铬的形态分析研究与进展

综述了Cr(Ⅲ)、Cr(Ⅵ)形态分析的发展。内容包括概述、样品分离富集、光谱分析、色谱分析等。引用文献43篇。     

Characterization of low molecular weight components of [(ViMe2SiO1/2)x(PhSiO3/2)y(SiO4/2)z], [(ViMe2SiO1/2)x(SiO4/2)y], and [(SiO4/2)x(HO1/2)y(tBuO1/2)z] silsesquioxanes by electrospray ionization fourier transform mass spectrometry (ESI-FTMS)

This paper describes the characterization of low molecular weight components of four materials using electrospray ionization Fourier transform mass spectrometry (ESI-FTMS). The materials in the current study are [(ViMe₂SiO_1/2)_x(PhSiO_3/2)_y(SiO_4/2)_z] (MTQ), [(ViMe₂SiO_1/2)_x(SiO_4/2)_y] (MQ), and [(SiO_4/2)_x(HO_1/2)_y(^tBuO_1/2)_z] (Q) silsesquioxanes. Accurate mass measurements coupled with knowledge of resin chemistry afforded siloxane composition determination that was used to propose specific structures for the oligomers. Branched or linear (T_nQ_mM_n+2m+2), and monocyclic (T_nQ_mM_n+2m) structures are predominant structures for the low molecular weight species in MTQ. For MQ and Q, more condensed structures, such as partially opened cage structures (Q_mM_2m?6 and Q_mM_2m?8), were identified. The differences between MQ, Q, and MTQ are likely attributed to differences in intrinsic structure and reactivity of T and Q building blocks. The structural information obtained for these oligomeric species will ultimately provide a better understanding of new resin materials and their associated physical properties.     

A semi-rigid bis(imidazolyl) ligand for the construction of nanoscopic supramolecules. From the molecular rectangle to the 1D coordination polymer

Reaction of the semi-rigid ligand 2,4-bis(1-imidazolylmethyl)-mesitylene (m-bimms) with CdCl₂ afforded a boat-like molecular rectangle [Cd(m-bimms)Cl₂]₂ · 1/2H₂O (1), with the orientation of the two imidazolyl arms of the ligand in syn-conformation and bridging chloride ions bisecting the macrocycle. Weak Cl· · ·H—C interations further extended the dimers into 1D infinite chains with nanoscopic channels. An analogous reaction with Cd(NO₃)₂ gave a 1D coordination polymer [Cd(m-bimms)₂(NO₃)₂]_n · 2nH₂O (2) composed of nanoscopic metallamacrocycles, where the two imidazolyl arms adopt an anti-conformation. Different anions result in different ligand conformations and thus determine the varied molecular architectures.     

Photopolymerization induced by a benzophenone derivative photoinitiator

A benzophenone derivative photoinitiator, HBP-TDI-HQ-TDI-HBP （HTCTH）, was synthesized based on 4-hydroxy benzophenone （HBP）, toluene-2,4-diisocyanate （TDI） and hydroquinone （HQ）. HTCTH was a more effective photoinitiator which had longer wavelength absorption in the UV-vis absorption spectra than the low molecular counterpart benzophenone （BP）. It showed that both rate of polymerization （Rp） and final conversion （P） increased with increase of amine and HTCTH concentration in photopolymerization.     

含氮宾或卡宾的金属羰基簇合物的结构化学研究——Ⅰ.H_2Fe_3(N-C_6H_5)(CO)_9和Fe_3(N-C_6H_5)(μ_3-CO)(CO)_9的合成和结构

含氮宾的两个三核羰基铁簇合物是由[Et_3NH][HFe_3(CO)_(11)]与C_6H_5NCO在苯中反应获得。应用四园衍射仪测定了H_2Fe_3(N-C_6H_5)(CO)_9(Ⅰ)和Fe_3(N-C_6H_5)(μ_3-CO)(CO)_9(Ⅱ)的晶体结构。晶体数据为:C_(15)H_7NO_9Fe_3(Ⅰ),空间群P2_1/a,a=18.343(2),b=9.072(1),c=11.451(1)(?),β=102.03(1)°,V=1863.7(?)~3,Z=4,D_c=2.143g/cm~3;C_(16)H_5NO_(10)Fe_3(Ⅱ),空间群P2_1/c,a=8.634(1),b=13.026(1),c=17.642(2)(?),β=97.68(1)°,V=1966.3(?)~3,Z=4,D_c=1.820g/cm结构系用直接法解出,最后R_(Ⅰ)因子为0.033,R_(Ⅱ)因子为0.027。测定结果表明,(Ⅰ)和(Ⅱ)分子均具有C_s对称性,且三个Fe原子共面,呈近似等边三角形结构。(Ⅰ)中面桥N原子以不对称方式与三个Fe原子成键;(Ⅱ)中面桥羰基以不对称方式与三个Fe原子键连。Fe-N和Fe-C键长分别在1.896-1.938(?)和2.006-2.110(?)之间。     

Study on structural variation of silica gel using Nd3+ as a probe by photoacoustic spectroscopy

The structural variations of silica gels heated at different temperatures have been firstly studied using Nd(3+) as a probe by photoacoustic spectroscopy (PAS), together with IR spectroscopy and thermal analysis. With increasing temperature, the f-f transitions of Nd(3+) show a red shift and the PA intensities increase. The PA branching vector of the transitions from ground state to 4G(5/2)+(2)G(7/2), which are hypersensitive transitions, increase and the others decrease or change little. These indicate that the covalency of the bond that Nd(3+) forms increases and the symmetry around Nd(3+) decreases, which reflects the structural variations of silica gels.     

Determination of Organophosphorus Pesticides in Soil by MMSPD-GC-NPD and Confirmation by GC-MS

A novel method, modified matrix solid-phase dispersion (MMSPD), has been developed for quantitative analysis of organophosphorus pesticide residues in soil. It was based on matrix solid-phase dispersion (MSPD) and continuous liquid-solid extraction (continuous LSE), using Florisil as sorbent and dichloromethane as the recycling solvent. Two soils with different texture and physicochemical properties were studied to validate the method. The effect of residence time of pesticides in soil was also studied. MMSPD was compared with MSPD and continuous LSE respectively. Determination was carried out by gas chromatography with nitrogen-phosphorus detection (GC-NPD). The method gave recoveries ranging from 72–105% with relative standard deviations (RSDs) lower than 15% for the pesticides studied. The limits of detection (LODs) ranged from 0.1 to 0.6 ng g⁻¹. Two pesticide residues have been detected in real soil samples from Fujian, China, using MMSPD. The pesticides were confirmed by gas chromatography-mass spectrometry (GC-MS) in a selected-ion monitoring (SIM) mode. Revised: 4 and 9 April 2006     

二苄亚砜硝酸钕的晶体结构

二苄亚砜硝酸钕Nd(NO_3)_3·[(C_6H_5CH_2)_2S0]属三斜晶系,P1空间群,晶胞参数:a=9.835(2),b=12.445(2),c=19.971(5)A,α=104.13(2)°,β=90.34(2)°γ=74.96(1)°Z=2。晶体结构用重原子法解出,经最小二乘修正后R因子为0.031。钕离子由九个氧配位,形成稍歪扭的三帽三方棱柱配位多面体,其中一个三角面由三个二苄亚砜(DBSO)提供的氧形成,其他氧原子则由硝酸根提供。平均Nd-O(DBSO)=2.379A,Nd-O(NO_3)=2.536A。     

CICOCO自由基的研究

就我们所知，CICOCO自由基尚未被研究．本文报导了对它的构型、能量和振动频率进行的。b响计加计算，以及在红外光谱实验中观察到的该自由基的振动光谱．1理论计算以（CICO）。分子平衡构型的各种键长、键角为初始值，并且不再限制CICOC（）自由基具有平面对称性，在UHF／6－31     

化学复合镀Ni-P-PTFE镀层的组成分析

近年来化学复合镀技术在工业中应用日益广泛 ,本文运用ＳＥＭ、ＡＥＳ和ＸＰＳ等手段对用化学复合镀制得的Ｎｉ Ｐ ＰＴＦＥ镀层的结构和组分进行了分析 ,并就其耐腐蚀性能与前期得到的Ｎｉ Ｓｎ Ｐ[1 ] 、Ｃｕ Ｓｎ Ｐ[2 ] 、Ｎｉ Ｐ ＣｅＯ2 [3] 、Ｎｉ Ｐ ＳｉＯ2 [4] 镀层进行了比较 ,结果表明 :含量一定的ＰＴＦＥ(聚四氟乙烯 )的共存增强镀层的耐腐蚀性及镀层表面的润滑性。1　实验部分1 1　仪器日产Ｄ/ＭＡＸⅢＡ型Ｘ 射线衍射仪 ,铜靶 ,管压 2 5ｋＶ ,电流 1 0ｍＡ。国产ＪＪＣ 1型润滑湿角测量仪。美国ＰＥＲＫＩＮ ＥＬＭＥＲＰ…