standard heavy atom methods and refined with all non-hydrogen atoms anisotrophic to final R factors, R₁ 0.034 and R₂ 0.042. The iridium metallocycle has approximate C_s symmetry with the mirror plane passing through the four-membered IrSiOSi ring. The average IrP, IrSi and SiO bond lengths are 2.38, 2.41, and 1.68 Å, respectively. The IrCO and CO bond lengths are 1.903(8) and 1.133(8). The H atom bonded to Ir was not located.The Ir atom is raised out of the basal, P₂Si₂ plane toward the carbonyl by about 0.26 Å. The most striking feature of the structure is the strain apparent in the four-membered ring. The internal angels are: 64.7 (SiIrSi), 96.8 (IrSiO), 97.8 (IrSiO), and 99.8 (SiOSi). In an unstrained molecule, the SiOSi angle is normally in the 130–150° range. It is proposed that the strain in the ring is consistent with the catalytic activity of the metallocycle.     

Basische metalle : IX. Synthese und kristallstruktur von C5H5Co(PMe3)CS2. Reaktionen zu zweikernkomplexen mit Co(SCS)Cr- und Co(SCS)Mn-Brückenbindungen

C₅H₅Co(PMe₃)CS₂ (IV) is formed in practically quantitative yield in the reaction of C₅H₅Co(PMe₃)₂ (I) or the heterobinuclear complex C₅H₅(PMe₃)Co(CO)₂Mn(CO)C₅H₄Me (III) with CS₂. The crystal structure shows that the carbon disulfide bonds as a dihapto ligand through the carbon and one sulfur atom (S(2)) (CoC = 1.89, CoS(2) = 2.24 Å, S(2)CS(1) = 141.2°). The two CS bond lengths in IV (CS(2) = 1.68, CS(1) =1.60 Å) are greater than in free CS₂ (1.554Å) which is in agreement with the strong π-acceptor character of h²-CS₂ as shown in the spectroscopic data. IV reacts with Cr(CO)₅THF and C₅H₅Mn(CO)₂THF to give the complexes C₅H₅(PMe₃)Co(SCS)Cr(CO)₅ (V) and C₅H₅(PMe₃)Co(SCS)Mn(CO)₂C₅H₅ (VI) respectively, in which the sulfur atom S(1) that is not bound to cobalt coordinates to the 16-electron fragments Cr(CO)₅ and Mn(CO)₂C₅H₅. The spectroscopic data of IV, V and VI are discussed.     

Antiferromagnetic complexes involving metalmetal bonds IV. Synthesis,molecular structure and magnetic properties of the heterotrinuclear cluster, (C5H5Cr)2(μ2-SCMe3)(μ3-S)2Fe(CO)3, with direct and indirect exchange between CrIII and FeI centers

The photochemical reaction between the antiferromagnetic complex (C₅H₅-CrSCMe₃)₂S (I) (containing a CrCr bond 2.689 Å long) and Fe(CO)₅ results in the elimination of two carbonyl groups and one tert-butyl radical to give (C₅H₅Cr)₂(μ²-SCMe₃)(μ³-S)₂ · Fe(CO)₃ (III). As determined by X-ray diffraction, III contains a CrCr bond of almost the same length as in I (2.707 Å), together with one thiolate and two sulphide bridges. The latter are also linked with the Fe atom of the Fe(CO)₃ moiety (average FeS bond length 2.300 Å). Fe also forms a direct bond, 2.726 Å long, with one of the Cr atoms, whereas its distance from the other Cr atom (3.110 Å) is characteristic for non-bonded interactions. Complex III is antiferromagnetic, the exchange parameter, ?2J, values for CrCr, Cr(1)Fe and Cr(2)…Fe are 380, 2600 and 170 cm^?1, respectively. The magnetic properties of III are discussed in terms of the “exchange channel model”. The contributions from indirect interactions through bridging ligands are shown to be insignificant compared with direct exchange involving metalmetal bonds. The effects of steric factors and of the nature of the M(CO)_n fragments on the chemical transformations of (C₅H₅CrSCMe₃)₂S · M(CO)_n are discussed.     

Synthesis and structure of FeRu3(CO)13(μ-PPh2)2; A “64-electron” cluster complex with a planar triangulated rhomboidal array of metal atoms

The species FeRu₃(CO)₁₃(μ-PPH₂)₂, synthesized from Ru₃(CO)₁₂ and Fe(CO)₄(Ph₂PPPh₂),has been characterized both spectroscopically and via a single-crystal X-ray structural analysis. This complex crystallizes in the centrosymmetric triclinic space group P$\text{1}$ [No. 2, C_i¹] with a  10.066(3), b  12.899(3), c  17.003(4) Å, α  111.89(2), β  91.02(2), γ  102.00(2)°, V  1992.7(9) ų, Z  2, ?(obsd)  1.79(2) g cm^-3 and ?(calcd)  1.82 cm^-3. Diffraction data were collected with a Syntex P2₁ automated four-circle diffractometer and the structure was refined to R_F  6.0% and R_WF  3.6% for all 5213 reflections (R_F  3.8%, R_WF  3.6% for those 4140 reflections with |F_o|> 3σ(|F_o|).The metal atoms define a planar triangulated rhombus, with atoms Ru(1) and Ru(2) at the bridgehead, and Fe(1) and Ru(3) at the acute apices. Fe(1) is linked to four terminal carbonyl ligands and is associated with the heteronuclear bonds Fe(1)Ru(1)  2.861(1) Å and Fe(1)Ru(2)  2.868(1) Å. The ruthenium atoms are each bonded to three terminal carbonyl groups. The retheniumruthenium distances are Ru(1)Ru(2)  3.098(1), Ru(1)Ru(3)  3.147(1), and Ru(2)Ru(3)  3.171(1) Å. The structure is completed by Ph₂P bridges across the Ru(1)Ru(3) and Ru(2)(ru(3) vectors (<Ru(1)P(1)Ru(3)  84.89(5)° and <Ru(2)P(2)Ru(3)  85.56(6)°).     

Polysilane derivatives of the transition metals II. The crystal and molecular structure of [tris(trimethylsilyl)silyl]pentacarbonylmanganese, (Me3Si)3SiMn(CO)5

The crystal and molecular structures of [tris(trimethylsilyl)silyl]pentacarbonylmanganese, (Me₃Si)₃SiMn(CO)₅, have been determined from three-dimensional X-ray data obtained by counter methods. The compound crystallizes in space group P$\text{1}$ of the triclinic system, with two molecules in a unit cell of dimensions: a = 9.002(2), b = 9.655(2), c = 15.639(3) Å, α = 83.66(1), β = 105.65(1), γ = 114.61(1)°.The observed and calculated densities are 1.20 (±0.03) and 1.23 g-cm^?3 respectively. Full-matrix least-squares refinement of the structure has led to a final value of the conventional R factor of 0.059 for the 818 independent reflections having F² > 3σ(F²).The coordination geometry about the manganese atom is approximately octahedral and, about the silicon atom bonded to the manganese atom, tetrahedral.The relative orientations of carbonyl and trimethylsilyl groups, when viewed down the MnSi bond, appear consistent with minimization of energy due to nonbonded interactions.Two of the equatorial carbonyl groups are displaced out of the equatorial plane towards the silicon ligand by 6°. The SiMn bond is 2.564(6) Å long and has no multiple character.     

Die konformation des μ-bis[tetracarbonylrhenium(I)]-bis-[tetracarbonyl(trithiocarbonato)rhenium(I)], eines überraschenden reaktionsproduktes bei der umsetzung von CF3Re(CO)5 mit CS2

The molecular structure of [(C₆H₅)₃P]₂Pd(C₃H₄) has been determined from three-dimensional X-ray diffraction data. The crystal belongs to the triclinic system, space group P$\text{1}$, with two formula units in a cell of dimensions: a = 19.475(2), b = 10.204(2), c = 18.341(2) Å, α = 108.46(2), β = 85.46(1), and γ = 118.80(1)°.One of the olefinic bonds of allene is coordinated to the palladium atom: PdC(1) = 2.118(9) and PdC(2) = 2.067(8) Å. The coordinated allene is no longer linear, the C(1)C(2)C(3) angle being 148.3(8)°. The C(1)C(2) distance is 1.401(11) Å, whereas the uncoordinated bond remains unchanged [C(2)C(3) = 1.304(12) Å]. The Pd, P(1), P(2), C(1) and C(2) atoms lie almost in the same plane.     

The structure of the metallated iridium complex [(C8H12)Ir{P(OC6H3Me)(OC6H4Me)2} {P(OCH2)3CMe}]

The crystal structure of [(C₈H₁₂)$\text{Ir{P(OC}$₆H₃Me)(OC₆H₄Me)₂} {P(OCH₂)₃CMe}] has been determined. a 18.32, b 18.98, c 9.35 Å, U 3251 ų, Pn2_1^a, Z = 4, R = 0.048, 2541 observed data.The coordination about the iridium atom is distorted trigonal bipyramidal; the two phosphorus atoms are equatorial, the σ-bonded carbon is axial, and the bidentate cyclooctadiene is bonded axialequatorial. The IrC(axial) bonds are longer than the IrC(equatorial) bonds: 2.22, 2.26; 2.17, 2.19 Å. The IrC(σ) bond length is 2.19 Å, not significantly different from the formally π-bonded C to Ir distances. The IrP lengths of 2.201 and 2.240 Å and the PIrP angle of 108.7° are normal. The longer IrP bond is in the five-membered chelate ring. The inertness to substitution is discussed.     

Metal—metal bonding in dinuclear complexes of platinum(I). The crystal and molecular structure of carbonyl(chloro)-bis-μ-[bis(diphenylphosphino)methane]diplatinum hexafluorophosphate

The structure of [Pt₂Cl(CO) (μ-Ph₂PCH₂PPh₂)₂] [PF₆] was determined by $\text{X}$-ray methods and refined to $\text{R}$ = 0.082, using diffractometric intensities of 5646 independent reflections. The crystals are monoclinic, space group $\text{P}$2₁/$\text{n}$, $\text{a}$ = 12.919(3), $\text{b}$ = 15.576(6), $\text{c}$ = 25.151(5)Å, β = 94.82(3)°, $\text{Z}$ = 4. They are built of octahedral hexafluorophosphate anions and dinuclear platinum(I) cations. The latter contain PtCl and PtCO fragments linked to one another by a PtPt σ-bond and by two bridging bis(diphenylphosphino)methane ligands. The platinum atoms are in square planar environments and the dihedral angle between the two coordination planes is 40.1°. Selected bond lengths are: PtPt 2.620(1), PtCl 2.384(5), PtC 1.89(3) and PtP 2.291(5) – 2.308(5)Å.     

Cluster chemistry XXIV. X-ray structure of H4 Ru4(CO)9(PMe2 Ph)[P(OC6H4 Me-p)3]-[P(OCH2)3CEt], a chiral cluster complex containing four different ligands

The X-ray structure of H₄Ru₄(CO)₉(PMe₂Ph)[P(OC₆H₄Me-p)₃][P(OCH₂)₃CEt], a chiral cluster complex, has been determined. The complex is triclinic, space group P$\text{1}$, a 19.812(7), b 14.299(4), c 10.323(4) Å, α 100.09(3), β 98.18(3), γ 102.23(3)°. The unit cell contains an enantiomeric pair of molecules. The Ru₄ core contains two short (av. 2.785 Å) and four long (2.967 Å) RuRu separations with approximate D_2d symmetry. RuP separations are 2.254(6) Å [to P(OCH₂)₃CEt], 2.270(6) Å [to P(OC₆H₄Me-p)₃] and 2.326(7) Å [to PMe₂Ph]; all P-donor ligands are trans to short RuRu vectors.     

Acyl-platinum(II) and -palladium(II) complexes derived from 2-hydroxybenzaldehyde derivatives. X-ray structure of [Pt(OC6H4CO) (P(p-CH3C6H4)3)2]

Platinum(II) and palladium(II) complexes containing chelating acyl ligands have been synthesized from salicylaldehyde, 2-hydroxynaphthaldehyde and 2-hydroxy-3-methoxybenzaldehyde. The platinum(II) complexes [Pt(acyl)L₂], acyl  OC₆H₄CO, OC₁₀H₆CO, O(m-CH₃OC₆H₃CO), L  tertiary phosphine, 1/2 diphenylphosphinoethane, can be isolated with both monodentate and chelating diphosphines, whereas for palladium only the compounds with chelating phosphines are readily obtainable. The reactions of [Pt(OC₆H₄CO)L₂] with HCl afford trans-[PtCl(OHC₆H₄CO)L₂], L  monodentate tertiary phosphine and cis-[PtCl(OHC₆H₄CO)L₂], L2  1,2-bis-diphenylphosphinoethane, in which the metal—carbon bond remains intact. The structure of [Pt(OC₆H₄CO)-(P(p-CH₃C₆H₄)₃)₂] has been determined by X-ray diffraction methods and found to have the expected square planar structure. Some relevant bond lengths and angles are: PtP; 2.271(4) and 2.348(5) Å; PtC; 1.96(2) Å and PtO; 2.07(1) Å; PPtP  101°, CPtO  82°.     

Die molekül- und kristallstruktur von thallium-tris(bistrimethylsilylamin), Tl[N(SiMe3)2]3

The molecular and crystal structure of tris(bistrimethylsilylamin)thallium was determined by means of single-crystal X-ray spectroscopy: in the space group P$\text{3}$1c with a = 16.447(7), c = 8.456(7) Å; and D_c = 1.149 g cm^?3 two molecules are located in the unit cell. The compound is isomorphous to the analogues Fe[N(SiMe₃)₂]₃ or Al[N(SiMe₃)₂]₃, respectively, which show a propellar-twist of the Si₂N-groups versus the plane of the metal atom and the three nitrogen-atoms: Tl(N)₃/Si₂N 49.1°; SiNSi 122.6°; NSiC 111.8°; CSiC 107.1°; TlN 2.089 Å;; SiN 1.738 Å;; $\text{SiC}$ 1.889 Å;.     

The enthalpies of formation of CH3Mn(CO)5 and of CH3Re(CO)5, and the strengths of the CH3Mn and CH3Re bonds

From measurements of the heats of iodination of CH₃Mn(CO)₅ and CH₃Re(CO)₅ at elevated temperatures using the ‘drop’ microcalorimeter method, values were determined for the standard enthalpies of formation at 25° of the crystalline compounds: ΔH^o_f[CH₃Mn(CO)₅, c] = ?189.0 ± 2 kcal mol^?1 (?790.8 ± 8 kJ mol^?1), ΔH^o_f[Ch₃Re(CO)₅,c] = ?198.0 ± kcal mol^?1 (?828.4 ± 8 kJ mo^?1). In conjunction with available enthalpies of sublimation, and with literature values for the dissociation energies of MnMn and ReRe bonds in Mn₂(CO)₁₀ and Re₂(CO)₁₀, values are derived for the dissociation energies: D(CH₃Mn(CO)₅) = 27.9 ± 2.3 or 30.9 ± 2.3 kcal mol^?1 and D(CH₃Re(CO)₅) = 53.2 ± 2.5 kcal mol^?1. In general, irrespective of the value accepted for D(MM) in M₂(CO)₁₀, the present results require that, D(CH₃Mn) = $\text{1}\text{2}$D(MnMn) + 18.5 kcal mol^?1 and D(CH₃Re) = $\text{1}\text{2}$D(ReRe) + 30.8 kcal mol^?1.     

[Rh12Sb(CO)27]3-. an example of encapsulation of antimony by a transition metal carbonyl cluster

The reaction of Rh(CO)₂acac with triphenylantimony in the presence of cesium benzoate in tetraethylene glycol/dimethyl ether solution resulted in the selective formation of [Rh₁₂Sb(CO)₂₇]^3- (66% yield) after 3 h of contact time under ≈400 atm of carbon monixide and hydrogen (CO/H₂  1) at 140–160°C. The cluster has been isolated as the [Cs(18-Crown-6)₂]⁺, [(CH₃)₄]⁺, [(C₂H₅)₄N]⁺, (Ph₃P)₂N]⁺ and [PhCH₂N(C₂H₅)₃]⁺ salts. The [(C₂H₅)₄N]₃ [Rh₁₂Sb(CO)₂₇] complex has been characterized via a complete three-dimensional X-ray diffraction study. The complex crystallizes in the space group R$\text{3}$c with a  23.258(13) Å, c  22.811(4) Å, V  10 686 ų and p(calcd.)  2.334 g cm^-3 for mol.wt. 2503.66 and Z  6. Diffraction data were collected with an Enraf-Nonius CAD 4 automated diffractometer using graphite-monochromatized Mo-Kα radiation. The structure was solved by direct methods and refined by difference-Fourier and least-squares techniques. All non-hydrogen atoms have been located and refined: final discrepancy indices are R_f  3.5% and R_wf  4.6% for 3011 reflections. The anion's structure consists of twelve rhodium atoms situated at the corners of a distorted icosahedron with contacts of 2.807(1), 2.861(1), 2.874(1), 2.999(1), 3.017(1) and 3.334(1) Å and rhodium—antimony contacts of 2.712(0) Å. Rhodium—rhodium bond distances of 2.807 and 3.017 Å are in the range usually found for these complexes although a distance of 3.334 Å may be longer than expected from bonding interactions. The sum of the covalent radii of antimony and rhodium, 2.80 Å, is intermediate between the two observed RhSb contacts. The anion cluster structure is that of distorted icosahedron. This polyhedron has previously been found in [B₁₂H₁₂]^2- but not with transition metal clusters. A comparison between the structures of rhodium carbonyl clusters and boranes shows the occurrence of similar structural features. Applications of bonding theories based on the boranes, such as Wade's rules, to rhodium carbonyl clusters shows the extent in which these rules are obeyed.     

The crystal structure of Mn(NO)3P(C6H5)3: The first x-ray analysis of a mononuclear metal trinitrosyl complex

The structure of Mn(NO)₃PPh₃ has been analyzed by single-crystal X-ray diffraction. It shows a tetrahedral geometry with essentially linear nitrosyl groups, and an eclipsed configuration around the MnP bond. Average distances and angles are: MnN 1.686(7) Å, MnP 2.315(2) Å, NO 1.165(10) Å, PC 1.815(4) Å, MnNO 177.2(7)°, PMnN 103.6(2)°, NMnN 114.7(4)°. Final R factor 7.3% for 2064 non-zero reflections. The structure of the five-coordinate nitrito complex Mn(NO)₂(ONO)(PEt₃)₂ is also mentioned briefly.     

Bulky Arylgallium and Indium Derivatives with Co(CO)4 and Mn(CO)5 Substituents

Further investigation of the reaction of Ar*GaCl₂ (Ar* = 2,4,6-t-Bu₃C₆H₂) with Na[Mn(CO)₅] resulted in the new compound, [Ga(Ar*){Mn(CO)₅}₂] 2 . The new indium compounds, [In(Ar*){Co(CO)₄}₂] 3 and [In(Ar*){Mn(CO)₅}₂] 4 , have been prepared by the treatment of Ar*InBr₂ with Na[Co(CO)₄] and Na[Mn(CO)₅], respectively. The structure of 3 was established by single-crystal X-ray diffraction: space group P1 (No. 2), Z = 2, a = 8.625(1) Å, b = 10.557(2) Å, c = 17.55(2) Å, α = 88.43(1)°, β = 83.45(1)°, γ = 71.14(1)°. The X-ray crystal structure of [Ga{Mn(CO)₅}₃] is also reported: space group Pbca (No. 61), Z = 8, a = 12.83(3) Å, b = 11.753(2) Å, c = 29.662(6) Å, α = β = γ = 90°.     

X-ray comparison of the molecular structures of 4a-methyl-1,3,9-triphenyl-4a-H-fluorene and its Fe(CO)3 complex

4a-Methyl-1,3,9-triphenyl-4a-H-fluorene, which is a tetrameric product formed on vigorous dehydration of acetophenone, has structure 1, in which rings A and B form an indene fragment, the diene ring C approximates to half-chair configuration, and the three phenyl rings, D, E, and F, are considerably rotated relative to rings B,C about their connecting bonds. In the Fe(CO)₃ complex, 3, a marked change has occurred in the conformation of ring C to allow Fe coordination on the side opposite to the methyl group. The complexed FeC distances are 2.117, 2.049, 2.067, 2.220 Å, and there are marked changes in the bond lengths in the complexed diene, but all other bond lengths correspond closely in the two molecules. 1 (C₃₂H₂₄) is triclinic, a 12.506, b 10.237, c 10.121 Å, α 108.53, β 84.93, γ 112.32°; space group P$\text{1}$, Z = 2. The complex, C₃₂H₂₄Fe(CO)₃, is monoclinic, a 30.283, b 12.709, c 14.514 Å, β 92.73°; space group B2₁/c, Z = 8.     

Characteristic structural features of cyclopentadienyl derivatives of post-transition metals : II. Synthesis and structure of tris(triphenylphosphinegold)tetraphenylcyclopentadiene tetrafluoroborate

The trinuclear cationic complex [Ph₄C₅(AuPPh₃)₃⁺[BF₄]^- (I) obtained by interaction of C₅HPh₄AuPPh₃ or Ph₄C₅(AuPPh₃)₂ with [AuPPh₃⁺[BF₄]^- in THF was studied by X-ray diffraction. In the presence of benzene, triclinic crystals of the solvate [Ph₄C₅(AuPPh₃)₃]⁺[BF₄]^-· 2 C₆H₆ are formed, a = 12.845(6), b = 16.042(8), c = 22.642(11) Å, α = 86.62(4), β = 77.51(4), γ = 76.05(4)°, space group P$\text{1}$, Z = 2, 9494 reflections with I > 2σ (λ(Mo-K_α), θ/2θ scan, 2θ < 46°), with absorption correction R = 0.054. The complex represents a diaurated cation of tetraphenylcyclopentadienyl(triphenylphosphine)gold, containing a triangular Au₂C fragment (AuAu 2.820(1) Å) which is bonded to the third Au atom (AuAu 3.021(1) Å), coordinated to the cyclopentadienyl ligand by a bond intermediate between η¹(σ) and η³ (AuC 2.21(2), 2.60(2) and 2.71(2) Å).