Silver Nanoparticles in Polyacrylamide and Hyperbranched Polyamine Matrix

Silver nanoparticles have been prepared in a polyacrylamide (PA) matrix, as well as in the presence of a hyperbranched polyamine/polyacrylamide combined system (HB‐PA) by using a reductive technique. The stability of colloidal solution of silver nanoparticles is higher (5 months) in combined matrix compared to PA alone (4 months). The prepared silver nanoparticles were characterized by different spectroscopic and analytical techniques such as FTIR, UV‐visible, X‐ray diffraction, TEM etc. TEM and XRD studies confirmed the formation of well‐dispersed nanoparticles with an average size of 9.91 nm and 8.5 nm for PA and HB‐PA matrices, respectively. The antibacterial activity of silver nanoparticles in both the matrices was tested against Bacillus Subtilis bacteria by using the diffusion disc technique. The result shows that the antibacterial activity of the active agent, Ag(0) is a little higher in the case of HB‐PA system. The dielectric constant of the matrices decreases with an increase in frequency, but the values increase with an increase of concentration of silver nanoparticles in PA matrix.     

Identification of mechanisms of toxic action for skin sensitisation using a SMARTS pattern based approach

Skin sensitisation is a key endpoint under REACH as it is costly and its assessment currently has a high dependency on animal testing. In order to reduce both the cost and the numbers of animals tested, it is likely that (quantitative) structure–activity relationships ((Q)SAR) and read-across methods will be utilised as part of intelligent testing strategies. The majority of skin sensitisers elicit their effect via covalent bond formation with skin proteins. These reactions have been understood in terms of well defined nucleophilic–electrophilic reaction chemistry. Thus, a first step in (Q)SAR analysis is the assignment of a chemical's potential mechanism of action enabling it to be placed in an appropriate reactivity domain. The aim of this study was to design a series of SMARTS patterns capable of defining these reactivity domains. This was carried out using a large database of local lymph node assay (LLNA) results that had had potential mechanisms of action assigned to them using expert knowledge. A simple algorithm was written enabling the SMARTS patterns to be used to screen a database of SMILES strings. The SMARTS patterns were then evaluated using a second, smaller, test set of LLNA results which had also had potential mechanisms of action assigned by experts. The results showed that the SMARTS patterns provided an excellent method of identifying potential electrophilic mechanisms. The findings are supported, in part, by molecular orbital calculations which confirm assignment of reactive mechanism of action. The ability to define a chemical's potential reaction mechanism is likely to be of significant benefit to regulators and risk assessors as it enables category formation and subsequent read-across to be performed.     

含取代基苯基羧酸与柔性含氮配体构筑的三个过渡配位化合物的合成、晶体结构与物理性质

利用3,5-二硝基苯甲酸（3,5-DNBH）,1,2-双咪唑亚甲苯（1,2-bimb）与3种过渡金属盐通过水热反应成功地构筑3个过渡金属配位化合物,即[M（3,5-DNB）₂（1,2-bimb）]（M=Co（Ⅱ） （1）,Cd（Ⅱ）（3））和[Zn（3,5-DNB）₂（1,2-bimb）]_n （2）。通过红外光谱、元素分析、单晶和粉末X射线衍射表征了这三个化合物。化合物1和3是同构的,含有一个双核单元[M₂（COO）₂],该双核单元由金属离子、3,5-二硝基苯甲酸根以及1,2-bimb分子构成。双核单元再通过O…π弱相互作用形成超分子结构,该弱相互作用是通过3,5-二硝基苯甲酸根上的硝基氧原子与1,2-bimb上的苯环所形成。化合物2是一维链结构,链与链之间再通过3,5-二硝基苯甲酸根和1,2-双咪唑亚甲苯配体上苯环之间的π…π相互作用,形成了一个超分子结构。室温条件下研究了化合物2和3分散在甲醇中的荧光性质。热重测试结果显示3个化合物具有相对较高的热稳定性。可见光照射条件下化合物1对罗丹明B具有一定的催化降解能力。此外,直流磁化率结果显示化合物1中金属离子之间存在反铁磁相互作用。     

4,4'-联吡啶桥联的三个铜有机膦酸配合物的合成、结构及磁性

在水热条件下,以N-氧化-2-吡啶膦酸（H2L）为主配体,4,4＇-联吡啶（bpy）为桥联配体,合成了3个铜有机膦酸配合物： {[CuL（bpy）0.5（H₂O）]·2H₂O}_n（1）, {[Cu（HL）₂（bpy）]·4H₂O}_n（2）和{[Cu₂（L）₂（bpy）]·3H₂O}_n（3）。配合物1中,相邻的铜离子由2个膦酸根连成二聚体,二聚体之间通过bpy桥联成一维链。配合物2中,单核[Cu（HL）₂]被bpy连接成一维链。配合物3中,四聚体[Cu₂（L）₂]₂被bpy连接成“砖块状”结构的二维层。磁性研究表明,配合物1和3中铜离子之间存在反铁磁性耦合。     

炔桥联不对称苯基取代双二茂铁衍生物的设计合成和电化学性质

以四苯基环戊二烯酮为起始原料,经过八步连续反应,成功地合成了3个炔桥联不对称五苯基取代双二茂铁衍生物Fc''-C≡C-Fc（1）、Fc''-C≡C-C≡C-Fc（2）和Fc''-C≡C-C≡C-Fc''（3）（Fc''=五苯基二茂铁基,Fc=二茂铁基）。在设计合成双二茂铁衍生物的过程中,首先经过4步反应,制备出已知化合物Fc''-H（4）,再连续进行3步反应,分别得到3个中间化合物Fc''-COCH₃（5）,Fc''-CCl=CHCHO（6）和Fc''-C≡CH（7）,最后利用偶联反应,得到目标化合物1~3。利用X射线单晶衍射和循环伏安法,测定了化合物1、2和5、7的晶体结构,研究了化合物1~7的电化学性质。研究结果表明,分子的C-H…π键相互作用和空间位阻是导致化合物1和2分子中Fc''和Fc基空间排布取向不同的主要原因。当二茂铁的一个环戊二烯环上引入5个苯取代基时,铁中心的氧化还原电位将升高（E_p^a（Fc''-H）=0.658 V,E_p^a（Fc-H）=0.511 V）。与已知化合物Fc-C≡C-Fc（ΔE=0.215 V）和Fc-C≡C-C≡C-Fc（ΔE=0.134 V）相比,化合物1~3的氧化电位差值（ΔE）均有不同程度地提高（ΔE₁=0.236 V;ΔE₂=0.170 V;ΔE₃=0.146 V）。将1与Fc-C≡C-Fc,2与Fc-C≡C-C≡C-Fc和3进行比较发现,当炔桥两端连接不同的基团Fc''和Fc时,其氧化电位差值（ΔE）将明显提高。     

5-异烟酰胺异钛酸构筑的Cu(Ⅰ)-Eu和Ni(Ⅱ)-Eu化合物的合成、晶体结构和性质研究

利用不同过渡金属盐在溶剂热中合成了2个新型杂核化合物{[CuEu₂（INAIP）₃（HCOO）（H₂O）₃]·3H₂O}_n（1）和{[NiEu₂（INAIP）₄（H₂O）₄]·4H₂O}_n（2）（INAIP=异烟酰胺吡啶基异酞酸根）,并对其进行了元素分析、IR及X-射线衍射法表征。晶体结构研究表明：配合物1和2都属于三斜晶系,P1空间群。晶胞参数：配合物1a=1.0887（3）nm,b=1.5158（4）nm,c=1.5644（2）nm,V=2.3332（10）nm³,Z=2,D_c=1.955g·cm^-3,μ=3.203mm^-1,F（000）=1352,R_int=0.027,R₁=0.0505,wR₂=0.1309。配合物2a=1.0134（3）nm,b=1.0836（6）nm,c=1.3741（2）nm,V=1.4530（9）nm³,Z=1,D_c=1.878g·cm^-3,μ=2.554mm^-1,F（000）=818,R_int=0.0458,R₁=0.0341,wR₂=0.0869。配合物1是由配体异烟酰胺吡啶基异酞酸连接而成的三维二重贯穿sqc27拓扑结构,而配合物2是由配体异烟酰胺吡啶基异酞酸连接稀土铕离子形成二维层状结构,该二维层通过Ni-O和Ni-N键连接成三维非贯穿网络结构。配合物1和2具有典型的稀土铕离子红色荧光和高的热稳定性。     

含三乙醇胺及硫氰酸根的混价七核锰配合物{K[MnⅡMn6Ⅲ(teaH)3(tea)3(NCS)6]}n的合成、结构和磁性研究

采用MnCl2(或Mn(NO3)2)与teaH3和KSCN混合配体合成了1个七核锰配合物{K[MnⅡMnⅢ6(teaH)3(tea)3(NCS)6]}n(1)(teaH3=三乙醇胺),通过元素分析和红外光谱对其进行了表征,并通过X-单晶衍射确定了其晶体结构。1的阴离子由外围6个锰髥与1个中心Mn髤通过6个μ3-O键连接成1个类似车轮的环状结构。直流磁化率研究结果表明,该配合物具有较高的自旋基态(S=29/2),其磁性行为说明在高自旋的Mn髤和Mn髥之间存在铁磁性相互作用。