Mechanism of the reduction of molecular nitrogen to hydrazine by niobium (iii) hydroxide

The effect of the concentration of water on the rate of reduction of molecular nitrogen to hydrazine by niobium(iii) hydroxide in alkaline H₂O−MeOH and D₂O−MeOD mixtures was studied. In both cases, the reaction rate is maximum when [H₂O]=4 mol L⁻¹, and the inverse isotopic effect (K ^D/k ^H>1) is observed when [H₂O]<20 mol L⁻¹. Similar regularity was observed for the reaction of hydrogen elimination. It was found that HD is formed in the H₂O−MeOH system in the presence of D₂. The conclusion was made that the ratedetermining stage in hydrazine formation is the transfer of a hydride ion to the dinitrogen molecule coordinated to the binuclear Nb^III center. A kinetic scheme satisfactorily explaining the effect of the concentration of water ([H₂O]=1.5−49.0 mol L⁻¹) on the reaction rate constant was proposed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1600–1604, September, 1997.     

Thermochemistry of Bu<Subscript>4</Subscript>NBr solutions in binary solvents containing formamide

The heats of solution of tetrabutylammonium bromide have been measured in mixtures of formamide (FA) with methanol (MeOH) and ethylene glycol (EG) at 313.15 K by calorimetric method. The standard enthalpies of solution in binary mixtures have been extrapolated to infinite dilution by Redlich–Rosenfeld–Meyer type equation using the literary data at 298.15 K and the present paper data at 313.15 K. The Debye–Hückel limiting law slope A _H required for calculation of the ∆_sol H ⁰ value has been obtained with application the new additive scheme of determination of the physic-chemical characteristics of binaries. The scheme is tested on the example of Bu₄NBr solutions in FA–MeOH mixture at 298.15 K. Its application yields the ∆_sol H ⁰ value very closed on the ones determined with the real (non-additive) characteristics of binaries. The standard enthalpies of solution extrapolated by Redlich–Rosenfeld–Meyer type equation are in a good agreement with the ones computed in terms of the Debye–Hückel theory in the second approximation. The heat capacities characteristics of Bu₄NBr have been calculated in H₂O–FA, MeOH–FA and EG–FA mixtures using the literary and present data. The sequence of solvents H₂O > FA > EG > MeOH located on their ability to solvophobic solvation found by us earlier for enthalpic characteristics is confirmed by the ∆C _p ⁰ values. The comparison of thermochemical characteristics of Bu₄NBr solutions in aqueous and non-aqueous mixtures containing FA has been carried out. The own structure of water remains in the region of small additions of formamide to co-solvents. It considerably differs the H₂O–FA mixture from the investigated non-aqueous systems.     

Solid state complexes of nickel(II) and 4-imidazoleacetic acid: X-ray crystallography and spectroscopic investigation

The stoichiometric reaction of NiCl₂·6H₂O with sodium 4-imidazoleacetate Na(IA) in absolute MeOH yields blue crystals of Ni(IA)₂·4H₂O·2MeOH (1). This product decomposes rapidly in air, losing two MeOH molecules and producing Ni(IA)₂·4H₂O (2). Compound (1) when left in the mother liquor, slowly recrystallizes forming [Ni(IA)₂(MeOH)₂] (3), which is stable in air and suitable for single crystal X-ray diffraction studies. These crystals consist of slightly distorted octahedral coordination units in which the carboxylic oxygen, imidazole N3 nitrogen and the MeOH oxygen atoms act as coordination centers. The i.r. features, due to MeOH molecules, were employed to characterize the compounds studied. The reflectance spectrum of (3) was interpreted on the basis of octahedral and tetragonal symmetry of the NiO₄N₂ chromophore.     

Determination of the stability constant and thermodynamic parameters between Tl<Superscript>+</Superscript>, Ag<Superscript>+</Superscript> and Pb<Superscript>2+</Superscript> cations with 2,6-di(furyl-2yl)-4-(4-methoxy phenyl)pyridine as a new synthesis ligand

The complexation reaction between Tl⁺, Ag⁺ and Pb²⁺ cations with 2,6-di(furyl-2yl)-4-(4-methoxy phenyl)pyridine as a new synthesis ligand in acetonitrile (ACN)–H₂O and methanol (MeOH)–H₂O binary solutions has been studied at different temperatures using conductometric method. The conductometric data show that the stoichiometry of the complexes is 1: 1 [M: L] and the stability constant of complexes changes with the binary solutions identity. Also, the structure of the resulting 1: 1 complexes was optimized using the LanL2dz basis set at the B3LYP level of theory using GAUSSIAN03 software. The results show that the change of logK_f for (DFMP.Pb)²⁺ and (DFMP.Ag)⁺ complexes with the mole ratio of acetonitrile and for (DFMP.Ag)⁺ and (DFMP.Tl)⁺ complexes with the mole ratio of methanol have a linear behavior, while the change of logK_f of (DFMP.Tl)⁺complex in ACN–H₂O binary solutions (with a minimum in X_ACN = 0.5) and (DFMP.Ag)⁺ complex in MeOH–H₂O binary solutions (with a minimum in X_MeOH = 0.75) show a non-linear behavior. The selectivity order of DFMP ligand for these cations in mol % CAN = 25 and 75 obtain Tl⁺ > Pb²⁺ > Ag⁺ but in mol % CAN = 50, the selectivity order observe Pb²⁺ > Tl⁺ > Ag⁺. Also, this selectivity sequence of DFMP in MeOH–H₂O (mol % MeOH = 75 and 100) and (mol % MeOH = 50) is obtained Pb²⁺ > Ag⁺ and Tl⁺ > Ag⁺ > Pb²⁺ respectively. The values of thermodynamic parameters show that these values are influenced by the nature and the composition of binary solution. In all cases, the resulting complexes are enthalpy stabilized and entropy destabilized. The TΔS_C^° versus ΔH_C^° plot of all obtained thermodynamic data shows a fairly good linear correlation which indicates the existence of enthalpy-entropy compensation in the complexation reactions.     

Etude Experimentale et Modelisation des Equilibres Solide—Liquide du Systeme Binaire H2O—UO2(NO3)2

The binary system H₂O—UO₂(NO₃)₂ was studied by solubility measurements and constant heat flow thermal analysis. Temperature and composition of the eutectic transformation between ice and uranyl nitrate hexahydrate were accurately defined. A new hydrate with 24 molecules of water decomposes at –21°C according to the peritectoid reaction<UO₂(NO₃)₂·24H₂O> <UO₂(NO₃)₂·6H₂O> + 18<H₂O>The quasi-ideal model was applied to the solid—liquid equilibria, using the following reaction hypothesis:((UO ₂ ²⁺ )) + 2((NO ₃ ^– ))+ h((H₂O)) ((UO₂OH⁺aq)) + ((H₃O⁺aq + 2((NO ₃ ^– aq))A complete calculation of the binary system was carried out with a global ionic hydration number h equal to 9 in the aqueous solutions. It allowed to the melting enthalpies of uranyl nitrate hydrates.

This revised version was published online in November 2005 with corrections to the Cover Date.     

Adsorption and desorption of different gases on Ru film in the dark and under UV irradiation

The adsorption and desorption of some vapors and gases (water, hydrogen, dinitrogen oxide, carbon monoxide, oxygen) on Ru film has been investigated at 305 K using a Tian-Calvet microcalorimeter. The initial heat of adsorption, the irreversible coverage and the temperature of maximum desorption rate indicate the following binding energy order: H₂>N₂O>H₂O>CO>O₂. The amount of photoadsorption (for H₂O, N₂O, H₂) and photodesorption (for CO and O₂) has also been determined by recording the pressure changes induced by UV irradiation of the Ru film.     

Study of complexation process between N-phenylaza-15-crown-5 with yttrium cation in binary mixed solvents

The complexation reaction between Y³⁺ cation with N-phenylaza-15-crown-5(Ph-N15C5) was studied at different temperatures in acetonitrile–methanol (AN/MeOH), acetonitrile–propanol (AN/PrOH), acetonitrile–1,2 dichloroethane (AN/DCE) and acetonitrile–water (AN/H₂O) binary mixtures using the conductometric method. The results show that in all cases, the stoichiometry of the complex is 1:1 (ML). The values of formation constant of the complex which were determined using conductometric data, show that the stability of (Ph-N15C5.Y)³⁺ complex in pure solvents at 25?°C changes in the following order: PrOH?>?AN?>?MeOH and in the case of binary mixed solutions at 25?°C it follows the order: AN–DCE?>?AN–PrOH?>?AN–MeOH?>?AN–H₂O. The values of standard thermodynamic quantities (?H _c ^° and ?S _c ^° ) for formation of (Ph-N15C5.Y)³⁺ complex were obtained from temperature dependence of the formation constant using the van’t Hoff plots. The results show that in most cases, the complex is entropy and enthalpy stabilized and these parameters are influenced by the nature and composition of the mixed solvents. In most cases, a non-linear behavior was observed for variation of log K_f of the complex versus the composition of the binary mixed solvents. In all cases, an enthalpy–entropy compensation effect was observed for formation of (Ph-N15C5.Y)³⁺ complex in the binary mixed solvents.     

Effects of solvent on the reactions of coordination complexes: Part 17. Kinetics and mechanism of base hydrolysis of (αβS) (salicylato) (tetraethylenepentamine)cobalt (III) in methanol + water and dimethylsulphoxide + water media

The base hydrolysis of (αβS) (salicylato) (tetraethylenepentamine)cobalt(III) has been investigated in MeOH + water and DMSO + water media (0–70% (v/v) cosolvents) at 20.0 ? t°C ? 35.0 and I = 0.10 mol dm^?3 (ClO₄^?). The phenoxide species [(tetren)CoO₂CC₆H₄O]⁺ undergoes both OH^?-independent and OH^?-catalyzed hydrolysis via SN₁ICB and SN₁CB mechanism, respectively. The OH^?-independent hydrolysis of the phenoxide species is catalyzed by both DMSO + water and MeOH + water media, the former exerting a much stronger rate accelerating effect than the latter. The OH^?-catalyzed reaction is strongly accelerated by DMSO + water medium but insensitive to the composition of MeOH + water medium up to 40% (v/v) MeOH beyond which it was not detectable under the experimental conditions. Data analysis has been attempted on the basis of the solvent stabilizing and destabilizing effects on the initial state and transition state of the concerned reactions. The nonlinear variation of the activation parameters, ΔH^≠ and ΔS^≠, with solvent compositions presumably indicates that the solvent structural effects mediate the energetics of solvation of the initial state and transition state of the concerned reactions. The linearity in ΔH^≠ vs. ΔS^≠ plot accomodating all data for k₁ and k₂ paths in DMSO + water and MeOH + water further suggests that the solvent effects on these parameters are mutually compensatory.     

Molecular architecture based on manganese triangles: Monomer, dimer, and one-dimensional polymer

The reaction of salicylaldoxime (H₂salox) with MnCl₂·4H₂O and NEt₄OH in MeOH affords the trinuclear manganese complex (NEt₄)[Mn₃O(salox)₃(MeOH)₂(H₂O)₂Cl₂]·MeOH (1·MeOH). A similar reaction of 1·MeOH was carried out using MnBr₂·4H₂O to obtain the hexanuclear manganese complex (NEt₄)₃{NaBr₂[Mn₃O(salox)₃(H₂O)₄Br₂]₂} (2). The reaction of 2-hydroxy-4-methoxybenzaldehyde oxime (4-MeO-H₂salox) and Mn(ClO₄)₂·6H₂O with 1,2-di(4-pyridyl)ethylene (dpe) in MeOH/DMF mixtures yields the one-dimensional complex {[Mn₃O(4-MeOsalox)₃(dpe)_1.5(DMF)₂(H₂O)](ClO₄)}_n (3·DMF·H₂O). Complex 1·MeOH shows a typical structure of a [Mn^III₃O]⁷⁺ core, and complex 2 contains a dimer [Mn^III₃O]⁷⁺ core connected by a Na⁺ ion. Complex 3 has a one-dimensional chain structure constructed from [Mn^III₃O]⁷⁺ units linked by dpe ligands. Magnetic analysis shows that all three complexes exhibit antiferromagnetic interactions between the Mn^III ions.     

Transition metal complexes with thiosemicarbazide-based ligands,Part II,Synthesis and characterisation of nickel(II), cobalt(II), manganese(II) and zinc(II) complexes with the pentadentate ligand, 2,6-diacetylpyridine bis(S-methylisothiosemicarbazone)

Summary The reaction of warm alcoholic solutions of acetates of Co^II, Mn^II, Zn^II and Ni^II with 2, 6-diacetylpyridine andS-methylisothiosemicarbazide hydrogen iodide yielded the complexes: [Co(H₂L)I₂]·H₂O, [Mn(H₂L)(MeOH)₂]I₂, [Zn(H₂L)(MeOH)I]I and [Ni(HL)]I, (H₂L=the pentadentate pentaaza-ligand 2, 6-diacetylpyridine bis(S-methylisothiosemicarbazone)). The reaction of methanolic solutions of [Ni(HL)]I and NH₄NCS or LiOAc.2H₂O, give [Ni(HL)]NCS and NiL, respectively. For the complexes of Co^II, Mn^II and Zn^II, a pentagonal bipyramidal configuration is proposed, with H₂L in the equatorial plane and two unidentate ligands (I and/or MeOH) in the axial positions. The complexes [Ni(HL)]X (X=I or NCS) and NiL probably have monomeric five- and dimeric six-coordinate structures, respectively, in which only the chelate ligand is involved in coordination.     

Supramolecular cobalt(II) complexes: syntheses,crystal structures and solvent effects

Two Co^II complexes, namely {[CoL(MeOH)(μ-OAc)]₂Co}·2MeCN·2MeOH (1) and {[CoL(EtOH)(μ-OAc)]₂Co}·3EtOH (2) (H₂L=3,3′-dimethoxy-2,2′-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol), have been synthesized and characterized by X-ray crystallography. Both complexes contain octahedral coordination geometries, comprising three Co^II atoms, two deprotonated bisoxime L²⁻ units in which four μ-phenoxo oxygen atoms form two [CoL(X)] (X = MeOH or EtOH) units, two acetate ligands coordinated to three Co^II centers through Co–O–C–O–Co bridges, and coordinated and non-coordinated solvent. Both complexes exhibit 2D supramolecular networks through different intermolecular hydrogen-bonding interactions.     

Effect of chelation on the polycondensation of monomers having an active ester group

Various amino acid esters and dicarboxylic acid esters having a β-thioether group have been synthesized and their polycondensation with diamine was found to occur at room temperature to form polyamide thioether. The effect of solvents or chelating agents on their polycondensation reaction was investigated. Metal acetylacetonates or inorganic salts had a great influence on the rate of the polycondensation reaction, and the catalytic activity of metal acetylacetonates M(AcAc)_n or inorganic salts decreased in the following order: Mg(AcAc)₂?Th(AcAc)₄>Cu(AcAc)₂>Li(AcAc)>None>Zr(AcAc)₄, MgCl₂·6H₂O>CuCl₂·.2H₂O>ZnCl₂>MgCl₂>None. It was also found that the amount of polyamide thioether was dependent on solvents or the presence of chelating agents because the polycondensation rate and the apparent equilibrium between ring and chain structures were both greatly influenced by solvents or chelating agents. These effects of solvents or chelating agent on the polycondensation may be attributable to formation of a complex with the thioether group which enhances the reactivity of ester.     

Study of complex formation between 18-crown-6 and diaza-18-crown-6 with uranyl cation (UO2 2+) in some binary mixed aqueous and non-aqueous solvents

The complexation reaction between UO₂ ²⁺ cation with macrocyclic ligand, 18-crown-6 (18C6), was studied in acetonitrile–methanol (AN–MeOH), nitromethane–methanol (NM–MeOH) and propylencarbonate–ethanol (PC–EtOH) binary mixed systems at 25 °C. In addition, the complexation process between UO₂ ²⁺ cation with diaza-18-crown-6 (DA18C6) was studied in acetonitrile–methanol (AN–MeOH), acetonitrile–ethanol (AN–EtOH), acetonitrile–ethylacetate (AN–EtOAc), methanol–water (MeOH–H₂O), ethanol–water (EtOH–H₂O), acetonitrile–water (AN–H₂O), dimethylformamide–methanol (DMF–MeOH), dimethylformamide–ethanol (DMF–EtOH), and dimethylformamide–ethylacetate (DMF–EtOAc) binary solutions at 25 °C using the conductometric method. The conductance data show that the stoichiometry of the complexes formed between (18C6) and (DA18C6) with UO₂ ²⁺ cation in most cases is 1:1 [M:L], but in some solvent 1:2 [M:L₂] complex is formed in solutions. The values of stability constants (log K_f) of (18C6 · UO₂ ²⁺) and (DA18C6 · UO₂ ²⁺) complexes which were obtained from conductometric data, show that the nature and also the composition of the solvent systems are important factors that are effective on the stability and even the stoichiometry of the complexes formed in solutions. In all cases, a non-linear relationship is observed for the changes of stability constants (log K_f) of the (18C6 · UO₂ ²⁺) and (DA18C6 · UO₂ ²⁺) complexes versus the composition of the binary mixed solvents. The stability order of (18C6 · UO₂ ²⁺) complex in pure studied solvents was found to be: EtOH > AN ≈ NM > PC ≈ MeOH, but in the case of (DA18C6 · UO₂ ²⁺) complex it was : H₂O > MeOH > EtOH.     

Regiochemical control of the ring-opening of aziridines by means of chelating processes. Part 4: Regioselectivity of the opening reactions with MeOH of 1-(benzyloxy)-2,3- and -3,4-N-(methoxycarbonyl)aziridoalkanes under condensed and gas-phase operating conditions

The regioselectivity of the addition reaction of MeOH both in the condensed phase (MeOH/H₂SO₄) and in the gas-phase (MeOH/D₃⁺) was examined in a series of activated aziridines. The results indicate that gas-phase operating conditions are particularly favorable for the occurrence of D⁺-mediated chelated bidentate species, which influence the regioselectivity of the opening process. In the condensed phase, the chelating MeOH/LiClO₄ protocol turned out to be decidedly less effective for regioselectivity and also in determining the composition of the reaction mixture.     

Study of Complex Formation between N-Phenylaza-15-Crown-5 with Mg2+, Ca2+, Ag+ and Cd2+ Metal Cations in Some Binary Mixed Aqueous and Non-aqueous Solvents using the Conductometric Method

The complexation reactions between Mg²⁺, Ca²⁺, Ag⁺ and Cd²⁺ metal cations with N-phenylaza-15-crown-5 (Ph-N15C5) were studied in acetonitrile (AN)–methanol (MeOH), methanol (MeOH)–water (H₂O) and propanol (PrOH)–water (H₂O) binary mixtures at different temperatures using the conductometric method. The conductance data show that the stochiometry of all of the complexes with Mg²⁺, Ca²⁺, Ag⁺ and Cd²⁺ cations is 1:1 (L:M). The stability of the complexes is sensitive to the solvent composition and a non-linear behaviour was observed for variation of log K _f of the complexes versus the composition of the binary mixed solvents. The selectivity order of Ph-N15C5 for the metal cations in neat MeOH is Ag⁺>Cd²⁺>Ca²⁺>Mg²⁺, but in the case of neat AN is Ca²⁺>Cd²⁺>Mg²⁺>Ag⁺. The values of thermodynamic parameters (ΔH _c ^o , ΔS _c ^o ) for formation of Ph-N15C5–Mg²⁺, Ph-N15C5–Ca²⁺, Ph-N15C5–Ag⁺ and Ph-N15C5–Cd²⁺ complexes were obtained from temperature dependence of stability constants and the results show that the thermodynamics of complexation reactions is affected by the nature and composition of the mixed solvents.     

含吡啶二脲配体汞(II)、镉(II)配合物的合成及其晶体结构

以2,2′-二氨基二苯醚和4-吡啶异氰酸酯反应合成了含吡啶二脲配体(L),并分别与HgCl_2和Cd(ClO_4)2进行了配位反应,得到2个配位聚合物{[Hg(L)Cl_2]·2DMF}_n(1)和{[Cd(L)_2(H_2O)_2](ClO_4)_2·4DMF·2H_2O·2CH_3OH}_n(2),采用1H NMR、MS、FTIR和元素分析等对化合物L进行了表征。通过X射线单晶衍射技术测定了配体及2个配合物的单晶结构,结构解析表明,2个配合物均为一维链状结构。进一步考察了2个配合物的热稳定性及其对甲醇蒸气的吸附性能。     

Ion-solvent molecule interaction in nonaqueous solutions: Spin-lattice relaxation time of7Li

The spin-lattice relaxation time (T ₁) of⁷Li⁺ was measured in solutions of LiCl and LiClO₄ in protic (MeOH, EtOH,n-PrOH,i-PrOH,n-BuOH, sec-BuOH, formamide, N-methylformamide) and aprotic (MeCN, acetone, methyl ethyl ketone, propylene carbonate, dimethyl sulfoxide, dimethylformamide, hexamethylphosphotriamide) solvents and in mixtures of H₂O-formamide, H₂O–N-methylformamide, H₂O–N,N-dimethylformamide, H₂O-DMSO, H₂O-hexamethylphosphotriamide, and formamide-N,N-dimethylformamide at 25°C. The values of (1/T ₁)₀ obtained by extrapolation are discussed in terms of current theories of the magnetic relaxation of ionic nuclei. Linear correlations were found between (1/T ₁)₀ and Gutmann's donor numbers and Kosower's Z-values. These correlations indicate that relaxation of⁷Li⁺ is dominated by donor-acceptor interaction of the cation with solvent molecules. Concentration dependences of 1/T ₁ for LiCl and LiClO₄ differ from one another in a given solvent, a fact which is accounted for by a specific cation-anion short-range potential. The quantity 1/T ₁ of⁷Li⁺ atC=1 mole per 55.5 moles of mixed solvent as a function of solvent composition show characteristic features, which are discussed in terms of the relaxation mechanism proposed.     

Formation of Cyclic Ketals from Hydroxyalkyl Enol Ethers,a stereoelectronically controlled endo-trig-cyclization process

Acid-catalyzed cyclic ketal formation vs. hydrolysis of a series of hydroxyalkyl cyclic enol ethers in the presence of 1 equiv. of H₂O, and acid-catalyzed cyclic-ketal formation (same ketals as above) vs. methanolysis of a series of mixed pent-4-enyl hydroxyalkyl ketals with N-bromosuccinimide in the presence of 4 equiv. of MeOH led to the same result: the intramolecular cyclization processes occur at similar rates as the intermolecular H₂O or MeOH attacks independently of the size of the rings formed (five-, six-, or seven-membered), by cyclizations. These results can be explained by the facts that, due to stereoelectronic effects which impose a torsional strain to the sp² hybridized O-atom, the cyclization activation enthalpy decreases, as the length of the hydroxyalkyl chain increase (ease of cyclization: 7 > 6 > 5), whereas the entropy factor favors the cyclization in the reverse fashion (ease of cyclization: 5 > 6 > 7). The various reaction pathways have been examined using the semi-empirical Hamiltonian AM1, and the results obtained confirm that large-ring formation is enthalpically much favored over the cyclization processes leading to small rings (ease of cyclization: 7 > 6 > 5).     

Formation of the CuII–Phenoxyl Radical by Reaction of O2 with a CuII–Phenolate Complex via the CuI–Phenoxyl Radical

Reaction of Cu(ClO₄)₂ ⋅ 6 H₂O with a tripodal 2N2O ligand, H₂Me₂NL, having a p-(dimethylamino)phenol moiety, in CH₂Cl₂/MeOH (1:1 v/v) under basic conditions under an inert gas atmosphere gave [Cu(Me₂NL)(H₂O)] ( 1 ). The same reaction carried out under aerobic conditions gave [Cu(Me₂NL)(MeOH)]ClO₄ ( 2 ), which could be obtained also from the isolated complex 1 by reaction with O₂ in CH₂Cl₂/MeOH. The X-ray crystal structures of 1 and 2 revealed similar square-pyramidal structures, but 2 showed the (dimethylamino)phenoxyl radical features. Complex 1 exhibits characteristic Cu^II EPR signals of the d ground state in CH₂Cl₂/MeOH at 77 K, whereas 2 is EPR-silent. The EPR and X-ray absorption fine structure (XAFS) results suggest that 2 is assigned to the Cu^II–(dimethylamino)phenoxyl radical. However, complex 1 showed different features in the absence of MeOH. The EPR spectrum of the CH₂Cl₂ solution of 1 exhibits distortion from the d ground state and a temperature-dependent equilibrium between the Cu^II–(dimethylamino)phenolate and the Cu^I–(dimethylamino)phenoxyl radical. From these results, Cu^II–phenoxyl radical complex 2 is concluded to be formed by the reaction of 1 with O₂ via the Cu^I–phenoxyl radical species.     

Photosolvolysis of 2-Allylated Anilines to 2-Indanols

It is shown that 2-allylated anilines (cf. Schemes 2–4, 7, and 8) on irradiation in protic solvents such as H₂O. MeOH, and EtOH in the presence of H₂SO₄ undergo a novel photosolvolysis reaction to yield specifically trans-2-hydroxy- and trans-2-alkoxy-1-methylindanes. Intermediates are presumably tricyclo[4.3.0.0^1,8]nona-2,4-dienes formed in an intramolecular [2s + 2s] cycloaddition reaction (cf. Scheme 7). On the other hand, N,N,N-trimethyl-2-(1′-methylallyl)anilinium salts 18 (Scheme 6) and 2-(3′-butenyl)-N,N-dimethylaniline ( 17 ) lose on irradiation in MeOH or H₂SO₄/MeOH the ammonium group reductively to yield (1-methylallyl)benzene ( 19 ) and 1-methylindane ( 20 ), respectively.