多溴联苯醚理化性质的定量构效关系

为研究多溴联苯醚(PBDEs)理化性质,提出其分子中顶点原子(基团)特征值(δi)新的计算方法,并在修正的距离矩阵基础上构建了拓扑距离特征定位指数(T);采用文献程序软件和Gaussian 03程序软件分别计算,得到其分子电性距离矢量(Mt)和多种量子化学参数。用最佳变量子集回归方法建立了相关参数与PBDEs的色谱保留时间(RRT)、正辛醇/空气分配系数(lgKOA)和298 K超冷流体蒸气压(lgPL)的3个定量构效关系模型。模型复相关系数(R)分别为0.9953、0.9983和0.9982,逐一剔除法交叉验证相关系数(Q)分别为0.9948、0.9975和0.9975,标准偏差(SD)分别为0.0222、0.0754和0.0868,均优于前人的工作。研究结果表明,所建模型具有良好的稳健性和预测能力,拓扑距离特征定位指数对PBDEs性质的表征是有效的。     

金莲花挥发性组分色谱保留值的构效关系研究

为了研究金莲花挥发性组分的色谱保留性质,基于分子价连接性指数(mXtV)和原子类型电性拓扑状态指数(Ek),构建金莲花挥发性组分分子结构与色谱保留时间的定量构效关系模型,其多元线性回归方程的相关系数为0.987,并用Jackknife法对模型的稳健性进行检验,其相关系数均在0.985~0.989之间,具有高度的稳健性和良好的预测能力,有效地揭示了影响金莲花挥发性组分色谱保留时间的本质因素。     

多溴联苯醚理化性质的定量构效关系

为研究多溴联苯醚（PBDEs）理化性质,提出其分子中顶点原子（基团）特征值（δ_i）新的计算方法,并在修正的距离矩阵基础上构建了拓扑距离特征定位指数（T）;采用文献程序软件和Gaussian 03程序软件分别计算,得到其分子电性距离矢量（M_t）和多种量子化学参数。用最佳变量子集回归方法建立了相关参数与PBDEs的色谱保留时间（RRT）、正辛醇/空气分配系数（lgK_OA）和298 K超冷流体蒸气压（lgP_L）的3个定量构效关系模型。模型复相关系数（R）分别为0.9953、0.9983和0.9982,逐一剔除法交叉验证相关系数（Q）分别为0.9948、0.9975和0.9975,标准偏差（SD）分别为0.0222、0.0754和0.0868,均优于前人的工作。研究结果表明,所建模型具有良好的稳健性和预测能力,拓扑距离特征定位指数对PBDEs性质的表征是有效的。     

硅烷偶联剂折光率的全息定量构效关系研究

建立了85个硅烷偶联剂折光率的全息定量构效关系(HQSAR)模型。当设置参数fragment distinction为“A、B、C、H、DA”、fragment size为“4～7”、holograms length为“151”时可建立最优HQSAR模型。采用外部测试集验证和留一交叉验证两种方法评估了模型的预测能力和稳健性。外部测试集验证的RMSRE、RMSEP、Q²_F3、CCC分别为0.916、0.013、0.924、0.936，留一交叉验证的RMSRE、RMSECV、q²_cv和R²分别为1.364、0.020、0.659和0.829。验证结果表明建立的HQSAR模型稳健可靠，可用于预测硅烷偶联剂的折光率。此外，通过所得HQSAR模型的分子贡献图可知，硅烷偶联剂中苯基和氧原子上长链烷基的存在会提高折光率。     

抗糖尿病新药熔点的定量构效关系研究

为了研究新的抗糖尿病药物的构效关系,定义并计算了多取代香豆素磺酰脲类化合物的原子特征值iδ,利用量子化学计算方法构建了新的拓扑指数T和基团参数N,基于多元回归技术研究了对这种降血糖药物的熔点作出精确估算的定量构效关系,得到的二元回归方程为:mp=-6.393 1T 107.425 7N 260.080 9,T和N不仅对这些化合物具有较好的结构选择性,而且与其熔点具有较好的相关性。为了检验模型的稳健性和预测能力,还进行了留一法交互校验。     

多氯联苯热力学性质的构效关系

通过计算二噁英类化合物多氯联苯（PCBs）217种分子的定位指数和基团对应指数，以这些分子的热力学性质的文献值为建模样本，运用多元线性回归方法建立了多氯联苯的标准熵（S0）、标准焓（H0）、标准自由能（G0）、分子总能量（ET）、热能校正值（Eth）、零点振动能（Ezpv）及恒容热容（Cv0）等热力学性质的定量结构-性质相关方程，相关系数均在0.99以上。这些模型能较好地解释多氯联苯热力学性质的递变规律，而且相关系数高，稳定性好，预测能力强。采用留一法对模型稳健性进行了检验，得到的预测模型对另外一些多氯联苯分子的热力学性质进行预测，预测结果和文献值基本吻合。     

非离子表面活性剂构效关系的研究

使用量子化学及拓扑指数等描述符,建立了非离子表面活性剂浊点的定量结构性质关系模型(QSPR).这些描述符包括相对氧原子数RnO、最高占有轨道能量EHOMO、最低空轨道能量ELUMO、O阶Kier & Hall指数KHO、价连接性指数oJ和价键连通性指数Xo.最佳模型包括4类不同结构的直链烷基聚氧乙烯醚、烷基酚聚氧乙烯醚、十二烷基聚氧乙烯聚氧丙烯醚和支链烷基聚氧乙烯醚等65种非离子表面活性剂,复相关系数R2=0.962,与现有的模型相比,精度有了很大的提高,而且应用范围也更广.     

卤代苯对呆头鱼、发光菌急性毒性的构效关系研究

基于分子拓扑邻接矩阵,计算了11种卤代苯的分子形状指数（K_m）。通过最佳变量子集回归方法,建立了11种上述化合物对发光菌和呆头鱼等急性毒性(pC₅₀:pEC₅₀,pLC₅₀)的QSAR模型。对于发光菌的pEC₅₀模型的判定系数（R²）和校正判定系数R_adj²依次为0.884和0.855,相应呆头鱼pLC₅₀模型为0.897和0.871。经R²,R_adj²等检验,上述模型具有令人满意的稳健性和预测能力。     

高聚物分子定量构效关系的研究与进展

综述了国内外研究高聚物分子定量构效关系(QSAR)的发展;介绍了研究分子定量构效的3种数学模型的统计方法:逐步多元回归分析法、人工神经网法和偏最小二乘法;重点介绍了多维定量构效关系,同时简要介绍了分子等值面图以及QSAR/QSPR在研究表面活性剂中的应用;最后展望了分子构效的应用前景。     

定量构效关系在化合物性质研究中的应用

概述了定量构效关系（QSPR/QSAR）的基本原理以及定量构效关系在化合物性质研究中的应用,重点介绍了定量构效关系在化合物毒性、水溶性和LogPow等方面的应用。     

A computational toolbox for molecular property prediction based on quantum mechanics and quantitative structure-property relationship

Chemical industry is always seeking opportunities to efficiently and economically convert raw materials to commodity chemicals and higher value-added chemicalbased products.The life cycles of chemical products involve the procedures of conceptual product designs,experimental investigations,sustainable manufactures through appropriate chemical processes and waste disposals.During these periods,one of the most important keys is the molecular property prediction models associating molecular structures with product properties.In this paper,a framework combining quantum mechanics and quantitative structure-property relationship is established for fast molecular property predictions,such as activity coefficient,and so forth.The workflow of framework consists of three steps.In the first step,a database is created for collections of basic molecular information;in the second step,quantum mechanics-based calculations are performed to predict quantum mechanics-based/derived molecular properties(pseudo experimental data),which are stored in a database and further provided for the developments of quantitative structure-property relationship methods for fast predictions of properties in the third step.The whole framework has been carried out within a molecular property prediction toolbox.Two case studies highlighting different aspects of the toolbox involving the predictions of heats of reaction and solid-liquid phase equilibriums are presented.     

量子拓扑指数法预测多氯联苯醚的热力学性质

应用密度泛函理论(DFT),在B3LYP/6-31+G(d)基组上优化和振动分析计算了多氯联苯醚（PCDEs）所有209种可能的分子空间几何结构,得到其各原子之间空间拓扑距离,并建立拓扑空间距离矩阵。结合分子中各原子的支化度,应用原子的平衡电负性对分子图进行着色,得到量子拓扑指数PX₁、PX₂。采用多元线性回归技术建立联苯醚和209种可能结构的多氯联苯醚PCDEs 3种少见报道的热力学性质--标准生成热、标准生成自由能和相对自由能与PX₁、PX₂的定量关系拓扑模型,并用该模型分别对不同热力学性质进行预测与估算。结果表     

固体核磁共振在膦酸基质子交换膜中的应用

综述了固体核磁共振(NMR)技术的特点及其在燃料电池用膦酸基质子交换膜分析研究中的应用,重点介绍了运用¹H、³¹P、²⁹Si固体NMR以及¹H、³¹P变温固体NMR技术表征膦酸基质子交换膜的化学结构、氢键网络和质子传导机理等方面的研究进展。该综述表明固体NMR技术是一种研究膦酸基质子交换膜中氢键网络以及局部质子移动性的有效手段,并能进一步探索其质子传导的机理,为固体NMR技术在其他类型质子交换膜研究中的应用给予借鉴,为质子交换膜结构的表征提供一种新的方法。     

SOLVATION EFFECTS IN CATALYTIC TRANSFORMATIONS OF OLEFINS IN SULFURIC ACID

Analysis of literature and ab initio quantum chemical calculations indicate that the properties of anhydrous H₂SO₄ as a superacid are determined not by the extent of dissociation of this acid but by the unusually high chemical activity of the weakly solvated protons. In a similar way, the selectivity of the acid-catalyzed transformations of olefins is also determined by solvation of the active intermediates. Depending on the concentration of sulfuric acid, the properties of the active species are changing from almost free carbenium ions in the anhydrous acid to the hydrated oxonium ions in the moderately dilute sulfuric acid. In the later case, similar to zeolites, the carbenium-ion-like alkyl species are formed only as transition states. The subsequent hydrolysis of oxonium ions upon stronger dilution of the acid results in the formation of alcohols. These conclusions are supported by ab initio quantum chemical calculations and by in situ ¹³C-NMR of protonated active intermediates.     

跨尺度方法研究聚合物载药胶束的定量构性关系

以两亲性聚合物自组装载药胶束为案例, 基于宏观到微观的跨尺度方法研究化学产品的定量构性关系(QSPR), 提出嵌段单元自相关方法计算表征两亲性聚合物结构的描述符, 结合遗传函数算法和多元线性回归建立了不同药物/聚合物配比下聚合物胶束载药量的QSPR预测模型, 经内部验证(R²>0.854, Q_loo-cv²>0.651, RMSE<0.089)、Y-随机化检验和外部验证(Q_ext²>0.629), 以及应用域定义分析评估了模型的可靠性、稳定性和预测能力。通过对描述符的分析和载药机制解释, 很好地阐释了聚合物嵌段单元和聚合物拓扑结构对胶束载药量的影响。QSPR模型的建立将指导新聚合物及其载药胶束体系的设计, 并预测其载药能力, 这种跨尺度研究方法有望促进复杂结构化产品的设计和开发。     

Modification of vanadium phosphorus oxides used for n-butane oxidation to maleic anhydride by interaction with niobium phosphate

A new family of vanadium phosphorus oxides (VPO) catalysts has been identified. It consists in a mixture of VPO with niobium phosphate (NbPO). The amorphous NbPO material is introduced during the preparation of the VOHPO₄·0.5H₂O precursor. It is observed that the VPO–NbPO catalyst is more rapidly activated and gives better performances (n-butane conversion and maleic anhydride selectivity) for mild oxidation of n-butane to maleic anhydride. VPO phases and the NbPO material have been identified in the VPO–NbPO precursor and in the VPO–NbPO catalyst. Nb in VPO crystals and V in NbPO particles have been respectively observed by EDX-STEM. No other VPO crystals than the VOHPO₄, 0.5H₂O precursor, and (VO)₂P₂O₇ for the catalyst, have been identified by XRD and ³¹P NMR. ³¹P NMR by spin echo mapping and ³¹P MAS NMR have confirmed an interaction of the VPO precursor with Nb and of the NbPO amorphous material with V, as evidenced by EDX-STEM. This should be the reason for the observed improvement of the catalytic results by a redox effect of niobium on the VPO catalyst modifying the V⁵⁺/V⁴⁺ balance in a favourable way.     

磷改性ZSM-5分子筛在甲醇制芳烃反应中催化性能的固体核磁研究

甲醇制芳烃反应在化工领域具有重要的现实意义，ZSM-5分子筛是这一反应的优良催化剂，磷改性是提高ZSM-5分子筛催化性能的常见方法。利用固体核磁共振技术对改性催化剂进行1H、27Al和31P表征，结合催化考评结果，推测或论证影响催化活性的因素，对反应条件的优化提出有益的帮助和支持。     

Study of Mn incorporation into SAPO framework: Synthesis, characterization and catalysis in chloromethane conversion to light olefins

MnAPSO-34 molecular sieve has been synthesized with triethylamine as the template, characterized with XRD, XRF, ³¹P, ²⁷Al and ²⁹Si NMR and FT-IR techniques and compared with SAPO-34. The template decomposition and removal have been investigated with TG–DTG–DSC coupled with mass spectrometer. Mn incorporation generates a negligible difference on the chemical shift in ³¹P and ²⁷Al MAS NMR, while an effect on the intensity of resonance peaks is revealed. ²⁹Si MAS NMR study has demonstrated that Mn incorporation favors the Si island formation, which may give rise to the stronger acidic sites. The thermal analysis (TG–DSC) on template removal in a diluted oxygen atmosphere, leading to the formation of CO₂, NO and H₂O, showed, besides a low temperature endothermic weight loss due to the desorption of water, two weight losses (200–400 and 400–600 °C) for SAPO-34 and MnAPSO-34, suggesting two different chemical location environments of template molecules in these two molecular sieves. The quantity of template removed at higher temperature range is much higher in MnAPSO-34, indicating stronger template–framework interaction and stronger acidity after calcination. The acid difference caused by Mn incorporation has also been evidenced by ammonia adsorption evaluated by FT-IR. Chloromethane transformation was carried out over MnAPSO-34 and SAPO-34 and the catalytic performance showed that both molecular sieves are very active and selective catalyst for light olefins production. MnAPSO-34 demonstrated higher activity and light olefins selectivity.