N-对甲基苯基-N′-（2-吡啶基）脲的低温热容及热分析

通过低温量热和热分析方法,测定了N-对甲基苯基-N′-（2-吡啶基）脲(以下简称NPMPN′2PU)的低温热容和热力学性质.通过对NPMPN′2PU进行低温量热,得到了NPMPN′2PU在80～370 K 温区的热容曲线,热容曲线光滑,没有任何热异常现象,由此实验热容数据计算出NPMPN′2PU在这段温区内的热力学数据.从DSC实验结果发现, NPMPN′2PU熔化峰值出现在173.86 ℃,熔化焓为204.45 kJ•mol－1.紧接熔化峰后NPMPN′2PU开始分解,分解峰只有一个,分解峰值温度为226.11 ℃.TG和DTG的实验结果表明,NPMPN′2PU失重的峰值为227.2 ℃,这些结果与DSC实验结果吻合.     

Polystyrene bis[N-(2-pyridyl) sulfonamide] palladium(II): Synthesis,characterization as a catalyst for coupling reactions

The [N-(2-pyridyl)] para-styrene sulfonamide (PSS) was prepared as a monomer, from the reaction of para-styrene sulfonyl chloride and 2-amino pyridine in the presence of potassium hydroxide solution 0.5 M as a base, and CH₃Cl. Polystyrene [N-(2-pyridyl) sulfonamide] (PPSS) was synthesized from the polymerization of [N-(2-pyridyl)] para-styrene sulfonamide (PSS). The Polystyrene bis [N-(2-pyridyl) sulfonamide] palladium (II) as a polymer- supporting palladium complex was also prepared from the reaction of PdCl₂ (CH₃CN)₂ with PPSS in the presence of KOH 0.5 M. Polystyrene bis [N-(2-pyridyl) sulfonamide] palladium (II) is produced as a novel heterogeneous catalyst for coupling reactions for C-C bond formation. This method includes higher yield and has an easier work-up procedure. The structures of the monomer, polymer and its Pd complex were confirmed by using FT-IR and ¹H-NMR spectroscopy. Elemental analysis of Pd by inductively coupled plasma (ICP) technique and hot filtration test showed loading of the metal into solution from the catalyst The heterogeneous catalyst was recycled without any loss in its properties.     

4,6-二甲氧基-2-嘧啶氨基甲酸甲酯的热力学研究

用精密自动绝热量热计测定了自行合成并提纯的4,6-二甲氧基-2-嘧啶氨基甲酸甲酯在80～380 K温区的摩尔热容.实验结果表明,在345～360 K温区,该化合物有一固-液熔化过程.经两次重复测定,得其熔化温度、摩尔熔化焓以及熔化熵分别为:(357.201±0.080) K, (26.289±0.029) kJ·mol^-1和(73.597±0.070) J·mol^-1·K^-1.通过分步熔化法得到该物质绝对纯样品的熔点为357.449 K.根据热力学关系和热容数据,计算出了该化合物相对于标准参考温度298.15 K的热力学函数.用DSC和TG热分析技术在300～500 K温区对该物质的热力学性质作了进一步研究,得到与绝热量热法一致的固-液熔化过程热力学参数,并得到该化合物蒸发过程的热力学参数:沸点为488.06 K,摩尔蒸发焓为81.73 kJ·mol^-1.     

N-（2,4-二氯苯基)-N′-(苯甲酰基)硫脲脱硫物合铜(Ⅱ)配合物的合成与晶体结构

在甲醇中由N-(2,4-二氯苯基)-N’-(苯甲酰基)硫脲(H2met)和CuCl2回流,合成了脱H2S的CuL2(HL=N-(苯甲酰基)-O-甲基-N’-(2,4-二氯苯基)假硫脲),其中HL由H2met脱硫得到。在室温条件下,采用缓慢挥发溶剂法培养出适合用于X射线衍射测试的单晶。由X单晶衍射确定了其晶体和分子结构,在配合物分子中,Cu(Ⅱ)与2个配体分子(HL)的N原子和2个羰基O原子发生配位,形成了2个六元螯合环[N(1A)—Cu—N(1)的键角为180.0°,O(1A)—Cu(1)—O(1)的键角为180.0°]组成的配合物。     

Synthesis and Crystal Structure of a Copper(II) Compound Constructed by N-(4,6- Dimethoxylpyrimidin)-N'-(ethoxycarbonyl)thiourea

A copper(Ⅱ) complex Cu(L)2(NO3)2 constructed by the L (L = N-(4,6-dime- thoxylpyrimidin)-N'-(ethoxycarbonyl)thiourea) ligand crystallizes in monoclinic, space group C2/c with a = 16.2416(16), b = 9.1385(7), c = 22.0008(18) (A),β = 108.077(2)°, V ＝ 3104.3(5)(A)3, Dc = 1.627 g/cm3, Z = 4, C20H28CuN10O14S2, Mr = 760.18, μ(MoKα) = 0.920 mm-1, F(000) = 1564, R = 0.0471 and wR = 0.1284 for 2239 observed reflections (I > 2σ(I)). X-ray diffraction shows the existence of weak complementary intramolecular N-H…O (DA) hydrogen bonds which further strengthen the coordination from the two L ligands with the Cu(II) ion, intermolecular C-H…O hydrogen bonds and weak π…π stacking interactions, leading to the formation of a multi-dimen- sional supramolecular network.     

Interlayer-type Crystal Structure of N-（1-Adamantyl） urea

1 INTRODUCTION In the context of supramolecular chemistry, mo- lecules are joined together by intermolecular interac- tions to form a supramolecule whose physical pro- perties largely depend on the orientation and packing of molecules in the crystal structures[1]. The adaman- tane is a kind of cage alkane with high symmetry and stable framework. Its derivatives are extensively applied in the fields of medicine, macromolecular materials, aviation and so on due to the unique structures and …     

Ambidentate coordination of the tripyridyl ligands 2,2′:6′,2″-terpyridyl,tris(2-pyridyl)-amine,tris(2-pyridyl)methane and tris(2-pyridyl)phosphine to carbonylrhenium centres: Structural and spectroscopic studies

The reactions of [Re(CO)₅Cl] with the ligands tpy (2,2′:6′,2″-terpyridine), py₃N {tris(2-pyridyl)-amine}, py₃CH {tris(2-pyridyl)methane}, and py₃P {tris(2-pyridyl)phosphine} in toluene solution realize compounds with the general formulation [Re(ligand)(CO)₃Cl] in which the tripyridyl ligands are bidentate. X-ray structural determinations of fac-[Re(typ)(CO)₃Cl].H₂O and fac-[Re(py₃N)(CO)₃Cl] confirm these assignments. [Re(tpy)(CO)₃Cl].H₂O (C₁₈H₁₃ClN₃O₄Re) is monoclinic, space group P2₁/n, with cell dimensions a = 7.432(2) Å, b = 17.016(4) Å, c = 14.466(2) Å, β = 93.51(2)°, and Z = 4; full-matrix least-squares refinement on 2435 reflections with I ? 2.5σ(I) converged to a final R = 0.028 and R_w = 0.029. [Re(py₃N)(CO)₃Cl] (C₁₈H₁₂ClN₄O₃Re) is triclinic, space group P1 with cell dimensions a = 13.761(2) Å, b = 14.636(6)Å, c = 11.110(2) Å, α = 110.70(2)°, β = 102.45(2)°, γ = 107.48(2)°, and Z = 4; full-matrix least-squares refinement on 3459 reflections with I ? 2.5σ(I) converged to a final R = 0.038 and R_w = 0.039. If the synthetic procedure is undertaken under irradiation by visible light, for the ligand py₃N a species [Re(py₃N)(CO)₂Cl] (characterized by infrared spectroscopy and conductance measurements) is also formed, in which the ligand py₃N is tridentate. No analogous tridentate species is formed with the ligands tpy or py₃P, although there is evidence that it also forms for py₃CH.     

Synthesis and Characterization of 2,5-Bis(2-pyridyl)thiophene

2-[2-(Trimethylsilyl)ethynyl] pyridine ( 6 ) was prepared in 95% yield by reaction of 2-bromopyridine with trimethylsilylacetylene in triethylamine in the presence of bis(triphenylphosphine)Palladium(II) chloride and Copper(I) iodide. Desilylation of ( 6 ) by refluxing with sodium hydroxide in methanol (yield 95%) of 2-ethynylpyridine ( 5 ). Oxidative coupling of ( 5 ) in pyridine by oxygen in the presence of Copper(I) chloride gives 70% yield of 1,4-bis(2-pyridyl)1,3-butadiyne ( 4 ). Reaction of 4 with sodium sulfide affords 100% of 2,5-bis(2-pyridyl) thiophene ( 1 ).     

A study on the thermodynamic properties of polyimide BTDA-ODA by adiabatic calorimetry and thermal analysis

Polyimide BTDA-ODA sample was prepared by polycondensation or step-growth polymerization method. Its low temperature heat capacities were measured by an adiabatic calorimeter in the temperature range between 80 and 400 K. No thermal anomaly was found in this temperature range. A DSC experiment was conducted in the temperature region from 373 to 673 K. There was not phase change or decomposition phenomena in this temperature range. However two glass transitions were found at 420.16 and 564.38 K. Corresponding heat capacity increments were 0.068 and 0.824 J g^–1 K^–1, respectively. To study the decomposition characteristics of BTDA-ODA, a TG experiment was carried out and it was found that this polyimide started to decompose at ca 673 K.This revised version was published online in November 2005 with corrections to the Cover Date.     

A one-flask synthesis and characterization of novel symmetrical pyridyl monoselenides and X-ray crystal structure of bis(5-bromo-2-pyridyl) selenide and bis(2-bromo-5-pyridyl) selenide

The present work reports an efficient one-pot synthesis of symmetrical pyridyl monoselenides by the reaction of bromo-/iodopyridines with the isopropylmagnesium chloride, ⁱPrMgCl followed by quenching with selenyl chloride, SeCl₂. The current methodology constitutes a convenient synthesis of bis(5-bromo-2-pyridyl) selenide (I), bis(2-bromo-5-pyridyl) selenide (II) and bis(2,5-dibromo-3-pyridyl) selenide (III) under cryogenic conditions requiring shorter time duration to give satisfactory yields. The hitherto unknown compounds have been characterized by elemental analysis and various spectroscopic techniques i.e., ¹H NMR, ¹³C NMR, FT-IR, mass spectrometry and X-ray crystallography.     

Synthesis of tetrakis(2-pyridyl)methane: the first tetrapyridylmethane

Tetrakis(2-pyridyl)methane has been synthesized as the first member of tetrapyridylmethane family by nucleophilic aromatic substitution of 2-chloropyridine with tris(2-pyridyl)methyl anion in refluxing aromatic hydrocarbons; the use of 2-bromopyridine resulted in electron transfer giving rearranged dimer of tris(2-pyridyl)methyl radical.     

Calorimetric study and thermal analysis of [ErY(Ala)4(H2O)8](ClO4)6 (Ala=ALANINE)

A solid complex of rare-earth compounds with alanine, [ErY(Ala)₄(H₂O)₈](ClO₄)₆ (Ala=alanine), was synthesized, and a calorimetric study and thermal analysis for it was performed through adiabatic calorimetry and thermogravimetry. The low-temperature heat capacity of [ErY(Ala)₄(H₂O)₈](ClO₄)₆ was measured with an automated adiabatic precision calorimeter over the temperature range from 78 to 377 K. A solid-solid phase transition was found between 99 and 121 K with a peak temperature at 115.78 k. The enthalpy and entropy of the phase transition was determined to be 1.957 Kj mol^-1, 16.90 j mol^-1 k^-1, respectively. Thermal decomposition of the complex was investigated in the temperature range of 40~550°C by use of the thermogravimetric and differential thermogravimetric (TG/DTG) analysis techniques. The TG/DTG curves showed that the decomposition started from 120 and ended at 430°C, completed in three steps. A possible mechanism of the thermal decomposition was elucidated. This revised version was published online in July 2006 with corrections to the Cover Date.     

2,4-二氯苯氧乙酰氨基（硫）脲类衍生物的合成及生物活性

二氯苯氧乙酰氨基（硫）脲;植物生长调节剂;生物活性     

N-对甲基苯基-N′-(2-吡啶基)脲的低温热容及热分析

通过低温量热和热分析方法,测定了N-对甲基苯基-N′-(2-吡啶基)脲(以下简称NPMPN′2PU)的低温热容和热力学性质.通过对NPMPN′2PU进行低温量热,得到了NPMPN′2PU在80～370K温区的热容曲线,热容曲线光滑,没有任何热异常现象,由此实验热容数据计算出NPMPN′2PU在这段温区内的热力学数据.从DSC实验结果发现,NPMPN′2PU熔化峰值出现在173.86℃,熔化焓为204.45kJ·mol-1.紧接熔化峰后NPMPN′2PU开始分解,分解峰只有一个,分解峰值温度为226.11℃.TG和DTG的实验结果表明,NPMPN′2PU失重的峰值为227.2℃,这些结果与DSC实验结果吻合.     

Palladium(II) Complexes of N-(2-Thienylmethylidene)aniline Derivatives

Coordination reactions of N-(2-thienylmethylidene)aniline derivatives, L, with PdCl₂ or [PdCl₄]^2? in ethanol yield stable complexes of the type trans-(L)₂PdCl₂ with the azomethine nitrogen atoms as σ donors. These are not readily convertible to othor-palladated complexes. An X-ray crystallographic study of the complex (L₂)₂PdCl₂ reveals a centrosymmetric geometry. The structure is in the triclinic space group $ {\rm P}\bar 1 $ with a = 8.633(2) Å, b = 12.759(3) Å, c = 8.398(2) Å, α = 96.65(5)°, β = 111.47(5)*, γ= 101.28(6)°, and Z = 1. The final R factor is 0.043 (Rw = 0.044) for 2396 observed reflections. There is no real bonding between a thiophene sulfur atom and a central palladium ion. However, a long distance interaction between S and Pd does exist.     

Studies on Binuclear Co(II) and Cu(II) Complexes of Tridentate N-(2-Carboxyphenyl)Salicylideneimine

Homo Cu(II) and Co(II) binuclear complexes H[MLClMCl₂] formed by using the donor properties of the cis two oxygen atoms of the tridentate N-(2-carboxyphenyl)-salicylaldimine Schiff base derived from salicylaldehyde and anthranilic acid have been synthesized. It was found that the Cu(II) “complexed ligand” readily reacts with CoCl₂ to form mononuclear Co(II) and binuclear oxygen bridged Co(II) complex [Co₂-L₂](H₂O)₂. The structure of the so prepared complexes was investigated using microchemical analysis, molar conductance measurements as well as electronic and vibrational spectral studies. It was concluded that in the Cu(II) binuclear complex, the Cu(II) ion inside the “complexed ligand” has a planar structure while the other Cu(II) ion is distorted away from planarity. In the Co(II) binuclear complex, the Co atom of the “complexed ligand” is distorted from tetrahedral structure when it coordinates to the second Co atom.     

Six-membered ring chelate complexes of Pd(II) and Pt(II) derived from di-(2-pyridyl)pyrimidin-2-ylsulfanylmethane

Cis-[MLCl₂] complexes of di-(2-pyridyl)pyrimidin-2-ylsulfanylmethane ligand (L), where M = Pd (1), and M = Pt (2) have been synthesized. Reaction of 1 with L in presence of Na[BF₄] and hot acetonitrile produced the complex [PdL₂](BF₄)₂ (3). Complexes 1-3 and ligand L have been characterized by elemental analyses, IR and NMR spectroscopy. Crystal structures of 1, 3 and L were determined by single crystal X-ray diffraction analyses, showing nonplanar structures with the pyridinic rings twisted around the bridging carbon and the ipso carbon bonds. 1 and 3 displayed a bidentate coordination of L to the palladium atom with the formation of six-membered chelate rings, where the local geometry at palladium atom was distorted square planar. In 3 the palladium atom was coordinated to two dipyridyl ligands through two of the pyridinic nitrogen atoms to form a cationic complex stabilized by two tetrafluoroborate counter-ions.     

2-(2-氨基-3-吡啶基)-苯并咪唑的合成、晶体结构和荧光特性研究

在合成2-(2-氨基-3-吡啶基)-苯并咪唑的基础上,利用NMR(1H、13C、COSY、HSQC和HMBC)、MS、IR和UV进行了详细表征;通过X-ray单晶衍射仪测定了该化合物的晶体结构,实验结果表明该晶体属于三方晶系(空间群R3,a=1.833 7(3)nm,b=1.833 7(2)nm,c=1.777 7(4)nm,V=5.176 4(15)nm3,Z=18),很好地支持了波谱表征的结果。同时,结合密度泛函计算,研究了2-(2-氨基-3-吡啶基)-苯并咪唑的荧光光谱。结果表明,化合物的双荧光不是由同一种异构体发射的,而是来源于不同异构体:长波区500~600 nm的荧光由K构型发射,短波区350~450 nm的发射由异构体E1和E2共同产生,理论预测的光谱与实验一致。