Preparation of Substituted N-Methacryloxy Phthalimides for E-Beam Lithography

Poly (methyl methacrylate) (PMMA) is a very good option for electron-beam resists, but suffers from poor radiation sensitivity and poor plasma etch resistance. These problems can be offset, at least in part, by functionalizing the PMMA with photo-labile, plasma etch-resistance groups. Toward this end, a series of N-methacryloxy phthalimides with different substitutuents (methyl, nitro, tetrahydrogen and dichloro) were synthesized as possible useful radiation-sensitive resists. The work discussed here focuses on the cycloimido group, which can be easily attached to methacrylic acid to form a radiation-sensitive resist material for use in electron beam lithography. The labile N–O bond of the cycloimido group, upon exposure to radiation, cleaves and forms a radical on the main chain of the polymer, which leads to polymer degradation. Cursory evaluations showed that these new materials are deserving of further study.     

重氮化反应及其应用

综述了重氮盐的几种主要合成方法,包括以浓硫酸、硫酸/醋酸混合物、硫酸/磷酸混合物及盐酸为反应介质的合成方法,阐述了几种重要的重氮盐反应及其应用,包括重氮离子的取代反应、偶联反应、形成叠氮衍生物和三氮烯的反应,并且简要描述重氮化合物在食品、染料、检验等方面的应用。     

Iridium‐Catalyzed Asymmetric Allylic Etherification and Ring‐Closing Metathesis Reaction for Enantioselective Synthesis of Chromene and 2,5‐Dihydrobenzo[b]oxepine Derivatives

Iridium‐catalyzed asymmetric etherifications of allylic carbonates with 2‐vinylphenols and 2‐allylphenols were realized. With a catalyst generated from 2 mol% of [Ir(cod)Cl]₂ (cod=cycloocta‐1,5‐diene) and 4 mol% of the phosphoramidite ligand L2 , the etherification products were obtained in excellent ees and then subjected to the ring‐closing metathesis reaction providing an efficient synthesis of enantioenriched 2H‐chromene and 2,5‐dihydrobenzo[b]oxepine derivatives.     

Aluminum Triflate as a Powerful Catalyst for Direct Amination of Alcohols,Including Electron‐Withdrawing Group‐Substituted Benzhydrols

Direct aminations of allylic alcohols, benzylic alcohols, and benzhydrols with electron‐withdrawing (F, Br, I, NO₂, or CN) substituents were efficiently catalyzed by aluminum triflate [Al(OTf)₃] to afford the corresponding biarylamines in high yield, and the dibromo‐substituted product was further transformed into letrozole.     

Influences of gallium substitution on the phase stability,mechanical strength and cellular response of β-tricalcium phosphate bioceramics

β-tricalcium phosphate (β-TCP), a well-accepted synthetic bone grafting biomaterial, is confronted with limitations of poor phase stability and lacking the capacity to mediate the biological functions. In the current study, gallium (Ga) was substituted for calcium in the β-TCP, and the influences of Ga substitution on the phase stability, compressive strength and cellular response of β-TCP bioceramics were investigated. The results indicated that substitution of at least 2.5 mol% Ga for calcium prevented the β-TCP from transforming into α-TCP at 1250 °C. The β-TCP bioceramics substituted with 2.5 mol% Ga attained the highest compressive strength. The β-TCP bioceramics substituted with 2.5 and 5 mol% Ga showed good cytocompatibility, and suppressed in vitro osteoclastic activity as well as osteoblastic differentiation. Considering the favorable mechanical strength and the inhibitory effect on the osteoclastic activity, the β-TCP bioceramics substituted with 2.5 mol% Ga are promising for treating the bone defect in the pathological state of excessively rapid bone resorption.     

Structure analysis,tuning photoluminescence and enhancing thermal stability on Mn4+-doped La2-xYxMgTiO6 red phosphor for agricultural lighting

Currently, phosphor-converted LEDs (pc-LEDs) are revolutionizing the industry of plant growth lighting. To meet the requirements of this technology, phosphors with tunable photoluminescence, high thermal stability and luminous intensity are required. Herein, we found that the simple substitution of yttrium for lanthanum in La₂MgTiO₆:Mn⁴⁺ (LMT:Mn⁴⁺) system could satisfy above three criteria simultaneously. The photoluminescence properties can be regulated by continuously controlling the chemical composition of La_2-xY_xMgTiO₆:Mn⁴⁺ solid solution. The La sites are occupied by Y ions, causing a significant blue shift in the emission spectra which owing to the change of local crystal field strengthen. Meanwhile, the thermal stability and decay lifetimes are also varied due to the variation of local structure and band gap energy. The thermal stability of the material reaches 83.5% at 150 °C, which is better than the reported La₂MgTiO₆:Mn⁴⁺ and Y₂MgTiO₆:Mn⁴⁺ phosphors. The electronic luminescence (EL) of pc-LED devices using La_2-xY_xMgTiO₆:Mn⁴⁺ red phosphor is evaluated, which matching the absorption regions of plant pigments well, reflecting the superiority of the studied phosphors in plant growth lighting areas.     

Sn substitution endows NaTi2(PO4)3/C with remarkable sodium storage performances

The further development of clean energy requires the use of more stable and reliable energy storage system. In addition to lithium ion battery power supplies, sodium ion batteries also have prospects for application and development thanks to the low cost and abundant resource. NaTi₂(PO₄)₃ has attracted much attention due to its three-dimensional channels for sodium ion transfer. In order to meliorate sodium storage properties of NaTi₂(PO₄)₃ electrode, a facile strategy of Sn substitution at Ti sites was employed, and a series of electrodes were successfully synthesized through sol-gel route. The electrochemical performances of Sn substituted composites are significantly improved compared with bare NaTi₂(PO₄)₃/C. And it was found that NaSn_0.2Ti_1.8(PO₄)₃ (NTP/C-Sn-2) delivers the largest capacity, and it also demonstrates the outstanding cycling performances. NTP/C-Sn-2 has discharge capacity of 131.1 mAh g⁻¹ at 4 A g⁻¹ in rate test and 121.4 mAh g⁻¹ at 1 A g⁻¹ after 1000 cycles in cycling test. The experimental results show that NaTi₂(PO₄)₃/C with Sn substitution with proper content exhibits the great potential in anode for sodium ion batteries, and can further provide reference for next generation electrode materials and battery systems.     

Thermal expansion coefficient tailoring of LAS glass-ceramic for anodic bondable low temperature co-fired ceramic application

The Li–Al–Si glass-ceramics were prepared by conventional glass-ceramic fabrication method. The influences of Na₂O content on the sintering property, microstructure, and coefficient of thermal expansion were investigated. The results show that the coefficient of thermal expansion of LAS glass-ceramics can be tailored to match that of silicon by the addition of Na₂O content. Na₂O has a remarkable influence on the crystallinity of Li–Al–Si glass-ceramic. The coefficient of thermal expansion of Li–Al–Si glass-ceramic is thus tunable between that of glass phase and crystal phase. The Si–O bond length change in stretch vibration modes introduced by Na₂O also contributes to the variation of coefficient of thermal expansion of the Li–Al–Si glass-ceramics. The coefficient of thermal expansion of the Li–Al–Si glass-ceramic with 1.5 wt% Na₂O addition is about +3.34 ppm/°C at 350 °C and shows a good compatibility to that of silicon in a wide temperature range, which makes it a promising candidate for anodic bondable low temperature co-fired ceramic substrate applications.     

重氮盐芳环上的羟基取代反应研究

报道了对苯二酚、邻/对甲氧基苯酚的合成方法。研究了重氮水解液的酸浓度、水解温度、硫酸铜用量对产物收率的影响。改进了常用的后处理提纯方法,采用了层析柱法分离浓缩产物,研究了不同的脱附剂对产物收率的影响。实验结果表明层析柱分离方法提高了产物收率,并比较分析了不同基团对水解收率的影响。     

以废催化剂为原料制备氧化锌及铜粉的研究

以铜-锌废催化剂为原料制备高纯、肤色活性氧化锌等产品,不仅回收了资源,而且减少了环境污染。研究采用氨络合转换方法,制备了医用或化妆品活性氧化锌等产品。