Alkylation of tricarbonylcyclohexadienyliron salts (1) with lithium alkyls

The salts $\text{1}$ (Y=H, OMe, Me) react with RLi(R=Me, n-Bu, i-Pr, t-Bu) in CH₂Cl₂ at low temperature to give $\text{2}$ and $\text{3}$ in excellent yields. Nucleophilic addition at the 1-position of $\text{1}$ (Y=OMe) has been observed for the first time.     

The spin 32 state (?) in six-coordinate iron (III). A Mössbauer and EPR investigation

Tris-(4-morpholinecarbodithioato-S,S′) iron (III) (FeM) and its dichloromethane solvate, (FeM·CH₂Cl₂), have been prepared and their temperature-dependent Mössbauer and EPR spectra have been determined at temperatures between liquid nitrogen and ambient. The Mössbauer spectra of FeM·CH₂Cl₂ differ considerably from that of FeM and is interpreted in terms of a four-line spectrum at 77 K. The EPR spectra of the two complexes indicate that the lower spin state of FeM·CH₂Cl₂ populates much more rapidly in the temperature range studied (100–300 K) than does FeM. These results support the postulation of an S = $\text{5}\text{2}$ ? S = $\text{1}\text{2}$ spin-equilibrium for FeM and a corresponding S = $\text{5}\text{2}$ ? S = $\text{3}\text{2}$ equilibrium for FeM·CH₂Cl₂.     

The chemical oxidation and electronic spectra of the complexes trans-[M(CNR)2(Ph2PCH2CH2PPh2)2] (M = Mo or W)

Oxidation of the complexes $\text{trans}$-[M(CNR)₂(dppe)₂] (A) (M = Mo or W; R = Me, Bu^t or CH₃C₆H₄-$\text{4}$; dppe = Ph₂PCH₂CH₂PPh₂) with diiodine or silver (I) salts gives the paramagnetic cations $\text{trans}$-[M(CNR)₂(dppe)₂]⁺, (M = Mo, R = CH₃C₆H₄-$\text{4}$; M = W, R = Bu^t) and $\text{trans}$-[M(CNR)₂(dppe)₂]²⁺ (M = Mo, R = Me or CH₃C₆H₄-$\text{4}$; M = W, R = Me or Bu^t). Mixtures of products are generally produced when dichlorine or dibromine are the oxidising agents, however pure salts, the seven-coordinate complex cations [MX(CNC₆H₄CH₃-$\text{4}$)₂(dppe)₂]⁺ (B, X = Cl or Br) have been isolated. A simple molecular orbital scheme is proposed for complexes (A) and used to discuss their electronic spectra and their oxidation.     

Dichlorobis(organonitrile)palladium(II) catalysis of cis- to trans- isomerization of ethylchrysanthemate and chrysanthemic acid

Complexes of the type L₂PdCl₂ (L = CH₃,CN, CH₃CH₂CN, PhCN) in benzene or chloroform act as homogeneous catalysts in the room temperature $\text{cis}$ to $\text{trans}$ isomerization of ethylchrysanthemate and chrysanthemic acid.     

Action of tert-butyl azidoformate on the conjugate bases of 1,2,3,4-tetrahydro-9H-carbazole and other indole derivatives

tert-Butyl azidoformate ($\text{2}$) reacts with the conjugate bases of $\text{3a}$, $\text{7a}$, $\text{9}$ (R¹ = R² = CH₃), and $\text{9}$ (R¹ = CH₃, R² = H) to give products [$\text{4}$, $\text{8}$, $\text{12}$, and $\text{14}$, respectively] in addition to the expected N-(tert-butoxycarbonyl)indole derivatives.     

Electric moments,polarizabilities and hyperpolarizabilities for BH(X1Σ+ and CH+ (X1Σ+)

The electric moments and static polarizabilities of BH(1σ²2σ²3σ², X¹Σ⁺) and CH⁺ (1σ²2σ²3σ², X¹Σ⁺) were calculated at the experimental internuclear separation in the LCAO SCF MO approximation. Most of the molecular properties reported in this paper for BH and CH⁺ appear for the first time and should be close to the Hartree—Fock limit. All tensors up to the fourth rank have been included in this study. The isotropy and anisotropy of the α, β and γ tensors are, in atomic units. $\text{α}$ = 22.71, Δα = ?0.26, $\text{β}$ = 55.1, Δβ = ?183.7, $\text{γ}$ = 12428, Δ₁γ = 37895, Δ₂γ = 25120 for BH and $\text{α}$ = 7.73, Δα = 0.39, $\text{β}$ = ?12.4, Δβ = ?11.7, $\text{γ}$ = 344, Δ₁γ = 1515, Δ₂γ = 750 for CH⁺.     

The intramolecular addition of sulphenic acids to alkynes: Bicyclic alkenyl sulphoxides

The preparation of the bicyclic alkenyl sulphoxides $\text{1}$ (n = 1 and 2; R = CH₂CH₃) from the alkynyl sulphenic acids $\text{2}$ is described.     

Phosphorus heterocycle synthesis by RPX2,· AlX3 addition to [1,n]dienes VII.

The RPX₂·AlX₃ complex ($\text{1}$) reacts with unsaturated ketones and imines to give novel 7-oxa and 7-aza-2-phosphabicyclo[2.2.1]heptanes (compounds $\text{3}$ and $\text{6}$ respectively).A new 1,3-dipolar addition of (CH₃)₂ CCH₂P?XR to nArN=C=S was disclosed resulting in the formation of the 2-imino-1,3-thiaphospholanes ($\text{7}$).     

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.     

CH3O(X2E) production from 266 nm photolysis of methyl nitrite and reaction with NO

The CH₃O($\text{X}$²E) radical produced by the 266 nm photolysis of CH₃ONO is characterized by laser-induced fluorescence. Using a flowing gas cell the reaction rate of CH₃O($\text{X}$²E) with NO is measured to be (2.08 ± 0.12) × 10^?11 cm³ s^?1 molecule^?1 based upon disappearance of CH₃O and appearance of HNO detected by laser induced fluorescence. Upper limits for CH₃O reactions with CH₄, CO, N₂O, NH₃, CH₃OH, (CH₃)₃CH and CH₂CHCH₂CH₃ are reported. These reactions are all too slow to measure under our experimental conditions.     

Equilibrium and kinetics of reversible capture of solvated electron-sodium+ pairs by 1,1-diphenylethylene in tetrahydrofuran

Solvated electron-Na⁺ pairs, e^?,Na⁺, and 1,1-diphenylethylene reversibly recombine in THF, the capture constant = 3 × 10⁷ M^?1 s^?1 and the detachment constant = 46 s^?1; the e^?,Na⁺, formed by flash-photolysis of Na⁺,$\text{C}\text{?}$(Ph)₂CH₂CH₂$\text{C}\text{?}$(Ph₂, Na⁺ survive for 0.1 s in this solvent at ambient temperature without any detectable decay.     

Photofragmentation of CH3Br in the A band

CH₃Br is photodissociated in the first continuum. Dissociation takes place into ground state CH₃ and Br [ = Br(²P_{$\text{3}\text{2}$}] or Br* [ = Br(*P_{$\text{1}\text{2}$})]. Time of flight and angular distributions of the CH₃ fragments are measured. The Br*/Br ratios upon excitation at 222 and 193 nm are found to be 1.00 and 0.20 respectively. The anisotropy parameters at these wavelengths are β = 0.28±0.04 and β = ?0.23±0.02, respectively. The total absorption cross section is decomposed into partial absorption cross sections of the ¹Q, ³Q₀ and ³Q₁ states. It appears that excitation at 222 nm takes place to the ³Q₀ and ³Q ₁ states whereas at 193 nm the ¹Q and ³Q₀ states are excited. Contrary to CH₃I, the adiabatic curve crossing between the ³Q₀ and the ¹Q states in Ch₃Br is not important. The dissociation energy of the CBr bond is determined to be D₀(CH₃Br) = 2.87±0.02 eV.     

Yield of I(2Psol:12) in the photodissociation of CH2I2

The production of I(²P_{$\text{1}\text{2}$}) in the photolysis of CH₂I₂ has been studied optoacoustically at excitation wavelengths between 365.5 and 247.5 nm. Bands found at 32200 and 47000 cm^?1 correlate with I(²P_{$\text{3}\text{2}$}) whilst those at 34700 and 40100 cm^?1, which correlate with I(²P_{$\text{1}\text{2}$}), give final ²P_{$\text{3}\text{2}$}/²P_{$\text{1}\text{2}$} ratios of 1.75 and 1.1, respectively, after curve crossing.     

Mutual solubility of n-butanol + water under high pressures

The mutual solubilities of {xCH₃CH₂CH₂CH₂OH+(1-x)H₂O} have been determined over the temperature range 302.95 to 397.75 K at pressures up to 2450 atm. An increase in temperature and pressure results in a contraction of the immiscibility region. The results obtained for the critical solution properties are: T_o(U.C.S.T.) = 397.85 K and x_o = 0.110 at 1 atm; $\text{(}\text{dT}{}_{\mathrm{o}}\text{d}\text{p}\text{) = ?(12.0±0.5)×10}{}^{\mathrm{?3}}\text{K atm}{}^{\mathrm{?1}}$ at p < 400 atm and $\text{(}\text{dT}{}_{\mathrm{o}}\text{d}\text{p}\text{) = ?(7.0±0.7)×10}{}^{\mathrm{?3}}\text{K atm}{}^{\mathrm{?1}}$ at 800 atm < p < 2500 atm; $\text{(}\text{dx}{}_{\mathrm{o}}\text{d}\text{T}\text{) = ?(4.0±0.5)×10}{}^{\mathrm{?4}}\text{K}{}^{\mathrm{?1}}$.     

Aroyl anion trapping reactions. A preliminary study of direct nucleophilic aroylation by means of low temperature, insitu (CH3)nC6H5nLi/CO Systems.

Results of studies of the $\text{in}$$\text{situ}$ nucleophilic aroylation of PhCO₂Me, Me₃CCO₂Me and Ph₂CO by several low temperature ArLi/CO systems (Ar =C₆H₅, p-CH₃C₆H₄, $\text{o}$-CH₃C₆H₄, 2,6-(CH₃)₂C₆H₃ and 2,4,6-(CH₃)₃C₆H₂) are reported. The experiments with C₆H₅Li were unsuccessful and the best results were obtained with 2,6-(CH₃)₂-C₆H₃Li.     

Charge transfer complexes between I2 and selenoamido entity contained in some pentaatomic rings

Spectrophotometric studies on the charge transfer complexes between molecular iodine and some pentaatomic rings containing the selenoamido entity, i.e. $\text{X · CH}{}_2\text{· CH}{}_2\text{· NR · C}$ = Se (where for R = H, X = CH₂, NH, NMe, NEt, S; for R = Me, X = NMe, S; for R = Et, X = NEt) have been carried out in CCl₄ and CH₂Cl₂ solutions. The presence of isosbestic points are indicative of 1:1 molecular adducts.The simultaneous determination of the stability constants (K) and molar extinction coefficients (?) has been carried out by using no linear least square methods. In order to improve the reliability of K and ? a criterion for selecting the experimental points is reported. The association constants obtained for the present compounds and the thioketonic isologues are correlated with the ionization energies of the lone pairs of the exoatom.     

Polymérisation cationique du chloro-1 butadiène et copolymérisation avec l'isobutène

The cationic homopolymerization of 1-chlorobutadiene and its copolymerization with isobutene have been carried out in dichloromethane solution. The catalyst-cocatalyst pairs used were AlEt₂Cl-(CH₃)₃CCl and AlEtCl₂-(CH₃)₃CCl. In the latter case, the use of (CH₃)₃CCl was not necessary. According to experimental conditions, high molecular weight copolymers ($\text{M}{}_{\mathrm{n}}\text{= 200,000}$) insoluble in CH₂Cl₂, or soluble low polymers ($\text{M}{}_{\mathrm{n}}\text{= 20,000}$) were obtained. Homopoly-1-chlorobutadienes were soluble low molecular weight polymers ($\text{M}{}_{\mathrm{n}}\text{= 10,000}$). The 1-chlorobutadiene units in the polymers are nearly exclusively 3,4 (mainly trans). Consequently, this method is not convenient to prepare elastomers with a 1,4 structure similar to that of chlorinated butyl rubber.     

Stéréosélectiveté de la condensation aldolique. Réaction du benzaldéhyde et d'énolates carbéniates magnésiens α-chlorés

Alkyl chloracetates III (R′ = H) and phenylchloracetates III (R′ = Ph) condense with PhCHO in the presence of (i-Pr)₂NMgBr giving alkyl-2-chloro-3-hydroxy-3-phenyl propionates (RS, RS) (I) and (RS, SR) (II) in equal ratio ($\text{1}\text{1}$) for III (R′ = H) and in the ratio $\text{65}\text{35}$ for III (R′ = Ph) irrespective of the group R. When the same reaction is performed with alkyl chloropropionates III (R′ = CH₃) the isomer ratio is dependent upon the group R. These results are interpreted by considering a planar (R′ = H or Ph) or pyramidal (R′ = CH₃) geometry of the intermediate enolate-carbeniate.     

The octant rule. XIV. synthesis and circular dichroism of α-exo and endo-deuteriobicyclo[3.2.1]octan-3-one and 6,6-dimethybicyclo[3.1.1]heptan-3-one

(1R,5S)-2S-Deuteriobicyclo[3.2.1]octan-3-one ($\text{1}$) and (1R,5S)-2R-Deuteriobicyclo[3.2.1]octan-3-one ($\text{2}$), prepared by diazomethane ring enlargement of (1S,4R)-2(exo)-deuteriobicyclo-[2.2.1] heptan-2-one and (1S,4R)-2(endo)-deuteriobicyclo[2.2.1]heptan-2-one respectively, both gave (?) n-π^* circular dichroism (CD) Cotton effects, Δε^max₂₉₄ = ?0.05 and Δε^max₂₉₄=?0.1, respectively, in hydrocarbon solvent. (1S,5R)-2S-Deuterio-6,6-diaethylbicyclo[3.1.1] heptan-3-one ($\text{3}$) and (1S,5R)-2R-deuterio-6,6-dimethylbicyclo[3.1.1] heptan-3-one ($\text{4}$), prepared from (-) myrtenal, both exhibited extraordinary vibrational fine structure for the n-π^* CD transitions observed in hydrocarbon solvent and oppositely?signed CEs, Δε^max₂₈₂=?0.01 and Δε^max₂₇₉=+0.01 respectively in CF₃CH₂OH solvent.