KF/Al2O3催化下4-芳基-9,10-二氢萘并[2,1-b]-4H-吡喃衍生物的合成

在KF/Al₂O₃催化下, α,β-不饱和腈或α,β-不饱和羧酸酯和7-甲氧基-1,2,3,4-四氢-2-萘酮反应, 生成了一系列4-芳基-9,10-二氢萘并[2,1-b]-4H-吡喃衍生物. 产物的结构通过红外光谱和核磁共振氢谱进行表征, 并通过X单晶衍射分析进一步证实产物的结构.     

Fe2O3/Al2O3二元气凝胶合成高质量单壁纳米碳管

通过溶胶和超临界干燥方法制得了Fe₂O₃/Al₂O₃二元气凝胶，其比表面积和孔隙体积分别为246 m²·g^-1和1.89 cm³·g^-1，并具有较宽的孔径分布。以Fe₂O₃/Al₂O₃二元气凝胶作催化剂，通过甲烷催化裂解成功地合成了高质量的单壁纳米碳管。利用FESEM、TEM和HRTEM、Raman光谱等分析手段研究了反应温度对单壁纳米碳管生长的影响。结果表明在900 ℃时合成单壁纳米碳管的质量较高，并且合成的炭产物为毡状，该炭产物主要为高质量的单壁纳米碳管。     

KF/Al2O3催化下芳醛和4-羟基喹啉-2-酮的反应研究

以芳醛和4-羟基喹啉-2-酮为原料, 在KF/Al₂O₃催化下以乙醇为溶剂, 在80 ℃合成了一系列新的双(4-羟基-2-氧代喹啉-3-基)-芳基甲烷衍生物, 反应条件温和, 产率较高, 并通过IR, ¹H NMR和元素分析确证产物的结构.     

ZrO4/SiO2-Al2O3催化肉桂醛MPV转移加氢性能

以九水合硝酸铝（Al（NO₃）₃·9H₂O）与正硅酸乙酯（TEOS）为前驱盐,采用溶胶-凝胶法制备一系列不同Al₂O₃含量的SiO₂-Al₂O₃复合氧化物,并通过浸渍硝酸氧锆引入ZrO₂,制备ZrO₂/SiO₂-Al₂O₃复合氧化物催化剂,考察催化剂在肉桂醛（CAL）MPV转移加氢中的催化性能,并结合N₂物理吸附、X射线粉末衍射（XRD）、傅里叶变换红外光谱（FTIR）、NH₃-程度升温脱附（NH₃-TPD）、Py-原位红外（Py-IR）等技术,研究催化剂结构、织构以及表面性质与其催化性能间的构效关系.研究表明,所制备的催化剂均以L酸为主,并含有少量B酸中心,这使得加氢产物以肉桂醇（COL）为主,并含有少量1-苯丙烯-2-丙基醚（CPE）.Al₂O₃含量不仅影响催化剂表面的酸中心数量,而且对催化剂的织构参数有较大影响.随Al₂O₃含量的增加,催化剂表面L酸与B酸中心均有所增加,而孔径则持续变小,这使得催化反应呈现CAL转化率先增加后减少、目标产物COL选择性先稍有减小后有所增加的趋势.在Si/Al比为2时,催化剂具有最优的催化性能,优化反应条件下,CAL转化率达96%,目标产物COL选择性达90%.     

KF-Al2O3催化下吡喃并[2,3-d]嘧啶衍生物的一步合成

以芳醛、丙二腈和4,6-二羟基嘧啶为原料, 以乙醇为溶剂, 在80 ℃以KF/Al₂O₃为催化剂合成了一系列的吡喃并[2,3-d]嘧啶衍生物, 产物的结构通过IR, ¹H NMR和元素分析表征, 并进一步通过X射线衍射分析确证.     

二维层状Ti3C2Tx-MXene@VS2用于高性能锂离子电池负极

为探索一种高性能的锂离子电池负极材料,采用酸刻蚀法制备了高导电性、高稳定性的二维层状Ti₃C₂T_x,通过溶剂热法制备了具有高理论比容量的花瓣状VS₂纳米片,再经过简单的液相混合得到了二维层状Ti₃C₂T_x-MXene@VS₂复合物。通过扫描电子显微镜、透射电子显微镜、X射线光电子能谱、X射线衍射和能谱分析对复合材料的形貌和结构进行了表征,采用循环伏安、恒流充放电、长循环和交流阻抗谱对复合材料的电化学性能进行了研究。结果表明：VS₂纳米片均匀地分布在Ti₃C₂T_x的层间及表面,该复合物具有高的可逆容量(电流密度为0.1A·g^-1时,比容量为610.5mAh·g^-1)、良好的倍率性能(电流密度为2A·g^-1时,比容量为197.1mAh·g^-1)和良好的循环稳定性(电流密度为0.2 A·g^-1时,循环600圈后比容量为874.9 mAh·g^-1;电流密度为2 A·g^-1时,循环1 500圈后比容量为115.9mAh·g^-1)。     

H2SO4处理的Nb2O5/γ -Al2O3催化剂表面酸性与催化性能研究

用Hammett指示剂法、红外光谱（IR）、示差扫描量热-热重法（DSC-TG）和微型催化反应装置等研究了H₂SO₄处理的负载型Nb₂O₅/γ-Al₂O₃催化剂表面酸性和催化异丁烯（IB）与异丁醛（IBA）反应生成2，5-二甲基-2，4-己二烯（DMHD）的催化性能。结果表明随所用H₂SO₄浓度增加，Nb₂O₅/γ-Al₂O₃催化剂表面酸性增强，B酸量增加，L酸量先增加后下降。经H₂SO₄处理的Nb₂O₅/γ-Al₂O₃催化剂的催化活性明显增加，但当H₂SO₄浓度超过0.05 mol·L^-1时催化活性又急剧下降，这可能是因为在H₂SO₄处理的催化剂表面形成的强酸中心上，产物分子进一步转化为积炭且封闭催化剂活性表面，导致催化活性下降。     

溶剂热方法合成Cu2ZnSnS4空心球

以氯化亚铜,硝酸锌,氯化锡和硫脲作为反应前驱体,聚乙二醇作为模板,利用溶剂热方法合成Cu₂ZnSnS₄中空球。其中,聚乙二醇对于产物的最终形成起到关键作用。文章讨论了Cu₂ZnSnS₄中空球的生长机制,并通过X射线衍射(XRD)、拉曼光谱、场发射电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线能量色散谱(EDX)、X射线光电子谱(XPS)、选区电子衍射谱(SAED)和紫外-可见光分光光度计(UV-Vis)等技术对样品的微结构以及光学性质进行了表征和分析。结果显示Cu₂ZnSnS₄中空球为四方晶体,尺寸为600 nm。其禁带宽度为1.52 eV,适用于制作光伏器件。     

溶剂热方法合成Cu2ZnSnS4空心球

以氯化亚铜,硝酸锌,氯化锡和硫脲作为反应前驱体,聚乙二醇作为模板,利用溶剂热方法合成Cu₂ZnSnS₄中空球。其中,聚乙二醇对于产物的最终形成起到关键作用。文章讨论了Cu₂ZnSnS₄中空球的生长机制,并通过X射线衍射(XRD)、拉曼光谱、场发射电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线能量色散谱(EDX)、X射线光电子谱(XPS)、选区电子衍射谱(SAED)和紫外-可见光分光光度计(UV-Vis)等技术对样品的微结构以及光学性质进行了表征和分析。结果显示Cu₂ZnSnS₄中空球为四方晶体,尺寸为600 nm。其禁带宽度为1.52 eV,适用于制作光伏器件。     

KF-alumina 催化下2-氨基-4-芳基-5,6-二氢化-4H-吡喃[3,2-c]喹啉-5-酮-3-羧酸酯衍生物的一步合成

以芳醛、氰乙酸酯和4-羟基喹啉-2-酮为原料, 乙醇为溶剂, 在KF-Al₂O₃催化下80 ℃, 一步合成了2-氨基-4-芳基-5,6-二氢化-4H-吡喃[3,2-c]喹啉-5-酮-3-羧酸酯衍生物, 和其它方法相比, 具有反应条件温和, 容易操作和产率高等优点, 产物4a的结构通过X单晶衍射分析确证.     

Synthesis, Structure, and 31P NMR of Sulfur/Oxygen-Bridged Incomplete Cubane-Type Molybdenum and Tungsten Clusters with Triphenylphosphine Ligands

Sulfur/oxygen-bridged incomplete cubane-type triphenylphosphine molybdenum and tungsten-clusters [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·3THF (1A), [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (2A), [Mo₃OS₃Cl₄(H₂O)₂(PPh₃)₃]·2THF (1B), and [W₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (1C) were prepared from the corresponding aqua clusters and PPh₃ in THF/MeOH. On recrystallization from THF, procedures with and without addition of hexane to the solution gave 1A and 2A, respectively, while the procedures gave no effect on the formation of 1B and 1C. Crystallographic results obtained are as follows: 1A: monoclinic, P2₁/n, a=17.141(4) Å, b=22.579(5) Å, c=19.069(4) Å, =96.18(2)°, V=7337(3) ų, Z=4, R(R _w)=0.078(0.102); 1C: monoclinic, P2 ₁/c, a=12.635(1) Å, b=20.216(4) Å, c=27.815(3) Å, =96.16(1)°, V=7062(2) ų, Z=4, R(R _w)=0.071(0.083). If the phenyl groups are ignored, the molecule [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃] in 2A has idealized CS symmetry with the mirror plane perpendicular to the plane determined by the metal atoms, while the molecule in 1A does not have the symmetry. The tungsten compound 1C is isomorphous with the molybdenum compound 2A. ³¹P NMR spectra of 1A, 2A, and 1C were obtained and compared with similar clusters with dmpe (1,2-bis(dimethylphosphino)ethane) ligands.     

Reactions of pyridine-2-ethyl/methyl cyclopentadienes with metal carbonyls

Abstract

Thermal treatment of pyridine-2-ethyl cyclopentadiene (1) with Fe(CO)₅ and Ru₃(CO)₁₂ gave novel intramolecular C–H activated dinuclear products (3 and 5). In the case of Fe(CO)₅, the reaction also afforded the normal bis(cyclopentadienyl) diiron complex (4). However, similar reaction of pyridine-2-methyl cyclopentadiene (2) with Fe(CO)₅ and Ru₃(CO)₁₂ only afforded the normal bis(cyclopentadienyl) dinuclear metal complexes (7 and 8). For Ru₃(CO)₁₂, the reaction also yielded a pendant η¹-pyridyl-coordinated product (9). In addition, the reactions of 1 and 2 with Re₂(CO)₁₀ formed the corresponding pyridylethyl/pyridylmethyl cyclopentadienyl rhenium tricarbonyl complexes 10 and 11, which further underwent pyridine to rhenium cyclization via photoirradiation to provide the rhenium dicarbonyl complexes 12 and 13. The molecular structures of 3, 5, 6, 7, 8, 9, and 12 were determined by X-ray diffraction.     

Coordination interactions in the crystalline lattice of alkaline ions with the polyoxometalate [V12B18O60H6]10− ligand

In the present work, the synthesis and structural characterization of two new polyoxovanadoborate (BVO) frameworks, based on the [V₁₂B₁₈O₆₀H₆]^10? polyanion, are reported, K(H₃O)(enH₂)₄[V₁₂B₁₈O₆₀H₆]·9.60H₂O (1) and Li₈(NH₄)₂[V₁₂B₁₈O₆₀H₆]·8.02H₂O (2). Both compounds are obtained in a mixed valence ratio of 10V^IV/2V^V. Framework 1 is characterized by potassium ions coordinated by the BVO cluster and ethylenediammonium and hydronium ions as charge-compensating agents. In framework 2, the BVO clusters are coordinating lithium ions and the charge is compensated by ammonium ions. Using the SHAPE 2.1 program, it was possible to calculate the best geometry for the existing lithium and potassium ions. For 2, the lithium ions are five-coordinate, best described by a square pyramid (SPY-5), while the coordination sphere around the potassium ions in 1 are six-coordinate. For 1, the coordination sphere of the existing potassium ions in the framework can be described as trigonal prism (TPR-6). Calculations were also done for a previously reported cluster [Na₁₀[(H₂O)V₁₂B₁₈O₆₀H₆]·18H₂O] (3), in which the sodium ions are six-coordinate but in two different geometries, these being octahedral and TPR-6. The influence of the interactions of the alkali ions with the [V₁₂B₁₈O₆₀H₆]^10? polyanion, on the vanadate and borate absorption bands observed in the infrared spectra, is discussed.     

Synthesis and characterization of a new cyclic phosph(V)azane ligand [(C6H5N)P(O)H]2 and its zinc(II) complex

The new cyclic phosph(V)azane ligand [(C₆H₅N)P(O)H]₂ (2) is obtained from the reaction between PCl₃ and PhNH₂ in toluene followed by controlled hydrolysis of the product in an H₂O–CHCl₃ solution. Compound 2 is the first example of P(V) dimer [(µ-NC₆H₅)P(H)=O]₂, a P₂N₂ ring with two P(O)H moieties. The reaction of 2 with ZnCl₂ in a molar ratio of 1?:?1 in tetrahydrofuran yields the cyclophosph(V)azane complex Cl₂Zn[(C₆H₅N)P(O)H]₂ (3) in which Zn–O bonds form directly between a cyclic phosph(V)azane ligand and Zn(II). The products have been characterized by infrared, multinuclear (¹H, ³¹P, ¹³C) NMR, mass spectrometry, and elemental analysis.     

Reactions of GeMe2-bridged dicyclopentadienes with molybdenum carbonyl: formation of germylidyne trimolybdenum clusters

In thermal reactions of the doubly bridged dicyclopentadienes (C₅H₃R(SiMe₂))(C₅H₃R(GeMe₂)) (R=H (1), ^tBu (5)) with Mo(CO)₆, the bridging GeMe₂ is cleaved to give the corresponding degermylated products [(η⁵-C₅H₃R)₂(SiMe₂)]Mo₂(CO)₆ (3, rac-7), or both GeMe₂ and SiMe₂ are cleaved to afford the nonbridged products [(η⁵-C₅H₄R)Mo(CO)₃]₂ (2, 6). The reactions also produce germylidyne trimolybdenum clusters [(η⁵-C₅H₃R)₂(SiMe₂)](η⁵-C₅H₄R)[Mo(CO)₂]₃(μ₃-GeMe) (4, rac-/meso-7) containing the Mo₃(μ₃-GeMe) units. Similarly, reaction of the single GeMe₂-bridged dicyclopentadienes (C₅H₅)₂GeMe₂ (9) with Mo(CO)₆ also results in the degermylated 2, as well as the similar trimolybdenum cluster [(η⁵-C₅H₅)Mo(CO)₂]₃(μ₃-GeMe) (10). The molecular structures of 4 and trans-5 were determined by X-ray diffraction.     

Synthesis,characterization of SiO2 supported-industrial phosphoric acid catalyst for hydrolysis of NaBH4 solution

Abstract

Tunisian industrial phosphoric acid H₃PO₄ was supported on silica gel SiO₂ (SIPA) to catalyze the hydrolysis reaction of aqueous alkaline sodium borohydride (NaBH₄). The SiO₂ was produced from purified quartz sand using alkali fusion-acidification chemical process. The BET surface area results indicate that the prepared silica gel could reach a specific surface area up to 585 m²/g. The addition of PO₃H₂ functional groups resulted in an increase of surface acidity of SiO₂ catalyst as shown by FT-IR and DTA-DTG spectra. The total acidity of SIPA catalyst was determined by titration to be 2.8?mmol H⁺/g. SEM/EDS maps reveal the distribution of heavy metals on the silica surface. The effect of supported PO₃H₂ functional groups and heavy metals on the NaBH₄ hydrolysis reaction was studied for different ratios of SIPA catalyst to NaBH₄. The sample 12SIPA/NaBH₄ leads to a very high hydrogen generation rate (up to 90%). The activation energy of hydrogen generation by NaBH₄ hydrolysis was 25.7?kJ mol^?1.     

Assembly of three supramolecular compounds based on [P2Mo5O23]6− and Ni(II) complexes

Three supramolecular compounds based on [P₂Mo₅O₂₃]^6? and Ni(II)–bim, [Ni(bim)₃]₃[P₂Mo₅O₂₃]·2H₂O (1), [Ni(Hbim)(bim)₂]₄[P₂Mo₅O₂₃]₂·3H₂O (2), and [Ni(bim)(Hbim)(phen)]₂[P₂Mo₅O₂₃]·7H₂O (3) (bim?=?2,2′-biimidazole, phen?=?1,10-phenanthroline), have been synthesized under hydrothermal conditions and characterized by elemental analysis, single-crystal X-ray diffraction, IR, and TG. All the compounds show 3-D supramolecular networks constructed from weak interactions among free Ni(II) complex, water, and oxygens of [P₂Mo₅O₂₃]^6?. Compound 3 represents the first supramolecular example integrating {Ni(bim)(Hbim)(phen)} with Strandberg-type phosphomolybdate. The compounds display good electrocatalytic activity to reduce hydrogen peroxide and intense fluorescence properties in solution at room temperature.     

Synthesis and chemistry of tris(2-pyridyl)phosphine and bis(2-pyridyl)phenylphosphine complexes of mercury(II) X (X = Br,Cl) and X-ray crystal structural determination of [HgBr2(PPh(2-py)2)2]

Mercury(II) halide complexes [HgX₂(P(2-py)₃)₂] (X?=?Br (1), Cl (2)) and [HgX₂(PPh(2-py)₂)₂] (X?=?Br (3), Cl (4)) containing P(2-py)₃ and PPh(2-py)₂ ligands (P(2-py)₃ is tris(2-pyridyl)phosphine and PPh(2-py)₂ is bis(2-pyridyl)phenylphosphine) were synthesized in nearly quantitative yield by reaction of corresponding mercury(II) halide and appropriate ligands. The synthesized complexes are fully characterized by elemental analysis, melting point determination, IR, ¹H, and ³¹P-NMR spectroscopies. Furthermore, the crystal structure of [HgBr₂(PPh(2-py)₂)₂] determined by X-ray diffraction is also reported.     

ZUR KENNTNIS DES NATRIUMDIPHENYLPHOSPHINOFORMIATS Ph2PCOONa1

Abstract

Ph ₂ PCOONa 2, hergestellt dutch Reaktion von Ph₂PNa mit CO₂, wird in protischen Medien rasch unter Bildung von Ph₂PH and CO₂ hydrolysiert. Die Hydrolyse verlauft in Natronlauge sehr viel langsamer and es bilden sich zusätzlich geringe Mengen Ph₂P(O)O^? und HCOO^?, Aus 2 and stöchiometrischen Mengen RI bilden sich tertiäre Phosphine Ph₂PR (R[dbnd]Me, Et) während mit überschüssigem MeI das Phosphoniumsalz [Ph₂PMe₂]I erhalten wird. Ph₂PCOOMe, Ph₂PCOOSiMe₃ bzw. Ph₂PCSSNa wurden durch Umsetzung von 2 mit (MeO)₂SO₂, Me₃SiCl bzw. CS₂ synthetisiert. Ph₂P(O)ONa and Ph₂P(S)SNa entstanden bei der Reaktion von 2 mit O₂ oder S₈ in Benzol.

Concerning Sodiumdiphenylphosphinoformiate Ph2PCOONa¹.

Ph₂PCOONa 2, prepared from Ph₂PNa and CO₂, is readily hydrolyzed in protic media with formation of Ph ₂ PH and CO₂. Hydrolysis is much slower in NaOH and small quantities of Ph₂P(O)O^? and HCOO^? are additionally formed. Reactions of 2 with RI in stoichiometrical amounts gave tertiary phosphines Ph₂PR (R[dbnd]Me, Et) while the phosphonium compound [Ph₂PMe₂]I resulted from 2 and MeI in excess. Ph₂PCOOMe, Ph₂PCOOSiMe₃ or Ph₂PCSSNa were obtained from 2 and (MeO)₂SO₂, Me₃SiCl or CS₂. Ph₂P(O)ONa and Ph₂P(S)SNa were isolated when 2 was reacted with O₂ or S₈ in benzene.