Synthesis of enantiopure β-amino alcohols via AKR/ARO of epoxides using recyclable macrocyclic Cr(III) salen complexes

A series of chiral macrocyclic Cr(III) salen complexes 1-8 were synthesized and characterized. These complexes were found to be highly active, regio-, diastereo-, and enantioselective catalysts in aminolytic kinetic resolution (AKR) of racemic trans-epoxides as well as asymmetric ring opening (ARO) of prochiral meso-epoxides with various anilines as nucleophiles at room temperature in 18-24 h. Excellent yields (>99% with respect to the nucleophile) with high enantioselectivity (ee, >99%) of chiral anti-β-amino alcohols was achieved with concomitant recovery of corresponding epoxides in high ee (up to >99%). The complex 1 also catalyzed the ARO of meso-epoxides to provide corresponding syn-β-amino alcohols in high yield (99%) and ee (up to 91%). Due to built-in basic sites in the catalyst, no external base (as an additive) was required to promote AKR and ARO reactions. The catalyst 1 was conveniently recycled several times with retention of its performance. The AKR of trans-stilbene oxide with aniline was successfully demonstrated at relatively higher scale (10 mmol) using the catalyst 1.     

Non-covalent Interactions in the Crystal Lattices of Copper(II) Complexes with Macrocyclic Ligands Containing Aryl Substituents

It has been established that, depending on the structure of the substituents in the ligand, macrocyclic complexes of copper(II) show in the crystal lattice different types of non-covalent interactions (hydrophobic, CH- interactions, and -stacking) which lead to the formation of intermolecular aggregates (dimers) and the formation of layer structures with alternating hydrophobic and hydrophilic regions.     

Discrete Magnesium Hydride Aggregates: A Cationic Mg13H18 Cluster Stabilized by NNNN‐Type Macrocycles

Large magnesium hydride aggregates [Mg₁₃(Me₃TACD)₆(μ₂‐H₁₂)(μ₃‐H₆)][A]₂ ((Me₃TACD)H=1,4,7‐trimethyl‐1,4,7,10‐tetraazacyclododecane; A=AlEt₄, AlnBu₄, B{3,5‐(CF₃)₂C₆H₃}₄) were synthesized stepwise from alkyl complexes [Mg₂(Me₃TACD)R₃] (R=Et, nBu) and phenylsilane in the presence of additional Mg^II ions. The central magnesium atom is octahedrally coordinated by six hydrides as in solid α‐MgH₂ of the rutile type. Further coordination to six magnesium atoms leads to a substructure of seven edge‐sharing octahedra as found in the hexagonal layer of brucite (Mg(OH)₂). Upon protonolysis in the presence of 1,2‐dimethoxyethane (DME), this cluster was degraded into a tetranuclear dication [Mg₂(Me₃TACD)(μ‐H)₂(DME)]₂[A]₂.     

自组装中的苯二甲酸阴离子形貌及质子化效应

在高效合成大环主体化合物环[2][2,6-二（1H-咪唑基）]吡啶[2]（1,4-二亚甲基苯）[cyclo[2]（2,6-bis（1H-imidazol-1-yl）pyridine）[2]（1,4-dimethylenebenzene）;1⁴⁺]的基础上,通过溶液中核磁¹H谱、扩散排序核磁共振谱（Diffusion Ordered NMR Spectroscopy;DOSY）、二维核磁欧沃豪斯效应增强谱（Nuclear Overhauser Effect Spectroscopy;NOESY）波谱方法,气相中质谱（ESI-MS）及固相中X射线单晶衍射方法,详细考察1⁴⁺与一系列苯二甲酸阴离子客体的相互作用. 发现苯二甲酸阴离子客体的形貌与质子化因素对主客体的作用模式、相互作用的化学计量比以及形成超分子自组装复合物的结合常数均起着决定性的作用. 本文结果将有助于指导后继新型大环主体化合物与多羧酸阴离子构筑的自组装体系的设计和研究.     

大环多胺配体ODTH的合成及其性质的研究

A new dinucleating 36-membered octoazadiphenol macrocyclic ligand， 3，6，9，12，20，23，26，29-octoaza-35，36-dihydroxy-16，33-dimethyl-tricyclo-hexatriacontane-1(34)，14，16，18(36)，31，32-hexene， ODTH， was synthe-sized by NaBH4 hydrogenation of the corresponding Schiff base obtained from the [2+2] condensation between triethylenetetraamine and diformyl-p-cresol. It was characterized by elemental analysis， IR， UV-Vis， 1H NMR and MS. The protonation constants of ODTH and the stability constants of its complexes with Cu(Ⅱ) in 1∶1 and 1∶2 system(metal-ODTH)， have been determined potentiometrically at 25.0℃ and μ=0.100 mol·L^-1 KCl. Poten-tiometric equilibrium studies indicate that a variety of deprotonated and protonated mononuclear and dinuclear， as well as hydroxy-bridged complexes， form in the pH range 2～12 in aqueous solution. The species distributions and the characteristics of ODTH and the complexes are also described.     

RuII complexes incorporating tetrathiamacrocycles: synthesis and conformational analysis

The synthesis of a series of RuII complexes incorporating thiacrown ligands ([12]ane-S4, [14]ane-S4, [16]ane-S4), as well as 2,2'-bipyridine (bpy) or pyridine, is reported. Structural studies on these complexes have been carried out using a variety of techniques. Detailed 1H NMR spectroscopic studies on the previously reported [Ru([12]ane-S4)(bpy)]2+ (1) reveal that-contrary to earlier reports-the observed fluxional 1H NMR behavior is not due to chemical exchange involving cleavage of the bpy Ru--N bond but is, in fact, due to lone-pair inversion of coordinated macrocyclic sulfur donor atoms. This phenomenon is also observed for the [14]ane-S4 and [16]ane-S4 analogues of 1. For the first time, using a combination of X-ray crystallography, more detailed 1H NMR experiments, and computational methods, an in-depth study on the energetics and dynamics of invertomer formation and conversion for macrocyclic coordination complexes has been carried out. These studies reveal that the steric constraints of assembling each sulfur macrocycle and bpy ligand around the octahedral Ru(II) center lead to close intramolecular contacts. These contacts are largely dependent on the orientation of the electron lone pairs of equatorial sulfur donor atoms and correlate with the comparative stability of the different invertomeric forms. Thus, the conformational preferences of the three macrocyles in [Ru([n]ane-S4)(bpy)]2+ complexes are determined by steric rather than electronic effects.     

2，3，12，13－二苯并－1，5，8，11，15，18－六氧杂－环二十－2，12－二烯（anti－DB20C6）的晶体和分子结构研究

２，３，１２，１３－二苯并－１，５，８，１１，１５，１８－六氧杂－环二十－２，１２－二烯（ａｎｔｉ－ＤＢ２０Ｃ６）的晶体和分子结构研究毛治华黄枢周宗华孟杰（四川联大东区化学系成都６１００６４）洪洲（四川联大东区分析测试中心成都６１００６４）关键词晶体...     

基质辅助激光解吸电离质谱表征新型环状聚芳酯预聚体

应用基质辅助激光解吸电离质谱技术对新型环状聚芳酯预聚体进行了表征，从而确定了该环素聚合物不同聚合度（ｎ＝１，２……８）的存在，获得了满意的结果。实验证明本方法是测定环状聚合物不同聚合度快速、有效、准确的方法。