The Synthesis of the Arene Clusters Ru6C(CO)14(η6-Arene) (Arene = C6H5CHMe2, C6H5C4H9, C6H5C3H7, and C6H5C3H5)

On reaction with Ru₃(CO)₁₂, isopropenylbenzene and 4-phenyl-l-butene undergo hydrogenation, to yield the clusters, Ru₆C(CO)₁₄(⁶-C₆H₅CHMe₂) 1 and Ru₆C(CO)₁₄(⁶-C₆H₅C₄H₉) 2, respectively. With allylbenzene, both hydrogenation and isomerization occurs affording Ru₆C(CO)₁₄(⁶-C₆H₅C₃H₇) 3 and Ru₆C(CO)14(⁶-C₆H₅C₃H₅) 4. The structures of 1 and 2 have been established by single crystal X-ray diffraction. One of the Ru–Ru bond lengths in 2 is unusually long and extended Hückel molecular orbital calculations have been used in an attempt to rationalize this feature.     

Critical temperatures,pressures, and densities for the mixtures CO2–C3H8, CO2–nC4H10, C2H6–C3H8, and C3H8–nC4H10

A simple method is developed to estimate mixture critical temperatures (T_c), pressures (P_c), and densities (ρ_c) as a function of overall composition (X) from near critical region experimental coexistence data. This three-step method is applied to four mixtures, CO₂–C₃H₈, CO₂–nC₄H₁₀, C₂H₆–C₃H₈, and C₃H₈–nC₄H₁₀. Isothermal liquid–vapor coexistence data, which includes temperature, vapor pressure, coexisting densities (ρ^ℓ and ρ^v), and coexisting compositions for the more volatile component (x₁^v and x₁^ℓ) are used. In the first step, the difference of the saturated liquid and vapor densities (ρ^ℓ−ρ^v) is fitted to an empirical function in ((P_c−P)/P_c) to obtain P_c. Then P/P_c and ((ρ^ℓ+ρ^v)/2ρ_c) are simultaneously fitted to functions of a polynomial in (X₁−(x₁^v+x₁^ℓ)/2) yielding estimates of ρ_c and X₁. Finally, the discrete estimated critical data points are fitted with an equation to provide a continuous representation of the critical lines. The method is successfully tested for the mixtures, CO₂–C₃H₈ and CO₂–nC₄H₁₀, for which there is a reasonable amount of isothermal data. The procedure is then applied to the mixtures, C₂H₆–C₃H₈ and C₃H₈–nC₄H₁₀, for which there are sparse data. For all four mixtures, the critical temperature line, T_c vs. X₁, matches literature values within ±0.5%. The critical pressure line, P_c vs. X₁, and critical density line, ρ_c vs. X₁, match literature values, in general, within ±2%.     

Synthesis of Highly Regioregular,Head-to-Tail Coupled Poly(3-octylesterthiophene) via C―H/C―H Coupling Polycondensation

Highly regioregular,head-to-tail coupled poly(3-octylesterthiophene)was synthesized by the Pd-catalysed oxidative the effects of various reaction factors including polymerization temperature,solvents and catalysts etc.on the yield,molecular weight and structural regioregularity of the resultant polymers were systematically studied.The optical,electrochemical and crystallization properties of the resultant P3OET with different HT regioregularities in solution and film state were studied by UV-Vis and fluorescent spectroscopy,cyclic voltammetry and X-ray diffraction(XRD),resepectively.     

The mechanism and kinetics of energy transfer processes in the Xe–CCl4–M (M=CH4, C2H2, C2H4, C2H6 C3H6 and C3H8) mixtures irradiated by xenon resonance light

The mechanism and kinetics of energy transfer from Xe(6s[3/2]₁) resonance state (E=8.44 eV) to selected hydrocarbon molecules have been investigated by XeCl(B–X) (λ_max=308 nm) fluorescence intensity measurements at stationary conditions in Xe–CCl₄–M systems. Steady-state analysis of the fluorescence intensity dependence on the xenon and M pressure at constant CCl₄ concentration shows that these process occur in the two- and three-body reactions: Xe(6s[3/2]₁⁰)+M→products, Xe(6s[3/2]₁⁰+M+Xe→products. The two- and three-body rate constants for these reactions have been found (see Table 1Table 1. Experimental parameters of Eq. (8)found by least square method in Xe–CCl₄–C₂H₂ and Xe–CCl₄–C₂H₄ systems for chosen xenon pressures in the range 25–150 Torr. Linear correlation coefficients (R) are also shown     

6.

Photochemical Reaction Mechanism of Intramolecular H Transfer Reaction of H2C3O+⋅ Radical Cation     

Prof. Dr. Joonghan Kim  Dakyeung Oh  Eunji Park  Jeongmin Park  Jungyoon Kim  Prof. Dr. Jeong Sik Lim 《Chemphyschem》2023,24(13):e202300048

The photochemical reaction mechanism underlying the intramolecular H-transfer of the H₂C₃O⁺⋅ radical cation to the H₂CCCO⁺⋅ methylene ketene cation was elucidated using time-dependent density functional theory and high-level ab initio methods. Once the D₁ state of H₂C₃O⁺⋅ is populated, the reaction proceeds to form an intermediate (IM) in the D₁ state (IM4_D1). The molecular structure of the conical intersection (CI) was optimized using a multiconfigurational ab initio method. The CI is readily accessible because it lies slightly above the IM4_D1 in energy. In addition, the gradient difference vector of the CI is almost parallel to the intramolecular H-transfer reaction coordinate. Once the vibration mode of IM4_D1 which is parallel to the reaction coordinate is populated, the degeneracy of the CI is readily lifted and H₂CCCO⁺⋅ was formed via a relaxation pathway in the D₀ state. Our calculated results clearly describe the photochemical intramolecular H transfer reaction reported in a recent study.     

7.

Gas-phase radical-radical reaction dynamics of O(3P)+C2H3→C2H2+OH     

Park MJ  Kang KW  Lee GW  Choi JH 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(41):11410-11414

     

8.

Copper complexes with N-allylisoquinolinium halides: Synthesis and crystal structures of [C9H7N(C3H5)]2CuIICl2.86Br1.14, [C9H7N(C3H5)CuIBr2] · H2O, and [C9H7N(C3H5)CuIBr2]     

A. V. Pavlyuk  V. V. Kinzhibalo  T. Lis  M. G. Mys’kiv 《Russian Journal of Coordination Chemistry》2007,33(7):501-508

Crystals of the copper bromide complexes with N-allylisoquinolinium halides of the composition [C₉H₇N(C₃H₅)]₂Cu^IICl_2.86Br_1.14 (I), [C₉H₇N(C₃H₅)]Cu^IBr₂ · H₂O (II), and [C₉H₇N(C₃H₅)]Cu^IBr₂ (III) are prepared by ac electrochemical synthesis, and their structures are studied by X-ray diffraction analysis (DARCh-1 (for I) and KUMA/CCD (for II and III) diffractometers). The crystals of compound I are monoclinic: space group P2₁/n, a = 15.053(5) Å, b = 10.486(4) Å, c = 17.179(10) Å, γ = 109.77(3)°, V = 2552(4) ų, Z = 4. The crystals of complex II are triclinic: space group P $\overline 1 $ , a = 7.040(1) Å, b = 7.610(2) Å, c = 12.460(2) Å, α = 79.54(3)°, β = 86.73(3)°, γ = 89.51(1)°, V = 655.4(2) ų, Z = 2. The crystals of complex III are monoclinic: space group P2₁/n, a = 12.799(1) Å, b = 7.692(1) Å, c = 13.491(1) Å, β = 111.08(1)°, V = 1239.3(2) ų, Z = 4. The structure of compound I is built of the Cu^IIX ₄ ^2? tetrahedra and N-allylisoquinolinium cations united by the C-H···X contacts into corrugated layers. The crystal structure of π-complex II is formed of dimers of the composition [C₉H₇(C₃H₅)]₂ Cu ₂ ^I Br₄ forming layers in the direction of the z axis due to the C-H···X contacts. An important role in structure formation belongs to water molecules that cross-link the organometallic layers through the O-H···X contacts into a three-dimensional framework. When kept in the mother liquor for 6 months, the crystals of compound II transformed into crystals of compound III, whose structure consists of {[C₉H₇(C₃H₅)]₂Cu ₂ ^I Br₄} _n columns united through the C-H···Br contacts (H···Br 2.84(3)?2.92(4) Å) into a three-dimensional framework.     

9.

Temperature Dependence of the Ratios of C—H (C—D) Bond Breaking Rates in Reactions of Cycloalkanes C5H10, C6H12, C6D12 with Adamantyl Carbocations in Sulfuric Acid     

Rudakov  E. S.  Volkova  L. K. 《Theoretical and Experimental Chemistry》2003,39(5):296-302

We have determined the differences in the parameters log A and E of the Arrhenius equations for the kinetic isotope effect (KIE) (c-C₆H₁₂/c-C₆D₁₂) and the 5/6 effect (c-C₅H₁₀/c-C₆H₁₂) in reactions of the C—H bonds of cycloalkanes with adamantyl (Ad⁺) carbocations (1-adamantanol in 92.8% H₂SO₄, 40-97 °C). We have established the compensation relations between log A and E for the kinetic isotope effect and the 5/6 effect for anthracene (AH⁺), hydroxymethyl (CH₂OH⁺), Ad⁺ carbocations and the hypothetical "infinitely strong reagent," supporting a hydride transfer mechanism in such reactions.     

10.

Complexation of N-Allyl Derivatives of Morpholinium with Copper(I) Halides: Synthesis and Crystal Structure of [C4H8ON(C3H5)2]+[Cu4Cl5]–, [C4H8ONH(C3H5)]+[CuBr2]–, and [C4H8ONH(C3H5)]+[CuBr1.41Cl0.59]–     

Goreshnik  E. A.  Mys'kiv  M. G. 《Russian Journal of Coordination Chemistry》2003,29(7):505-511

The compounds [C₄H₈ON(C₃H₅)₂]⁺[Cu₄Cl₅]^– (I), [C₄H₈ONH(C₃H₅)]⁺[CuBr₂]^– (II), and [C₄H₈ONH(C₃H₅)]⁺[CuBr_1.41Cl_0.59]^– (III) were prepared for the first time by ac electrochemical synthesis from mono- and di-N-allyl derivatives of morpholinium and copper(I) halides in ethanol solution and structurally characterized. In the structure of I π-complex, the centrosymmetric Cu₈Cl₁₀ fragments are associated into layers perpendicular to the b axis. The N,N"-diallylmorpholinium cation functions as a bridge, which coordinates two copper atom of the adjacent inorganic fragments by both allyl groups. The trigonal-pyramidal surrounding of the Cu(I) atom, as well as the distorted tetrahedral coordination sphere of Cu(2), involves three chlorine atoms and the C=C bond, whereas the planar trigonal surrounding of the Cu(3) atom and trigonal-pyramidal surrounding of the Cu(4) atom involve only chlorine atoms. In the isostructural II and III σ-complexes, the edge-shared CuX₄ tetrahedra form the infinite copper-halide chains running along the a axis. The inorganic fragments and organic N-allylmorpholinium cations are united into the three-dimensional crystal structures by N–H···X and C–H···X (X = Cl, Br) hydrogen bonds.     

11.

Organopotassium-Catalyzed Silylation of Benzylic C(sp3)−H Bonds     

Baptiste Neil  Lamine Saadi  Prof. Dr. Louis Fensterbank  Dr. Clément Chauvier 《Angewandte Chemie (International ed. in English)》2023,62(31):e202306115

Benzylsilanes have found increasing applications in organic synthesis as bench-stable synthetic intermediates, yet are mostly produced by stoichiometric procedures. Catalytic alternatives based on the atom-economical silylation of benzylic C(sp³)−H bonds remain scarcely available as specialized directing groups and catalytic systems are needed to outcompete the kinetically-favored silylation of C(sp²)−H bonds. Herein, we describe the first general and catalytic-in-metal undirected silylation of benzylic C(sp³)−H bonds under ambient, transition metal-free conditions using stable tert-butyl-substituted silyldiazenes (tBu−N=N−SiR₃) as silicon source. The high activity and selectivity of the catalytic system, exemplified by the preparation of various mono- or gem-bis benzyl(di)silanes, originates from the facile generation of organopotassium reagents, including tert-butylpotassium.     

12.

Copper-catalyzed oxidative C‒H,N‒H coupling of azoles and thiophenes     

Shinobu Mitsuda  Taiki Fujiwara  Katsuyoshi Kimigafukuro  Daiki Monguchi  Atsunori Mori 《Tetrahedron》2012,68(18):3585-3590

C?H, N?H coupling of azole and thiophene derivatives takes place in the presence of a catalytic amount of Cu(OAc)₂ and an additive. The reaction of azoles smoothly occurs with several amines and amides catalyzed by 20 mol % of Cu(OAc)₂–2PPh₃ and 4 equiv of NaOAc under O₂ or in the presence of Ag₂CO₃ under N₂. The coupling reaction leads to a facile synthesis of a N-substituted analogue of 2,5-diarylthiazole, which shows photoluminescent properties with extended π-conjugation. Spectroscopic characteristics of the obtained thiazole derivatives are discussed by measurements of UV–vis absorption and photoluminescent spectra. Under the reaction conditions using Ag₂CO₃ as an additive and Cu(OAc)₂–2PPh₃ as a catalyst, thiophene derivatives also react with 2-pyrrolidone to undergo C?H, N?H amidation.     

13.

Synthesis, characterization and standard molar enthalpy of formation of Nd(C7H5O3)2·(C9H6NO)     

L. Qiang-Guo  H. Yi  L. Xu  Y. Li-Juan  X. Sheng-Xiong  Y. De-Jun  L. Yi 《Journal of Thermal Analysis and Calorimetry》2008,91(2):615-620

The complex from reaction of neodymium chloride six-hydrate with salicylic acid and 8-hydroxyquinoline, Nd(C₇H₅O₃)₂·(C₉H₆NO), was synthesized and characterized by IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard molar enthalpies of solution of [NdCl₃·6H₂O(s)], [2C₇H₆O₃(s)], [C₉H₇NO(s)] and [Nd(C₇H₅O₃)₂·(C₉H₆NO)(s)] in a mixed solvent of anhydrous ethanol, dimethyl formamide (DMF) and perchloric acid were determined by calorimetry at 298.15 K. Based on Hess’ law, a new chemical cycle was designed, and the enthalpy change of the reaction

Photochemical Reaction Mechanism of Intramolecular H Transfer Reaction of H2C3O+⋅ Radical Cation

The photochemical reaction mechanism underlying the intramolecular H-transfer of the H₂C₃O⁺⋅ radical cation to the H₂CCCO⁺⋅ methylene ketene cation was elucidated using time-dependent density functional theory and high-level ab initio methods. Once the D₁ state of H₂C₃O⁺⋅ is populated, the reaction proceeds to form an intermediate (IM) in the D₁ state (IM4_D1). The molecular structure of the conical intersection (CI) was optimized using a multiconfigurational ab initio method. The CI is readily accessible because it lies slightly above the IM4_D1 in energy. In addition, the gradient difference vector of the CI is almost parallel to the intramolecular H-transfer reaction coordinate. Once the vibration mode of IM4_D1 which is parallel to the reaction coordinate is populated, the degeneracy of the CI is readily lifted and H₂CCCO⁺⋅ was formed via a relaxation pathway in the D₀ state. Our calculated results clearly describe the photochemical intramolecular H transfer reaction reported in a recent study.     

Copper complexes with N-allylisoquinolinium halides: Synthesis and crystal structures of [C9H7N(C3H5)]2CuIICl2.86Br1.14, [C9H7N(C3H5)CuIBr2] · H2O, and [C9H7N(C3H5)CuIBr2]

Crystals of the copper bromide complexes with N-allylisoquinolinium halides of the composition [C₉H₇N(C₃H₅)]₂Cu^IICl_2.86Br_1.14 (I), [C₉H₇N(C₃H₅)]Cu^IBr₂ · H₂O (II), and [C₉H₇N(C₃H₅)]Cu^IBr₂ (III) are prepared by ac electrochemical synthesis, and their structures are studied by X-ray diffraction analysis (DARCh-1 (for I) and KUMA/CCD (for II and III) diffractometers). The crystals of compound I are monoclinic: space group P2₁/n, a = 15.053(5) Å, b = 10.486(4) Å, c = 17.179(10) Å, γ = 109.77(3)°, V = 2552(4) ų, Z = 4. The crystals of complex II are triclinic: space group P $\overline 1 $ , a = 7.040(1) Å, b = 7.610(2) Å, c = 12.460(2) Å, α = 79.54(3)°, β = 86.73(3)°, γ = 89.51(1)°, V = 655.4(2) ų, Z = 2. The crystals of complex III are monoclinic: space group P2₁/n, a = 12.799(1) Å, b = 7.692(1) Å, c = 13.491(1) Å, β = 111.08(1)°, V = 1239.3(2) ų, Z = 4. The structure of compound I is built of the Cu^IIX ₄ ^2? tetrahedra and N-allylisoquinolinium cations united by the C-H···X contacts into corrugated layers. The crystal structure of π-complex II is formed of dimers of the composition [C₉H₇(C₃H₅)]₂ Cu ₂ ^I Br₄ forming layers in the direction of the z axis due to the C-H···X contacts. An important role in structure formation belongs to water molecules that cross-link the organometallic layers through the O-H···X contacts into a three-dimensional framework. When kept in the mother liquor for 6 months, the crystals of compound II transformed into crystals of compound III, whose structure consists of {[C₉H₇(C₃H₅)]₂Cu ₂ ^I Br₄} _n columns united through the C-H···Br contacts (H···Br 2.84(3)?2.92(4) Å) into a three-dimensional framework.     

Temperature Dependence of the Ratios of C—H (C—D) Bond Breaking Rates in Reactions of Cycloalkanes C5H10, C6H12, C6D12 with Adamantyl Carbocations in Sulfuric Acid

We have determined the differences in the parameters log A and E of the Arrhenius equations for the kinetic isotope effect (KIE) (c-C₆H₁₂/c-C₆D₁₂) and the 5/6 effect (c-C₅H₁₀/c-C₆H₁₂) in reactions of the C—H bonds of cycloalkanes with adamantyl (Ad⁺) carbocations (1-adamantanol in 92.8% H₂SO₄, 40-97 °C). We have established the compensation relations between log A and E for the kinetic isotope effect and the 5/6 effect for anthracene (AH⁺), hydroxymethyl (CH₂OH⁺), Ad⁺ carbocations and the hypothetical "infinitely strong reagent," supporting a hydride transfer mechanism in such reactions.     

Complexation of N-Allyl Derivatives of Morpholinium with Copper(I) Halides: Synthesis and Crystal Structure of [C4H8ON(C3H5)2]+[Cu4Cl5]–, [C4H8ONH(C3H5)]+[CuBr2]–, and [C4H8ONH(C3H5)]+[CuBr1.41Cl0.59]–

The compounds [C₄H₈ON(C₃H₅)₂]⁺[Cu₄Cl₅]^– (I), [C₄H₈ONH(C₃H₅)]⁺[CuBr₂]^– (II), and [C₄H₈ONH(C₃H₅)]⁺[CuBr_1.41Cl_0.59]^– (III) were prepared for the first time by ac electrochemical synthesis from mono- and di-N-allyl derivatives of morpholinium and copper(I) halides in ethanol solution and structurally characterized. In the structure of I π-complex, the centrosymmetric Cu₈Cl₁₀ fragments are associated into layers perpendicular to the b axis. The N,N"-diallylmorpholinium cation functions as a bridge, which coordinates two copper atom of the adjacent inorganic fragments by both allyl groups. The trigonal-pyramidal surrounding of the Cu(I) atom, as well as the distorted tetrahedral coordination sphere of Cu(2), involves three chlorine atoms and the C=C bond, whereas the planar trigonal surrounding of the Cu(3) atom and trigonal-pyramidal surrounding of the Cu(4) atom involve only chlorine atoms. In the isostructural II and III σ-complexes, the edge-shared CuX₄ tetrahedra form the infinite copper-halide chains running along the a axis. The inorganic fragments and organic N-allylmorpholinium cations are united into the three-dimensional crystal structures by N–H···X and C–H···X (X = Cl, Br) hydrogen bonds.     

Organopotassium-Catalyzed Silylation of Benzylic C(sp3)−H Bonds

Benzylsilanes have found increasing applications in organic synthesis as bench-stable synthetic intermediates, yet are mostly produced by stoichiometric procedures. Catalytic alternatives based on the atom-economical silylation of benzylic C(sp³)−H bonds remain scarcely available as specialized directing groups and catalytic systems are needed to outcompete the kinetically-favored silylation of C(sp²)−H bonds. Herein, we describe the first general and catalytic-in-metal undirected silylation of benzylic C(sp³)−H bonds under ambient, transition metal-free conditions using stable tert-butyl-substituted silyldiazenes (tBu−N=N−SiR₃) as silicon source. The high activity and selectivity of the catalytic system, exemplified by the preparation of various mono- or gem-bis benzyl(di)silanes, originates from the facile generation of organopotassium reagents, including tert-butylpotassium.     

Copper-catalyzed oxidative C‒H,N‒H coupling of azoles and thiophenes

C?H, N?H coupling of azole and thiophene derivatives takes place in the presence of a catalytic amount of Cu(OAc)₂ and an additive. The reaction of azoles smoothly occurs with several amines and amides catalyzed by 20 mol % of Cu(OAc)₂–2PPh₃ and 4 equiv of NaOAc under O₂ or in the presence of Ag₂CO₃ under N₂. The coupling reaction leads to a facile synthesis of a N-substituted analogue of 2,5-diarylthiazole, which shows photoluminescent properties with extended π-conjugation. Spectroscopic characteristics of the obtained thiazole derivatives are discussed by measurements of UV–vis absorption and photoluminescent spectra. Under the reaction conditions using Ag₂CO₃ as an additive and Cu(OAc)₂–2PPh₃ as a catalyst, thiophene derivatives also react with 2-pyrrolidone to undergo C?H, N?H amidation.     

Synthesis, characterization and standard molar enthalpy of formation of Nd(C7H5O3)2·(C9H6NO)

The complex from reaction of neodymium chloride six-hydrate with salicylic acid and 8-hydroxyquinoline, Nd(C₇H₅O₃)₂·(C₉H₆NO), was synthesized and characterized by IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard molar enthalpies of solution of [NdCl₃·6H₂O(s)], [2C₇H₆O₃(s)], [C₉H₇NO(s)] and [Nd(C₇H₅O₃)₂·(C₉H₆NO)(s)] in a mixed solvent of anhydrous ethanol, dimethyl formamide (DMF) and perchloric acid were determined by calorimetry at 298.15 K. Based on Hess’ law, a new chemical cycle was designed, and the enthalpy change of the reaction

Structure of (C3H5NH3)2H2P2O7·H2O

The bis(cyclopropylammonium)dihydrogenodiphosphate monohydrate is a new diphosphate associated with the organic molecule C₃H₅NH₂. We report the chemical preparation and the crystal structure of this organic cation diphosphate. (C₃H₅NH₃)₂H₂P₂O₇.H₂O is orthorhombic (S.G. : P2₁2₁2₁), with Z = 4 and the following unit-cell parameters : a = 4.828(1) Å, b = 11.011(1) Å, c = 25.645(2) Å. The P₂O₇ groups and H₂O water molecules form a succession of bidimensional layers perpendicular to the c axis. The organic cations ensure the three-dimensional cohesion by NH-O hydrogen bonds.     

Synthesis, crystal structure, and IR spectral study of Na[(UO2)(C3H7COO)3] · 0.25H2O and K[(UO2)(C3H7COO)3]

Synthesis, IR spectral study and X-ray diffraction analysis of single crystals of Na[(UO₂)(C₃H₇COO)₃] · 0.25H₂O (I) and K[(UO₂)(C₃H₇COO)₃] (II) were carried out. Compound I is monoclinic, unit cell parameters are: a = 13.5671(15) ?, b = 20.070(2) ?, c = 13.6139(15) ?, ?? = 106.839(2)°, space group P2₁, Z = 8, R = 0.0493. Compound II is orthorhombic, unit cell parameters are: a = 17.1325(9) ?, b = 19.6966(11) ?, c = 21.9686(11) ?, space group P2₁2₁2₁, Z = 16, R = 0.0563. Mononuclear groups [UO₂(C₃H₇COO)₃]^? related to the A ₃ ⁰¹ crystal-chemical group (A = UO ₂ ²⁺ , B ⁰¹ = C₃H₇COO^?) of uranyl complexes are the uranium-containing structural units of crystals I and II. The data of IR spectral study agree well with X-ray diffraction data.     

Site-Selective Pd-Catalyzed C(sp3)−H Arylation of Heteroaromatic Ketones

A ligand-controlled site-selective C(sp³)−H arylation of heteroaromatic ketones has been developed using Pd catalysis. The reaction occurred selectively at the α- or β-position of the ketone side-chain. The switch from α- to β-arylation was realized by addition of a pyridone ligand. The α-arylation process showed broad scope and high site- and chemoselectivity, whereas the β-arylation was more limited. Mechanistic investigations suggested that α-arylation occurs through C−H activation/oxidative addition/reductive elimination whereas β-arylation involves desaturation and aryl insertion.     

Synthesis, Crystal Structure and Properties of Complex VO（C10H9NO3） （C13H10NO2）

Complex VO(C10H9NO3)(C13H10NO2)(C10H9NO2-3=N-salicylidene-L-alaninate, C13H10NO-2=N-phenylbenzohydroxamate) was synthesized and characterized by means of elemental analysis, IR, UV, 1H NMR spectroscopies, cyclic voltammetry and single crystal X-ray diffraction. The complex crystallized in a monoclinic system with space group P21 and crystal cell parameters a=0.9720(1) nm, b=1.8274(2) nm, c=1.2542(1) nm, β=104.868(9)°, V=2.1532(4) nm3, Mr=470.34, Z=2. The two oxygen atoms and the one nitrogen atom of the tridentate Schiff base ligand and the one oxime oxygen atom of the hydroxamate ligand coordinate to the vanadium atom, forming an equatorial plane, the two axial positions are respectively occupied by the oxygen atom of the oxovanadium and the carbonyl oxygen atom of the hydroxamate and the vanadium atom exhibits a distorted octahedral VO(ONO)(OO) coordination sphere. The 1H NMR spectrum suggests that the two isomers, endo and exo in a molar ratio of 1/1.7, coexist in the solution of the title complex in CDCl3. There exists a quasi-reversible one-electron redox reaction corresponding to VⅤ/VⅥ couple in the three non-aqueous solvents, and the redox potential E1/2 of the title complex substantially shifts in the direction of the positive voltage increase in the order: CH2Cl2＜CH3CN＜DMF.     

Reactivity, 31P, 13C, 1H NMR and IR Studies of Δ5-3-Dimethylamino-3-Oxo-1,2,3- Diazaphospholines

Abstract

In precedent work research (1)(2) we have reported a new synthesis method of the Δ⁵-3- dimethylamino-3-oxo-l,2,3 diazaphospholine derivatives (D_i). In this present work, we have to detail the reactivity and the structure of those heterocycles by N.M.R. (³¹P, ¹³C, ¹H) and I.R. In Infra-Red spectroscopy, we show the existence of the intermolecular hydrogen bond of some compounds. The spectrum(³¹P, ¹³C, ¹H) and I.R. was reported of (D_i).     

Two Light-Metal Dihydrogenisocyanurate Hydrates Linked by Diagonal Relationship: Syntheses,Crystal Structures,and Vibrational Spectra of Li[H2N3C3O3]·1.75 H2O and Mg[H2N3C3O3]2·8 H2O

Single-crystalline materials of Li[H₂N₃C₃O₃] · 1.75 H₂O and Mg[H₂N₃C₃O₃]₂ · 8 H₂O were obtained by dissolving stoichiometric amounts of the respective carbonates with cyanuric acid in boiling water followed by gentle evaporation of excess water after cooling to room temperature. Even though both of these compounds crystallize in the triclinic space group P1 according to X-ray structure analyses of their colorless and transparent single crystals, they adopt two new different structure types. Li[H₂N₃C₃O₃] · 1.75 H₂O exhibits the unit-cell parameters a = 884.71(6) pm, b = 905.12(7) pm, c = 964.38(7) pm, α = 67.847(2)°, β = 62.904(2)° and γ = 68.565(2)° (Z = 4), whereas the lattice parameters for Mg[H₂N₃C₃O₃]₂ · 8 H₂O are a = 691.95(5) pm, b = 1055.06(8) pm, c = 1183.87(9) pm, α = 85.652(2)°, β = 83.439(2)° and γ = 79.814(2)° (Z = 2). In both cases, the singly deprotonated isocyanuric acid forms monovalent anions consisting of cyclic [H₂N₃C₃O₃]^– units, which are arranged in ribbons typical for most hitherto known monobasic isocyanurate hydrates. The structures are governed by the oxophilic strength of the respective cation which means that they fulfil their oxophilic coordination requirements either solely with water molecules ([Mg(OH₂)₆]²⁺ for Mg²⁺) or with crystal water and one or two direct coordinative contacts to carbonyl oxygen atoms (O_(cy)) of [H₂N₃C₃O₃]^– anions ([(Li(OH₂)_2–3(O_(cy)1–2]⁺ for Li⁺). In both structures occur dominant hydrogen bonds N–H ··· O within the anionic [H₂N₃C₃O₃]^– ribbons as well as hydrogen bonds O–H ··· O between these ribbons and the hydrated Li⁺ and Mg²⁺ cations.     

Crystal structure and properties of H3[PMo12O40] · 3C2H6O

The title compound H₃[PMo₁₂O₄₀]· 3C₂H₆O was prepared and characterized by X-ray crystallography, its i.r. spectrum, cyclic voltammetry and e.s.r. spectra. The anion of the title compound is a Keggin-type heteropoly structure based upon a central PO₄ tetrahedron surrounded by 12 MoO₆ octahedra arranged in four groups of three edge-shared octahedra Mo₃O₁₃. Weak hydrogen bonds exist between the organic solvent molecules and the heteropoly anion. The catalytic activity of the title compound was determined by the synthesis of butyl acetate. The conversion of n-BuOH reached 93.3% and the yield of MeCO₂Bu-n was 92.0% when the ratio of MeCO₂H to n-BuOH, catalyst amount, reaction time, reaction temperature were 2:1, 0.24% of the reactants (50 mg), 2.0 h and 115 120 °C, respectively.