Racemic Tartrate/Malate Anions Combine with Racemic Complex Cations to Form Optically Active Ionic Crystals

Spontaneous resolution has attracted continuing attention in various research fields since Pasteur's work on the crystallization behavior of racemic tartrate. Here, a unique example of this phenomenon is reported, involving ionic crystals generated from racemic RR/SS- tartrate or R/S-malate and racemic ΔΔ/ΛΛ-[Ag₃Rh₂(2-aminoethanethiolato)₆]³⁺ (ΔΔ/ΛΛ-[ 1 ]³⁺) in water. RR- and SS-tartrate selectively recognize the ΛΛ and ΔΔ isomers of [ 1 ]³⁺ to produce ionic crystals of (ΛΛ-[ 1 ])₂(RR-tartrate)₃ and (ΔΔ-[ 1 ])₂(SS-tartrate)₃, respectively, which can undergo spontaneous resolution. While spontaneous resolution also occurs when using R/S-malate, R- and S-malate select the opposite isomers of [ 1 ]³⁺ to give ionic crystals of (ΔΔ-[ 1 ])₂(R-malate)₃ and (ΛΛ-[ 1 ])₂(S-malate)₃, respectively. In the presence of S-aspartate, (ΛΛ-[ 1 ])₂(R-tartrate)₃ and (ΔΔ-[ 1 ])₂(S-tartrate)₃ are preferentially crystallized from ΔΔ/ΛΛ-[ 1 ]³⁺ and RR/SS-tartrate at solution pH values of 6 and 10, respectively. This finding provides significant insight into the optical resolution of chemical species by spontaneous resolution and the origin of homochirality in nature.     

Synthesis and Magnetism of the Complexes of Hexaisothiocyanatochromate Anions with Radical Cations

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Chiral Crystals,Jack, Conductivity and Magnetism

Recently, the application of magnetic fields to chiral chemical systems has been rewarding. In a forward-looking 1986 paper, ‘Chiral Metals?’, Wallis, Karrer, and Jack D. Dunitz forecast ‘that the limitation to proper symmetry elements in a chiral conductor could be associated with the emergence of new properties, those connected with interactions between applied electric and magnetic fields and their internal counterparts.’ This was a prescient remark, but it has become manifest in ways that would not have been foreseen in its details by the authors. Here are reviewed the development of chiral conductors broadly imagined by Dunitz and coworkers, based on enantiopure tetrathiafulvalene derivatives that restrict space groups to those that have only symmetry operations of the first kind, as well as the new emergent properties associated with the transport of electrons when magnetic fields are applied to chiral crystals among other systems. These include electrical magnetochiral anisotropy (eMChA), inverse electrical magnetochiral anisotropy (ieMChA), helimagnetism and chirality induced spin selectivity (CISS). The conclusion discussing the circumstances under which achiral TTF crystals becomes chiral, only seems to introduce an oxymoron.     

碳包裹软磁金属纳米粒子的绿色合成及热稳定性研究

本文报道了一种制备碳包裹软磁金属纳米粒子的绿色合成方法:将金属醋酸盐溶液与可溶性淀粉均匀混合,蒸发、烘干后在N2保护下热处理,得到金属纳米复合粒子(C@Ni,C@Co,C@Fe,C@CoNi,C@CoFe,C@FeNi)。TEM结果表明金属粒子均匀分散在碳介质中,粒径为3~5 nm。样品在室温下具有良好的抗氧化性、热稳定性和软磁性能。     

分子磁学中的单位制*

系统阐释了分子磁性研究中磁场强度、磁感强度、磁矩、磁化强度、磁化率等基本物理量的概念和单位,并厘清了以上物理量在国际单位制和电磁单位制中的转换关系。在此基础上讨论了使用分子磁学基本公式、Van Vleck公式和Brillouin函数计算分子摩尔磁化强度和摩尔磁化率时的注意事项。     

多原子桥联异多核配合物的分子磁性研究进展

评述了与分子基磁体密切相关的5类多原子桥联异核配合物(草胺酸类、草酰胺类、草酸根类、二肟类和氰根类)磁性研究的最新进展,并对该领域进行了简要展望.     

Suboxides with Complex Anions: The Suboxoindate Cs9InO4

Salty metal : In the suboxometallate Cs₉InO₄, metallic cesium columns (see picture; blue) lie next to ionic oxoindate(III) columns. The chemistry of the suboxides is thus expanded to structures containing complex anions.

     

Photoluminescent Ferroelastic Molecular Crystals

Ferroelasticity has been reported for several types of molecular crystals, which show mechanical‐stress‐induced shape change under twinning and/or spontaneous formation of strain. Aiming to create materials that exhibit both ferroelasticity and light‐emission characteristics, we discovered the first examples of ferroelastic luminescent organometallic crystals. Crystals of arylgold(I)(N‐heterocyclic carbene)(NHC) complexes bend upon exposure to anisotropic mechanical stress. X‐ray diffraction analyses and stress‐strain measurements on these ferroelastic crystals confirmed typical ferroelastic behavior, mechanical twinning, and the spontaneous build‐up of strain. A comparison with single‐crystal structures of related gold‐NHC complexes that do not show ferroelasticity shed light on the structural origins of the ferroelastic behavior.     

Molecular Lanthanide Switches for Magnetism and Photoluminescence

Solvation of [(CNT)Ln(η⁸-COT)] (Ln=La, Ce, Nd, Tb, Er; CNT=cyclononatetraenyl, i.e., C₉H₉⁻; COT=cyclooctatetraendiid, i.e., C₈H₈²⁻) complexes with tetrahydrofuran (THF) gives rise to neutral [(η⁴-CNT)Ln(thf)₂(η⁸-COT)] (Ln=La, Ce) and ionic [Ln(thf)_x(η⁸-COT)][CNT] (x=4 (Ce, Nd, Tb), 3 (Er)) species in a solid-to-solid transformation. Due to the severe distortion of the ligand sphere upon solvation, these species act as switchable luminophores and single-molecule magnets. The desolvation of the coordinated solvents can be triggered by applying a dynamic vacuum, as well as a temperature gradient stimulus. Raman spectroscopic investigations revealed fast and fully reversible solvation and desolvation processes. Moreover, we also show that a Nd:YAG laser can induce the necessary temperature gradient for a self-sufficient switching process of the Ce(III) analogue in a spatially resolved manner.     

Linear Copper Complex Arrays as Versatile Molecular Strings: Syntheses,Structures, Luminescence,and Magnetism

The defined linear arrangement of metal atoms in discrete coordination complexes or polymers is still one of the most intriguing challenges in synthetic chemistry. These chain arrangements are of fundamental importance, because of their potential applications as molecular wires and single molecule magnets (SMM) in microelectronic devices on a molecular scale. Oligonuclear Group 11 metal complexes with suitable bridging ligands, specifically those that are based on copper as the first choice of a cheap precursor coinage metal, are of particular interest in this regard. This is due to the superior luminescence properties of these linear clusters that often show d¹⁰⋅⋅⋅d¹⁰ interactions in their molecular structures. The combination of Cu^I with heavier coinage metal ions results in tunable emissive arrays that are also stimuli-responsive. Thus, both linear multinuclear Cu^I and linear heteropolymetallic Cu^I/Ag^I as well as Cu^I/Au^I clusters are excellent candidates for applications in molecular/organic light-emitting devices (OLEDs). Alternatively, paramagnetic multinuclear cupric arrays are prominent as potential molecular wires with enhanced magnetic properties through multiple coupled d⁹ centers. This Review covers the whole range of linear multinuclear assemblies of cuprous and cupric ions in complexes and coordination polymers, their syntheses, photophysical behavior, and magnetic properties. Moreover, recent advances in the rapidly progressing field of hetero-Cu^I/Ag^I and Cu^I/Au^I molecular strings are also discussed.     

Crystal Structures and Phase Sequences of Metallocenium Salts with Fluorinated Anions: Effects of Molecular Size and Symmetry on Phase Transitions to Ionic Plastic Crystals

Sandwich compounds often exhibit various phase transitions, including those to plastic phases. To elucidate the general features of the phase transitions in metallocenium salts, the thermal properties and crystal structures of [Fe(C₅Me₅)₂]X ([ 1 ]X), [Co(C₅Me₅)₂]X ([ 2 ]X), and [Fe(C₅Me₄H)₂]X ([ 3 ]X) have been investigated, where the counter anions (X) are Tf₂N (=(CF₃SO₂)₂N^?), OTf (=CF₃SO₃^?), PF₆, and BF₄. The Tf₂N salts commonly undergo phase transitions from an ordered phase at low temperatures to an anion‐disordered phase, followed by a plastic phase and finally melt at high temperatures. All these salts exhibit a phase transition to a plastic phase, and the transition temperature generally decreases with decreasing cation size and increasing anion size. The crystal structures of these salts comprise an alternating arrangement of cations and anions. About half of these salts exhibit phase transitions at low temperatures, which are mostly correlated with the order–disorder of the anion.     

密度泛函理论在分子磁学中的应用

通过对桥联双核铁的磁耦合常数的计算，探讨了密度泛函理论计算条件对计算 结果的影响。基于密度泛函理论下的破损态方法，着重讨论了双核 Fe(III)_2的 d~5-d~5电子通过氧桥的超交换作用。研究发现分子的反铁磁通道主要是Fe(III) d_yz和d_z~2与μ-O的p轨道形成的，具有π*/π*和σ*/σ*特征的超交换通道。     

分子磁性的量子化学研究进展

本文概述了研究分子磁性的量子化学方法和研究进展。首先介绍分子磁性研究中的量子化学原理和所使用计算方法,总结了有代表性的自由基、自由基-金属配合物、桥联多核过渡金属配合物等分子磁性的研究情况,并对今后研究分子磁性的量子化学方法作了展望。     

分子晶体中的几种分子间相互作用

描述了ＨＥＫ－ＤＤＱ，［Ｃｏ（Ｃ_５Ｈ_５）_２］［Ｎｉ（ｄｍｉｔ）_２］，ＢＢＢＴ－ＤＴＴ三个晶体结构中的π…π；Ｓ…Ｓ；Ｂｒ…Ｂｒ分子间相互作用，讨论了分子晶体中的分子间相互作用的材料化学意义。     

Catalytic Selective Dihydrosilylation of Internal Alkynes Enabled by Rare-Earth Ate Complex

Hydrosilylation of alkynes generally yield vinylsilanes, which are inert to the further hydrosilylation because of the steric effects. Reported here is the first successful dihydrosilylation of aryl- and silyl-substituted internal alkynes enabled by a rare-earth ate complex to yield geminal bis- and tris(silanes), respectively. The lanthanum bis(amido) ate complex supported by an ene-diamido ligand proved to be the ideal catalyst for this unprecedented transformation, while the same series of yttrium and samarium alkyl and samarium bis(amido) ate complexes exhibited poor activity and selectivity, indicating significant effects of the ionic size and ate structure of the rare-earth catalysts.     

杯[4]芳烃硫脲衍生物的合成及其对阴离子的络合性能

杯[4]芳烃四丁醚经过对位硝化反应后在水合肼作用下被还原成氨基衍生物， 并进一步与异硫氰酸苯酯反应得到单取代与1，3－二取代的杯[4]芳烃硫脲衍生物 ，总收率为50％。它们对系列阴离子的络合实验表明氢键的形成在络合过程中有重 要作用，其中杯[4]双硫脲衍生物5b对H2PO4^-显现出良好的选择性络合能力。     

Superfluorinated Ionic Liquid Crystals Based on Supramolecular,Halogen‐Bonded Anions

Unconventional ionic liquid crystals in which the liquid crystallinity is enabled by halogen‐bonded supramolecular anions [C_nF_{2 n+1}‐I???I???I‐C_nF_{2 n+1}]^? are reported. The material system is unique in many ways, demonstrating for the first time 1) ionic, halogen‐bonded liquid crystals, and 2) imidazolium‐based ionic liquid crystals in which the occurrence of liquid crystallinity is not driven by the alkyl chains of the cation.     

2D Inorganic Materials: from Atomic Crystals to Molecular Crystals

rof.Zhai Tianyou and co-workers introduce the concept of 2D inorganic molecular crystals,which are different from traditional 2D atomic crystals,such as graphene,MoS2,black phosphorus,MXene,etc.The materials system is unique,and completely new to the community.Another research boom on 2D molecular materials may thus be drawn in the scope of electronics,energy and environment.This work has been published online in the Nature Communications in October 17,2019.     

A Critical Contact in Molecular Crystals

Moscow University Chemistry Bulletin - Abstract—The definitions of the critical contact and critical energy coordination number (CECN) of a molecular crystal are introduced. Some...