Solvothermal syntheses and crystal structures of two new thiogermanates [M(dap)3]4Ge4S10Cl4 (M?=?Co, Ni) with metal complexes as counterions

Abstract  

Two new transition-metal thiogermanates [M(dap)₃]₄Ge₄S₁₀Cl₄ (M = Co, Ni; dap = 1,2-propanediamine) have been solvothermally synthesized and structurally characterized. The two thiogermanates are isostructural and consist of discrete Ge₄S₁₀⁴⁻ adamantane-like ions, free Cl⁻ ions, and [M(dap)₃]²⁺ cations as counterions. The Ge₄S₁₀⁴⁻ anion is built from corner-sharing connection of four GeS₄⁴⁻ tetrahedra. Although some chalcogenidogermanates have been obtained by use of in situ generated transition-metal complexes as structure-directing agents under mild solvothermal conditions, their anions are usually dimeric [Ge₂Q₆]⁴⁻ (Q = S, Se) species. The new thiogermanates are rare examples of adamantane-like (Ge₄S₁₀⁴⁻) thiogermanates combined with transition-metal complexes. Their optical properties have been investigated by UV–Vis spectra.     

(1R,5S)-3-羟基二环[3.1.0]己基-6-基(苯基)甲酮的合成及其Norrish Ⅱ型光化学反应研究

以二环[3.1.0]己烷为骨架设计了合理的合成路线,成功合成了具有Norrish Ⅱ型光化学特点的光化学反应前体(1R,5S)-3-羟基-6-二.环[3.1.0]己基苯基甲酮(10),并通过1H NMR,13C NMR,DEPT135,H-H COSY,HMQC,HMBC,ROESY,6-H- 1D-NOE,9-H- ...     

N,N,N',N'-四[(二苯基膦)甲基]乙二胺钯配合物催化Heck反应研究

以乙二胺为骨架的含氮四膦配体N’NN,N',N'-四[(二苯基膦)甲基]乙二胺和钯组成的催化体系用于丙烯酸酯和芳卤的Heck反应,该催化体系对许多卤代芳烃,尤其含吸电基的溴代芳烃显示了良好的催化活性.对活化底物对溴苯甲醛,即使底物与催化剂的物质的量比达到1000000,其转化率也能达到96％;催化非活化溴代芳烃对溴苯甲醚以及难以反应的氯代芳烃,在Pd含量为0.1 mol％时同样表现出优良催化性能.     

2-氰基-3-取代胺基-3-[2-(4-氟苯基)-乙胺基]丙烯酸乙酯类化合物的合成及生物活性研究

以氰基乙酸乙酯为原料,经与二硫化碳、硫酸二甲酯反应合成了2-氰基-3,3-二甲硫基丙烯酸乙酯(1),然后引入对氟苯乙胺得到化合物(3),其与脂肪胺反应合成了新型含对氟苯乙氨基的2-氰基丙烯酸乙酯类化合物5a～5h,其结构经元素分析,IR1H NMR和13C NMR等确证.初步生物活性试验表明,部分化合物具有一定抗烟草花叶病毒活性.     

Novel Red Phosphorescent Polymers Bearing Both Ambipolar and Functionalized IrIII Phosphorescent Moieties for Highly Efficient Organic Light‐Emitting Diodes

A series of novel red phosphorescent polymers is successfully developed through Suzuki cross‐coupling among ambipolar units, functionalized Ir^III phosphorescent blocks, and fluorene‐based silane moieties. The photophysical and electrochemical investigations indicate not only highly efficient energy‐transfer from the organic segments to the phosphorescent units in the polymer backbone but also the ambipolar character of the copolymers. Benefiting from all these merits, the phosphorescent polymers can furnish organic light‐emitting diodes (OLEDs) with exceptional high electroluminescent (EL) efficiencies with a current efficiency (η _L) of 8.31 cd A⁻¹, external quantum efficiency (η _ext) of 16.07%, and power efficiency (η _P) of 2.95 lm W⁻¹, representing the state‐of‐the‐art electroluminescent performances ever achieved by red phosphorescent polymers. This work here might represent a new pathway to design and synthesize highly efficient phosphorescent polymers.

     

Nitrile Oxide‐Norbornene Cycloaddition as a Bioorthogonal Crosslinking Reaction for the Preparation of Hydrogels

This communication describes the first application of cycloaddition between an in situ generated nitrile oxide with norbornene leading to a polymer crosslinking reaction for the preparation of poly(ethylene glycol) hydrogels under physiological conditions. Hydrogels with high water content and robust physical strength are readily formed within 2–5 min by a simple two‐solution mixing method which allows 3D encapsulation of neuronal cells. This bioorthogonal crosslinking reaction provides a simple yet highly effective method for preparation of hydrogels to be used in bioengineering.

     

Thermal behavior of 1,2,3-triazole nitrate

The thermal decomposition behaviors of 1,2,3-triazole nitrate were studied using a Calvet Microcalorimeter at four different heating rates. Its apparent activation energy and pre-exponential factor of exothermic decomposition reaction are 133.77 kJ mol⁻¹ and 10^14.58 s⁻¹, respectively. The critical temperature of thermal explosion is 374.97 K. The entropy of activation (ΔS ^≠), the enthalpy of activation (ΔH ^≠), and the free energy of activation (ΔG ^≠) of the decomposition reaction are 23.88 J mol⁻¹ K⁻¹, 130.62 kJ mol⁻¹, and 121.55 kJ mol⁻¹, respectively. The self-accelerating decomposition temperature (T _SADT) is 368.65 K. The specific heat capacity was determined by a Micro-DSC method and a theoretical calculation method. Specific heat capacity equation is C_\textp ( \textJ mol ^{- 1} \text K ^{- 1} ) = - 42.6218 + 0.6807T C_{\text{p}} \left( {{\text{J mol}}^{ - 1} {\text{ K}}^{ - 1} } \right) = - 42.6218 + 0.6807T (283.1 K < T < 353.2 K). The adiabatic time-to-explosion is calculated to be a certain value between 98.82 and 100.00 s. The critical temperature of hot-spot initiation is 637.14 K, and the characteristic drop height of impact sensitivity (H ₅₀) is 9.16 cm.     

Fabrication of free-standing nanoporous silver by selectively dissolving gold from gold–silver alloys via a novel converse dealloying method

A novel converse dealloying method was developed to fabricate free-standing nanoporous silver (np-Ag). One remarkable characteristic of the new dealloying method is that inert component (Au) is selectively removed from Au–Ag alloys while active component (Ag) is left undissolved. Thiourea plays a key role in the formation of a free-standing porous Ag framework since it not only leads to anodic dissolution of Au component but also causes the surface passivation of Ag component. Because of the excellent electrocatalytic activity toward the reduction of trichloroacetic acid (TCA), the as-prepared np-Ag materials can be directly used as working electrodes to detect TCA in the concentration range from 2.50 to 25.0 mM.     

BTATz-CMDB propellants

The high-pressure thermal properties and their correlation with burning rates of the composite modified double base (CMDB) propellants containing 3,6-bis (1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz), a substitute of hexogen (RDX), were investigated using the high-pressure differential scanning calorimetry (PDSC). The results show that there is a main exothermal decomposition process with the heating of each propellant. High pressure can restrain the volatilization of NG, accelerate the main decomposition reaction, and make the reaction occur easily. High pressure can change the main decomposition reaction mechanism function and kinetics, and the control process obeys the rule of Avrami–Erofeev equation at high pressure and chemical reaction at normal pressure. However, the mechanism function can not be changed by the ballistic modifier. The correlation between PDSC characteristic values and burning rates was carried out and found that u and ( p  \Updelta H_\textd / \Updelta T ) ^{1 / 2} \left( {p \, \Updelta H_{\text{d}} { / }\Updelta T} \right)^{ 1 / 2} keep a good linear relation, k _u keeps a similar changing trend with u, and it can be used to study the effect of the ballistic modifier or the other component on the burning rates.     

Study on surface hydrolytic kinetics of poly(vinyl acetate) grafted onto polyurethane film

Alkali catalytic hydrolysis of poly(vinyl acetate) (PVAc) grafting onto polyurethane film surface was a heterogeneous reaction. The hydrolysis was carried on the PVAc particle surface, and the concentration of the alkali in the system was tested by titration method. The kinetics of PVAc surface hydrolytic reaction was studied by simple second-order reaction model. From linear regression analysis of experimental data, we inferred that the activation energy (E _a ) and pre-exponential factor (A) of PVAc surface hydrolytic reaction were 70.7 ± 0.2 kJ mol^?1 and (5.7 ± 0.5) × 10¹² kg mol^?1 s^?1, respectively. The results of transmission electron microscopy stated that the apparent hydrolytic degree was 2.1% when the surface of PVAc particle hydrolyzed absolutely.