基于磺酰基杯[4]芳烃的Co16笼簇的合成、结构及电化学性质

以氯化钴、 对叔丁基磺酰杯[4]芳烃(H₄TC4A-SO₂)和非对称性3-(1H-四唑-5-基)苯甲酸(H₂L)为原料, 通过溶剂热法合成了一个具有四面体配位笼结构的16核化合物[Co₁₆(TC4A-SO₂)₄(OH)₄(L)₈]·[(C₈H₂₀N)(C₄H₁₂N)₂(C₂H₈N)]·solvent(Co₁₆-TC4A-SO₂). 采用X射线单晶衍射、 X射线粉末衍射、 热重分析、 红外光谱方法对配合物进行了表征. 将Co₁₆-TC4A-SO₂笼簇直接负载到碳纸上(Co₁₆-TC4A-SO₂/CP)用作工作电极, 其对析氧反应(OER)展现出较好的催化性能. 在1 mol/L KOH中, Co₁₆-TC4A-SO₂/CP在343.8 mV的过电位下达到10.0 mA/cm ²电流密度, Tafel斜率为79.31 mV/dec, 并且在20.0 mA/cm ²电流密度下表现出长达48 h的催化稳定性.     

High-pressure methane storage and selective gas adsorption in a cyclohexane-functionalised porous organic cage

ABSTRACT

Porous organic cages are a class of adsorbents that have shown promise for a variety of applications. The octahedral cyclohexane-functionalised imine-based cage, commonly referred to as CC3, is perhaps most recognisable in this regard. However, most gas adsorption studies concerning this cage have focused on chromatographic or noble gas separations. Here, we examine this cage for the adsorptive separation of a wide variety of small molecules, including acetylene, ethylene, ethane, methane, and others. The internal surface of the cage is an optimal binding environment for gaseous substrates and as such the material displays adsorption enthalpies of ?15 to ?35 kJ/mol, depending on adsorbate. These values are particularly high for an adsorbent lacking coordinatively unsaturated metal sites and are likely a result of optimal cage geometry, which can be inferred from its isostructural nature to one of the pores in a well-known metal-organic framework, HKUST-1. Given this and the soluble nature of this cage, we additionally report optimisation of the high-pressure methane storage properties of this cage by tuning its density.     

W态纠缠实现双腔远程控制原子的非经典特性

考虑将双模纠缠相干光场的两模场同时分别注入两个腔中,初态处于W态的三体纠缠二能级原子中的两个分别在这两个腔内,并且都与光场发生共振相互作用,经腔QED演化之后,对纠缠相干光场进行光子探测和对纠缠原子进行选择性测量,通过操纵相互作用的时间和光场的参数可控制W态中处于腔外的第三个原子的非经典效应,如粒子数布居差的崩塌一回复现象和偶极压缩现象,从而实现了更强地远程控制原子的非经典特性.     

A 116-Nuclear Metallosupramolecular Cage-of-Cage Showing Multistep Single-Crystal-to-Single-Crystal Transformation

Here a unique single-crystal-to-single-crystal (SCSC) transformation of a 116-nuclear Au^I₇₂Cd^II₄₀Na^I₄ cage-of-cage ( 2 _CdNa) is reported, which was created from a trigold(I) metalloligand with d -penicillamine by way of a 9-nuclear Au^I₆Cd^II₃ cage ( 1 ). Cage-of-cage 2 _CdNa is composed of 12 cages of 1 that are linked by 4 Cd²⁺ and 4 Na⁺ ions, with its surface being covered by 12 NO₃⁻ ions to form a discrete, spherical molecule with a diameter ca. 4.7 nm. In crystal 2 _CdNa, the cage-of-cage molecules are packed in a cubic lattice with a huge cell volume of ca. 4.5×10⁵ ų_, so as to have large interstices with diameters of more than 3 nm. Upon soaking crystals 2 _CdNa in aqueous Cu(NO₃)₂, all Cd²⁺ and Na⁺ were quickly exchanged by Cu²⁺ to produce an analogous Au^I₇₂Cu^II₄₄ cage-of-cage ( 2 _Cu) in a SCSC manner. Prolonged soaking led to the SCSC transformation to another supramolecular structure ( 2′ _Cu) consisting of 152-nuclear Au^I₇₂Cu^II₈₀ cage-of-cages that are alternately H-bonded with the Au^I₇₂Cu^II₄₄ cage-of-cages. 2′ _Cu showed the accommodation of MoO₄²⁻ and the conversion of MoO₄²⁻ to β-Mo₈O₂₆⁴⁻ in the crystal, with retention of single-crystallinity.     

Nanobody-Ferritin Conjugate for Targeted Photodynamic Therapy

Ferritin is an iron-storage protein nanocage that is assembled from 24 subunits. The hollow cavity of ferritin enables its encapsulation of various therapeutic agents; therefore, ferritin has been intensively investigated for drug delivery. The use of antibody-ferritin conjugates provides an effective approach for targeted drug delivery. However, the complicated preparation and limited protein stability hamper wide applications of this system. Herein, we designed a novel nanobody-ferritin platform (Nb-Ftn) for targeted drug delivery. The site-specific conjugation between nanobody and ferritin is achieved by transglutaminase-catalyzed protein ligation. This ligation strategy allows the Nb conjugation after drug loading in ferritin, which avoids deactivation of the nanobody under the harsh pH environment required for drug encapsulation. To verify the tumor targeting of this Nb-Ftn platform, a photodynamic reagent, manganese phthalocyanine (MnPc), was loaded into the ferritin cavity, and an anti-EGFR nanobody was conjugated to the surface of the ferritin. The ferritin nanocage can encapsulate about 82 MnPc molecules. This MnPc@Nb-Ftn conjugate can be efficiently internalized by EGFR positive A431 cancer cells, but not by EGFR negative MCF-7 cells. Upon 730 nm laser irradiation, MnPc@Nb-Ftn selectively killed EGFR positive A431 cells by generating reactive oxygen species (ROS), whereas no obvious damage was observed on MCF-7 cells. Given that ferritin can be used for encapsulation of various therapeutic agents, this work provides a strategy for facile construction of nanobody-ferritin for targeted drug delivery.     

The Effect of Viscosity on the Diffusion and Termination Reaction of Organic Radical Pairs

The effect of viscosity on the diffusion efficiency (F_dif) of an organic radical pair in a solvent cage and the termination mechanism, that is, the selectivity of disproportionation (Disp) and combination (Comb) of the geminated caged radical pair and the diffused radicals encountered, were investigated quantitatively by following the photolysis of dimethyl 2,2′-azobis(2-methylpropionate) (V-601) in the absence and presence of PhSD. F_dif and Disp/Comb selectivity outside the cage [Disp_(dif)/Comb_(dif)] are highly sensitive to the viscosity. In contrast, the Disp/Comb selectivity inside the cage [Disp_(cage)/Comb_(cage)] is rather insensitive. The difference in viscosity dependence between Disp_(cage)/Comb_(cage) and Disp_(dif)/Comb_(dif) is explained by the spin state of the radical pair inside and outside the cage and the spin state dependent configurational changes of the radical pair upon their collision. Given that the configurational change of the radicals associates the displacement and reorganization of solvents around the radicals, the termination outside the cage, which requires larger change than that inside the cage, is highly viscosity dependent. Furthermore, while the bulk viscosity of each solvent shows good correlation with F_dif and Disp/Comb selectivity, microviscosity is the better parameter predicting F_dif and Disp_(dif)/Comb_(dif) selectivity regardless of the solvents.     

Experimental and numerical study of an aquaculture net cage with floater in waves and current

The mooring loads on an aquaculture net cage in current and waves are investigated by dedicated model tests and numerical simulations. The main purpose is to investigate which physical effects are dominant for mooring loads, and in this respect, to investigate the validity of different rational hydrodynamic load models. Also structural and numerical aspects are investigated. The model tests are performed to provide benchmark data, while the numerical model is used to study the effect and sensitivity of different load models and parameters.Compared to a realistic aquaculture plant, the total system is simplified to reduce the complexity. The system does, however, include all the four main components of an aquaculture plant: net cage, floater, sinker weights and moorings. The net cage is bottomless, flexible and circular. It is attached to a circular, elastic floater at the top and has 16 sinker weights at the bottom. The system is nearly linearly moored with four crow feet mooring lines.The loads are measured in the four mooring lines. A systematic variation of current only, wave only as well as combined current and wave conditions is carried out. The numerical simulation results are first benchmarked towards the experimental data. The mean loads in general dominate over the dynamic part of the loads in combined current and waves, and they significantly increase in long and steep waves, relative to current only. Next, a sensitivity study is carried out. A rigid floater significantly alters the loads in the mooring lines compared to a realistic, elastic floater. The theoretical model for the wave matters. The mooring loads are rather insensitive to a majority of the parameters and models, in particular: frequency dependent added mass of the floater and nonlinear restoring loads. It seems not to be necessary to represent the net cage with a very fine numerical mesh.     

Unprecedented Ring–Ring Interconversion of N,P,C‐Cage Ligands

The novel N,P,C‐cage complexes 5 a – f and 6 a – f have been obtained by the reaction of the P‐pentamethylcyclopentadienylphosphinidene complex 2 , generated thermally from 2H‐azaphosphirene complex 1 , with N‐methyl‐C‐arylcarbaldimines 3 a – f . Li/Cl phosphinidenoid complex 8 reacted with 3 a , b to give N,P,C‐cage complexes 6 a , b , whereas with 3 c – f , complexes 6 c – f were obtained in negligible amounts only. Both types of ligand N,P,C‐cage structures 5 and 6 were found to be in an unprecedented equilibrium, with 5 a , f as the predominant species. Transient electrophilic terminal phosphinidene complexes 10 a – f serve as intermediates in both ligand interconversions ( 5 a , f ? 6 a , f ), as evidenced through trapping reactions with phenylacetylene and N‐methyl‐C‐phenylcarbaldimine, thus leading to the novel N,P,C‐cage complexes 13 b and 15 . DFT calculations predicted a small difference in the relative energies of the two types of N,P,C‐cage ligands, and a remarkable stabilisation of the aminophosphinidene complex 10 as the common precursor, thereby providing an insight into this surprising 5‐ring–3‐ring interconversion. In depth analysis of intermediate 10 revealed the occurrence of both through‐bond (conventional inductive/mesomeric effects) and through‐space (non‐covalent interactions) mechanisms, which amount to 67.8 and 14.4 kcal mol^?1, respectively, and account for the remarkable stabilisation of this intermediate.     

Interpenetrated Cage Structures

This Review covers design strategies, synthetic challenges, host–guest chemistry, and functional properties of interlocked supramolecular cages. Some dynamic covalent organic structures are discussed, as are selected examples of interpenetration in metal–organic frameworks, but the main focus is on discrete coordination architectures, that is, metal‐mediated dimers. Factors leading to interpenetration, such as geometry, flexibility and chemical makeup of the ligands, coordination environment, solvent effects, and selection of suitable counter anions and guest molecules, are discussed. In particular, banana‐shaped bis‐pyridyl ligands together with square‐planar metal cations have proven to be suitable building blocks for the construction of interpenetrated double‐cages obeying the formula [M₄L₈]. The peculiar topology of these double‐cages results in a linear arrangement of three mechanically coupled pockets. This allows for the implementation of interesting guest encapsulation effects such as allosteric binding and template‐controlled selectivity. In stimuli‐responsive systems, anionic triggers can toggle the binding of neutral guests or even induce complete structural conversions. The increasing structural and functional complexity in this class of self‐assembled hosts promises the construction of intelligent receptors, novel catalytic systems, and functional materials.