Two Coordination Polymers Constructed from 5‐(4‐Pyridyl)‐1H‐tetrazole Ligands with Different Organic Carboxylates: Structure and Luminescence Properties

Two coordination polymers (CPs), namely, [Cu(Hptz)₂(Hhba)₂]_n ( 1 ) [Hptz = 5‐(4‐pyridyl)‐1H‐tetrazole, H₂hba = 2‐hydroxybenzoic acid] and [Zn₃(ptz)₂(hpa)₂]_n ( 2 ) (H2hpa = 2‐hydroxy‐2‐phenylacetic acid), were synthesized by solvothermal reactions. Both complexes were characterized by elemental analysis, infrared spectroscopy, powder X‐ray diffraction, thermogravimetric analysis, and single‐crystal X‐ray diffraction analysis. Compound 1 exhibits a 2D (4,4) network, where each layer connects to four adjacent layers to construct a 3D supramolecular framework. Compound 2 has a 3D framework structure composed of 1D SUBs, which are formed by both carboxyl and tetrazole groups. The complexes represent two rare examples of CPs constructed from Hptz and organic carboxyl acid ligands. Complex 2 exhibits intense, red‐shifted emissions in the visible region at room temperature.     

A silver(I)-catalyzed reaction of 2-alkynylbenzaldoxime with arylsulfonyl chloride

A silver-catalyzed reaction of 2-alkynylbenzaldoxime with arylsulfonyl chloride proceeds smoothly at room temperature to afford 4-tosyloxyisoquinolines in moderate to good yields. Additionally, the resulting 4-tosyloxyisoquinolines could be further elaborated through palladium-catalyzed coupling reactions leading to diverse isoquinolines.     

Highly efficient asymmetric Michael addition of aldehydes to nitroalkenes with 4,5-methano-l-proline as organocatalysts

The 4,5-methano-l-prolines were used as chiral organocatalysts in asymmetric Michael addition of aldehydes to nitroolefins. These proline-like catalysts are unique for their rigid bicyclic structure with a cyclopropane and two H atoms attached to the bridgehead C atoms lying on the same side of the ring. They therefore showed high efficiency in asymmetric Michael addition of aldehydes to nitroolefins. Under the optimal conditions, excellent diastereo- and enantioselectivities (up to 97/3 dr and 98% ee) were obtained in high yields for a series of aldehydes and nitroolefins using only 5 mol % catalyst loading. The methodology features easily available catalysts, high catalytic efficiency and environmentally friendly procedures.     

Characterization of radioactive cobalt on graphene oxide by macroscopic and spectroscopic techniques

Graphene oxide (GO) was synthesized using the modified Hummers method and characterized by XRD and FTIR. The sorption of ⁶⁰Co(II) on GO as a function of contact time, pH, polyacrylic acid, ionic strength, temperature and solution concentration was studied by batch technique. The sorption kinetics indicated that the sorption of ⁶⁰Co(II) on GO could be simulated by the pseudo-second-order model very well. The maximum sorption capacities of GO for ⁶⁰Co(II) calculated from Langmuir model at pH 6.40 and T = 300 K was ~62.0 mg/g. The thermodynamic parameters from the temperature-dependent sorption isotherms indicated that the ⁶⁰Co(II) sorption on GO was an endothermic and spontaneous process. The interaction mechanism between GO and Co(II) were outer-sphere surface complexation or ion exchange at pH <7, whereas the inner-sphere surface complexation was observed at pH 7–9 in terms of the analysis of XPS spectra.     

Radiosynthesis and evaluation of 188Re-c(RGDyK)-His as a novel radiotherapeutic agent for integrin αvβ3 targeting tumour

The successes of noninvasive methods to visualize and quantify integrin α_vβ₃ expression in vivo have paved the way for radiolabeling anti-integrin therapy in clinic. Arginine-glycine-aspartice (RGD) peptide and related derivatives labeled with radionuclides for radio-therapy, which specifically targeting integrin α_vβ₃-positive tumors, could be used to treat these tumors. We have labeled c(RGDyK)-His, a RGD derivative, with ¹⁸⁸Re and the radio-therapy efficiency has been evaluated in model nude mice. c(RGDyK)-His was labeled with ¹⁸⁸Re by chelating with [¹⁸⁸Re(CO)₃(H₂O)₃]⁺ under a slightly basic condition. The in vitro specific binding affinity to U87 MG cell lines and the biodistribution of ¹⁸⁸Re-c(RGDyK)-His in the animal tumor models was measured. The inhibitory effects of ¹⁸⁸Re-c(RGDyK)-His were observed more than 1 month, and evaluated by microPET/CT imaging with ¹⁸F-FDG. Results of in vivo, cell uptake demonstrated ¹⁸⁸Re-c(RGDyK)-His had a high specific binding affinity to receptor integrin α_vβ₃. In biodistribution experiment, ¹⁸⁸Re-c(RGDyK)-His was accumulated in the tumor and cleared fast from the normal tissues. In radiotherapy study, tumor growth inhibition was significantly higher in the treatment groups than in the control groups. These studies showed that ¹⁸⁸Re-c(RGDyK)-His could be effectively used for integrin α_vβ₃ targeting therapy. This may offer a potential therapeutic strategy for the treatment of integrin-positive tumors in clinic.     

基于表面等离子体子共振成像技术研究苏拉明和顺铂对肝癌细胞生长的抑制作用简

基于表面等离子体子共振成像(SPRi)技术提出了一种实时、非标记的新型抗癌药物药效评估方法. 以聚二甲基硅氧烷(PDMS)为材料,制作了包含微柱结构的微流控芯片作为流通反应池,配合自行设计组装的SPRi生物传感器完成肿瘤细胞的特异性捕获及检测,研究了苏拉明和顺铂对肝癌细胞HepG2的生长抑制作用. 同时引入辅助验证实验,即采用常规八肽胆囊收缩素(简称CCK-8)法测定上述药物对肝癌细胞增殖的抑制作用. SPRi检测结果表明,苏拉明和顺铂能抑制肿瘤细胞HepG2增殖并呈现剂量、时间依赖关系.     

Photofragment translational spectroscopy at 304 nm from C-H symmetric stretch excited CH3I [v 1 = 1]

The 304 nm photodissociation of the C-H symmetric stretch excited CH3I[v1=1,v2=0](v1 denotes the C-H symmetric stretch mode,and v2 denotes the umbrella mode)is studied with our simple photofragment translational spectrometer.An IR laser is used to excite the ground state CH3I[0,0]to the C-H symmetric stretch excited CH3I[1,0].With IR laser OFF and ON,the fractions of photofragments CH3(ν1,ν2)from the 304 nm photodissociation of CH3I[1,0]have been determined through the photofragment translational spectra(PTS)from measuring I and I*and also through the PTS from measuring CH3(0,0)(1,0)(0,1)and(1,1).The experimental results show that the C-H symmetric stretch vibration(v1=1)in parent molecules is about 66%retained in the photofragments in the I channel,but only 24%in the I*channel.The populations of photofragments CH3(0,2)and(0,3)are higher than CH3(0,0)and(0,1),showing strong inverted population both in I and I*channels.     

Polypeptide‐b‐Poly(Phenyl Isocyanide) Hybrid Rod‐Rod Copolymers: One‐Pot Synthesis,Self‐Assembly,and Cell Imaging

Hybrid rod‐rod diblock copolymers, poly(γ‐benzyl L‐glutamate)‐poly(4‐cyano‐benzoic acid 2‐isopropyl‐5‐methyl‐cyclohexyl ester) (PBLG‐PPI), with determined chirality are facilely synthesized through sequential copolymerization of γ‐benzyl‐L‐glutamate N‐carboxyanhydride (BLG‐NCA) and phenyl isocyanide monomers bearing chiral menthyl pendants using a Ni(cod)(bpy) complex as the catalyst in one‐pot. Circular dichroism and absorption spectra reveal that each block of the block copolymers possesses a stable helical conformation with controlled helicity in solution due to the induction of chiral pendants. The two diastereomeric polymers self‐assemble into helical nanofibrils with opposite handedness due to the different chiral induction of the L‐ and D‐menthyl pendants, confirmed by transmission electron micro­scopy (TEM). Deprotection of the benzyl groups of the PBLG segment affords biocompatible amphiphilic diblock copolymers, poly(L‐glutamic acid)‐poly(4‐cyano‐benzoic acid 2‐isopropyl‐5‐methyl‐cyclohexyl ester) (PLGA‐PPI), that can self‐assemble into well‐defined micelles by cosolvent induced aggregation. Very interestingly, a chiral rhodamine chromophores RhB(D) can be selectively encapsulated into the chiral polymeric micelles, which is efficiently internalized into living cells when directly monitored with a confocal microscope. This contribution will be useful for developing novel rod‐rod biocompatible hybrid block copolymers with a controlled helicity, and may also provide unique chiral materials for potential bio‐medical applications.

     

基于偏微分方程的增长网络结构分析

为了研究网络的功能,需要首先研究增长网络的拓扑结构,包括网络的度分布和节点度等。当网络规模足够大时,将网络节点的度看作连续变量,根据网络演化过程中所满足的马尔科夫性,建立网络节点数量的变化方程,从而化简变形得到基于一阶双曲方程的增长网络模型。求解得到了兼具优先和随机2种连接机制的网络度分布P(k)和节点度kt0(t),同时也发现了节点度函数与双曲方程特征线之间的关系。根据网络的演化机制,通过对该增长网络模型进行随机模拟,验证了度分布与节点度理论结果的正确性。将网络的度分布计算转化为偏微分方程求解问题,将节点度的变化视为偏微分方程的特征线,将偏微分方程应用于增长网络的建模中,从而可以解析地对网络结构进行分析。