新型含2-噁唑啉基三角架配体-银(I)一维配位聚合物的合成与结构

通过含2-噁唑啉基三角架配体1,3,5-三(2-噁唑啉基)苯(L)与三氟醋酸银反应合成了配合物[Ag₄(L)₂(CH₃CN)₂(CF₃CO₂)₄]_n (1), 并利用元素分析、电喷雾质谱、X射线单晶衍射等方法对其进行了表征. 晶体结构解析结果显示配合物1属三斜晶系, 空间群P-1, a＝0.83731(6) nm, b＝1.22828(9) nm, c＝1.33997(10) nm, α＝102.9760(10)°, β＝107.3050(10)°, γ＝93.8600(10)°, Z＝1, R＝0.0365, wR₂＝0.0929. 该配合物是由[Ag₄(L)₂(CF₃CO₂)₂]^2＋笼状结构单元通过另外两个三氟醋酸根双桥连形成的一维链状结构. 相邻的链间通过C—H…O氢键进一步扩展为二维网状结构. 电喷雾质谱研究结果显示在实验条件下, 溶液中配合物1是以聚合状态存在的.     

夹心三明治结构的二十五核银硫簇合物[Ag25(SC6H4Pri)18 (dppp)6](CF3SO3)7·CH3CN：结构表征及光学性能

在本研究中,使用(ⁱPrC₆H₄SAg)_n作为合成银硫纳米簇合物的前驱体。当存在辅助的双膦配体1, 3-双(二苯基膦)丙烷(dppp)及可溶性银盐(CF₃SO₃Ag),在超声合成条件下,获得了一例二十五核银硫簇合物Ag₂₅,并借助X射线单晶衍射技术确定相应的分子结构。该银硫簇合物具有夹心三明治的骨架结构：分别由两个结构相似的圆柱体共享一个七核纯银簇所构成的金属簇平面。固态紫外可见漫反射光谱测试表明该簇合物的能级带隙为2.5 eV,属于半导体材料的范畴。固态发光测试显示,该簇合物在室温下发射绿光。     

High-humidity Sensor of a New Trinuclear Ti3-Oxo Cluster

Crystalline polyoxo-titanium clusters （PTCs）,as a molecular model of TiO₂ nanomaterials,have attracted unprecedented attention due to their designable structure,tunable band gap,catalysis,and photochromic properties.A new trinuclear Ti₃-oxo cluster,[Ti₃（μ₂-O）(μ₃-O)（abz）₆（OⁱPr）₂]·CH₃CN·H₂O （Ti3）,was synthesized by solvothermal method with a yield of 60%by using 4-aminobenzoic acid as liga...     

一系列基于杂多酸构筑的配合物的合成,晶体结构及光催化性能

通过引入菲咯啉衍生物配体并改变反应体系中的金属盐,得到了3个新的含有杂多酸的金属-有机配合物（MOCs）,{[Cu₂（Do）₂（H₂O）₄(SiW₁₂O₄₀)]·10H₂O}_n（1）,[Ag₃（Do）₅][Ag（Do）₂](SiW₁₂O₄₀)（2）,[Cu₂（Do）₄（H₂O）₂Cl](PMo₁₂O₄₄)·2CH₃OH（3）（Do=1,10-菲咯啉-5,6-二酮）。在配合物1中,Keggin型杂多酸与Cu（Ⅱ）连接形成了二维网状结构。配合物2中的Ag（Ⅰ）显示了多种不同的配位模式,构建了一个新颖的线性三核簇状结构。在配合物3中,Cu（Ⅱ）通过氯原子连接形成了一个双核结构。结构多样性表明金属离子与第二配体Do在构建不同结构的POMs中起到很重要的作用。光催化研究表明,配合物3不仅能在UV光照射下有效地催化降解罗丹明B（RhB）,而且很稳定,能够从反应体系中分离以循环利用。     

银镍合金团簇Ag4Ni2(SPhMe2)8 (SPhMe2 = 2, 4-二甲基苯硫酚)的合成及其结构表征

具有精确结构的纳米团簇因其有利于分析团簇结构与性质之间的关系而被广为研究。之前的研究结果表明金属银和金属镍在亚纳米尺寸可以形成团簇(Ag₄Ni₂(DMSA)₄ (DMSA =二巯基丁二酸),但其晶体结构并没有得到具体表征。在本工作中,我们合成了硫醇配体保护的银镍合金纳米团簇：Ag₄Ni₂(SPhMe₂)₈ (SPhMe₂ = 2, 4-二甲基苯硫酚),并通过X射线单晶衍射、X射线光电子能谱、质谱和热失重等分析手段对结构进行了表征和确认。该工作拓展了合金团簇的基础研究。     

亚乙基桥联多取代茚-芴锆、铪配合物的合成、结构及催化丙烯选择性齐聚研究

合成并表征了一系列新型亚乙基桥联多取代茚-芴锆、铪配合物ansa-C₂H₄-{2-Me-3-Bn-5,6-[1,3-（CH₂）₃]Ind}-（Flu） ZrCl₂（C1）,ansa-C₂H₄-{2-Me-3-Bn-5,6-[1,3-（CH₂）₃]Ind}（2,7-^tBu₂-Flu） ZrCl₂（C2）,ansa-C₂H₄-{2-Me-3-Bn-5,6-[1,3-（CH₂）₃]Ind}（3,6-^tBu₂-Flu） ZrCl₂（C3）,ansa-C₂H₄-{2-Me-3-Bn-5,6-[1,3-（CH₂）₃]Ind}（Flu） HfCl₂（C4）,并对典型配合物进行了X射线单晶衍射分析,确定了其空间结构.研究了该系列配合物在助催化剂作用下催化丙烯齐聚的行为,考察了催化剂结构及反应条件对齐聚反应的影响.配合物C1～C4与改性甲基铝氧烷（MMAO）或三异丁基铝/三苯甲基四（五氟苯基）硼酸盐（TIBA/TrB）组成的催化体系对丙烯齐聚表现出中等到高的催化活性.锆配合物C2和C3在40～100℃条件下普遍具有较高的β-甲基消除（β-Me消除）选择性（最高可达86%）,实现了分子量M_n在400到4500 g·mol^－1范围内的烯丙基封端丙烯齐聚物的高效合成.铪催化剂体系C4/TIBA/TrB的β-Me消除选择性明显高于相应的锆催化剂体系,同时所得齐聚物的分子量更低.     

新型金属-双二硫杂戊烯(M-BDT)配合物的合成、表征及X射线的指标化

合成了4个新型NiBDT配位化合物,BDT为具有9个S原子的杂戊烯.元素分析、IR谱、UV谱确定这4个新配合物的化学式分别为[(CH₃)₄N]₂[Ni(C₅S₉)₂](1),[(C₂H₅)₄N]₂·[Ni(C₅S₉)₂](2),[(C₄H₉)₄N]₂[Ni(C₅S₉)₂](3),[(C₆H₅)(CH₃)₃N]₂[Ni(C₅S₉)₂](4).采用Ito法对配合物1的X射线粉末图进行了指标化,确定该晶体属单斜晶系,简单晶格,晶胞参数:a=0.680nm,b=0.714nm,c=2.302nm,γ=111.4°,Z=2.     

功能化酸性离子液体脱除模拟油品中的非碱性氮

合成了一系列功能化酸性离子液体并用于模拟油品中非碱性氮-吲哚的脱除。结果表明,离子液体的阴离子对脱氮率有较大影响,离子液体的酸性越强,对吲哚的选择性脱除效果越好,不同阴离子的脱氮率顺序为：HSO₄^- > CF₃COO^- > H₂PO₄^- > CH₃COO^-。以（CH₃CH₂）₃N（CH₂）₃SO₃HHSO₄为例,考察了剂油比、剂水比、沉降时间、反应时间和温度对油品脱氮率的影响。结果表明,在优化的工艺路线下,（CH₃CH₂）₃N（CH₂）₃SO₃HHSO₄对油品中的吲哚脱除率可达99.12%,重复使用六次后,脱氮活性未见明显降低,具有良好的稳定性,。     

多核多氧硫钼酸盐化合物的合成及质子传导性能

质子交换膜燃料电池(PEMFC)因能量转化率高、 污染小、 工作温度低、 启动速度快而被广泛应用. Nafion系列膜成本高、 结构特性模糊, 阻碍了质子传导性能的进一步提高和对传导机理的精确理解. 因此开发具有结构明确、 传导路径清晰的高质子传导率的晶态材料对于燃料电池领域具有重要意义. 本文利用有机配体5-羟基间苯二甲酸作为模板诱导[Mo₂S₂O₂]²⁺阳离子, 自组装成一种多核多氧硫钼酸盐簇[N(CH₃)₄]₂H₂· [(Mo₂S₂O₂)₈(OH)₁₆(C₈O₅H₄)₂]·22H₂O(Mo₁₆). 该化合物清晰明确的结构和结构中存在的密集氢键网络可用于进行质子传导性能的研究. 交流阻抗测试结果表明, Mo₁₆在宽温度范围内具有较高的质子传导性能. 在97%湿度(RH), 85 ℃条件下其质子传导率可达1.9×10^-2 S/cm, 表明该化合物具有作为高效质子导体的良好前景.     

偏氟乙烯与全卤代烷烃的调聚反应及其产物的研究

偏氟乙烯能够分别与四氯化碳和全氟叔丁基碘进行自由基的调聚反应,得到新型的调聚物CCl₃(CH₂CF₂)_nCl(n=1～6)和(CF₃)₃C(CH₂CF₂)_nI(n=1,2).调聚物的结构由核磁共振谱、红外光谱、元素分析和化学转化所证实.反应中亲电自由基·CCl₃与·C(CF₃)₃主要进攻偏氟乙烯上无氟碳原子,亦即在偏氟乙烯的自由基加成中,极性因素对加成方向起决定性作用.     

Ag nanoparticles from the mechanochemical decomposition of Ag oxalate

The present work focuses on the chemical reactivity of Ag oxalate powders under mechanical processing conditions. The powders were submitted to mechanical loads in the presence of an aqueous solution containing a polymeric surfactant. A gradual decrease of the total mass of powders was observed, ascribable to the occurrence of a decomposition process. X-ray diffraction and UV-vis spectrophotometric analyses indicated that the Ag oxalate decomposes into metallic Ag and gaseous carbon dioxide. Transmission electron microscopy showed that metallic Ag exists in the form of particles with average size of about 5 nm. The formation of nanometer-sized Ag particles can be related to the plastic deformation and attrition processes taking place at the points of contacts between neighboring particles during the mechanical loading at collision.     

The first measured Ag I, Ag II and Ag III Stark broadening parameters

The Stark widths (W) and shifts (d) of two neutral (520.908 and 546.550 nm), eleven singly (211.382, 224.643, 224.874, 232.029, 232.468, 233.140, 241.141, 241.323, 243.781, 244.793 and 276.754 nm) and three doubly (216.189, 231.004 and 239.569 nm) ionized silver (Ag I, Ag II and Ag III, respectively) spectral lines have been measured in nitrogen plasma at about 18,000 K electron temperature and electron density ranged between 0.65 × 10²³ and 1.15 × 10²³ m^− 3. They are the first measured W and d values while those of the Ag II and Ag III lines are the first published data in these spectra. The modified version of the linear, low-pressure, pulsed arc was used as a plasma source operated in nitrogen with silver atoms, as impurities, evaporated from silver cylindrical plates located in the homogeneous part of the discharge. No theoretical predictions exist for W and d values of above mentioned spectral lines. Besides, we have checked the transition probability ratio of two investigated Ag I lines. An agreement with theoretical predictions was found.     

银纳米粒子修饰的银电极测定酪氨酸

通过Na BH4还原Ag NO3得到胶体银纳米粒子,制作了以该纳米粒子修饰的银电极,研究了其在电催化中的应用,并对相关机理进行了探讨。基于酪氨酸对纳米银的还原信号有明显抑制作用,建立了胶体银纳米粒子修饰银电极在Na Ac-HAc缓冲溶液中用差分脉冲法检测酪氨酸的方法,并讨论了优化工作条件。结果表明,在p H=5.5时,峰电流与酪氨酸的浓度在1.0×10-8~1.0×10-3mol/L范围内呈良好的线性关系,检出限为4.2×10-9mol/L,峰电流Ip与酪氨酸浓度的负对数p C的线性回归方程为Ip(μA)=7.64 p C-15.69(R=99.73%)。用该方法检测氨基酸注射液中酪氨酸的含量,加标回收率在95.2%~107.8%之间。     

Structural variation of silver clusters from Ag13 to Ag160

The structures of silver clusters from Ag(121) to Ag(160) were optimized with a modified dynamic lattice searching (DLS) method, named as DLS with constructed core (DLSc). The interaction among silver atoms is modeled by the Gupta potential. Structural characteristic of silver clusters with the growth of cluster size is investigated with the newly optimized structures and our previous results from Ag(13) to Ag(120). A set of amorphous structures was obtained in the size range of 13-48, together with several ordered structures. The putative stable motif is an icosahedron from Ag(49) to Ag(61) and then changes to a decahedron in the size range of 62-160. Some of the results are consistent with experiments. Furthermore, it was also found that, for clusters with decahedral motif, the stable structure is a result of the competition among the different Marks decahedral motifs. On the other hand, different from the Lennard-Jones cluster, there are some silver clusters with the face-centered cubic (fcc) motif in the size range of 13-160. But the fcc motif can only be obtained for some specific sizes.     

Migration of Ag in low-temperature Ag2S from first principles

Using the density-functional theory combined with the nudged elastic band method, we have calculated migration pathways and estimated the activation energy barriers for the diffusion of Ag ions in low-temperature Ag2S. The activation energy barriers for four essential migrations for an Ag ion, namely, from a tetrahedral (T) site to an adjacent T vacancy (VT), from an octahedral (O) site to an adjacent O vacancy (VO), from T to VO, and from O to VT, are estimated as 0.461, 0.668, 0.212, and 0.318 eV, respectively, which are comparable to experimental values. This means that diffusions of Ag ions between nonequivalent sites are preferable to those between equivalent sites, and that direct T-VT and O-VO diffusions are less likely to occur than indirect T-VO-T and O-VT-O diffusions. These diffusion behaviors between nonequivalent sites have also been supported by ab initio molecular dynamics simulations, in which the diffusion pathways are directly observed.     

Alternating Array Stacking of Ag26Au and Ag24Au Nanoclusters

An assembly strategy for metal nanoclusters using electrostatic interactions with weak interactions, such as C?H???π and π???π interactions in which cationic [Ag₂₆Au(2‐EBT)₁₈(PPh₃)₆]⁺ and anionic [Ag₂₄Au(2‐EBT)₁₈]^? nanoclusters gather and assemble in an unusual alternating array stacking structure is presented. [Ag₂₆Au(2‐EBT)₁₈(PPh₃)₆]⁺ [Ag₂₄Au(2‐EBT)₁₈]^? is a new compound type, a double nanocluster ion compound (DNIC). A single nanocluster ion compound (SNIC) [PPh₄]⁺ [Ag₂₄Au(2‐EBT)₁₈]^? was also synthesized, having a k‐vector‐differential crystallographic arrangement. [PPh₄]⁺ [Ag₂₄Au(2,4‐DMBT)₁₈]^? adopts a different assembly mode from both [Ag₂₆Au(2‐EBT)₁₈(PPh₃)₆]⁺ [Ag₂₄Au(2‐EBT)₁₈]^? and [PPh₄]⁺ [Ag₂₄Au(2‐EBT)₁₈]^?. Thus, the striking packing differences of [Ag₂₆Au(2‐EBT)₁₈(PPh₃)₆]⁺ [Ag₂₄Au(2‐EBT)₁₈]^?, [PPh₄]⁺ [Ag₂₄Au(2‐EBT)₁₈]^? and the existing [PPh₄]⁺ [Ag₂₄Au(2,4‐DMBT)₁₈]^? from each other indicate the notable influence of ligands and counterions on the self‐assembly of nanoclusters.     

Ligand and counterion control of Ag(I) architectures: assembly of a {Ag8} ring cluster mediated by hydrophobic and Ag...Ag interactions

A strategy combining ligand design and counterion variation has been used to investigate the assembly of silver(I) complexes. As a result, dinuclear, octanuclear, and polymeric silver(I) species have been synthesized by complexation of the rigid aliphatic amino ligands cis-3,5-diamino-trans-hydroxycyclohexane (DAHC), cis-3,5-diamino-trans-methoxycyclohexane (DAMC), and cis-3,5-diamino-trans-tert-butyldimethylsilylanyloxycyclohexane (DATC) with silver(I) triflate, nitrate, and perchlorate. The compositions of these aggregates, established by X-ray crystallography and elemental analysis, are [{Ag(DAHC)}2](CF3SO3)2 (1), [{Ag(DAMC)}2](CF3SO3)2 (2), [{Ag(DAMC)}2](NO3)2 (3), [{Ag(DATC)}6{Ag(DAHC)}2](NO3)8 (4), and [{Ag(DATC}n](NO3)n (5), where the DAHC present in 4 is formed by in situ hydrolysis of the acid labile silyl ether group. The type of aggregate formed depends both upon the noncoordinating O-substituent of the ligand and the (also noncoordinating) counterion, with the normal preference of the ligand topology for forming Ag2L2 structures being broken by introduction of the bulky, lipophilic O-tert-butyldimethylsilyl (TBDMS) group. Of particular note is the octanuclear silver ring structure 4, which is isolated only when both the O-TBDMS group and the nitrate counteranion are present and is formed from four Ag2L2 dimers connected by Ag...Ag and hydrogen-bonding interactions. Diffusion rate measurement of this {Ag8} complex by 1H NMR (DOSY) indicates dissociation in CD3OD and CD3CN, showing that this supramolecular ring structure is formed upon crystallization, and establishing a qualitative limit to the strength of Ag...Ag interactions in solution. When solutions of the {Ag8} cluster in methanol are kept for several days though, a new UV-vis absorption is observed at around 430 nm, consistent with the formation of silver nanoparticles.     

Destabilization of Ag nanoislands on Ag(100) by adsorbed sulfur

Sulfur accelerates coarsening of Ag nanoislands on Ag(100) at 300 K, and this effect is enhanced with increasing sulfur coverage over a range spanning a few hundredths of a monolayer, to nearly 0.25 monolayers. We propose that acceleration of coarsening in this system is tied to the formation of AgS(2) clusters primarily at step edges. These clusters can transport Ag more efficiently than can Ag adatoms (due to a lower diffusion barrier and comparable formation energy). The mobility of isolated sulfur on Ag(100) is very low so that formation of the complex is kinetically limited at low sulfur coverages, and thus enhancement is minimal. However, higher sulfur coverages force the population of sites adjacent to step edges, so that formation of the cluster is no longer limited by diffusion of sulfur across terraces. Sulfur exerts a much weaker effect on the rate of coarsening on Ag(100) than it does on Ag(111). This is consistent with theory, which shows that the difference between the total energy barrier for coarsening with and without sulfur is also much smaller on Ag(100) than on Ag(111).     

Disc-Like Silver Nanocluster Ag93 Built with Bicapped Hexagonal Prismatic Ag15 and Ino Decahedral Ag13 Units

The reduction of alkynyl-silver and phosphine-silver precursors with a weak reducing reagent Ph₂SiH₂ led to the formation of a novel silver nanocluster [Ag₉₃(PPh₃)₆(C≡CR)₅₀]³⁺ (R=4-CH₃OC₆H₄), which is the largest structurally characterized cluster of clusters. This disc-shaped cluster has a Ag₆₉ kernel consisting of a bicapped hexagonal prismatic Ag₁₅ unit wrapped by six Ino decahedra through edge-sharing. This is the first time that Ino decahedra are used as a building block to assemble a cluster of clusters. Moreover, the central silver atom has a coordination number of 14, which is the highest in metal nanoclusters. This work provides a diverse metal packing pattern in metal nanoclusters, which is helpful for understanding metal cluster assembling mechanisms.