Coupling and Cyclization of Sydnone Compounds

Cyclization were occurred via the coupling reactions of some mercuric chloride derivatives of sydnone with LiPdCl₃-CuCl₂. A unique six-membered ring, 3,3′-ethylene-4,4′-bissydnone, was obtained by the cyclization reation of 1,2-di[3-(4-chloromercuric)sydnonyl]ethane. However, the seven-membered 3,3′-trimethylene-4,4′-bissydnone and 1,3-di[3-(4-chloro)sydnonyl]-propane were obtained from the corresponding mercuric chlroide of sydnone. Onyl substitution reaction took place when 4,4′-di[3-(4-chloromercuric)sydnonyl]biphenyl, 4,4′-di[3-(4-chloromercuric)sydnonyl]benzene, di(p-[3-(4-chloromercuric)sydnonyl]-phenyl}methane and, di(p-[3-(4-chloromercuric)sydnonyl]phenyl]ether were treated using the same process.     

3-Substituted Sydnone Derivatives. Structures of 3-Cyclohexylsydnone and of Two Forms of 3-(3-Pyridyl)sydnone

The crystal and molecular structures of three sydnone derivatives are reported. The compound 3-cyclohexylsydnone crystallizes in space group C2/c of the monoclinic system with sixteen molecules in a cell of dimensions a = 19.326 (3), b = 9.471 (2), c = 20.005 (4)Å, β = 106.85(1)°. The structure has been refined to a final value of 0.0581 for the conventional R-factor based on 2222 independent observed intensities. Form I of 3-(3-pyridyl)sydnone crystallizes in space group P2/n of the monoclinic system with eight molecules in a cell of dimensions a = 7.317(2), b = 9.283 (2), c = 20.891 (6) Å, β = 99.61(2)°. The structure has been refined to a final value of 0.0514 for the conventional R-factor based on 1208 independent observed intensities. Form II of 3-(3-pyridyl)sydnone crystallizes in space group P2₁/c of the monoclinic system with eight molecules in a cell of dimensions a=9.073 (2), b = 22.267 (5). c = 7.494(2)Å, β = 112.15 (2)°. The structure has been refined to a final value of 0.0462 for the conventional R-factor based on 1330 independent observed intensities. Each of the three structures contains two crystallographically independent molecules in the cell. In the case of 3-cyclohexylsydnone, one of the independent molecules exhibits disorder around the exocyclic bond at N(3). A comparison of bond lengths indicates that the (electron donating) cyclohexyl group brings about enhanced electron density in the N(3)-C(4) bond, and possibly in the N(3)-N(2) bond. All three structures studied here exhibit intermolecular hydrogen bonding involving C(4)-H(4)…O(6) interactions. Although there are no stacking interactions in the cyclohexyl derivative, there is evidence for such interactions in the 3-pyridyl derivatives.     

Formation and coordination of a terdentate dithiocarbazatopyrazoline derivative to technetium(V)

The potentially terdentate ligand 1-(S-methyldithio)-3,5-dimethyl-3-(S-methyldithiocarbazato)pyrazoline (H₂mdp) was prepared by the reaction of S-methyldithiocarbazate with acetylacetone in an acidic ethanol solution. The neutral complex [TcOCl(mdp)](1) was formed by the reaction of (n-Bu₄N)[TcOCl₄] with H₂mdp in ethanol at room temperature. Compound 1 has a square-pyramidal geometry with the thiolate, thiocarbonyl and amide donor atoms of the terdentate chelate mdp and chloride forming a square plane, with the oxo oxygen in the apical position.     

C60-吡咯烷衍生物的合成及非线性光学性质的研究

通过富勒烯C₆₀与肌氨酸和有机醛化合物的1,3-偶极环加成反应, 获得了九种含不同有机功能基团的C₆₀吡咯烷衍生物1～9, 用¹H NMR, ¹³C NMR, FTIR, UV-vis和FAB-MS进行了结构表征; 利用皮秒激光光源, 采用z扫描技术测定了分子的三阶非线性超极化率γ⁽³⁾, 结果显示: 化合物3 (γ⁽³⁾＝4.14×10^－33 esu)具有最大的三阶非线性光学系数, 说明增加噻吩共轭链的长度, 使三阶非线性活性增加; 对具有相同共轭链的C₆₀-噻吩吡咯烷衍生物(2, 5, 1和4), 吸电子取代基减小了三阶光学非线性活性, 给电子基增大了三阶光学非线性活性; 同时发现喹啉环2-位键联(7)比4-位(8)有更好的三阶光学非线性活性.     

Structural characterisation of trimethylsilyl-protected DNA bases

The structures of the silylated DNA bases, bis(trimethylsilyl)thymine (1), bis(trimethylsilyl)cytosine (2), bis(trimethylsilyl)adenine (3) and tris(trimethylsilyl)guanine (4), have been determined. 1 is O-silylated and displays no intermolecular interactions. 2 is silylated at both exocylic O, N positions and forms a chain structure through intermolecular NH…O and NH…N hydrogen bonds. 3 contains two SiMe₃ groups, on the exocylic NH and endocyclic N⁹ position, respectively; of two independent molecules in the asymmetric unit, one dimerises through complementary NH…N hydrogen bonds, while the other forms a strained intramolecular hydrogen bond through the same pair of donor and acceptor centres. 4 incorporates N, N, O–SiMe₃ moieties and forms chains via bifurcated CH…O/N hydrogen bonds, while the NH function remains unexploited. The effects of silylation on these pyrimidine and purine ring structures are also discussed in comparison with the native bases.

The structures of the silylated DNA bases, bis-(trimethylsilyl)thymine (1), bis-(trimethylsilyl)cytosine (2), bis-(trimethylsilyl)adenine (3) and tris-(trimethylsilyl)guanine (4), have been determined. While 1 displays no intermolecular interactions. 2 forms a chain structure through intermolecular NH…O and NH…N hydrogen bonds, 3 incorporates two independent molecules in the asymmetric unit, one dimerises through complementary NH…N hydrogen bonds while the other forms a strained intramolecular hydrogen bond through the same pair of donor and acceptor centres and 4 forms chains via bifurcated CH…O/N hydrogen bonds while the NH function remains unexploited.     

Orientational ordering of 4-substituted phenylcyclohexanes studied by carbon-13 two-dimensional N.M.R.

Abstract

An N.M.R. method combining the techniques of separated local field spectroscopy (SLF) and variable angle spinning (VAS) is valuable in the investigtion of nematic liquid crystals. Rapid sample spinning causes the nematic director to align along the spinning axis, resulting in narrow peaks in the C-13 N.M.R. spectrum. SLF is a two-dimensional N.M.R. method which produces a first order splitting pattern for each carbon signal from which C–H dipolar coupling constants can be determined. The order parameters for all segments of the liquid crystal molecule can then be calculated. Results for three 4′-cyanophenylcyclohexanes are considered here. These compounds are trans-substituted at the 4 position of cyclohexane ring with n-pentane (PCH5), 1-pentene (3d ₁CP) and 3-pentene (1d ₃CP), respectively.     

N-Lithio-N,N′,N″,N″-tetramethyldiethylenetriamine and N′-Lithio-N,N,N″,N″-tetramethyldiethylenetriamine; Oxidative Coupling of Aminomethyllithium Derivatives

N-lithio-N,N′,N″,N″-tetramethyldiethylenetriamine (I-Li) is formed from 2,5,8,11-tetramethyl-2,5,8,11-tetraazadodecane (III) or from 2,5,8,11,14,17-hexamethyl-2,5,8,11,14,17-hexaazaoctadecane (IV) with n-BuLi or sec-BuLi, respectively, its isomer N′ -lithio-N,N,N″,N″,-tetramethyldiethylene-triamine (II-Li) from tris(2-dimethylaminoethyl)amine (V) with n-BuLi. IV results from treatment of N-lithiomethyl-N,N′,N″,N″-tetramethyldiethylenetriamine (PMDTA-Li) with 1,2-dibromoethane.     

SYNTHESIS AND REACTIONS OF HALO DERIVATIVES OF 4-ISOPROPYL-2H-1,4-THIAZIN-3-ONE

Abstract

Reaction of 4-isopropyl-2H-1,4-thiazin-3-one 1 (R [dbnd] i-Pr) with N-chloro- and N-bromosuccinimide occurred exclusively at the 6-position to give 6-chloro and 6-bromo derivatives of 1 (R [dbnd] i-Pr), respectively, in high yield, in sharp contrast to the 2-aroyloxylation by benzoyl peroxide or m-chloroperbenzoic acid reported earlier.² Reaction of 1 (R [dbnd] i-Pr) with methanesulfonyl chloride in the presence of aluminum chloride afforded an addition compound, 4-isopropyl-5,6-dichloro-1,4-tetrahydrothiazin-3-one. The 2-chloro derivative 6 of 1 (R [dbnd] i-Pr) was successfully prepared by hydrolysis of the 2-m-chloroben-zoyloxy derivative of 1 (R [dbnd] i-Pr) followed by treatment with thionyl chloride. Derivative 6 reacted readily under mild conditions with water, alcohols, thiols, ammonia and amines to give various 2-substituted compounds of 1 (R [dbnd] i-Pr). With phenol as a nucleophile, 1 (R [dbnd] i-Pr) reacted exclusively at the para position. Reaction at carbon atoms also occurred with N,N-dimethylaniline and 2,6-xylidine.     

Synthesis and characterization of a novel η 2-iminoacyl monocyclopentadienyl titanium(IV) complex

An unusual complex, [CpTi(η²-(C,N)-2-ArNH–C₆H₄C=NAr)Cl₂] (Ar?=?2,6- ⁱ Pr₂C₆H₃) (1) has been synthesized and characterized by elemental analysis, NMR spectra, and single crystal X-ray diffraction. The ¹³C NMR resonance of the imine carbon atom of 1 at δ?221?ppm is consistent with the η²-(C,N) binding. This was confirmed by single crystal X-ray diffraction study of 1. In the complex, Ti atom is five-coordinate with a η²-bound iminoacyl ligand and one Cp ligand occupying the axial position in a distorted square pyramid.     

Syntheses and crystal structures of two copper(II) complexes derived from 2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]phenol

Two new copper(II) complexes, [CuL₂] (1) and [Cu₂L₂(NCS)₂] · 2CH₃CN (2) (HL = 2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]phenol), have been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Complex 1 was synthesized by reaction of HL with copper(II) acetate in methanol, while 2 was synthesized by adding ammonium thiocyanate to a methanol/acetonitrile (V : V = 2 : 1) solution of 1. Complex 1 crystallizes in the P2₁/n space group, and the thiocyanato-bridged dinuclear copper(II) complex, 2, crystallizes in the Pbcn space group. The Cu in 1 is four-coordinate square-planar with two imine N and two phenolate O atoms from two Schiff-base ligands. The Cu in 2 is five-coordinate square-pyramidal with NNO donor atoms of one Schiff-base ligand and one N atom of a bridging thiocyanate ligand defining the basal plane, and with one S atom of another bridging thiocyanate ligand occupying the apical position.     

Syntheses,spectral, thermal and structural characterization of copper(II) complexes of 2,3-pyrazinedicarboxylate with N,N ′-dimethylethylenediamine and 1,10-phenanthroline

Two copper(II) complexes of 2,3-pyrazinedicarboxylate (pzdca) with N,N′-dimethylethylenediamine (dmen), [Cu₂(pzdca)₂(H₂O)₂(dmen)₂] · 6H₂O (1) and 1,10-phenanthroline (phen), [Cu(pzdca)(phen)₂] · 5.5H₂O (2), have been prepared and characterized by elemental analyses, IR, UV/vis, magnetic measurement and single crystal X-ray diffraction. The complexes crystallize in the monoclinic space group P2₁ /c and triclinic space group P 1, respectively. In both complexes the copper coordinates pyrazine nitrogen and carboxylate oxygen as a bidentate ligand. The coordination sphere around Cu(II) is completed by two N atoms from dmen and four N atoms from phen groups and one axial position occupied by the carboxyl O atom from the symmetry related molecule in 1. The coordination sphere should be described as a distorted octahedral and (5 + 1)-geometry in 1 and distorted octahedral geometry in 2. While 1 shows a first dimeric arrangement, 2 is a monomer. The thermal analyses show that 1 and 2 decompose completely in four and five step thermal processes at 20–600°C temperature intervals.     

Coordination polymer incorporating cobalt(II) and glycine acid: structure and magnetism

We report the structure and magnetism of a cobalt(II) compound with glycine acid, Co(C₂H₄NO₂)₂ · H₂O (1). It crystallizes in the orthorhombic system, space group P2(1)2(1)2(1) with a = 5.2301(10) Å, b = 10.837(2) Å, c = 13.542(3) Å, R ₁ = 0.0448, wR ₂ = 0.1151. In 1, Co(II) has a slightly distorted square-pyramidal geometry defined by two O atoms and two N atoms from two glycine ligands, and by one O atom from an aqua ligand in the apical position. The molecules form a three-dimensional supramolecular network through O–H ··· O and N–H ··· O hydrogen bonds. Magnetic characterization shows 1 exhibits a negative Curie–Weiss constant and dominant spin-orbit coupling for Co(II).     

Studies on the Synthesis of the Sydnone Derivatives and its Properties IV: The Diarylation of Sydnone Compound

In the presence of H₂SO₄, the sydnone rings were condensed with formaldehyde to give diarylation in 4-position of the sydnone rings: 3,3′-diphenyl-4,4′-methylenedisydnone is obtained from 3-phenylsydnone in 61% yield, and 3,3′-di-p-methylphenyl-4, 4′-methylenedisydnone is obtained from 3-(4′-methylphenyl)sydnone in 70% yield. And the possible reaction mechanism is discussed.     

A combined theoretical and thermal analysis study on the solid state linkage isomerization of Ni(II)-nitrite complexes with ethylenediamine derivatives*

Solid state stepwise nitro–nitrito linkage isomerization of trans-[dinitrobis(ethylenediamine)nickel(II)], [Ni(en)₂(NO₂)₂] (N,N-en), trans-[dinitrobis(N,N′-dimethylethylenediamine)nickel(II)], [Ni(N,N′-dmen)₂(NO₂)₂] (N,N-dmen), and trans-[dinitritobis(N,N-dimethylethylenediamine)nickel(II)], [Ni(N,N-dmen)₂(ONO)₂] (O,O-udmen) were investigated by performing non-isothermal differential scanning calorimetry (DSC) analyses and the thermodynamic and thermokinetic parameters of isomerization were determined using DSC curves. Both N,N-en and N,N-dmen DSC curves show an endothermic peak at elevated temperatures, attributed to dinitro-to-dinitrito linkage isomerization. Similar exothermic peaks were observed in the cooling cycle, assigned to the reverse dinitrito-to-dinitro isomerization. The O,O-udmen isomer is more stable than the corresponding dinitro one at ambient temperatures, but an exothermic dinitrito-to-dinitro isomerization occurs upon cooling down to ?70 °C and reverts endothermically to dinitrito isomer upon heating up to ambient temperature. The overlapping DSC peaks associated with stepwise linkage isomerization were resolved using nonlinear fitting method. The peak temperature and the enthalpy changes of linkage isomerization are inversely dependent on the steric hindrance provided by diamine ligands, which increases in the order udmen > dmen > en. The results showed that the steric factor of the co-ligands also influences the kinetic parameters of isomerization, so that more bulky ligand substituent leads to higher isomerization rate constants. A DFT and TD-DFT calculations have been carrid out on both dinitro complexes of this investigation .     

Technetium(V) complexes of dithiocarbazate derivatives

The neutral complex [TcOCl(hdc)] (1) (hdc?=?S-methyl-β-N-(2-hydroxyphenylethylidene)dithiocarbazate) was prepared by reaction of (n-Bu₄N)[TcOCl₄] with an equimolar amount of H₂hdc in ethanol/dichloromethane at room temperature. With a fourfold mol excess of H₂hdc in methanol/acetone, the ‘3?+?2’ complex [TcO(hdc)(adc)] (2) (adc?=?S-methyl-β-N-(prop-2-ylidene)dithiocarbazate) was isolated. Adc was formed by ketone exchange between solvent acetone and the hydroxyacetophenone fragment of hdc. Compounds 1 and 2 were characterized by infrared spectroscopy, ¹H NMR spectrometry, elemental analysis and single-crystal X-ray crystallography. Complex 1 has square-pyramidal geometry with the SNO-donor atoms of the tridentate chelate hdc and chloride forming a square plane, with the oxo oxygen atom in the apical position. Complex 2 has a distorted octahedral geometry, with an S₂N₂ donor set in the equatorial plane and the oxo and phenolate oxygen atoms in trans apical positions.     

Influence of the position of the nitro group on the structural and spectroscopic characteristics of N"-(nitrobenzylidene)isonicotinic hydrazides in the crystalline state

N"-Substituted isonicotinic hydrazides of the general formula Py—C(=O)—N(H)-N"=C(H)—R, where R is o- (1), m- (2), or p-nitrophenyl (3), were studied by IR spectroscopy and X-ray diffraction analysis. The position of the nitro group in these compounds has no effect on the type of the crystal structure. The crystal packings are based on stacks consisting of antiparallel planar molecules. The molecules from the adjacent stacks are linked to each other via the N—H...N_Py hydrogen bonds. Depending on the position of the nitro group, the N...N_Py distance increases in the series 3 > 1 > 2 and the energy of the hydrogen bonds decreases (according to the IR spectroscopic data) from 3.9 to 3.1 kcal mol^–1. Analysis of the IR spectra demonstrated that the intensity of absorption in the (C—H) stretching region of the pyridine ring increases substantially as the the N—H...N_Py hydrogen bond is strengthened. Some regularities of the changes, which are observed for the (NO₂) bands in the spectra of the nitrophenyl-containing conjugated molecules in solutions, persist in the crystalline state.     

Chiral discotic derivatives of 1,3,5-triphenyl-6-oxoverdazyl radical

Two derivatives of 1,3,5-aryl-6-oxoverdazyl containing two 3,4,5-trioctyloxyphenyl and one 3,4,5-tri((S)-3,7-dimethyloctyloxy)phenyl group in position C(3) (1b) or N(1) (1c) were investigated by thermal, X-ray diffraction and magnetic methods. The results were compared to those obtained for achiral derivative 1a containing three 3,4,5-trioctyloxyphenyl groups. All three compounds exhibit an ordered columnar hexagonal phase, Col_h(o), and for chiral derivatives, 1b and 1c, a superstructure with doubled periodicity was found. The introduction of the three chiral alkoxy substituents in 1a lowered the mesophase stability by about 50 K and induced a Col_h phase in 1c. Thermochromic analysis showed a hypsochromic shift upon formation of the Col_h(o) phase similar for all three derivatives 1 (~0.3 eV), which coincides with a 5% drop in effective magnetic moment, μ_eff, for 1c. Analysis of magnetisation data in a range of 2–370 K at 200 Oe revealed weak antiferromagnetic interactions (θ = – 4 K) in the Col_h(o) phase.     

Organic-salt-mediated highly regioselective N3-alkylation of 2-thiophenytoin via Michael reaction under solvent-free conditions

A regioselective N3-alkylation of 5,5-diphenyl-2-thiohydantoin (2-thiophenytoin) using a very efficient mild base K₂CO₃ and α,β-unsaturated esters in the presence of organic salt TBAB (tetrabutylammonium bromide) at room temperature has been reported (3b–3h). The selectivity of this reaction is excellent and products have been produced in good yields under solvent-free conditions. The increase of the reaction temperature to 70°C mostly disappeared this selectivity and afforded only the N1,N3-dialkylated derivatives of 2-thiophenytoin in good yields (4b–4g). We were unable to selectively N3-alkylate 2-thiophenytoin with ethyl acrylate at both room temperature and 70°C under the same conditions (4a). Dimethyl and diethyl fumarates cannot work as Michael acceptors and were hydrolyzed to fumaric acid under reaction conditions.     

Ionic liquids from the cationic cobalt(III) Schiff base complex, [Co(acacen)L2][Tf2N] (acacen = N,N′-bis(acetylacetone)ethylenediamine,Tf2N = bis(trifluoromethanesulfonyl)amide)

Ionic liquids comprising cationic cobalt(III) complexes [Co(acacen)L₂][Tf₂N] (L?=?3-butylpyridine (1), 1-butylimidazole (2); acacen?=?N,N′-bis(acetylacetone)ethylenediamine, Tf₂N?=?bis(trifluoromethanesulfonyl)amide) were prepared. 1 is a liquid at room temperature and exhibits a glass transition at ?12?°C, whereas 2 is a solid at room temperature with a melting point of 74.6?°C and glass transition temperature of ?15?°C upon cooling from the melt. These salts are reddish brown diamagnetic materials that are stable against air and water; these properties differ from those of the corresponding iron(III) salt. Desorption of the axial ligands of 1 and 2 occurs at 180 and 207?°C, respectively.     

Synthesis of Differently Substituted N- and P-Aminodiphosphinoamine PNPN-H Ligands

Abstract

On the basis of the known aminodiphosphinoamine ligand Ph₂PN(i-Pr)P(Ph) N(i-Pr)-H (3a), differently substituted aminodiphosphinoamine PNPN-H ligands (3) were prepared. By using different synthetic methods, the N-substituted ligands Ph₂PN (i-Pr)P(Ph)N(c-Hex)-H (3b), Ph₂PN(c-Hex)P(Ph)N(i-Pr)-H (3g), and Ph₂PN(i-Pr)P(Ph) N[(CH₂)₃Si(OEt)₃]-H (3c), in addition to the formerly described Ph₂PN(n-Hex)P (Ph)N (i-Pr)-H (3h), Ph₂PN(i-Pr)P(Ph)N(Et)-H (3d), Ph₂PN(i-Pr)P(Ph)N(Me)-H (3e), and Ph₂PN(c-Hex)P(Ph)N(c-Hex)-H (3f), were obtained. In addition, Ph₂PN(i-Pr)P(Me)N(i-Pr)-H (3i), (cyclopentyl)₂PN(i-Pr)P(Ph)N(i-Pr)-H (3j), (-O-CH₂-CH₂-O-)PN(i-Pr)P(Ph)N(i-Pr)-H (3k), and (1-Ad)₂PN(i-Pr)P(Ph)N(i-Pr)-H (3l) were prepared with different P-substitutions. All compounds were characterized and the molecular structures of the intermediates Ph₂PN(i-Pr)P(Ph)Cl (1a) and (cyclopentyl)₂PN(i-Pr)P(Ph)Cl (1e) and the ligand (1-Ad)₂PN(i-Pr)P(Ph)N(i-Pr)-H (3l) were investigated by single-crystal X-ray diffraction.

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