Synthesis and Crystal Structure of a Complex Bimetallic Salt [Ni(trans_[14]diene)] [Ni (mnt)_2]

1INTRoDUCTIONMacrocycliccoordinationcomPOundshavebeenwidelyinvestigatedinthepastdecadesbecauseoftheirrelationshiptocomplexesofbiologicalsignificancesuchasthePorphyrinsandcorrins(lJ.Structuresofmanymacrocycliccompoundshavebeenre-ported,especiallythecompoundscontainingN4macrocyclicligands"'.However,toourknowledge,onlyafewcrystalstructuresofcomplexbimetallicsaltscontainingmacrocyclicligandshavebeendeterminedbyX-raydiffractionmethod.Inthispa-per,werePortthesynthesisandstructureofthetit1ecom…     

A Mechanically Interlocked [3]Rotaxane as a Light‐Harvesting Antenna: Synthesis,Characterization, and Intramolecular Energy Transfer

Mimicking photosynthesis : The concept of light‐harvesting by using a mechanically interlocked [3]rotaxane is developed through synthesis and characterization. Our results provide a new candidate for light‐harvesting systems and also open up the possibility of creating intelligent or controllable energy‐collecting machines (see figure).

     

金属有机盐[CpFe(C6H6)]2·[Ni(mnt)2]的合成及晶体结构

通过[CpFe(C6H6)]PF6与Na2[Ni(mnt)2]复分解反应合成了金属有机盐[CpFe(C6H6)]2·[Ni(mnt)2],用元素分析、红外光谱和1H NMR进行了鉴定,并用X射线测定了晶体结构.结构分析表明,该化合物属于三斜晶系,空间群P1.晶胞参数:α=0.838(2)nm,b=1.084(6)nm,c=1.816(7)nm,α=83.41(4)°β=89.30(3)°,γ=80.22(3)°Z=2.晶体中混式夹心的阳离子处于几乎互相垂直的取向.配阴离子平面也存在两种取向,它们形成75.4°的二面角.测试表明,化合物表现半导体属性,其粉末压片室温电导率为4.1×10-S·cm-1.     

Active Esters as Pseudostoppers for Slippage Synthesis of [2]Pseudorotaxane Building Blocks: A Straightforward Route to Multi‐Interlocked Molecular Machines

The efficient synthesis and very easy isolation of dibenzo[24]crown‐8‐based [2]pseudorotaxane building blocks that contain an active ester motif at the extremity of the encircled molecular axle and an ammonium moiety as a template for the dibenzo[24]crown‐8 is reported. The active ester acts both as a semistopper for the [2]pseudorotaxane species and as an extensible extremity. Among the various investigated active ester moieties, those that allow for the slippage process are given particular focus because this strategy produces fewer side products. Extension of the selected N‐hydroxysuccinimide ester based pseudorotaxane building block by using either a mono‐ or a diamino compound, both containing a triazolium moiety, is also described. These provide a pH‐dependent two‐station [2]rotaxane molecular machine and a palindromic [3]rotaxane molecular machine, respectively. Molecular machinery on both interlocked compounds through variation of pH was studied and characterized by means of NMR spectroscopy.     

Absolute Asymmetric Synthesis: Viedma Ripening of [Co(bpy)3]2+ and Solvent‐Free Oxidation to [Co(bpy)3]3+

Syntheses of [Co(bpy)₃]²⁺ yield racemic solutions because the Δ‐ and Λ‐enantiomers are stereochemically labile. However, crystallization and attrition‐enhanced deracemization can give homochiral crystal batches of either handedness in quantitative yield. Subsequently, solvent‐free oxidation with bromine vapour fixes the chirality because [Co(bipy)₃]³⁺ does not enantiomerize in solution at ambient temperature. This combination of Viedma ripening and the labile/inert Co^II/Co^III couple constitutes a convenient method of absolute asymmetric synthesis.     

Methacrylic Polymers Bearing in the Side-Chain an Optically Active Moiety Linked to the trans-4-Azobenzene Chromophore: Chiroptical Properties of Poly[(S)-(+)-N-methyl-(2-methacryloyloxypropanoyl)-4-aminoazobenzene]

The synthesis by radical homopolymerization of a novel optically active methacrylic polymer containing a side-chain chiral moiety linked to a photochromic chromophore has been carried out starting from the related monomer trans-(S)-(+)-N-methyl-(2-methacryloyloxypropanoyl)-4-aminoazobenzene. The chiroptical properties in solution of the polymer have been investigated by circular dichroism and compared with those of the corresponding low molecular weight model compound, trans-(S)-(+)-N-methyl-(2-pivaloyloxypropanoyl)-4-aminoazobenzene. The optical activity displayed by the polymer is discussed in terms of extent of chiral conformations assumed by the macromolecules as a consequence of dipole-dipole interactions between the azoaromatic chromophores.     

Front Cover: Dynamic Covalent Chemistry for Synthesis and Co-conformational Control of Mechanically Interlocked Molecules (Eur. J. Org. Chem. 8/2023)

Mechanically interlocked molecules have found extensive applications in areas all across the physical sciences, from materials to catalysis and sensing. However, introducing mechanical bonds and entanglements at the molecular level is still a significant challenge due to the inherent restriction in entropy needed to preorganize strands before interlocking. Over the last decade, dynamic covalent chemistry has emerged as one of the most efficient methods of forming rotaxanes, catenanes and molecular knots. By using reversible bonds such as imines, disulfides and boronate esters, one can use the inherent error-correction in these linkages to form interlocked architectures with high fidelity and often in excellent yields. This review reports on recent advances in the use of dynamic covalent chemistry to make mechanically interlocked molecules, systematically surveying clipping, capping and templating approaches with dynamic bonds. Furthermore, it is also discussed how dynamic bonds can be used to control motion, co-conformational expression and catalytic activity in mechanically interlocked molecular machinery.     

Synthesis and Structure of [Hg{OP(O)CF3(OH)}2(PMe3)3], a Distorted Trigonal Bipyramidal Complex Connected by Hydrogen Bridges to Polymeric Chains

The hydrolysis of [Hg{P(CF₃)₂}₂(PMe₃)₂] yields colourless crystals of [Hg{OP(O)CF₃(OH)}₂(PMe₃)₃]. The proposed multistep reaction proceeds via primary hydrolysis of the starting material giving HgO and HP(CF₃)₂. The latter is directly oxidized by HgO to (CF₃)₂P(O)OH. The bis(trifluoromethyl)phosphinic acid hydrolyses to CF₃P(O)(OH)₂ which reacts with [Hg{P(CF₃)₂}₂(PMe₃)₂] in the presence of PMe₃ to the title compound. The crystal structure was determined by X‐ray single‐crystal analysis (triclinic; P1¯; a = 860.7(1), b = 1007.6(2), c = 1625.0(3) pm; α = 96.09(2), β = 101.09(2), γ = 107.79(2)°; Z = 2) and exhibits distorted trigonal bipyramidal mercury complexes which are connected to polymeric chains. The acidic units, {OP(O)CF₃(OH)}^—, are connected via intermolecular hydrogen bridges, forming two individual centrosymmetric eight membered rings with asymmetric hydrogen bridges with O—O distances of 249.4(8) and 250.8(8) pm.     

Synthesis and Crystal Structure of a New Salt of the Water‐Stable Hexathiohypodiphosphate Anion: [py2Li]4[P2S6] ·2 py

A new rare example of a synthetic route in solution to the hexathiohypodiphosphate anion P₂S₆⁴⁻ is presented. Starting from P₄S₃, Li₂S, and elemental sulfur in pyridine, this reaction yields yellow block‐shaped crystals of [py₂Li]₄[P₂S₆] · 2 py ( 1 ). The molecular structure of this hitherto unknown compound was determined by single crystal X‐ray diffraction and reveals a heteronorbornane skeleton within the Li₄P₂S₆ entity.     

Structural Design and Synthesis of an SnO2@C@Co-NC Composite as a High-Performance Anode Material for Lithium-Ion Batteries

To overcome the drawbacks of the structural instability and poor conductivity of SnO₂-based anode materials, a hollow core–shell-structured SnO₂@C@Co-NC (NC=N-doped carbon) composite was designed and synthesized by employing the heteroatom-doping and multiconfinement strategies. This composite material showed a much-reduced resistance to charge transfer and excellent cycling performance compared to the bare SnO₂ nanoparticles and SnO₂@C composites. The doped heteroatoms and heterostructure boost the charge transfer, and the porous structure shortens the Li-ion diffusion pathway. Also, the volume expansion of SnO₂ NPs is accommodated by the hollow space and restricted by the multishell heteroatom-doped carbon framework. As a result, this structured anode material delivered a high initial capacity of 1559.1 mA h g⁻¹ at 50 mA g⁻¹ and an initial charge capacity of 627.2 mA h g⁻¹ at 500 mA g⁻¹. Moreover, the discharge capacity could be maintained at 410.8 mA h g⁻¹ after 500 cycles with an attenuation rate of only 0.069 % per cycle. This multiconfined SnO₂@C@Co-NC structure with superior energy density and durable lifespan is highly promising for the next-generation lithium-ion batteries.     

Li[B(OCH2CF3)4]: Synthesis,Characterization and Electrochemical Application as a Conducting Salt for LiSB Batteries

A new Li salt with views to success in electrolytes is synthesized in excellent yields from lithium borohydride with excess 2,2,2‐trifluorethanol (HOTfe) in toluene and at least two equivalents of 1,2‐dimethoxyethane (DME). The salt Li[B(OTfe)₄] is obtained in multigram scale without impurities, as long as DME is present during the reaction. It is characterized by heteronuclear magnetic resonance and vibrational spectroscopy (IR and Raman), has high thermal stability (T_{decomposition}>271 °C, DSC) and shows long‐term stability in water. The concentration‐dependent electrical conductivity of Li[B(OTfe)₄] is measured in water, acetone, EC/DMC, EC/DMC/DME, ethyl acetate and THF at RT In DME (0.8 mol L ^?1) it is 3.9 mS cm^?1, which is satisfactory for the use in lithium‐sulfur batteries (LiSB). Cyclic voltammetry confirms the electrochemical stability of Li[B(OTfe)₄] in a potential range of 0 to 4.8 V vs. Li/Li⁺. The performance of Li[B(OTfe)₄] as conducting salt in a 0.2 mol L ^?1 solution in 1:1 wt % DME/DOL is investigated in LiSB test cells. After the 40th cycle, 86 % of the capacity remains, with a coulombic efficiency of around 97 % for each cycle. This indicates a considerable performance improvement for LiSB, if compared to the standard Li[NTf₂]/DOL/DME electrolyte system.