Insertion of isocyanides into the palladium-(2-pyridyl) bond

The reaction of the pyridyl-bridged binuclear complex [PdBr(μ-2-C₅H₄N)(PPh₃)]₂ with isocyynides CNR (R  p-C₆H₄OMe, Me, C₆H₁₁) yields the complex $\text{PdBr}${(&2.dbnd;NR)C(&2.dbnd;NR) (2-C₅H₄N)}(PPh₃)] containing a C,N-chelated 1,2-bis(imino)-2-(2-pyridyl)ethyl group, which results from successive insertions of two isocyanides molecules into the palladium2-pyridyl bond. The mononuclear compound trans-[PdBr(2-C₅H₄N)(PMePh₂)₂] readily reacts with various CNR ligands (R  p-C₆H₄OMe, Me, C₆H₁₁, CMe₃) to give the imino(2-pyridyl)methylpalladium(II) derivatives, trans-[Pdbr{C(=NR)(2-C₅H₄N)} (PMePh₂)₂].     

Preparation and properties of new ferrocenyl heterobimetallic complexes with counterion dependent NLO responses

New ferrocenyl-based bimetallic cationic compounds of the type of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNRuCp(PPh₃)₂]X (X=PF₆, BF₄) and of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNFeCp(CO)₂]PF₆ have been obtained and characterized. The crystal structure of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNRuCp(PPh₃)₂]BF₄ has been established by means of X-ray diffractometry. The NLO responses of the compounds have been studied by the hyper-Rayleigh scattering technique and the hyperpolarizability is found to be dependent on the nature of the counterion.     

Inorganic Polymers : by N.H. Ray,Academic Press,New York/San Francisco/London, 1978, 174 pages, $ 17.35.

Insertion of CO or p-TolNC into a ZrC bond of [Zr(η-C₅H₅).(R)R′] under ambient conditions in C₆H₆ leads to the stable η²-acyl- or η²-iminoacyl-complex [Zr(η-C₅H₅)₂{η²-C(X)R}R′] (X = O or NTol-p); with [Zr(η-C₅H₅)₂{CH(SiMe₃)₂}Me] as substrate there is exclusive preference for scission of the more hindered ZrC bond.     

New η-allyl η-cyclopentadienylcobalt cations

[Co(R-η-C₃H₄)(η-C₅H₅)I] is a good precursor for the preparation of some new cationic complexes as the iodide can easily be replaced; thus addition of PEt₃ to the iodo-complex (R  H) gives [Co(η-C₃H₅)(η-C₅H₅)(PEt₃)]⁺. The reactions of [Co(R-η-C₃H₄)(η-C₅H₅))I] (R  H or 2-Me) with AgBF₄ give solutions containing the coordinatively unsaturated species [Co(R-η-C₃H₄)(η-C₅H₅)⁺. The presence of traces of water leads to the formation of [Co(R-ηC₃H₄)-(η-C₅H₅)(H₂O)]⁺. The addition of monodentate ligands L  PEt₃ PPh₃, AsPh₃, SbPh₃, CNCH₃ and bidentate ligands LL  Ph₂PCH₂CH₂PPh₂(dppe) and o-C₆H₄(AsMe₂)₂(diars), gives, respectively mononuclear [Co(2-Me-ηC₃H₄)-(η-C₅H₅)L]⁺ and binuclear ligand-bridged [(2-Me-ηC₃H₄)(η-C₅H₅)CoLLCo(2-Me-ηC₃H₄)(η-C₅H₅))]²⁺ complexes. Crystals of [Co(2-Me-ηC₃H₄)(η-C₅H₅)-(H₂O)]⁺[BF₄]^- are monoclinic, space group P2₁/c, with a 7.858(3), b 10.262(4), c 15.078(4) Å, β 98.36(1)°. The molecular structure contains the cobalt atom bonded to planar 2-Me-allyl and cyclopentadienyl substituents, which are almost parallel with the H₂O molecule in a staggered conformation with respect to the 2-Me group.     

Chlorinated organic derivatives containing MoHg and WHg bonds: Importance of the steric effects in their stabilization

A series of MoHg and WHg bonded complexes [RHgM(CO)₃Cp], (R = 2,4,6-C₆H₂Cl₃,2,3,5,6-C₆,HCl₄ and C₆Cl₅) have been prepared from ClHgR and the salts Na[M(CO)₃)Cp]. When R contains only one ortho chlorine atom (R = 2,5-C₆H₃Cl₂, 2,3,4-C₆H₂Cl₃ and 2,3,4,5-C₆HCl₄) a symmetrisation process occurs to give the corresponding HgR₂ and Hg[M(CO)₃Cp)₂2. These results indicate that steric effects are very important in the formation of compounds containing molybdenum- or tungsten—mercury bonds. Complexes of the type [(C₆Cl₅)HgM(CO)₂(PPh₃)Cp] (M = Mo and W) are obtained from [(C₆Cl₅)HgM(CO)₃Cp] and PPh₃ in boiling ethanol.     

The thiolate anion as a nucleophile Part III. Reactions with various fluorobenzenes

The reactions of the fluorobenzenes, C₆F₅H, o-C₆H₂F₄, m-C₆H₂F₄, p-C₆H₂F₄, 1,3,5-C₆F₃H₃, 1,2,4-C₆F₃H₃, o-C₆F₂H₄, m-C₆F₂H₄, p-C₆F₂H₄ and C₆F₅H with thiolate anion nucleophiles RS^? (primarily MeS^?), have been studied in ethylene glycol/pyridine mixtures as a solvent. Multiple replacement of fluorine atoms was observed in the more highly fluorinated compounds, but in all cases two aromatic fluorine atoms were not replaced. Difluorobenzene and fluorobenzene did not react. The product orientations have been deduced from their NMR spectra. The mass spectra of the isomeric products C₆F₂H₃(SMe), C₆F₃H₂(SMe) and C₆F₂H₂(SMe)₂ have been examined.     

Gas phase hydrogen/deuterium exchange reactions of fluorophenyl anions

Hydrogen/deuterium (H/D) exchange reactions of fluorophenyl and difluorophenyl anions (C₆H₄F^?, o-C₆H₃F ₂ ^? , m-C₆H₃F ₂ ^? , p-C₆H₃F ₂ ^? ) have been studied using the flowing afterglow-selected ion flow tube technique. The C₆H₄F^? anion exchanges all hydrogens for deuterium upon reaction with D₂O. The difluorophenyl anions o-, m-, and p-C₆H₃F ₂ ^? exchange three, two, and one hydrogen, respectively, with D₂O, whereas they undergo one, two, and three H/D exchanges, respectively, with CH₃OD. The structures of the anions and the isotope exchange dynamics within the intermediate ion-dipole complexes are discussed using ab initio molecular orbital calculations. Calculated values for the proton affinities of the most stable anions are 385.2, 378.0, 371.9, and 378.2 kcal/mol for C₆H₄F^?, o-C₆H₃F ₂ ^? , m-C₆H₃F ₂ ^? , and p-C₆H₃F ₂ ^? , respectively, in excellent agreement (within 2 kcal/mol) with the previous experimental values for the acidities of the corresponding fluorobenzenes. The H/D exchange results are explained by the energy differences of the intermediate DO^? and CH₃O^? species within the ion-dipole complexes; CH₃O^? is mobile within the “hot” intermediate complex, whereas DO^? is nearly “frozen” within the complex and cannot migrate across the barriers caused by the fluorine atoms or by the π electrons.     

The addition of small molecules to (η-C5H5)2Rh2(CO)(CF3C2CF3): IV. The sunlight assisted making and breaking of alkene CH bonds on the dirhodium centre; the crystal and molecular structures of (η-C5H5)2Rh2(CHCHCN){C(CF3)CF3)H} · H2O and (η-C5H5)2Rh2(CHCF2){C(CF3)C(CF3)H}

Bis-alkenyl complexes of the type (η-C₅H₅)₂RH₂(alkene − H)(alkyne + H) are obtained when the alkyne complex (η-C₅H₅)₂Rh₂(CO)(CF₃C₂CF₃) is treated with the following alkenes: H₂CCH₂, H₂CCHR (R = Me, Bu^t, Ph, CN), H₂CCF₂, RHCCHR′ (R = R′ = Me, Ph, Cl; R = Me, R′ = Et), cyclooctene and norbornene. An approximately equimolar amount of (η-C₅H₅)₂Rh₂(CO)₂(CF₃C₂CF₃) is also formed. The reactions are greatly accelerated when the reaction mixtures are exposed to sunlight. There is some regioselectivity in the reactions with H₂CCHR and MeHCCHet, with a preference for CH bond cleavage at the least crowded alkene-carbon. When the reaction with acrylonitrile is performed in the absence of sunlight, the complex (η-C₅H₅)₂(CO){(H₂CCHCN)(CF₃C₂CF₃)} can be isolated; upon exposure to sunlight, there is loss of CO and H-transfer to form two isomers of the appropriate bis-alkenyl complex.The molecular geometries of (η-C₅H₅)₂Rh₂(CHCHCN){C(CF₃)C(CF₃)H} and (η-C₅H₅)₂Rh₂(CHCF₂){C(CF₃)C(CF₃)H} have been ascertained by X-ray structure determination. Each molecule has two bridging alkenyl units spanning a RhRh single bond; the dihedral angle between the two RhRhCC planes is just above 90°. There is a cyclopentadienyl ring η⁵-attached to each metal. Crystal data: C₁₇H₁₃F₆NRh₂·H₂O, M 569.1, monoclinic, P2₁/n, a 15.014(7), b 14.882(7), c 8.590(5) Å, β 94.57(9)°, Z = 4, final R 0.056 for 2493 observed reflections; C₁₆H₁₂F₈Rh₂, M 562.1, monoclinic, P2₁/c, a 13.037(6), b 8.765(2), c 14.873(3) Å, β 103.16(3)°, Z = 4, final R 0.062 for 1820 observed reflections.     

Transition metal derivatives of arenediazonium ions: XIV. Reactions of arenediazomolybdenum(II) complexes with neutral and anionic Lewis bases

The reactions of arenediazomolybdenum(II) complexes such as [(η-C₅H₅)Mo(N₂C₆H₄CH₃-p)I₂]₂, (η-C₅H₅)Mo(CO species with neutral and anionic monodentate or chelating ligands have been investigated. The new arenediazo complexes isolated from these reactions include neutral species such as (η-C₅H₅)Mo(PPh₃)(N₂C₆H₄CH₃-p)I₂ and (η-C₅H₅)Mo(N₂C₆H₄CH₃-p) cations of the type [η-C₅H₅)Mo(bipy)(N₂C₆H₄CH₃-p)I]⁺ and the anion [(η-C₅H₅)Mo(N₂C₆H₄CH₃-p)I₃]^?. The structures of the new complexes are discussed.     

Reactions of (η5-C5H5)2Tir compounds with organic cyanides

The syntheses and properties of the titanium(III) complexes Cp₂Tir · R′CN (R = C₆H₅, o-, m-, p-CH₃C₆H₄, CH₂C₆H₅, C₆F₅, Cl; R′ = CH₃, t-C₄H₉, C₆H₅, o-CH₃C₆H₄, 2,6-(CH₃)₂C₆H₃) are described. In the complexes the nitrogen atom of the cyanide ligands is coordinated to the metal. The thermal stabilities of the complexes depend markedly on R and R′; on heating they undergo a novel reaction in which two cyanide ligands are coupled by formation of a CC bond, while the metal is oxidized to titanium(IV).     

Transition-metal mediated heteroatom removal by reactions of FeL+ [L=O,C4H6, c-C5H6, c-C5H5, C6H6, C5H4(=CH2)] with furan,thiophene, and pyrrole in the gas phase

Reactions of Fe⁺ and FeL⁺ [L=O, C₄H₆, c-C₅H₆, C₅H₅, C₆H₆, C₅H₄(=CH₂)] with thiophene, furan, and pyrrole in the gas phase by using Fourier transform mass spectrometry are described. Fe⁺, Fe(C₅H₅)⁺, and FeC₆H ₆ ⁺ yield exclusive rapid adduct formation with thiophene, furan, and pyrrole. In addition, the iron-diene complexes [FeC₄H ₆ ⁺ and Fe(c-C₅H₆)⁺], as well as FeC₅H₄(=CH₂)⁺ and FeO⁺, are quite reactive. The most intriguing reaction is the predominant direct extrusion of CO from furan by FeC₄H₆ ⁺, Fe(c-C₅H₆)⁺, and FeC₅H₄(=CH₂)⁺. In addition, FeC₄H ₆ ⁺ and Fe(c-C₅H₆)⁺ cause minor amounts of HCN extrusion from pyrrole. Mechanisms are presented for these CO and HCN extrusion reactions. The absence of CS elimination from thiophene may be due to the higher energy requirements than those for CO extrusion from furan or HCN extrusion from pyrrole. The dominant reaction channel for reaction of Fe(c-C₅H₆)⁺ with pyrrole and thiophene is hydrogen-atom displacement, which implies D^O(Fa(N₅H₅)⁺-C₄H₄X)>D^O(Fe(C₅H₅)⁺-H)=46±5 kcal mol^?1. D^O(Fe⁺-C₄H₄S) and D^O(Fe⁺-C₄H₅N)=D^O(Fe⁺-C₄H₆)=48±5 kcal mol^?1. Finally, 55±5 kcal mol^?1=D^O(Fe⁺-C₆H₆)>D^O(Fe⁺-C₄H₄O)>D^O(Fe⁺-C₂H₄)=39.9±1.4 kcal mol^?1. FeO⁺ reacts rapidly with thiophene, furan, and pyrrole to yield initial loss of CO followed by additional neutral losses. D^O(Fe⁺-CS)>D^O(Fe⁺-C₄H₄S)≈48±5 kcal mol^?1 and D^O(Fe⁺-C₄H₅N)≈48±5 kcal mol^?1>D^O(Fe⁺-HCN)>D^O(Fe⁺-C₂H₄)=39.9±1.4 kcal mil^?1.     

A convenient,one-step synthesis of the cationic η3-allyl-molybdenum complex [(η5-C5H5)2Mo(η3-C3H5)]+[p-CH3C6H4SO3]−

[(η⁵-C₅H₅)₂Mo(η³-C₃H₅)]⁺ [p-CH₃C₆H₄SO₃]⁻ is conveniently synthesized by the reaction of (η⁵-C₅H₅)₂MoH₂ with allyl alcohol in the presence of p-toluene sulfonic acid, the mechanism of which is explained by the electrophilic cleavage of the allylO bond of the coordinated allyl alcohol.     

Structures of two polymorphic modifications of tris(p-chlorophenyl)arsinoxide and comparison with the structure of tris(p-chlorophenyl)arsinsulfide

A full X-ray structure analysis of two polymorphic modifications of tris(p-chlorophenyl)arsinoxide, C₁₈H₁₂AsOCl₃, has been performed. Modification I is triclinic, space group P$\text{1}$, Z = 4; modification II is hexagonal, space group P6₃, Z = 2. The geometrical parameters of the molecules in the two polymorphs are similar; the mean values for the bond distances and angles are: AsO 1.641, AsC 1.928, CCl 1.736 Å; CAsC 107.3, CAsO 111.6°. The packing modes in I and II are significantly different: in I supersymmetrical relationships between the molecules independent of space-group symmetry are found: in II cylindrical cavities of diameter ca. 5 Å are present along the 6₃ axes. The structures of the molecules in I and II are compared with that of tris(p-chlorophenyl)arsinsulfide, C₁₈H₁₂AsSCl₃ (III, space group P2₁/b, Z = 4).     

Optisch aktive übergangsmetall-komplexe: XXXIII. Substituenteneinfluss auf die racemisierungs geschwindigkeit von (+)579und(−)579−C5H5MN(COC6H5)(NO)P(pC6H4Y)3

In the reaction of [C₅H₅Mn(CO)₂(NO)] [X] ([X] = [BF₄], [PF₆]) with p-substituted triarylphosphines P(p-C₆H₄?Y)₃ [Y = CF₃, Cl, F, C₆H₅, CH₃, OCH₃, N(CH₃)₂] the asymmetric monosubstitution products [C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃] [X] are formed, which can be converted into the neutral esters C₅H₅Mn(COOC₁₀H₁₉)(NO)P(p-C₆H₄?Y)₃ by natrium menthoxide. The diastereoisomers (+)₅₇₉^? and (?)₅₇₉^?C₅H₅Mn(COOC₁₀H₁₉)(NO)P(p-C₆H₄?Y)₃ are separated by fractional crystallisation and transformed into the enantiomeric salts (+)₅₇₉^? and (?)₅₇₉-[C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃] [X] by cleavage with HCl and precipitation with NH₄PF₆. The (+)₅₇₉^? and (?)₅₇₉^? rotating salts in the reaction with LiC₆H₅ yield the carbonyl addition products (+)₅₇₉^? and (?)₅₇₉^? C₅H₅Mn(COC₆H₅)(NO)P(p-C₆H₄?Y)₃ and the ring addition products (+)₅₇₉^? and (?)₅₇₉^?(exo-C₆H₅)C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃, which can be separated by chromatography.The salts (+)₅₇₉^? and (?)₅₇₉^?[C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃] [X] and the cyclopentadiene complexes (+)₅₇₉^? and (?)₅₇₉-(exo-C₆H₅)C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃ are configurationally stable, whereas the esters (+)₅₇₉^? and (?)₅₇₉^?C₅H₅Mn(COOC₁₀H₁₉)(NO)P(p-C₆H₄?Y)₃ and the benzoyl complexes (+)₅₇₉^? and (?)₅₇₉^?C₅H₅Mn(COC₆H₅)(NO)P(p-C₆H₄?Y)₃ epimerise or racemise in solution.The rate of racemisation of the benzoyl compounds (+)₅₇₉^? and (?)₅₇₉C₅H₅Mn(COC₆H₅)(NO)P(p-C₆H₄?Y)₃ was measured polarimetrically in the temperature range 0–45° C. It turned out that electron-releasingsubstituents Y in the ligand P(p-C₆H₄?Y)₃ increase the half-lives, whereas electron-attracting substituents decrease the half-lives. There is a linear correlation between the σ-constants of the substituents and the rate constants of the racemisation (reaction constant p = +2.14).     

The solid state structure of arene-mercury(II) complexes from magic-angle spinning carbon-13 NMR and the solution carbon-13 NMR of some complexes of mercury(II) with arenes having bulky aliphatic substituents

The cross-polarization magic angle spinning ¹³C NMR spectra of Hg(SbF₆)₂ - 2 Arene (Arene = C₆HMe₅, 1,2,4,5-C₆H₂Me₄, 1,2,3,4-C₆H₂Me₄, or C₆H₆) have been measured. The spectra of the complexes of C₆HMe₅ and 1,2,4,5-C₆H₂Me₄ are consistent with static η¹-bonding of the mercury to the arene at an unsubstituted carbon atom, while the spectra of the 1,2,3,4-C₆H₂Me₄ and C₆H₆ complexes show the arene to have time-averaged C_s or C₂, and C₆ symmetry respectively, at the temperature of measurement (300 K).The reduced temperature ¹³C NMR spectra of Hg(Arene)_n²⁺ (n = 1 or 2; Arene = 1,3,5-C₆H₃R₃ (R = Me, i-Pr, or t-Bu)) in SO₂ solution are also reported and affirm that in these intramolecularly mobile species the mercury bonds in an η¹-manner, with unsubstituted aryl carbon atoms being the strongly preferred point of mercury attachment. This site preference is further demonstrated by the solution ¹³C NMR spectra of Hg(Arene)_n²⁺ (Arene = 1,2,3,4-C₆H₂-Me₄, n = 1 or 2; Arene = 1,4-C₆H₄R₂, R = Me or t-Bu, n = 1). The spectra of the 1,4-C₆H₄R₂ complexes and Hg(p-C₆H₄-t-BuMe)²⁺ provide clear evidence for steric influence of the binding site.Like Hg(C₆Me₆)₂²⁺, but unlike most of the complexes of substituted benzenes which have been studied, Hg(1,3,5-C₆H₃-i-Pr₃)₂²⁺ exchanges only slowly with excess free ligand.     

Synthesis and molecular structure of niobocene(tricarbonyl)(π-cyclopentadienyl)molybdenum with metalmetal bond and unusual coordination of carbonyl groups

(C₅H₅)₂NbBH₄ reacts with C₅H₅M(CO)₃Me in toluene solution in the presence of Et₃N to give binuclear complexes (C₅H₅)₂NbM(CO)₃C₅H₅ where M is Mo or W (IV and V, respectively). The structure of IV has been studied by X-ray diffraction (the crystals are orthorhombic, a 12.748(5), b 16.745(6), c 14.314 $\text{A/ac>}\text{?}$;; Z = 8, space group of Pbca, automatic difractometer Syntex P2_I, λ(Mo-K_α, 1382 reflections, R = 0.056, R_w = 0.058). Molecule IV contains a wedge-like sandwich (π-C₅H₅)₂Nb (NbC 2.37–2.48, CC (av) 1.42 $\text{A/ac>}\text{?}$;, angle between ring planes 49°) linked with the (π-C₅H₅)Mo(CO) fragment by a direct NbMo bond (3.073 $\text{A/ac>}\text{?}$;) and two bridging CO groups, one nonsymmetrically bonded through the carbon atom only (CO 1.17, NbC 2.53, MoC 2.02 $\text{A/ac>}\text{?}$;) and the other σ-bonded to Mo (MoC 1.944 $\text{A/ac>}\text{?}$;) and π-bonded to Nb (CO 1.22, NbC 2.22, NbO 2.26 $\text{A/ac>}\text{?}$;). Three types of carbonyl groups present in IV give rise to strong IR bands at 1870, 1700 and 1560 cm^?1 assigned to the terminal, μ-bridging and σ, π-bridging CO groups respectively. Complex IV has a similar structure. The electronic structure of IV and its dissociation across the NbMo bond are discussed.     

Dynamic Jahn–Teller effect and average structure of dicyclopentadienylcobalt, (C5H5)2Co,studied by gas phase electron diffraction

The molecular structure of (C₅H₅)₂Co has been determined by gas phase electron diffraction. The best agreement between calculated and experimental intensity curves is obtained with a model with eclipsed C₅H₅ rings (symmetry D_5h), but a model with staggered rings (symmetry D_5d) cannot be ruled out. The mean CoC and CC bond distances are 2.119(3) Å and 1.429(2) Å respectively. The average angle between the CH bonds and the C₅ ring is 2.1(0.8)°. The value obtained for the CC vibrational amplitude, l(CC) = 0.055(1) Å, is significantly larger than the amplitude calculated from a molecular force field and the corresponding amplitudes in (C₅H₅)₂Fe and (C₅H₅)₂Ni determined by electron diffraction, and confirms the presence of a dynamic Jahn—Teller effect of the magnitude calculated from ESR data. The average structure is compared with those of the metallocenes of the other first row transition elements.     

Crystal field effects on the ground and lowest excited triplet states of benzene isotopes in a borazine host crystal

The phosphorescence spectra of the C₆H₆C₆H₅D₁p-C₆H₄D₂symp-C₆H₃D₃, C₆D₆ and ¹³CC₅D in a borazine host crystal are analyzed at high resolution. The spectral lines are sharp (～2 cm^?1 wide) indicating that the impurity molecules occupy a unique site in the borazine lattice which is probably substitutional. The phonon sidebands are weak,giving clean, well-resolved spectra much like those of isotopic mixed crystals. In contrast, however, the crystal field effects on the ground state vibrational levels are much smaller than those found for isotopic mixed crystals. The gas-to-crystal shifts are very small, the vibrational degeneracies are not removed and orientational splittings are only observable for a few select vibrational levels. For most vibrational levels and for the derivation of selection rules one can asume the effective crystal site symmetry to be D_3d. The data provide the first conclusive evidence that the splitting observed in the benzene phosphorescence spectrum results from a distortion of the molecule when excited to the zeroth vibrational level of the T₁ state. Furthermore, the data suggest that the distortion is intrinsic in nature (i.e.,is not caused by the crystal field).     

Structural studies on osmium carbonyl hydrides: XXXI. Crystal and molecular structure of CpWOs3(CO)9(μ-H)(μ-O)(μ-CHCH2C6H4Me), a hydrido-alkylidene produced by hydrogenation of a μ3-alkylidyne

The complex CpWOs₃(CO)₉(μ-H)(μ-O)(μ-CHCH₂C₆H₄Me), previously prepared by hydrogenation of CpWOs₃(CO)₉(μ-O)(μ₃-CCH₂C₆H₄Me), has been subjected to a single-crystal X-ray diffraction study. The complex crystallizes in the non-centrosymmetric monoclinic space group Cc(C_s⁴; No. 9) with a 14.1510(27), b 13.9257(22), c 13.3179(19) Å, β 92.023(13)°, V 2622.8(7) ų and D(calcd) 3.06 g cm^?3 for Z = 4 and mol. wt. 1206.8. Single-crystal X-ray diffraction data were collected with a Syntex P2₁ automated four-circle diffractometer and the structure was refined to R 3.5% for all 2476 independent observations (Mo-K_α radiation, 2θ = 4.5–40.0°) and R 3.4% for those 2430 data with | F₀| > 3.0σ(| F₀|). The molecule contains a tetrahedral WOs₃ core associated with 60 valence electrons. Each osmium atom is associated with three terminal carbonyl ligands and the tungsten atom is linked to an η⁵-C₅H₅ ligand. In addition, the μ-oxo ligand is involved in a WO: → Os bridge (in which WO(B) 1.737(17), Os(3)← :O(B) 2.167(16) Å and WO(B)Os(3) 96.0(7)°), the μ-hydride ligand spans the Os(1)Os(3) linkage and the μ-CHCH₂C₆H₄Me ligand bridges the WOs(2) linkage (WC(1) 2.068(26) and Os(2)C(1) 2.281(26) Å).     

Transition-metal complexes of two valence tautomers of a bulky phenoxide, 2,6-Bu-t2-4-MeC6H2O− (ArO−); preparation and crystal and molecular structure of a phenoxytitanium(III) and a cyclohexadienonylrhodium(I) complex, [Ti(η-C5H5)2 OAr] and [Rh(ArO-η5)(PPh3)2]

The 2,6-di-t-butyl-4-methylphenoxo ligand (ArO^?) is ambidentate, giving rise to the O-bonded 15-electron d¹ [Ti(η-C₅H₅)₂OAr] and the η⁵ -[C(2)-C(6)]-bonded 18-electron d⁸ complex [Rh(ArO-η⁵)(PPh₃)₂], obtained from [{Ti(η-C₅H₅)₂Cl}₂]-LiO Ar and [Rh{N(SiMe₃)₂}(PPh₃)₂]-ArOH, respectively; the average TiC(η) distance is 2.362(10) Å, TiO 1.892(2) Å, and O:C(of Ar) 1.352(3) Å, and TiOC 142.3(2)°; in the Rh^I complex, C(2)C(6) are coplanar (with CC(av.) 1.38(2) Å). C(1)O 1.28 Å, and Rh to C(2) C(6) bond lengthsare in the range 2.19–2.65 Å.