N,N'-双(3-甲酰基-4-羟基苯甲酸甲酯）缩环己二胺Schiff碱过渡金属配合物的合成及表征

N;N'-双(3-甲酰基-4-羟基苯甲酸甲酯）缩环己二胺Schiff碱过渡金属配合物的合成及表征     

三乙烯四胺-咪唑的非对称异双核配合物的合成及电化学性质

许多过渡金属含氮配合物具有抗菌、抗癌、抗病毒等生物活性,受到人们的广泛重视[1]。其中三乙烯四胺(trien)是有效的生成单双核配合物的含氮配体,已设计合成了一系列过渡金属及稀土金属的均双核和异双核配合物,并进行了结构表征和性能研究[2]。对于其异双核咪唑桥联配合物,前文     

2,4-二羟基-5-乙酰苯乙酮缩水杨酰肼单Schiff碱及其配合物的合成

以吡啶,DMF为溶剂,成功合成了未见文献报道的2,4-二羟基-5-乙酰苯乙酮缩水杨酰肼单Schiff碱(LH2)的过渡金属配合物[ML,M=Cu(Ⅱ),Zn(Ⅱ),Ni(Ⅱ)和Co(Ⅱ)],其结构经UV,1HNMR,IR,MS及元素分析表征。结果表明,Schiff碱是一种三齿配体,在配合物中溶剂分子参与了配位。     

不对称双席夫碱Cu(II)同双核及Cu(II)-Mg(II)- Cu(II)异三核配合物的合成与晶体结构

近年来的研究表明，某些过渡金属Schiff碱配合物具有抗菌、抗癌、抗病毒活性。不对称Schiff碱配合物因其特殊的结构和性质正日益受到人们的关注^[3]。但由于不对称双Schiff碱及其配合物的合成及单晶培养比较困难，国内有关其合成与结构的报道较少。我们曾首次合成了不对称双Schiff碱配合物HCuL (H₃L为N-3-羧基水杨醛-N^/-水杨醛-缩乙二胺)及其多个异三核配合物^[1，2]，本文报道的是该系列同双核配合物(HCuL)₂(1) 及Cu(II)-Mg(II)-Cu(II)异三核配合物（2），并通过X-射线衍射的方法解析了两个配合物的晶体结构。配合物1的晶体属单斜晶系，Cc空间群，晶胞参数为a=2.5326(5)nm, b=0.88861(18)nm, c=1.3738(3)nm, β =96.95(3)°, Z=4, R1=0.0520,wR2=0.0968, 此配合物是两个HCuL分子通过酚氧桥联而形成的双聚分子。配合物2的晶体属单斜晶系， Pc空间群，晶胞参数为a= 1.1816(2)nm, b=1.5599(3)nm, c=1.9642(4)nm, β =98.22°, Z=2, R1=0.0701,wR2=0.1498，其晶格的每个不对称单元包含两个异三核中性分子[CuL(H₂O)]Mg[CuL(CH₃OH)]}和{[CuL]Mg[CuL(H₂O)]}     

Schiff碱二价钐配合物[2-OC_6H_4CH═N(2,6-~iPr_2C_6H_3)]_2Sm(THF)_2催化己内酯开环聚合

(取代 )水杨醛缩合的 Schiff碱作为一种辅助配体广泛用于过渡金属有机化学中 ,如 Salen Al可以催化丙交酯、己内酯等环酯的开环聚合 [1]。近来 ,Grubbs等 [2 ]发现 ,(取代 )水杨醛和芳胺缩合的 Schiff碱后过渡金属 Ni配合物 ,在不加助催化剂的条件下 ,作为单组分催化剂 ,对乙烯等α-烯烃的聚合具有很高的催化活性[2 ] 。虽然类似的 Schiff碱稀土配合物也有一些报道 ,但有关其催化聚合反应性能的研究还很少见 [3]。我们选用 Sm I2 为起始原料 ,合成了 Schiff碱二价 Sm配合物 ,并发现这种配合物对己内酯开环聚合有高催化活性 ,生成聚合物…     

N,N′-双(2-羟基-3-甲氧基-5-甲基苯甲叉基)乙二胺合钴(Ⅱ)类似物的合成及其对氧分子的加合性能

2-羟基-3-甲氧基-5-甲基苯甲醛分别与乙二胺、1,2-丙二胺、1,3-丙二胺、2,3-二甲基-2,3-丁二胺及邻苯二胺反应,合成出一系列二元Schiff碱型化合物.测定Schiff碱与钴(Ⅱ)离子配合后的配合物对氧分子的加合常数,讨论了结构与加合性能之间的关系.配合物中二胺-钴螯合环的刚性对配合物的氧加合性有重要影响.     

大环Schiff碱化合物的合成、表征及其荧光活性研究

含乙酰丙酮类大环Schiff碱化合物一般都具有良好的荧光活性．采用模板合成法,用对苯二胺与乙酰丙酮反应合成得到的Schiff碱配体（H2L）与烷基二胺（即1,2-乙二胺,1,3-丙二胺,1,4-丁二胺）反应合成了3种新型大环Schiff碱化合物,通过元素分析,^1H NMR,IR,MS,UV,摩尔电导等手段对合成得到的化合物进行了组成和结构表征,同时在DMF溶液中对大环Schiff碱锌（Ⅱ）配合物的荧光活性进行了初步研究．     

SiO2负载的Pt-M(M=Cr,Mo,W)配合物双功能催化剂

过渡金属异双核金属有机化合物的研究是一个活跃的领域,人们期望从中制取对极性小分子(如CO,CO2等)具有双功能活化的催化剂.周期表前区过渡金属或稀土元素(如Ti,Zr,Mo,La,Ce等)作为添加组分可明显地增加SiO2负载的铑催化剂催化CO氢化反应的活性和含氧化合物的选择性[1].虽然一些异双核金属氢基羰基化合物已被合成和表征[2],但是关于SiO2负载的异双核金属配合物催化剂的研究还未见文献报道.我们合成、表征了(PPh3)HPt(μ-PPh2)(μ-CO)M(CO)4(M=Cr,Mo,W)异双核配合物[3](I).本文研究了SiO2负载的该配合物催化剂对CO氢化反应和对丙烯氢甲酰化反应的两种催化功能.     

含双水杨醛Schiff碱配体的双核配合物的合成及晶体结构

合成了4个含双水杨醛Schiff碱配体的双核过渡金属配合物,并通过元素分析、红外光谱、紫外光谱,热重分析以及X-射线单晶衍射等手段对所得配合物进行了表征。结果表明,配合物1、3和4都属于三斜晶系,空间群为P1,而配合物2属于单斜晶系,空间群为C2/c。在配合物1中,2个Cu髤离子具有不同的配位构型,其中一个Cu髤形成了五配位的四角锥构型,而另一个Cu髤形成了平面正方形构型。配合物4中,通过酚氧原子的桥联作用,双核单元相互连接形成了一维链状结构。     

Cu(Ⅱ)-VO(Ⅱ)异双核Schiff碱配合物的合成、电化学和磁学性质

Cu(Ⅱ)-VO(Ⅱ)异双核Schiff碱配合物的合成、电化学和磁学性质;循环伏安法     

Analysis and assessment of the occurrence, the fate and the behavior of nanomaterials in the environment

Nanomaterials have one dimension <100 nm and possess physico-chemical properties dictated by their unusually small size, large surface area, shape and chemical composition. New properties of nanomaterials have boosted their production and industrial applications in many fields (e.g., microelectronics, catalysis, fuel cells, materials science, textiles, biotechnology and medicine). In biomedical fields, nanomaterials are of the appropriate dimensions to interact with biological matter. However, they may also have negative effects on biological systems. Nanotechnology is a major, innovative, scientific and economic growth area, but the increasing production and use of nanomaterials have led to calls for more information regarding the potential impacts that their release may have on human health and the environment.This review addresses analytical approaches for characterization and quantification of nanomaterials in the environment and recent studies on their occurrence, fate and behavior.     

New study of the stability and of the spectroscopy of the molecular anions NCO- and CNO-

Using highly correlated wave functions, the ground and the low lying excited states of the molecular NCO(-) and CNO(-) anions have been reinvestigated. The stability of the electronic ground state of the two isomers with respect to dissociation and to electron detachment has been checked along the isomerization pathway. The regions of stability of the excited electronic states have been analyzed and identified and it is shown that only the ground state is stable and the corresponding potential energy surface presents three equilibrium positions. The rovibronic spectroscopy of the X (1)Σ(+) state of both NCO(-) and CNO(-) isomers has been determined by a variational approach leading to remarkable agreement with experimental data.     

McBain and the centenary of the micelle

In 1913, J.W. McBain introduced the word “micelle” into surface and colloid chemistry in the context of the association of surfactant molecules in aqueous solution. This article gives a biographic account of McBain, and reviews the early work on micellar aggregation, leading up to the pioneering ideas of G.S. Hartley who introduced the first model of the spherical micelle that we would recognise today.     

The energy pump and the origin of the non-equilibrium flux of the dynamical systems and the networks

The global stability of dynamical systems and networks is still challenging to study. We developed a landscape and flux framework to explore the global stability. The potential landscape is directly linked to the steady state probability distribution of the non-equilibrium dynamical systems which can be used to study the global stability. The steady state probability flux together with the landscape gradient determines the dynamics of the system. The non-zero probability flux implies the breaking down of the detailed balance which is a quantitative signature of the systems being in non-equilibrium states. We investigated the dynamics of several systems from monostability to limit cycle and explored the microscopic origin of the probability flux. We discovered that the origin of the probability flux is due to the non-equilibrium conditions on the concentrations resulting energy input acting like non-equilibrium pump or battery to the system. Another interesting behavior we uncovered is that the probabilistic flux is closely related to the steady state deterministic chemical flux. For the monostable model of the kinetic cycle, the analytical expression of the probabilistic flux is directly related to the deterministic flux, and the later is directly generated by the chemical potential difference from the adenosine triphosphate (ATP) hydrolysis. For the limit cycle of the reversible Schnakenberg model, we also show that the probabilistic flux is correlated to the chemical driving force, as well as the deterministic effective flux. Furthermore, we study the phase coherence of the stochastic oscillation against the energy pump, and argue that larger non-equilibrium pump results faster flux and higher coherence. This leads to higher robustness of the biological oscillations. We also uncovered how fluctuations influence the coherence of the oscillations in two steps: (1) The mild fluctuations influence the coherence of the system mainly through the probability flux while maintaining the regular landscape topography. (2) The larger fluctuations lead to flat landscape and the complete loss of the stability of the whole system.     

Use of Isotope Effects To Understand the Present and Past of the Atmosphere and Climate and Track the Origin of Life

Stable isotope ratio measurements have been used as a measure of a wide variety of processes, including solar system evolution, geological formational temperatures, tracking of atmospheric gas and aerosol chemical transformation, and is the only means by which past global temperatures may be determined over long time scales. Conventionally, isotope effects derive from differences of isotopically substituted molecules in isotope vibrational energy, bond strength, velocity, gravity, and evaporation/condensation. The variations in isotope ratio, such as ¹⁸O/¹⁶O (δ¹⁸O) and ¹⁷O/¹⁶O (δ¹⁷O) are dependent upon mass differences with δ¹⁷O/δ¹⁸O=0.5, due to the relative mass differences (1 amu vs. 2 amu). Relations that do not follow this are termed mass independent and are the focus of this Minireview. In chemical reactions such as ozone formation, a δ¹⁷O/δ¹⁸O=1 is observed. Physical chemical models capture most parameters but differ in basic approach and are reviewed. The mass independent effect is observed in atmospheric species and used to track their chemistry at the modern and ancient Earth, Mars, and the early solar system (meteorites).     

Isolation and identification of the anti-isohumulones and the anti-acetylhumulinic acids

The anti-isohumulones [5-(3-methylbutanoyl)-2-(3-methylbut-2-enyl)-4-hydroxy-4-(4-methylpent-3-enoyl)-cyclopentane-1,3-diones] and the anti-acetylhumulinic acids [5-(3-methylbutanoyl)-2-(3-methylbut-2-enyl)-4-ethanoyl-4-hydroxy-cyclopentane 1,3-diones] have been isolated from an isomerisation reaction mixture of humulone [2-(3-methylbutanoyl)-4,6-di(3-methylbut-2-enyl)-6-hydroxy-cyclohexane-l,3,5-trione] by counter-current distribution and identified by spectroscopic techniques. The formation mechanism is presented and the stereochemical consequences are discussed. The anti-isohumulones are the most bitter hop compounds presently known.     

Decorating step-by-step and independently the surface and the core of dendrons

Dendrons possessing one activated vinyl group at the core and several chlorine atoms at the end of the branches are used as starting materials to study the possibility to react independently the surface functions and the core function. In particular, the most powerful sequence of reactions for decorating them by organometallic complexes as end groups and amine or alcohol at the core has been determined. In the first step, phenol phosphines are grafted as end groups of the dendrons, and they can be used for the complexation of metals. However, these phosphines must be kept free when amines are used to react with the vinyl core in the next step. Depending on the type of phosphine end groups and on the type of function of the core (amine or alcohol), the complexation of ruthenium ([RuCl₂(p-cymene)]₂) and rhodium ([RhCl(COD)]₂) derivatives by the phosphine end groups can occur without side reaction at the core.     

Influence of the molecular structure and the nature of the solvent on the absorption and fluorescence characteristics of rhodamines

A study of the equilibrium of the molecular forms of rhodamine 19 in aqueous and ethanolic solution is carried out by determining the absorption and fluorescence characteristics of the zwitterionic and the cationic forms of the dye. The optical properties of rhodamine 19 are compared with those obtained for rhodamine 6G and also with those previously reported for rhodamine 3B and for the molecular forms of rhodamine B in water and ethanol. Different aspects of the molecular structure of the rhodamines and solvent effects are discussed, as well as their influence on the photophysical properties of the rhodamines. The aggregation of the molecular forms of rhodamine 19 is also studied in water and ethanol.