碱土金属Mg外掺杂硼笼B40Mg6的储氢性能

对外掺杂碱土金属Mg的B₄₀硼笼的储氢性能进行了密度泛函理论研究. 结果表明, B₄₀笼含有2个六元环与4个七元环. 多个Mg原子对B₄₀笼进行外掺杂时不会发生成簇现象, 有利于进一步储氢. Mg原子外掺杂的B₄₀笼对H₂分子的平均吸附能介于物理吸附与化学吸附之间(0.1~0.8 eV). 体系的储氢密度达到7.60%(质量分数). 储氢结构能在常温常压下释放H₂分子, 因此, Mg原子外掺杂的B₄₀笼比Mg合金具有更好的储氢性能.     

1,3-双芳氧乙酰基-1,3,2-二氮磷杂环戊烷-2-硫(硒)代化合物的合成及除草活性研究

利用P(NEt₂)₃与双酰胺类化合物在干馏条件下的环缩合反应合成了一系列含双芳氧乙酰基的新型五元磷杂环,对所合成的化合物进行了元素分析和谱学表征.初步生物活性测定表明,部分化合物具有优良的选择性除草活性.合成中首次发现此类磷杂环的P⁼Se与P-Se的转化现象,通过X射线单晶衍射确证了产物的结构,并发现产物分子间氢键的存在     

基于环状酰亚胺还原反应绿色合成环状二级胺化合物

环状二级胺作为重要组成部分广泛存在于具备生物活性的分子中。常见的合成方法主要是采用LiAlH₄或者BF₃和NaBH₄的反应体系将环状酰胺类化合物还原,而危险性和环保隐患制约了其在生产中的应用。以环状酰亚胺为原料,通过BCl₃和NaBH₄的还原体系实现了环状二级胺的高效及绿色合成。以化合物1a作为模板底物,通过反应条件的筛选得到的最佳工艺条件为：1.0 eq.1a、 1.5 eq. BCl₃以及4.5 eq. NaBH₄在60℃下反应24 h,溶剂为四氢呋喃。经优化后合成了一系列环状二级胺化合物,其结构经¹ H NMR,¹³C NMR和HR-MS(ESI)确证。结果表明：该方法成本低廉,产率较高,可达78%～96%,底物适用范围广,可应用于环上有推电子基或者吸电子基的二级胺的合成。     

B24N24团簇的结构与稳定性

采用密度泛函理论,在B3LYP/6-31G^*水平下,对B₂₄N₂₄笼状团簇的12种异构体进行了优化,并对它们的几何构型、化学键性质、振动光谱和稳定性进行了探讨.研究表明:具有S₈对称的含有2个八元环、8个四元环和16个六元环的结构h是B₂₄N₂₄笼状团簇最稳定的异构体,只存在B-N键,而无N-N和B-B键.含有五元环结构的稳定性最低.B-B和N-N键对的数目越多,结构的稳定性越低.12种异构体的稳定性顺序为h＞a＞b＞I＞g＞l＞c＞k＞j＞d＞e＞f.     

铁基金属有机凝胶衍生的三氧化二铁纳米片用于光芬顿降解罗丹明B

光催化剂在工业废水处理中发挥着重要作用. 本工作以室温下一步合成的片状铁基金属有机凝胶(Fe-based Metal-organic gel, Fe-MOG)为前驱体, 在不同温度下煅烧得到了片状(300-Fe₂O₃和400-Fe₂O₃)和球形(500-Fe₂O₃和600-Fe₂O₃)两种形貌的衍生三氧化二铁(Fe₂O₃). 通过一系列测试手段对衍生Fe₂O₃的晶体结构和光电性能进行了表征. 其中, 具有碳骨架结构的400-Fe₂O₃因其优良的电子传输性能和较高的光生电荷分离效率表现出优异的光催化活性, 可在中性条件下60 min内光降解97.5%的罗丹明B (Rh B), 并且在连续五次循环实验后其降解效率仍能达到85.3%. 本工作为开发和设计具有优异催化活性的半导体光催化剂提供了新的思路.     

维生素B_(12)环B酰亚胺前体及琥珀胺类药物不对称合成的研究

从γ-丁内酯合成了维生素 B1 2 环 B酰亚胺前体及琥珀酰胺类药物的 3个衍生物 ,进行了其中不对称季碳的构筑 ,改进了 Ti Cl3还原硝基乙烯类化合物的反应 ,同时发现了一个简便合成乙琥酰胺环的新方法     

活性维生素D3类似物的合成及构效关系研究

1α,25-二羟基维生素D₃(1α,25-(OH)₂-D₃,125D)是维生素D中最具生理活性的代谢产物,但因高钙血症副反应而限制其临床应用。从对构效关系的研究出发,迄今已合成三千多种类似物。本文综述了近年来对某些A环修饰(C2位修饰、C3位修饰、芳香A环类似物、A环开环类似物)、侧链修饰、CD环修饰、seco-B环修饰和非开环甾体的活性维生素 D₃ 类似物的设计、合成以及构效关系的研究,旨在为新型较佳活性维生素D₃类似物的合成及临床开发提供参考。     

(烷基环戊二烯基)环戊二烯基二氯化钛的合成与反应

Richard在1959年合成了第一个环戊二烯基(取代环戊二烯基)钛衍生物,(CH₃C₅H₄)(C₅H₅)T1Cl₂^[1].我们曾报道了环戊二烯基(烯烃基环戊二烯基)二卤化钛的合成和反应^[2]。     

辅酶B12模型化合物的研究(Ⅵ)──轴向及平面配体对RCo(salen)L和RCo(SB)L中Co─C键稳定性的影响

合成与表征了两类14种烷基钴Schiff碱配合物RCo(chel)L(R=CH₃,C₂H₅,n-C₃H₇,n-C₄H₉,i-C₄H₉;chel=salen,SB;L=Py,γ-pic,PPh₃),其中RCo(SB)L是一类新的辅酶B₁₂模型化合物,五配位的C₂H₅Co(SB)也是首次报道。研究了在固态和溶液中配合物的性质,并讨论了影响配合物中Co─C键稳定性的因素。     

Zn/Ni双金属接力催化:一锅法分子内环异构化/分子间酰胺化反应构建噁唑衍生物

报道了一种新型的Zn/Ni双金属接力协同催化的串联反应,该方法通过Zn（OTf）₂和Ni（ClO₄）₂·6H₂O协同接力催化,一锅法进行分子内环异构化/分子间酰胺化反应构建噁唑衍生物.产物的形成主要是由Zn（OTf）₂活化炔丙基酰胺的三键,发生分子内的环化反应构建噁唑啉中间体,由Ni（ClO₄）₂·6H₂O催化3-羟基-2-苯甲基-异吲哚啉-1-酮类化合物形成酰亚胺离子,继而由噁唑啉中间体与酰亚胺离子发生分子间酰胺化反应实现了噁唑分子的合成.优化部分的对比实验证实Zn（OTf）₂和Ni（ClO₄）₂·6H₂O的存在对于该串联反应都是必须条件.大体而言,所有反应都是将各反应物和试剂一次性加入,在空气氛围下100℃加热进行反应.含有不同类型给电子取代基、含有不同富电子的芳环、含有不同吸电子取代基的炔丙基酰胺都可以顺利地和3-羟基-2-苯甲基-异吲哚啉-1-酮反应得到相应的噁唑衍生物,相比而言,含有吸电子基团的炔丙基酰胺比含有给电子基团或富电子的炔丙基酰胺所得到的产物的收率要低一些,这可能是因为含有吸电子基团的炔丙基酰胺所得到的噁唑啉中间体活性较低.3-羟基-2-苯基异吲哚啉-1-酮类化合物、3-羟基-2-苯甲基异吲哚啉-1-酮类化合物和3-羟基-2-苯乙基异吲哚啉-1-酮类化合物对反应同样表现出了良好的兼容性.该方法反应条件简单、原子经济性高、官能团兼容性好,对噁唑衍生物合成和酰亚胺离子形成具有重要的意义.     

咪唑类高铼酸盐催化微晶纤维素降解反应研究

以咪唑类高铼酸盐为催化剂,以离子液体1-烯丙基-3-甲基咪唑氯盐([Amim]Cl)为溶剂降解微晶纤维素(MCC)。分别考察反应温度、反应时间、反应物浓度、催化剂用量和结构对纤维素降解反应的影响。结果表明,以5%1-(3-磺酸)丙基-3-甲基咪唑高铼酸盐([mim-(CH_2)_3SO_3H]ReO_4)为催化剂,在微波辅助加热条件下,0.1 g纤维素在2.0 g离子液体[Amim]Cl中于160℃降解30 min,还原糖收率(TRS)和葡萄糖收率最高可达89.6%和46.7%。研究还对咪唑类高铼酸催化纤维素降解反应的催化机理进行讨论,认为催化剂芳环阳离子、ReO-4中Re=O与纤维素分子中羟基的相互作用是促进纤维素降解的关键     

Another example of carborane based trianionic ligand: Syntheses and catalytic activities of cyclohexylamino tailed ortho-carboranyl zirconium and titanium dicarbollides

In situ reaction of Li[closo-1-Ph-1,2-C₂B₁₀H₁₀] with 7-azabicyclo [4.1.0] heptane results in the formation of the disubstituted carborane, closo-1-Ph-2-(2′-aminocyclohexyl)-1,2-C₂B₁₀H₁₀ (1), in 63% yield. Decapitation of (1) with potassium hydroxide in refluxing ethanol produces the cage-opened nido-carborane, K[nido-7-Ph-8-(2′-aminocyclohexyl)-7,8-C₂B₉H₁₀]⁻ (2), in 80% yield. Deprotonation of the above monoanion with two equivalents of n-butyllithium followed by reaction with anhydrous MCl₄ · 2THF (M = Zr, Ti) provides d⁰-half-sandwich metallocarboranes, closo-1-M(Cl)-2-Ph-3-(2′-σ-(H)N-cyclohexyl)-2,3-η⁵-C₂B₉H₉ (3 M = Zr; 4 M = Ti) in 53% and 42% yields, respectively. The reaction of Li[closo-1,2-C₂B₁₀H₁₁] with 7-azabicyclo [4.1.0] heptane in THF affords closo-1-(2′-aminocyclohexyl)-1,2-C₂B₁₀H₁₀ (5) in 59% yield. Immobilization of the carboranyl amino ligand (1) to an organic support, Merrifield’s peptide resin (1%), has been achieved by the reaction of the sodium salt of (5) with polystyryl chloride in THF to produce closo-1-(2′-aminocyclohexyl)-2-polystyryl-1,2-C₂B₁₀H₁₀ (6) in 87% yield. Further reaction of the dianion derived from (6) with anhydrous ZrCl₄ · 2THF led to the formation of the organic polystyryl supported d⁰-half-sandwich metallocarborane, closo-1-Zr(Cl)-2-(2′-σ-(H)N-cyclohexyl)-3-polystyryl-2,3-η⁵-C₂B₉H₉ (7), in 38% yield. These new compounds have been characterized by elemental analyses, NMR, and IR spectra. Polymerizations of both ethylene and vinyl chloride with (3) and (7) have been performed in toluene using MMAO-7 (13% ISOPAR-E) as the co-catalyst. Molecular weights up to 32.8 × 10³ (M_w/M_n = 1.8) and 9.5 × 10³ (M_w/M_n = 2.1) were obtained for PE and PVC, respectively.     

酰代呲唑酮作为金属元素萃取剂的研究(Ⅱ)——不同基团取代的呲唑酮对于铈(Ⅲ)的萃取及其与二辛基亚砜的协同萃取作用

本文研究了不同基团取代的酰代吡唑酮对铈(Ⅲ)的萃取。采用斜率法和同位素示踪技术,测得它们在HCl和HNO₃体系中的萃合物组成和萃取平衡常数;还研究了它们与二辛基亚砜对铈(Ⅲ)的协同萃取。研究过程中,以HTTA作为对照。     

Synthesis of mer-[RuCl3(DMSO)(bpy)], reactivity and electrochemistry of mer-[RuCl3(DMSO)(bpy)] and mer-[RuCl3(TMSO)(bpy)] complexes

[H(DMSO)₂][trans-RuCl₄(DMSO)₂] (1) reacts with 2,2′-bipyridine in ethanol at room temperature resulting in the formation of a major compound, mer-[RuCl₃(DMSO)(bpy)] (bpy = 2,2′-bipyridine) 3 and a known minor compound, cis-[RuCl₂(DMSO)₄] (4). The compounds 3 and 4 are formed via an anticipated intermediate mer-[RuCl₃(DMSO)₃] (2). The reaction of 3 and mer-[RuCl₃(TMSO)(bpy)] (5) with small molecules like imidazole, carbon monoxide and KSCN yield, mer-[RuCl₃(bpy)(im)] · 2DMSO (im = imidazole) (6) and cis-[RuCl₂(TMSO)(CO)(bpy)] (7), cis-[RuCl₂(DMSO)(CO)(bpy)] (8) and K[RuCl₃(bpy)(SCN)] (9), respectively. The formations of 3, 6 and 7 have been authenticated by single crystal structure determinations. Compound 6 is formed by the substitution of DMSO or TMSO from 3 and 5, respectively, whereas 7 and 8 are formed by unprecedented one-electron reductions of 5 and 3. The reactions of 3 and 5 with KSCN resulted in the same compound, K[RuCl₃(NCS)(bpy)] (9). DFT calculations were performed to distinguish whether the thiocyanate ligand is bound to ruthenium through S or N. In the ruthenium bipyridine systems, the HOMO contains ruthenium d-orbitals and the LUMO is typically π^*-orbitals of the bipyridine ring. Complexes 3, 6 and 7 are redox active in acetone and DMSO solvent showing prominent a reduction peak and corresponding oxidation peak.     

A new dirbenium complex with an unsupported bridging hydride ligand

The reaction of Re₂(CO)₈(μ-H)2 with CH₂(NMe₂)₂ in chloroform at 25°C yielded the new compound Re₂(CO)₈(NHMe₂)(Cl)(μ-H) (1) in 31% yield. Compound 1 was characterized by IR, ¹H NMR and a single-crystal X-ray diffraction analysis. Crystal data: orthorhombic, Pbca, a = 13.787(4), b = 19.884(5), c = 12.296(2) Å. Solution by direct methods (MITHRIL), R = 0.035 for 1800 reflections. The complex contains two rhenium atoms linked by an unsupported hydride bridge, Re Re = 3.362(1) Å, Re(1)---H = 1.8(1) Å and Re(2)---H = 2.0(1) Å. A chloride ligand abstracted from the solvent is terminally bonded to Re(1), and a dimethylamine ligand abstracted from the CH₂(NMe₂)₂ is coordinated to Re(2). When heated to 68°C, the dimethylamine ligand was eliminated and the chloride ligand became a bridge in the new compound Re₂(CO)₈(μ-H)(μ-Cl) (2), yield 76%.     

Structural characterization of cyclopentadienyl(duroquinone)cobalt dihydrate

The structure of cyclopentadienyl(duroquinone)cobalt dihydrate, (C₅H₅)Co-[(CH₃)₄C₆O₂]·2H₂O, has been determined by three-dimensional X-ray analysis. The crystal structure consists of discrete cyclopentadienyl(duroquinone)cobalt molecules linked together by a complex network of hydrogen bonds between water molecules and duroquinone oxygen atoms. Each (C₅H₅)Co[(CH₃)₄C₆O₂] molecule consists of a cobalt atom sandwiched between a cyclopentadienyl ring and a duroquinone ring. A detailed comparison of the molecular parameters of this complex with those of closely related complexes is given. Crystallographic evidence that the metal---duroquinone interaction in cyclopentadienyl(duroquinone)cobalt dihydrate is considerably stronger than that in the electronically-equivalent 1,5-cyclooctadiene(duroquinone)nickel complex is given not only by the metal---C(olefin) distances being 0.12 Å (av) shorter in the duroquinone---cobalt complex [viz., 2.104(8) Å vs. 2.222(7) Å] but also by the much greater C_2v-type distortion of the duroquinone ring from the planar D_2h configuration in free duroquinone. The compound crystallizes with two formula species in a triclinic unit cell of symmetry P and reduced cell dimensions á = 8.60 Å, b = 9.00 Å, c = 10.15 Å, = 87° 34′, β = 84° 10′, γ = 73° 44′. Least-squares refinement yielded final unweighted and weighted discrepancy factors of R₁ = 10.8% and R₂ = 12.0%, respectively, for 2481 independent diffraction maxima collected photographically.     

DFT study on the reaction mechanisms of polyfluorosulfonate ester with F

Gas-phase reaction of C(1)F₃S(2)O₂O(3)C(4)H₂C(5)F₃ and F⁻(16) is investigated using DFT method. The geometries of various stationary points and their relative energies are obtained from 6-31+G*, 6-311G**, and 6-311++G** levels. In the S_N2(C) reaction leading to the cleavage of the C(4)–O(3) bond, the reaction complex results from attacking of F⁻ at a hydrogen atom H11 attached to carbon atom C(4). Afterward, F⁻ is attacking the atom C(4) from the backside of the atom O(3) with the help of the neighboring effect, and meanwhile a multi-membered ring, F(16)–H(11)–C(4)–C(5)–F(16), is being formed. The S_N2(C) reaction is irreversible. On the contrary, the S_N2(S) reaction leading to the cleavage of the S(2)–O(3) bond is reversible, and it is initiated by attacking of F⁻ at the atom S(2) from the backside of the atom O(3). The products of the reaction CF₃SO₃CH₂CF₃ +F⁻ should be, thermodynamically, controlled due to the reversibility of the S_N2(S) reaction, and those result, chemospecifically, from the cleavage of the C–O bond. At last, the SCRF calculations confirm that the solvent effect is preferable to the S_N2(C) reaction.     

Synthesis and crystal structures of (C8h8)Nd(C5H9C5H4) (THF)2 and [(C8H8)Gd(C5H9C4H4(THF)][(C8H8)GD(C5H9C5H4(THF)2]

LnCl₃ (Ln=Nd, Gd) reacts with C₅H₉C₅H₄Na (or K₂C₈H₈) in THF (C₅H₉C₅H₄ = cyclopentylcyclopentadienyl) in the ratio of 1 : to give (C₅H₉C₅H₄)LnCl₂(THF)_n (orC₈H₈)LnCl₂(THF)_n], which further reacts with K₂C₈H₈ (or C₅H₉C₅H₄Na) in THF to form the litle complexes. If Ln=Nd the complex (C₈H₈)Nd(C₅H₉C₅H₄)(THF)₂ (a) was obtained: when Ln=Gd the 1 : 1 complex [(C₈H₈)Gd(C_%H₉)(THF)][(C₈H₈)Gd(C₅H₉H₄)(THF)₂] (b) was obtained in crystalline form.

The crystal structure analysis shows that in (C₈H₈)Ln(C₅H₉C₅H₄)(THF)₂ (Ln=Nd or Gd), the Cyclopentylcyclopentadieny (η⁵), cyclooctatetraenyl (η⁸) and two oxygen atoms from THF are coordinated to Nd³⁺ (or Gd³⁺) with coordination number 10.

The centroid of the cyclopentadienyl ring (Cp′) in C₅H₉C₅H₄ group, cyclooctatetraenyl centroid (COTL) and two oxygens (THF) form a twisted tetrahedron around Nd³⁺ (or Gd³⁺). In (C₈H₈)Gd(C₅H₉C₅H₄)(THF), the cyclopentyl-cyclopentadienyl (η⁵), cyclooctatetraenyl (η⁸) and one oxygen atom are coordinated to Gd³⁺ with the coordination number of 9 and Cp′, COT and oxygen atom form a triangular plane around Gd³⁺, which is almost in the plane (dev. -0.0144 Å).     

Metal complexes of sterically hindered pyrzolylpyridines. The single crystal X-ray structure of [Cu(L)2]BF4 (L = 1-{pyrid-2-yl}-3-{2′,5′-dimethoxyphenyl}pyrazole)

Reaction of potassium 3{5}-(3′,4′-dimethoxyphenyl)pyrazolide with 2-bromopyridine in diglyme at 130°C for 3 days followed by an aqueous quench, affords 1-{pyrid-2-yl}-3-{3′,4′-dimethoxyphenyl}pyrazole (L²) in 69% yield after recrystallization from hot hexanes. Complexation of [Cu(NCMe)₄]BF₄ by 2 molar equivalents of 1-{pyrid-2-yl}-3-{2′,5′-dimethoxyphenyl}pyrazole (L¹) or L² in MeCN at room temperature, followed by concentration and crystallisation with Et₂O, gives [Cu(L)₂]BF₄ L = L¹, L²) in good yields. Treatment of AgBF₄ with L¹ or L² in MeNO₂ similarly gives [Ag(L)₂]BF₄ L = L¹, L²); reaction of AfBF₄ with L² in MeCN gives a product of stoichiometry [Ag(L²)(NCMe)]BF₄. The ¹H NMR spectra of the [M(L)₂]BF₄ complexes show peaks arising from a single coordinated environment. The single crystal X-ray structure of [Cu(L¹)₂]BF₄ shows a tetrahedral complex cation with Cu---N = 2.011(8), 2.036(8), 2.039(8), 2.110(8) Å. The Cu^I centre is close to tetrahedral, the dihedral angle between the least-squares planes formed by the Cu atom and the N donor atoms of the two ligands being 88.3(3)°. Complexation of hydrated Cu(BF₄)₂ by L² in MeCN at room temperature yields [Cu(L₂)₂](BF₄)₂. The cyclic voltammograms of the three Ag^I complexes in MeCN/0.1 M Bu₄ⁿ NPF₆ are suggestive of extensive ligand dissociation in this solvent.     

Synthesis and characterisation of four- and eight-membered ring auralactam complexes

The reactions of the cyclo-aurated gold(III) dihalide complex [{C₆H₃(CH₂NMe₂)-2-(OMe)-5}AuCl₂] with N-cyanoacetylurethane [NCCH₂C(O)NHCO₂Et], 2-benzoylacetanilide [PhC(O)CH₂C(O)NHPh] and acetoacetanilide [MeC(O)CH₂C(O)NHPh], and [{C₆H₄(CH₂NMe₂)-2}AuCl₂] with acetoacetanilide in dichloromethane with excess silver(I) oxide gives the first examples of auralactam complexes, containing (O)---CHR′ four-membered rings. A single-crystal X-ray diffraction study on the complex [{C₆H₄(CH₂NMe₂)-2}A H(COMe)}] reveals similar structural features to related metallalactam complexes of platinum(II) and palladium(II). When a CDCl₃ solution of the complex [{C₆H₃(CH₂NMe₂)-2-(OMe)-5}A HCN}] is allowed to stand for 18 h, a novel dimerisation reaction occurs, giving the insoluble product [{C₆H₃(CH₂NMe₂)-2-(OMe)-5}Au{N(CO₂Et)C(O)CHCN}]₂·2CDCl₃, characterised by an X-ray structure determination. The dimer contains an eight-membered A

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ring.