The use of transition-state theory to extrapolate rate coefficients for reactions of O atoms with alkanes

Conventional transition-state theory is used for extrapolating rate coefficients for reactions of O atoms with alkanes to temperatures above the range of experimental data. Expressions are developed for estimating structural properties of the activated complex necessary for calculating enthalpies and entropies of activation. Particular attention is given to the problem of the effect of the O atom adduct on the internal rotations in the activated complex. Differences between primary, secondary, and tertiary attack are discussed, and the validity of representing the activated complexes of all O + alkane reactions by a fixed set of vibrational frequencies and other internal modes is evaluated. Experimental data for reactions of O atoms with 15 different alkanes (CH₄, C₂H₆, C₃H₈, C₄H₁₀, C₅H₁₂, C₆H₁₄, C₇H₁₆, C₈H₁₈, i–C₄H₁₀, (CH₃)₄C, (CH₃)₂CHCH(CH₃)₂, (CH₃)₃CC(CH₃)₃, c–C₅H₁₀, c–C₆H₁₂, c–C₇H₁₄) are reviewed. The following approximate expressions for ΔS^?(298) and E(298), the entropy and energy of activation, respectively, are consistent with the experimental data and with the calculations: where n_C = number of carbon atoms in the alkane and n_H = the number of “equivalent” H atoms. Using the conventional transition state theory expression, k(298) = 10^15.06 exp(ΔS^?/R) exp(–E(298)/298R) L mol^?1s^?1, one then obtains: These expressions agree with experimental values within a factor approximately 2 for alkanes larger than C₃H₈.     

Self- and cross-disproportionation-to-combination rations for cyclopentyl and cyclohexyl radicals and their deuterated analogues

Hydrogen, cycloalkene, and bicycloalkyl were found to be the principal products which account for ≈?97% of all products formed in the gas-phase radiolysis of water vapor containing low concentrations of cycloalkanes. From the ratios of cycloalkene-to-bicycloalkyl yields extrapolated to the zero dose, the self- and cross-disproportionation-to-recombination rate constant ratios Δ = k_d/k_c were determined for the following 12 reactions: Δ(c-C₅H₉, c-C₅H₉) = 0.73; Δ(c-C₅D₉, c-C₅D₉) = 0.58; Δ(c-C₆H₁₁, cC₆H₁₁) = 0.59; Δ(c-C₆D₁₁, c-C₆D₁₁) = 0.46; Δ(c-C₅H₉, c-C₆H₁₁) = 0.28; Δ(c-C₅D₉, c-C₆H₁₁) = 0.28; Δ(c-C₅H₉, c-C₆D₁₁) = 0.24; Δ(c-C₅D₉, c-C₆D₁₁) = 0.24; Δ(c-C₆H₁₁, c-C₅H₉) = 0.33; Δ(c-C₆H₁₁, c-C₅D₉) = 0.25; Δ(c-C₆D₁₁, c-C₅H₉) = 0.35; and Δ(c-C₆D₁₁, c-C₅D₉) = 0.28, where in the case of the cross-disproportionation the symbol Δ(R₁,R₂) is used to represent k_d/k_c for the disproportionation in which radical R₁ captures a hydrogen (deuterium) atom from radial R₂. The geometrical mean rule holds in the cross-combination reactions of cyclopentyl and cyclohexyl radicals. The kinetic isotope effect in the disproportionation reaction was determined as 1.24 ± 0.06.     

Quenching of I(2P½) by R-OH compounds. Influence of the alkyl group on the quenching efficiency

The deactivation of I(²P_½) by R-OH compounds (R = H, C_nH_2n+1) was studied using time-resolved atomic absorption at 206.2 nm. The second-order quenching rate constants determined for H₂O, CH₃OH, C₂H₅OH, n-C₃H₇OH, i-C₃H₇OH, n-C₄H₉OH, i-C₄H₉OH, s-C₄H₉OH, t-C₄H₉OH, are respectively, 2.4 ± 0.3 × 10⁻¹², 5.5 ± 0.8 × 10⁻¹², 8 ± 1 × 10⁻¹², 10 ± 1 × 10⁻¹², 10 ± 1 × 10⁻¹², 11.1 ± 0.9 × 10⁻¹², 9.8 ± 0.9 × 10⁻¹², 7.1 ± 0.7 × 10⁻¹², and 4.1 ± 0.4× 10⁻¹² cm³ molec⁻¹ s⁻¹ at room temperature. It is believed that a quasi-resonant electronic to vibrational energy transfer mechanism accounts for most of the features of the quenching process. The influence of the alkyl group and its role in the total quenching rate is also discussed. © 1997 John Wiley & Sons, Inc.     

The Kinetics of alkyl radical reactions with aliphatic alcohol glasses as studied by electron spin resonance

Methyl radical reactions with matrix molecules in glasses C₂H₅OH, (CH₂OH)₂, n- and i-C₃H₇OH, n- and i-C₄H₉OH, n- and i-C₅H₁₁OH, C₂D₅OH, and i-C₃D₇OD, and the reactions of ?₂H₅, ?₃H₇, ?₄H₉, ?₅H₁₁ with methanol glasses have been studied. Alkyl radicals were produced by photolysis of diphenylamine–alkylhalide–alcohol mixtures using ultraviolet light. In all cases the alkyl radical decay follows the law c = c₀ exp(-k √t). The √t law should not be associated with alkyl radical diffusion in a matrix. A method of processing the kinetics of those reactions in which one paramagnetic species changes into another with the total concentration being constant and the electron spin resonance spectra of both species overlapping, is described.     

η-Alkynyl and vinylidene transition metal complexes: 10. Reaction of the metal-acetylide [(η-C5H5)(CO)(NO)W---CC---C(CH3)3]Li with 1,2-diiodoethane as electrophile and with various nucleophiles

Treatment of the η¹-acetylide complex [(η⁵-C₅H₅)(CO)(NO)W---CC---C(CH₃)₃]Li (4) with 1,2-diiodoethane in THF at −78 °C, followed by the addition of Li---CC---R [R=C(CH₃)₃, C₆H₅, Si(CH₃)₃, 6a–6c] or n-C₄H₉Li and protonation with H₂O, afforded the corresponding oxametallacyclopentadienyl complexes (η⁵-C₅H₅)W(I)(NO)[η²-O=C(CC---R)CH=CC(CH₃)₃] (7a–7c), 8c and (η⁵-C₅H₅)W(I)(NO)[η²-O=C(n-C₄H₉)CH=CC(CH₃)₃] (9). The formation of these metallafuran derivatives is rationalized by the electrophilic attack of 1,2-diiodoethane onto the metal center of 4 to form first the neutral complex [(η⁵-C₅H₅)(I)(CO)(NO)W---CC---C(CH₃)₃] (5). Subsequent nucleophilic addition of Li---CC---R 6a–6c or n-C₄H₉Li and a reductive elimination step followed by protonation leads to the products 7a–7c and 9. One reaction intermediate could be trapped with CF₃SO₃CH₃ and characterized by a crystal structure analysis. The identity of another intermediate was established by infrared spectroscopic data. The oxametallacyclopentadienyl complex 10 forms in the presence of excess 1,2-diiodoethane through an alternative pathway and crystallizes as a clathrate containing iodine.     

Alkane loss from collisionally activated alkylmethyleneimmonium ions

The collision-induced dissociation (CID) spectra of five alkylmethyleneimmonium ions (H₂C-N⁺R¹R², (a) R¹ = R² = C₂H₅, (b) R¹ = n-C₃H₇, R² = H, (c) R¹ = n-C₃H₇, R² = CH₃, (d) R¹ = n-C₃H₇, R² = C₂H₅, (e) R¹ = R² = n-C₃H₇) are reported and discussed in terms of the mechanism of alkane loss. The most abundant alkane losses result from 2-azaallylic bond cleavages within R¹ and R² leading to daughter ions of m/z 84. Ion d (R¹ = n-C₃H₇, R² = C₂H₅) was chosen for a deuterium-labelling study because it exhibited methane loss nearly free from interferences with other fragmentations. The methane lost consists to a great extent (95%) of the methyl moiety of R². Whereas the methyl moiety obviously stays intact during the fragmentation process, the hydrogen additionally needed originates from all positions of R¹ and the double-bonded methylene in an approximately random distribution, suggesting extensive hydrogen migrations preceding the transfer step.     

Synthesis, characterization and the crystal structure of 1-[(N-methyl-N-aryl)amino]ethylferrocenes

The reactions of ferrocenylketimines [(η⁵-C₅H₄CCH₃NAr)Fe(η⁵-C₅H₅)] (Ar=a variety of substituted phenyls) with methyl-iodide in refluxed dichloromethane followed by reduction with sodium borohydride in absolute ethanol led to [(η⁵-C₅H₄CH(CH₃)N(CH₃)Ar)Fe(η⁵-C₅H₅)]. Compound [(η⁵-C₅H₄CH(CH₃)N(CH₃)C₆H₄Cl-p)Fe(η⁵-C₅H₅)] (3d) has been characterized structurally. Compound 3d is monoclinic, space group P2₁/n, with a=8.908(2) Å, b=13.63(1) Å, c=14.510(3) Å and β=107.03°.     

Quenching of *UF6 (A state) by alkanes

The removal of *UF₆ (A state) molecules by selected alkanes has been investigated at 25°C. The following rate constants (units of 10¹¹ l/mol·sec) were evaluated: iso-C₄F₁₀, 0.0432 ± 0.0115; n-C₄F₁₀, 0.0764 ± 0.020; C₂F₆, 0.0192 ± 0.0052; CH₄, 0.0612 ± 0.0061; C₂H₆, 3.78 ± 0.60; C₃H₈, 5.08 ± 0.60; n-C₄H₁₀, 5.05 ± 0.78; iso-C₄H₁₀, 4.17 ± 1.15; neo-C₅H₁₂, 6.59 ± 0.93; CF₃? CH₃, 0.0385 ± 0.0056; CF₂H? CF₂H, 0.0729 ± 0.0074; and CF₂H? CFH₂, 0.149 ± 0.015. The perfluoro-alkane quenching of *UF₆ proceeds via a physical mechanism. The other alkane quenching reactions are consistent with a chemical mechanism also contributing in varying degrees which may involve removal of two hydrogens from the alkane.     

Gas-phase solvation of Cl− with H2O,CH3OH,C2H5OH,i-C3H7OH,n-C3H7OH,and t-C4H9OH

The gas-phase clustering reactions Cl⁻ (ROH)n−1 + ROH ⇄ Cl⁻ (ROH)_n with n ⩽ 11 for ROH = H₂O, CH₃OH, C₂H₅OH, i-C₃H₇OH, n-C₃H₇OH, and t-C₄H₉OH were measured using a high-pressure mass spectrometer. It seems likely that for CH₃OH and C₂H₅OH, six ligands complete the shell structure and that ligands with n ⩾ 7 belong to the outer shell. The bond energies D(ROH---Cl⁻) increase in the order H₂O < CH₃OH < C₂H₅OH < i-C₃H₇OH < t-C₄H₉OH < n-C₃H₇OH. The observed strong bond of n-C₃H₇OH---Cl⁻ may be due to the fact that both the acidic hydrogen atoms in the −OH and terminal −CH₃ of n-C₃H₇OH interact with Cl⁻ with the most favorable configuration. For Cl⁻ switching reactions, Cl⁻ (H₂O)_n + (ROH)_n ⇄ Cl⁻ (ROH)_n + (H₂O)_n, the ΔG⁰_n values converge to the values of free energies of transfer of Cl⁻ from water to ROH solvent ( = ΔG⁰_n with n → ∞) with n ≈ 7. The observed convergence of ΔG⁰_n is due to compensation of changes in enthalpy and entropy, i.e. both ΔH⁰_n and TΔS⁰_n show increasing divergence from the values of enthalpies and entropies of transfer of Cl⁻ from water to ROH solvent, respectively, with n = 1 → 7. This is due to the stronger interactions of ROH with Cl⁻ than that of H₂O in the inner shell of Cl⁻ (ROH)_n at the expense of the less favorable entropy changes (less freedom of motion for ligands in the inner shell).     

Synthesis and characterization of MH···HOR dihydrogen bonded ruthenium and osmium complexes(η~5-C_5H_4CH_2OH)MH(PPh_3)_2(M = Ru,Os)

Treatment of RuCl2(PPh3)3 with 6-dimethylaminopentafulvene in THF in the presence of water produced(η5-C5H4CHO) RuCl(PPh3)2, which was reduced by NaBH4 to give the Ru–H···HO dihydrogen bonded complex(η5-C5H4CH2OH) RuH(PPh3)2. The dihydrogen bonded complex(η5-C5H4CH2OH)RuH(PPh3)2 could also be synthesized by the reduction of complex(η5-C5H4CHO)RuH(PPh3)2, which was obtained by the reaction of RuHCl(PPh3)3 with 6-dimethylaminopentafulvene in the presence of water. The analogous dihydrogen bonded osmium complex(η5-C5H4CH2OH)OsH(PPh3)2 was similarly prepared. Single crystal structures and DFT calculations support the presence of intra-molecular H···H interaction, with separations of around 1.9 to 2.0 .     

Reactions of nucleophilic addition of primary amines to the nitrilium derivative of the <Emphasis Type="Italic">closo</Emphasis>-decaborate anion [2-B<Subscript>10</Subscript>H<Subscript>9</Subscript>(N≡CCH<Subscript>3</Subscript>)]<Superscript>−</Superscript>

Compounds (Bu₄N)[2-B₁₀H₉{NH=C(NHR)CH₃}]⁻ are obtained by reactions of the tetrabutylammonium salt of the [2-B₁₀H₉(N≡CCH₃)]⁻ anion with aliphatic and aromatic primary amines RNH₂ (R = n-C₃H₇, n-C₄H₉, cyclo-C₅H₉, C₆H₅, cyclo-C₆H₁₁, n-C₆H₁₃, C₇H₇, C₈H₈NH₂, C₆H₄NO₂, and C₁₈H₃₇) and identified by IR, ESI/MS, and NMR (¹H, ¹¹B, and ¹³C) spectroscopy. The structures of the amidine-type derivatives [2-B₁₀H₉{Z-NH=C(NH-cyclo-C₅H₉)CH₃}]⁻ and [2-B₁₀H₉{Z-NH=C(NH-C₇H₇)CH₃}]⁻ are determined by X-ray diffraction.     

Sels de Pyrylium. XVIII. Etude par RMN du Carbone-13 de Sels d'Aminopyrylium et des Barrières de Rotation dans quelques Cations N,N-Diméthylaminopyrylium

The C-2—N bond of 2-N,N-dimethylaminopyrylium cations has a partial π character due to the conjugation of the nitrogen lone-pair with the ring. The values of ΔG^≠, ΔH^≠, ΔS^≠ parameters related to the corresponding hindered rotation have been determined by ¹³C NMR total bandshape analysis. This conjugation decreases the electrophilic character of carbon C-4 so that the displacement of the alkoxy group is no longer possible. Such a hindered rotation also exists in 4-N,N-dimethylaminopyrylium cations and the corresponding ΔG^≠ parameters have been evaluated. Comparison of these two cationic species shows that hindered rotation around the C—N bond is larger in position 4 than in position 2. Furthermore, the barrier to internal rotation around the C-2? N bond decreases with increasing electron donating power of the substituent at position 4. ΔG^≠ values decreases from 19.1 kcal mol^?1 (79.9 kJ mol^?1) to 12.6 kcal mol^?1 (52.7 kJ mol^?1) according to the following sequence for the R-4 substituents: -C₆H₅, -CH₃, -OCH₃, -N(CH₃)₂.     

Carbonyl rhodium(I) complexes with α-diimines ligands

The reactions of [Rh(CO)₂Cl]₂ with α-diimines, RN=CR′-CR′=NR (R = c-Hex, C₆H₅, p-C₆H₄OH, p-C₆H₄CH₃, p-C₆H₄OCH₃, R′ = H; R = c-Hex, C₆H₅, p-C₆H₄OH, p-C₆H₄OCH₃; R′ = Me) in 2:1 Rh/R-dim ratio gave rise to ionic compounds [(CO)₂Rh.R-dim(R′,R′)][Rh(CO)₂Cl₂] which have been characterized by elemental analyses, electrical conductivity, ¹H-NMR and electronic and IR spectroscopy. Some of these complexes must involve some kind of metal-metal interaction. The complex [Rh(CO)₂Cl.c-Hex-dim(H,H)] has been obtained by reaction of [Rh(CO)₂Cl]₂ with the c-Hex-dim(H,H) ligand in 1:1 Rh/R-dim ratio. The reactions between [(CO)₂Rh.R-dim(H,H)][Rh(CO)₂Cl₂](R = c-Hex or p-C₆H₄OCH₃) with the dppe ligand have been studied. The known complex RhCl(CO)(PPh₃)₂ has been isolated from the reaction of [(CO)₂Rh.R-dim(H,H)]-[Rh(CO)₂Cl₂] (R = c-Hex or p-C₆H₄OCH₃) with PPh₃ ligand.     

Nonisothermal membrane phenomena across perfluorosulfonic acid-type membranes,Flemion S: part I. Thermoosmosis and transported entropy of water

Solvent transports across the perfluorosulfonic acid-type membrane Flemion S were measured for aqueous electrolyte solutions under a temperature difference and under an osmotic pressure difference. H⁺, Li⁺, Na⁺, K⁺, NH ₄ ⁺ , CH₃NH ₃ ⁺ , (CH₃)₂NH ₂ ⁺ , (CH₃)₃NH⁺, (CH₃)₄N⁺, (C₂H₅)₄N⁺, (n-C₃H₇)₄N⁺ and (n-C₄H₉)₄N⁺ were used as counterions. Water flux across the membrane in HCl solution is higher than that in the other electrolyte solutions because hydrogen ions can exchange with the hydrogen of the neighbor water molecules and contribute to the water transport across the membrane as a proton jump in conductivity. The direction of thermoosmosis across the membrane in HCl, NaCl, (CH₃)₄NCl and (C₂H₅)₄NCl solutions was from the cold side to the hot side and that in LiCl, KCl, NH₄Cl, CH₃NH₃Cl, (CH₃)₂NH₂Cl and (n-C₄H₉)₄NBr solutions was from the hot side to the cold side, although thermoosmosis across anion-exchange membranes always occurs toward the hot side.     

Kinetic Analysis of the Thermal Decomposition of Dialkyldithiocarbamates Chelates of Indium(III)

The kinetics of thermal decomposition of solid In(S₂CNR₂)₃ complexes, (R=CH₃, C₂H₅, n-C₃H₇,i-C₃H₇, n-C₄H₉ and i-C₄H₉), has been studied using isothermal and non-isothermal thermogravimetry. Superimposed TG/DTG/DSC curves show that thermal decomposition reactions occur in the liquid phase, except for the In(S₂CNMe₂)₃ and In(S₂CNPrⁱ ₂)₃ compounds. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and Polymerization of the Organometallic Monomer Series Based on Cymantrenylethyl Acrylate

{η⁵ -C₅H₄[CH(CH₃)OC(O)CH = CH₂])Mn(CO)3, {η⁵—C₅[CH-(CH₃)OC(O)C(CH₃)=CH₂]]Mn(CO)₃, and {η⁵—C₅H₄[CH(CH₃)-OC(O)CH=C(CH₃)2])Mn(CO)₃ were synthesized (63, 57, and 51%, respectively) from {η⁵—C₅H₄[CH(CH₃)OH])Mn(CO)₃, toluene-sulfonic acid, and the acrylic, methacrylic, and dimethylacrylic acids, and from (η⁵-C₅H₄[CH(CH₃)OH]}Mn(CO)₃, pyridine, and the acrylic, methacrylic, and dimethylacrylic acyl chlorides [26, 48, and 25% (impure), respectively]. No product was obtained when NaH was used as the base in the latter method. The acrylate and methacrylate monomers were bulk homopolymerized at 65°C with AIBN (75% yield, M_n = 88,550 g/mol; 78% yield, M_n = 349,350 g/mol, respectively). The dimethylacrylate did not polymerize under these conditions. The polymers lost vinylcymantrene upon heating to 257 and 279°C, respectively. The polymers did not exhibit a clear T_g but were observed to soften at 85 and 160°C, respectively, and they could be pulled into fibers.     

Reactions of coordinated propargyl and allene ligands in cyclopentadienyliron dicarbonyl complexes

Reactions of η⁵-C₅H₅Fe(CO)₂CH₂CCR (R  CH₃, C₆H₅, and CH₂Fe(CO)₂(η⁵-C₅H₅)) with HBF₄ in acetic anhydride yield [η⁵-C₅H₅Fe(CO)₂(η²CH₂CCHR)]⁺BF^?₄. The resultant cationic iron-η²-allene complexes react with a wide range of nucleophiles (Nu) to give the following types of behavior: (a) addition of Nu to carbon-1 of the η²-allene fragment (with NaBH₄, (C₂H₅)₂NH, and P(C₆H₅)₃, inter alia), (b) addition of Nu to carbon-2 of the η²-allene fragment (with NaOCH₃), (c) addition of Nu to the carbonyl carbon (with NaOC₂H₅), (d) deprotonation of the iron-η²-allene cation to the parent propargylic complex (with N(C₂H₅)₃), and (e) nonselective reactions to yield a mixture of products (with CH₃Li). Of these, the most common is behavior (a); together with the protonation of η⁵-C₅H₅Fe(CO)₂CH₂CCR it stimulates the two-step (3 + 2) cycloaddition reactions between electrophilic molecules and these iron-propargyl complexes.     

Schiff base derivatives of lanthanons-synthesis of La(III), Pr(III) and Nd(III) derivatives of β-ketoimines derived from 2,4-pentanedione

Reactions of the isopropoxides of some of the lighter lanthanons with bidentate -ketoimines, such asAAH-n-C₄H₉ andAAH-C₆H₅ (donor system: N,OH) and tridentate -ketoimines such asAA(CH₂CH₂)H₂ andAA(CH₂CHCH₃)H₂ (donor system: HO,N.OH) have led to products of the typesLn(O-i-C₃H₇)_3n (AA-R) _n ,Ln(Oi-C₃H₇) (AAR') andLn ₂(AAR')₃ [Ln=La(III), Pr(III) or Nd(III);n=1 or 2;R=-n-C₄H₉ or-C₆H₅ andR'=-CH₂CH₂-or-CH₂CHCH₃-]. Some undergo exchange reactions with an excess oftert-butanol, leading to the corresponding complexesLn(O-tert-C₄H₉)_3n (AA-n-C₄H₉) _n andLn(O-tert-C₄H₉) (AA-CH₂CH₂). All these have been characterised by elemental analysis, molecular weight determinations and their ir spectra. A thermogravimetric analysis of the diisopropoxy derivatives has also been carried out.

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Schiff-Basen Derivate von Lanthaniden-Synthese von La(III), Pr(III) und Nd(III) chelaten mit -Ketoiminen

Zusammenfassung Reaktionen von Lanthanid-Isopropoxiden mit zweizähnigen -Ketoiminen [AAH-n-C₄H₉ undAAH-C₆H₅; Donorsystem: N,OH] und dreizähnigen -Ketoiminen [AA(CH₂CH₂)H₂ undAA(CH₂CHCH₃)H₂; Donorsystem: OH, N,OH] führten zu Produkten vom, TypLn(O-i-C₃H₇)_3-n (AA-R) _n ,Ln(O-i-C₃H₇) (AAR') undLn ₂(AAR')₃ [Ln=La(III), Pr(III) oder Nd(III);n=1 oder 2;R=n-C₄H₉ oder C₆H₅ undR'=CH₂CH₂ oder CH₂CHCH₃]. Einige Komplexe unterliegen bei Behandlung mit einem Überschuß vontert-Butanol einer Austauschreaktion, die zu den entsprechenden Butoxid-Komplexen führt [Ln(O-tert-C₄H₉)_3-n , (AA-n-C₄H₉) _n undLn(O-tert-C₄H₉) (AACH₂CH₂)]. Alle Derivate wurden mittels Elementaranalyse, Molgewichtsbestimmung und IR-Spektroskopie charakterisiert. Eine thermogravimetrische Analyse der Diisopropoxi-Derivate wurde ebenfalls ausgeführt.

     

Crystal and molecular structure of(η-C5H5)W[C3(CME3)2Me](PME3)Cl2, a species with a tetrahedral WC3, core formed from a tungstenacyclobutadiene complex via attack on tungsten by a phosphorus-donor ligand

Mercury(II) chloride in refluxing methanol or acetone cleaves the molybdenum—tin bond of π-methylcyclopentadienylmolybdenum tricarbonyl triphenylstannyl [(η⁵-C₅H₄CH₃)(CO)₃MoSnPh₃] to give (η⁵-C₅H₄CH₃)(CO)₃MoHgCl. The same product was also obtained by reaction of [(η⁵-C₅H₄CH₃)(CO)₃Mo]₂Hg with HgCl₂ in acetone at room temperature. Similar reactions have given bimetallic complexes of the type (η⁵-C₅H₄CH₃)(CO)₃MoHgX (X = Br, I, SCN). The new complexes are air-stable crystalline solids. The structure of the compound (η⁵-C₅H₄CH₃)(CO)₃MoHgCl has been determined. It crystallizes in space group P2₁/c with Z = 4, a 6.613(2), b 13.647(4), c 13.257(4) Å, β 101.85(3)°, D_c 2.81 g/cm³, F(000) = 896, μ(Mo-K_α) 143.56 cm^?1. Final R = 0.055 for 1696 observed reflexions.     

Hydrogen fluoride vibrational energy distributions for the reactions of fluorine atoms with cyclanes

The hydrogen fluoride infrared chemiluminescence produced by the reactions of fluorine atoms with cyclopropane, cyclopentane, and cyclohexane have been studied. The emission data were used to determine the vibrational energy distributions for the abstraction of hydrogen from the secondary carbon–hydrogen bonds of these small cyclic hydrocarbons. The fraction of reaction exothermicity going into vibrational excitation of hydrogen fluoride was as follows: c-C₃H₆, 45%; c-C₅H₁₀, 53%; c-C₆H₁₂, 49%. The slightly lower fraction for the cyclopropane system may indicate that its radical reorganization energy is not completely available for excitation of product HF.