N.M.R.DETERMINATION OF THE STRUCTURE AND CONFORMATION OF BIOLOGICAL MOLECULES

IntroductionN.M.R.is known to be useful forstructure determination of natural products,but it's main advantage compared with otherphysical techniques like crystallography is     

BINUCLBAB COPPER(Ⅱ) COMPLEXES OF SOME PLANT GROWTH-STIMULATING SUBSTANCES.Ⅰ.SYNTHESIS AND STRUCTURE OF BIS(N,N-DIMETHYLFORMAMIDE)-TETHAKIS(μ-INDOLYL-3-ACETOXY) DICOPPER(Ⅱ)

<正> The structure of the title compound (Mr = 969.99) has been determined by X-ray analysis. The crystals are monoclinic, space group P21/n with a =14.746(2),b= 10.782(7), c = 15.531(3) A,β=113.74(2)°,Z=2,and DC=1.425g·cm-3. The final refinement converged with R = 0.067 and Hw=0.080 for 4491 observed reflections with I>3σ(I).     

N. K. Kochetkov (18.05.1915–21.12.2005)

In Memoriam

N. K. Kochetkov (18.05.1915–21.12.2005)     

CRYSTAL STRUCTURE OF COMPLEX OF Cu(Ⅱ) AND o-HYDROXYLBENZYLAMINE-O,N,N-TRIACETIC ACID(HBATA)

<正> [Cu(H2O)6][CuC13H12NO7]2.2H2O,Mr=904.5, Monoclinic, P21/n,a= 8.287(2), b=20.462(3), c=10.921(2)A,β=108.90(2), Z=2, V=1752.2A3, Dc=1.750 g/cm3, μ=13.166cm-1, R=0.042 for 2524 observed reflections. The title complex contains a [CuC13H12NO7]22- dimeric anion which consists of two mono-anions related by centrosymmetry and connecting each other by coordination bond Cu-O.The dimeric complex anion is compatible with an aquo-Cu(Ⅱ) cation that is located in centrosymmetric position. Here all Cu(Ⅱ) ions are six-coordinated with distorted octahedral configuration.     

PHOTOPHYSICS STUDIES OF ORCANIC COMPOUNDS (Ⅻ)——THE INVESTIGATION OF THE FLUORESCENCE SPECTRA OF N-SALICYLIDENE-p-(N,N-DIMETHYLAMINO)ANILINE

The fluorescence spectra of N--salicylidene-p-(N,N--dimethylamino)aniline have beeninvestigated in various solvents. Three kinds of fluorescence have been found in the solutionsof various concentrations. They are the excited intermediate (EI) which is formed when theproton transfer has occurred but essentially retains the geometry of the enol tautomer, theexciplex (EX) which consists of a ground monomer and an excited state intermediate and theexcited dimer (ED) which is caused by ground state aggregate. The fluorescence lifetimesof the fluorophores have been measured in tetrahydrofuran (THF). Luminescent mechanismhas been discussed based on the fluorescence spectra and the kinetic data of the compound.     

BINUCLEAR COPPER(Ⅱ) COMPLEXES OF SOME PLANT GROWTH-STIMULATING SUBSTANCES Ⅱ. SYNTHESES AND STRUCTURES OF BIS(N,N-DIMETHYLFORMAMIDE)-TETRAKIS-[μ-(N-p-(AND m-)METHYLPHENYLPHTHALAMINO)]DICOPPER(Ⅱ)TETRAKIS(N,N-DIMETHYLFORMAMIDE) SOLVATE

<正> [Cu2( -C-N-C6H4CH3-p)4(DMF)2]-4DMF(1), Mr = 1582.7, triclinic,Pl, a = 10.761(1), b = 13.930(3), c = 15.116(3) A;α= 114.74(1),β= 101.82 (1),r= 95.85(1)°,V = 1969.0 A3,Z=1,Dm= 1.36,DC =1.335 g/cm3.[Cu2(-C-N-C6H4Ch3-M)4.(DF)2].4DMF(2), Mr = 1582.7, triclinic, Pl,a = 10.588(5), b = 13.699(2), c = 15.759(4) A;α= 114.88(2),β= 103.89(3), γ=92.56(3)°, V =1985.3 A3, Z = 1, 0. = 1.39,Dc= 1.324 g/cm3.The four phthalamine groups in molecules of (1) and (2) are all biden-tate bridging ligands to Cu atoms and there are two terminal DMF ligands, one on each Cu atom. The Cu-Cu distances are 2.635(1) and 2.641(1) A for (1) and (2) respectively.     

STRUCTURES OF COPPER(I) AND ZINC(II) COMPLEXES WITH N,N′-BIS(2-PYRIDINYL)THIOUREA (BPT)

Abstract

Copper(I) and zinc(II) complexes with N,N′-bis(2-pyridinyl)thiourea (BPT), [Cu(BPT)₂]ClO₄ (1) and [Zn(BPT)₂](ClO₄)₂ (2) were synthesized by reaction of M(ClO₄)₂ (M = Cu, Zn) with BPT in methanol solution. The crystal structures of complexes (1) and (2) were characterized by X-ray diffraction: (1) is triclinic, space group P, with a = 10.162(2), b=14.483(6), c = 9.496(2) Å, α = 105.80(2)°, β = 106.94(2)°, γ = 82.71(3)°, V = 1284.4(7) ų, Z = 2, and final R = 0.047, R _w = 0.061; (2) is monoclinic, space group C2/c, with a = 15.15(1), b = 6.299(3), c = 30.16(1)Å, β = 93.49(7)°, V = 2872(2)ų, Z=4, and final R = 0.049, R_w = 0.070. Both of the complexes exhibit novel structures. Two N atoms and two S atoms from two BPT groups coordinate to one M atom. The M atom shows distorted tetrahedral geometry. IR spectra and ther-moanalyses of BPT and its complexes (1) and (2) are briefly discussed.     

SYNTHESIS AND CHARACTERISATION OF TIN(IV) AND ORGANOTIN(IV) COMPLEXES OF [N′-2-HYDROXYPHENYL-6-METHYLPYRIDINE-2-CARBALDIMINE. X-RAY CRYSTAL STRUCTURES OF n-BUTYLDICHLORO[N′-2-HYDROXYPHENYL-6-METHYLPYRIDINE-2-CARBALDIMINATO(1-)N,N′,O]TIN(IV) AND DIPHENYLCHLORO [N′-2-HYDROXYPHENYL-6-METHYL-PYRIDINE-2-CARBALDIMINATO(1-) N,N′,O]TIN(IV)

Abstract

The reactions of N′-2-hydroxyphenyl-6-methylpyridine-2-carbaldimine (LH) with tin(IV) chloride and organotin(IV) chlorides result in the formation of the corresponding tin(IV) and organotin(IV) complexes in which LH behaves as a uninegative tridentate ligand coordinating to the central tin atom via an N,N,O donor set. Crystal structure determinations of two of the compounds, n-butyldichloro[N′-2-hydroxyphenyl-6-methylpyridine-2-carbaldiminato(l-)N,N′,O]-tin(IV) (BuSnCl₂.L) and diphenylchloro[N′-2-hydroxyphenyl-6-methylpyridine-2-carbaldiminato(l-)N,N′,O]tin(IV) (Ph₂SnCl.L), have been performed and both structures feature distorted octahedral geometries about the tin centres. Systematic differences in the Sn-ligand separations are rationalised in terms of the reduced Lewis acidity of tin in Ph₂SnCl.L.     

OLEFIN SYNTHESIS VIA THE LITHIUM DERIVATIVE OF THE N,N,N′,N′-TETRAMETHYLDIAMIDES OF ARYLMETHANEPHOSPHONIC ACIDS. 3 SYNTHESIS OF SOME β-DISUBSTITUTED STYRENES

Abstract

The reaction of Li-derivatives of N,N,N′,N′-tetramethyldiamides of arylmethanephosphonic acids (1-Li) with alkanones, cycloalkanones, alkylaryl-and diarylketones 2a-h is studied. It is found that in THF at-70°C adducts 3-Li and 4-Li are formed, the corresponding hydroxyl compounds 3 and 4 being isolated in 36–81% yields, while by elevated temperatures the reaction is completely shifted to the starting 1-Li and 2. By thermolysis of 3 and 4 in neutral medium olefins 5 and 6 are obtained even from readily enolysable ketones. The stereochemistry of the addition reaction with nonsymmetrical ketones as well as the influence of the substituents at the carbonyl groups on the conformation and adsorption properties of the adducts are discussed.     

METAL COMPLEXES OF POLYCYCLIC TERTIARY AMINES. PART VI. PREPARATION AND CRYSTAL STRUCTURE OF HEXAMETHYLENETETRAMINE-SILVER(I) BROMIDE (1/4)

<正> C6H12N4Br4Ag4,Mr = 891.31, orthorhombic, Pnma, a = 8.778(2),b = 9.80.5(2), c = 16.906(3) A, V = 1455.1(4) A3, Z = 4, Dx = 4.069, Dm (displacement of H2O) = 4.03 g cm-3 , A(Mo-Ka) = 161.3 cm-1 , F(OOO) = 1615.77,T = 295°, final R = 0.052 arid Rw = 0.062 for 1472 observed reflections.All four lone pairs of each (CH2)6N4 molecule serve as ligand sites in a polymeric framework comprising octahedral AgBr5N, tetrahedral AgBr3N, and tetragonal pyramidal AgBr4N coordination polyhedra. The Ag-N and Ag-Br bond lengths lie in the ranges 2.366(12)-2.454(12) and 2.640(2)-3.178(2) A, respectively.     

STUDIES ON TRANSITION-METAL PERHALOPHENYL COMPOUNDS.VI.CRYSTAL STRUCTURE OF TRANS-BROMO-BIS(METHYLDIPHENYLPHOSPHINE) (σ-PENTABROMOPHENYL)NICKEL(II)

<正> M= 1010.62, D24-P212121, a=11.654(3), b=15.812(9), c=18.556(8) A, V=3419.5A3, Z=4, Dc=1.963 g·cm-3. Final R=0.066 for 2187 reflections. The central nickel(II) atom of the title compound is in slightly distorted square-planar coordination.     

CYCLOADDITION REACTION OF THE AZIDO-BRIDGED CYCLOMETALLATED COMPLEX [Pd(dmba)N3]2 WITH CS2. CRYSTAL AND MOLECULAR STRUCTURE OF DI(μ, N,S-l,2,3,4-THIATRIAZOLE-5-THIOLATE)BIS[(N,N-DIMETHYLBENZYL-AMINE-C2,N)PALLADIUM(II)]

Abstract

The 1,3-dipolar cycloaddition of carbon disulfide to the coordinated azide in the cyclometal-lated compound [Pd(dmba)(N₃)]₂ (1), dmba = N,N-dimethylbenzylamine, was investigated. The compound obtained di(μ, N, S-l,2,3,4-thiatriazole-5-thiolate)-bis[(N,N-dimethylbenzylamine-C², N)palladium(II)] (2), was characterized by IR spectroscopy and X-ray diffraction. Complex (2) is dimeric with the two [Pd(N,N-dimethylbenzylamine)] moieties being connected by the two vicinal bridging N, S-l,2,3,4-thiatriazole-5-thiolate anions in a square-planar coordination for the palladium atoms.     

AN INVESTIGATION OF THE REACTION PRODUCTS OF N3P3CL4(NH2)2 WITH NUCLEOPHILIC REAGENTS. EXAMPLES OF GEMINAL → NON-GEMINAL REARRANGEMENTS

Abstract

Based on its reactions with various nucleophiles both geminal and non-geminal structures have been earlier proposed for N₃P₃Cl₄(NH₂)₂, although its geminal structure is now considered established. The reactions of this compound with alcohols have been investigated and the products examined by NMR spectroscopy and X-ray crystallography. Evidence for both unrearranged as well as geminal → non-geminal rearranged alcoholysis products is presented.     

ELECTRON-TRANSFER REACTIONS OF CROSSLINKED POLY(1-PYRIDINIOMETHYL)STYRENE CHLORIDE 2. REDUCTION OF NITRO-COMPOUNDS

Continuing the study of electron transfer reactions of polypyridiniomethylstyrene chloride (PSPyCl), the reduction of nitro-compounds by the PSPyCl-Zn system was investigated. In general azoxy compounds were obtained as chief intermediate product of reduction. Reduction of nitrobenzo-15-crown-5 and its homologues give a new class of bis-crown ether compounds——azoxy-bisbenzocrown ethers. Azoxybisbenzocrown ethers undergo photoinduced trans-cis isomerization, which is reversible on irradiation with UV and on storage in darkness, similar to the case of azobiscrown ethers. Investigation of solvent extraction of various cations by azobiscrown ether isomers shows that cis-azoxybisbenzo-15-crown-5 exhibit good selectivity toward Nd~(3 ) from other rare earth cations.     

MOLECULAR REARRANGEMENTS. VI. THERMOLYSIS OF α-(N-ARYL)BENZYL ARYL SULFIDES

Abstract

In view of the significance of studying the effect of heat on organic compounds especially those containing nitrogen and/or sulfur, six substituted α-(N-aryl) benzyl aryl sulfides (4–9) were prepared and subjected to thermolysis at 200°C.

Surveying of the reaction products showed the formation of amines, benzylidene amines, sulfides, disulfides, dibenzyl, stilbene, benzthiazole, benzimidazole, tetraphenyl thiophene as principle products in variable ratios according to the type of the starting sulfide.

A mechanism involving the homolytic cleavage of the C[sbnd]S and the C[sbnd]N bond is suggested to rationalize the thermolysis products.     

PREPARATION AND CHARACTERIZATION OF BINUCLEAR μ-PHENOLATOCOPPER(II)CHELATES.

Two new water-soluble binuclear copper(II)chelates derived from the condensationof 2,6-diformyl-4-methylphenol with glycylglycine were characterized with spectral.magnetic and electrochemical techniques.     

POLAROGRAPHIC INVESTIGATION OF THE SYSTEMS ARSENIC(III)-TARTARIC ACID AND ARSENIC(III)-1,2-DIAMINO-CYCLOHEXANE-N,N,N′,N′-TETRAACETIC ACID (DCTA)

Abstract

The reactions between As(III), tartaric acid (H₂T)and DCTA were investigated polarographically. The conditional stability constants of As(III)-complexes at a given pH-value and variable ligand concentration were calculated from the change of the limiting currents. The optimum conditions for calculating stability constants from the current were also discussed. It was found that DCTA (H₄L)formed the complex [As(OH)₂HL]^2- whose overall formation constant was lgβ111=(20.67 ±0.09)atμ=0.1 and t°- (25.0±0.2)°C, whereas the complex between As(III) and H₂T was [As(OH)₂T]^? with an overall stability constant 1gβ 101= 6.62 ±0.14 at μ=0.1 and t°= (25 ± 0.2)°C.     

SYNTHESIS AND CHARACTERIZATION OF A NEW POLYSILOXANE CONTAINING N,N’-BIS(DIPHENYLSILYL)TETRAPHENYLCYCLODISILAZANE

A new kind of polysiloxane containing N,N'-bis(diphenylsilyl)tetraphenylcyclodisilazane was prepared by anionicnon-equilibrium polymerization with a "seed solution" as initiator. The monomer, N,N'-bis(hydroxydiphenylsilyl)-tetraphenyl-cyclodisilazane (BHPTPC), was synthesized via the hydrolysis of N,N'-bis(chlorodiphenylsilyl)tetraphenyl-cyclodisilazane (BCPTPC). A new method for the preparation of BCPTPC is also reported here with high yield and simplermanipulation. The synthesized polysiloxane containing N,N'-bis(diphenylsilyl)tetraphenylcyclodisilazane was characterized by ~1H-NMR, ~(29)Si-NMR, gel permeation chromatography (GPC) and intrinsic viscosity.     

REACTION OF BIS(β-ALANINATO)COPPER(II) WITH FORMALDEHYDE: X-RAY CRYSTAL STRUCTURE OF AQUABIS(N,N-DIMETHYL-β-ALANINATO)COPPER(II) HEXAHYDRATE

Abstract

The reaction of bis(β-alaninato)copper(II) with formaldehyde results in the formation of blue crystals of aquabis(N,N-dimethyl-β-alaninato)copper(II) hexahydrate, [Cu(C₅H₁₀NO₂)₂(OH₂)].6H₂O which crystallize in the monoclinic space group C2/c with unit cell dimensions a = 20.799(2), b = 8.112(1), c = 23.639(1)Å, β = 96.50(1)° and Z = 8. The structure has been refined to final R = 0.047 and R_w = 0.053 for 1690 reflections with I ≥ 2.55σ(I).     

INVESTIGATION OF THE ATRP OF n-BUTYL METHACRYLATE USING THE Cu(I)/N,N,N′,N″,N″-PENTAMETHYLDIETHYLENETRIAMINE CATALYST SYSTEM

The polymerization of n-butyl methacrylate was investigated using the Atom Transfer Radical Polymerization technique with CuBr and CuCl/N,N,N′,N″,N″-pentamethyldiethylenetriamine catalytic systems. Various combinations of catalyst systems and initiators were utilized in order to optimize the polymerization conditions and to obtain well-defined polymers (i.e. controlled molecular weights and low polydispersities). It has been found that the optimal initiator for this system is a chlorine-based initiator, when the catalyst used is a Cu(I) salt in conjunction with the N,N,N′,N″,N″-pentamethyldiethylenetriamine ligand. Bromine-based initiators tend to result in large amounts of initial termination, leading to polymers with less than ideal chain end functionality, even if CuCl is used as the Cu(I) species to invoke the halogen exchange. Additionally, the effects of the polymerization temperature, copper(1) species and the initiator structure were determined.