金属锡作用下炔丙基碘与醛类化合物的反应

金属锡作用下的烯丙基卤代物与羰基化合物的加成反应以其反应条件温和及能选择性地与含有其他反应活性基团的羰基化合物加成等特点而显示出在有机合成上的应用价值。但目前这类反应还只局限于烯丙基卤代物反应的范围内。本文首次报道金属锡作用下的炔丙     

Crystal Structures of Cs+-Crown Ether Complexes Containing Polynuclear Mercury Iodide Anions

Reactions of CsI and HgI₂ with benzo-15-crown-5 (B15C5) and 15-crown-5 (15C5) in an ethanol-acetone mixture produced [Cs(B15C5)₂]₂[Hg₂I₆] (1) and {[Cs(15C5)]₂[Hg₂I₆]}_n (2), respectively. The structures of the two complexes are quite different. Molar ratios of Cs⁺ : crown ether are 1 : 2 in 1 and 1 : 1 in 2. Complex 1 consists of two Cs(B15C5) ₂ ⁺ cations and a Hg₂I ₆ ^2- anion. Cs⁺ lies between the two crown-5 ligands, resulting in a sandwich-type cation. Cationic Cs(B15C5) ₂ ⁺ and anionic Hg₂I ₆ ^2- are linked together by electrostatic interactions and the complex 1 is an ion pair compound. Complex 2 consists of infinite [Cs(15C5)]₂[Hg₂I₆] units. Each structural unit contains two Cs(15C5)⁺ cations and a Hg₂I ₆ ^2- anion. Cs⁺ is coordinated by five oxygen atoms of 15C5, three iodine atoms of Hg₂I ₆ ^2- , and an iodine atom of Hg₂I ₆ ^2- in an adjacent structural unit. The interactions between the Cs⁺ of Cs(15C5)⁺ and an I^– in Hg₂I ₆ ^2- from adjacent structural units polymerize the complex 2, resulting in a one-dimensional network structure. The anions of Hg₂I ₆ ^2- in both complexes are similar. The two mercury atoms are linked through two bridging iodine atoms and each mercury is also coordinated by two terminal iodines. Crystal data for 1: space group P2₁/c (No. 14), a = 12.253(4), b = 20.945(7), c = 16.110(6) Å, = 111.0(1)°, V = 3860 ų, Z = 4, R = 0.082 (R _w = 0.089). Crystal data for 2: space group P2₁/c (No. 14), a = 12.157(4), b = 8.546(4), c = 20.666(6) Å, = 91.54(3)°, V = 2146 ų, Z = 4, R = 0.034 (R _w = 0.048).     

四丁基碘化铵催化甲基丙烯酸甲酯的可逆-休眠自由基溶液聚合

以四丁基碘化铵(BNI) 为有机催化剂, 碘单质(I₂) 与偶氮二异庚腈(ABVN) 原位生成的碘代异庚腈为引发剂, 进行甲基丙烯酸甲酯(MMA) 的溶液聚合. 以甲苯为溶剂, MMA:I₂:ABVN的摩尔比为200:1:1.7, 考察了催化剂用量对聚合的影响. 结果表明, 加入催化剂可以缩短诱导期, 当I₂:BNI摩尔比为1:1时聚合反应的诱导期最短(1.7 h); 当BNI:I₂摩尔比为0.25:1~2:1之间时, 聚合物实测分子量与理论值十分接近, 分子量分布较窄, 分子量分布指数(M_w/M_n) 多在1.2以下. 考察了在N,N'-二甲基甲酰胺(DMF)、 四氢呋喃(THF)、 苯甲醚、 苯和甲苯5种溶剂中的聚合反应, 发现在苯和甲苯中聚合可控性最佳, M_w/M_n多在1.2以下; 苯甲醚和THF中聚合速率较快, 聚合物分子量分布较苯中的略宽. 以DMF为溶剂时所得聚合物分子量分布很宽, 聚合可控性差. 核磁共振分析聚合物为碘封端结构, 碘原子封端的聚合物链所占比为91.6%.     

Optimization of Hydrogen‐Evolving Photochemical Molecular Devices

A molecular photocatalyst consisting of a Ru^II photocenter, a tetrapyridophenazine bridging ligand, and a PtX₂ (X=Cl or I) moiety as the catalytic center functions as a stable system for light‐driven hydrogen production. The catalytic activity of this photochemical molecular device (PMD) is significantly enhanced by exchanging the terminal chlorides at the Pt center for iodide ligands. Ultrafast transient absorption spectroscopy shows that the intramolecular photophysics are not affected by this change. Additionally, the general catalytic behavior, that is, instant hydrogen formation, a constant turnover frequency, and stability are maintained. Unlike as observed for the Pd analogue, the presence of excess halide does not affect the hydrogen generation capacity of the PMD. The highly improved catalytic efficiency is explained by an increased electron density at the Pt catalytic center, this is confirmed by DFT studies.     

手性高价碘试剂的发展及展望

在过去几十年中，高价碘化学已成为有机化学研究的重要领域.高价碘化合物在多种类型的化学转化中，展现与过渡金属相似的反应性质.而其温和的反应条件、低耗费、环境友好、低毒性等特点，使高价碘化学引起了广泛的研究兴趣，并取得了巨大的进展.手性的高价碘试剂或前体也得以发展并应用于一系列化学计量或催化的不对称反应.近年来，手性高价碘领域研究进展显著，但也存在诸多不足.在本综述中，根据其结构特点以及发展的时间线，对多种类型的手性高价碘试剂和前体做一个总结，这将有助于帮助本领域研究者更好地理解手性高价碘化学的发展以及不足之处.     

一种Λ型吡啶碘盐的合成和晶体结构

A new Λ type pyriding iodide was synthesized by reaction of 4-picoline and methyl diiodide. The structure was characterized by elemental analysis, IR, UV and TG. The crystal structure of the title compound was determined by X-ray single crystal diffraction. The crystal belongs to monoclinic with space group C2/c, a=18.812(4)?, b=8.7816(6)?, c=10.3165(12)?, β=93.71(1), V=1700.7(4)?³, Z=4. In the molecule, two 4-picoline molecules are bonded by -CH₂ group to form Λ type pyridine salt. CCDC: 180871.     

A New Polymeric Framework Formed by the Self Assembly of 5,10,15,20-tetra(3-pyridyl)porphyrin,HgI2 And C60

The X-ray structure of H₂T(3-Py)P·HgI₂·C_60, cocrystallized from a chlorobenzene/methanol solvent mixture containing 5,10,15,20- tetra(3-pyridyl)porphyrin, HgI₂ and C₆₀, has been determined. A new two dimensional arrangement of the tetra(3-pyridyl)porphyrin molecules joined by coordination to HgI₂ is formed. These assemblies are connected by close C₆₀-porphyrin π–π interactions leading to the alignment of the porphyrins into linear alternating fullerene porphyrin columns. The structure is compact with no significant cavities.     

二维离子色谱法同时测定环境水样中的碘离子、硫氰酸根和高氯酸根

建立了二维离子色谱法同时测定环境水样中的碘离子、硫氰酸根离子和高氯酸根离子的方法。先采用常规阴离子色谱柱(IonPac AS16, 250 mm×4 mm)将水样中的碘离子、硫氰酸根离子和高氯酸根离子与干扰离子进行分离。样品溶液通过抑制器后,将含有碘离子、硫氰酸根离子和高氯酸根离子的淋洗液导入富集柱(MAC-200, 80 mm×0.75 mm),再通过毛细管阴离子色谱柱(IonPac AS20 Capillary, 250 mm×0.4 mm)进行分离和定量分析。方法的线性范围为0.05～100 μg/L,相关系数达到0.9999,检出限为0.02～0.05 μg/L。样品中碘离子、硫氰酸根离子和高氯酸根离子的加标回收率在85.1%～100.1%之间,回收率的相对标准偏差(RSD)(n=6)在1.7%～4.9%之间。该法试剂用量小,灵敏度比常规离子色谱提高30～40倍,同时去除了样液中的高浓度基体杂质,适用于水样中低含量碘离子、硫氰酸根离子和高氯酸根离子的检测。     

碘化钾-乙基紫-水体系固相浮选分离镉的研究

研究了碘化钾 乙基紫 水体系固相浮选分离镉的行为及与常见金属离子分离的最佳条件。试验表明,将碘化钾溶液、乙基紫溶液和盐酸溶液混合稀释,生成稳定的CdI2-4·(EV+)2三元缔合物可很快浮于水相,使Cd(Ⅱ)被定量浮选。控制适当条件,可实现Cd(Ⅱ)与常见金属离子Mn(Ⅱ)、Al(Ⅲ)、Ni(Ⅱ)、Zn(Ⅱ)之间的分离。对合成水样进行了浮选分离测定,结果满意。