3~A’ and 3~A” Energy Surfaces for the VS~ CO_2 →VO~ COS Reaction

The title reaction proceeds via a one- and two-step mechanism along the 3A" and 3A’ surfaces, respectively. The 3A’ excited state surface has a lower barrier than the 3A" ground state surface (11.6 and 16.0 kcal/mol, respectively). We suggest that, at low energies, the reaction proceeds along the A’ surface and then makes an intersystem crossing to the A" surface and yields the ground state product VO (3∑-), which may explain the small VO cross-section at low energies observed in the experiment     

QSAR Studies on 7-Substituted Fluoroquinolones

1 INTRODUCTION Fluoroquionlones are potent antibacterials with a broad spectrum of activities against gram-positive and gram-negative organisims and mycobacteria by inhibiting bacterial topoisomerase II(DNA gyra- se)[1].These compounds have been successfully used in clinic for a decade and its market has risen in recent years only a little less than that of penicillins and macrolides[2]. The fluoroquinolones constitute a class of extremely potent and orally active broad spectrum antibact…     

零流电位法考察聚苯胺膜的pH响应性质

将经电化学聚合的聚苯胺膜修饰的铅笔芯电极连接于一种新型电化学检测系统中,采用零流电位法考察了聚苯胺膜的pH响应性质。结果表明:试验制得的聚苯胺膜主要以中间氧化态形态存在,在B-R缓冲溶液中pH可控的质子化和去质子化形态转换,导致零流电位E_(ZCP)-pH曲线呈现两段相交的线性关系,其pH范围分别为pH 1.81～5.43及pH 5.43～9.91,两直线的交叉点在pH 5.43处,由此求得中间氧化态的pK_a值为5.43。     

三种碳基电极材料的电化学性质对比研究(英文)

对硼掺杂纳米金刚石(BDND),硼掺杂微米金刚石(BDMD)和玻碳(GC)电极的电化学性质做了对比研究.利用扫描电子显微镜表征了BDMD和BDND电极,其表面粒子大小分别为1-5μm和20-100nm.利用Raman光谱对两种金刚石薄膜的成分进行了表征,结果表明利用热丝化学气相沉积法得到了高质量的BDND和BDMD薄膜.采用0.5mol·L-1H2SO4溶液测定了三种电极的电化学窗口,BDND和BDMD电极的电化学窗口分别为3.3和3.0V,远比GC电极(2.5V)的要宽.[Fe(CN)6]3-/[Fe(CN)6]4-溶液的循环伏安和交流阻抗测定表明,在BDND、BDMD和GC电极上的峰间距(△Ep)分别为73、92和112mV,且其电子传递电阻(Ret)分别为(98±5)、(260±19)和(400±25)Ω.我们也研究了0.1mmol·L-1双酚A在三种电极上的电化学氧化行为.上述的电化学测定结果表明,两种金刚石电极均比GC电极表现出了更宽的电化学窗口、更好的电化学可逆性质、更快的电子传递速度和更高的电化学稳定性,更为重要的是与BDMD相比BDND的电化学性质有进一步的提高.     

吡嗪四甲酸构筑的一维链状锰配位聚合物的合成、晶体结构及磁性研究

MnCl2.4H2O与吡嗪-2,3,5,6-四甲酸(H4pztc),1,10-邻菲罗啉(phen)通过水热反应合成了1个Mn的配位聚合物{[Mn2(phen)2(H2pztc)Mn2(phen)2(Hpztc)2(H2O)2].4H2O}n(1),并对配合物进行了IR、元素分析、X-射线单晶结构解析及磁性分析等表征。配合物1属于三斜晶系,P1空间群,a=0.955 02(19)nm,b=1.323 4(3)nm,c=1.515 7(3)nm,α=68.95(3)°,β=77.33(3)°,γ=81.92(3)°,V=1.740 3(6)nm3,Z=2。配合物中Mn(Ⅱ)离子为六配位和七配位,通过配体pztc与phen的连接形成一维链状结构。变温磁化率测试结果表明,在配合物1中,Mn(Ⅱ)离子之间存在反铁磁相互作用。