Anionic Ring-Opening Homo- and Copolymerization of Lactams by Latent, Protected N-Heterocyclic Carbenes for the Preparation of PA 12 and PA 6/12
摘要:
Laurolactam (LL) is polymerized in the bulk using strongly basic N-heterocyclic carbenes (NHCs) as initiators at temperatures of 180-200 degrees C to prepare the corresponding polyamide (PA 12). In-situ rheology of the polymerization progress reveals that an anionic mechanism is active, which is supported by the strong dependence of initiator activity on the basicity of the NHCs. GPC data and kinetic investigations show the process to be moderately controlled and fast, allowing high or quantitative yields in short polymerization times. Fifteen different NHC-CO2-adducts and NHC-metal complexes were used as thermally labile but room temperature stable NHC-precursors. Depending on the ring size and N-substituent, some of these protected NHCs allow forming a mixture of monomer and NHC-precursor that is suitable for long-term storage and readily polymerizable by simple heating. All polymerizations are executed without activator or other additives and thus represent a true one-component system for the production of PA 12. Finally, LL is copolymerized with epsilon-caprolactam (epsilon-CLA). It is found that a copolymer with a considerable gradient is formed, with epsilon-CLA being incorporated preferentially at the onset of the polymerization.
Lewis acid catalyst free synthesis of benzimidazoles and formamidines in 1,1,1,3,3,3-hexafluoro-2-propanol
作者:Samad Khaksar、Akbar Heydari、Mahmood Tajbakhsh、Seyed Mohammad Vahdat
DOI:10.1016/j.jfluchem.2010.10.002
日期:2010.12
A simple, inexpensive, environmentally friendly and efficient route for the synthesis of benzimidazole and formamidine derivatives by the reaction of O-phenylenediamines or amines with orthoesters using hexafluoroisopropanol as a solvent/catalyst is described.
A study on the influence of ligand variation on formamidinate complexes of yttrium: new precursors for atomic layer deposition of yttrium oxide
作者:Sebastian M. J. Beer、Nils Boysen、Arbresha Muriqi、David Zanders、Thomas Berning、Detlef Rogalla、Claudia Bock、Michael Nolan、Anjana Devi
DOI:10.1039/d1dt01634b
日期:——
The synthesis and characterization of a series of closely related Y(III) compounds comprising the formamidinate ligands (RNCHNR) (R = alkyl) is reported, with the scope of using them as prospective precursors for atomic layer deposition (ALD) of yttrium oxide (Y2O3) thin films. The influence of the side chain variation on the thermal properties of the resulting complexes is studied and benchmarked
报道了一系列包含甲脒配体 (RNCHNR) (R = 烷基)的密切相关的 Y( III ) 化合物的合成和表征,其范围是将它们用作氧化钇原子层沉积 (ALD) 的预期前体。 Y 2 O 3 ) 薄膜。通过热分析和蒸气压测量研究侧链变化对所得复合物的热性质的影响并作为基准。密度泛函理论(DFT)的研究得到的理论见解对水的化合物的反应性,这是针对作为共反应物为Y的沉积2 ö 3 经由下一步进行热 ALD。在分析的四种配合物中,三( N , N '-二叔丁基甲脒)钇( III ) [Y( t Bu 2 -famd) 3 ] 1被发现具有增强的热稳定性并被选择用于Y 2 O 3 ALD 工艺开发。获得了从 200°C 到 325°C 的广泛 ALD 窗口,产生了高成分质量的薄膜。此外,薄膜密度为 (4.95 ± 0.05) g cm -1接近体积值,多晶fcc Y 2 O 3 当在金属绝缘体半导体
CHEMICAL VAPOR DEPOSITION MATERIAL AND CHEMICAL VAPOR DEPOSITION
申请人:Sakai Tatsuya
公开号:US20060024443A1
公开(公告)日:2006-02-02
A chemical vapor deposition material comprising a ruthenium compound having a ligand represented by the following formula:
wherein R
1
, R
2
and R
3
are each independently a hydrogen atom, fluorine atom, trifluoromethyl group or hydrocarbon group having 1 to 10 carbon atoms,
and a method of forming a ruthenium film from the chemical vapor deposition material by chemical vapor deposition. A high-quality ruthenium film even when it is very thin can be obtained.
Condensed-ring aryl compounds of formula (I) and use of the same as a agrochemical for controlling noxious organisms wherein (X)
m
Q, A, R
1
, (Y)
n
and the grouping —W
1
—W
2
—W
3
—W
4
— are as defined herein.
next-generation batteries. For the controlled growth of SnO films at low temperatures, atomic layer deposition (ALD) is employed in this study, where the choice of the precursor plays a significant role. A comparative thermal evaluation of four different amidinate-based tin(II) precursors and the influence of the ligand sphere on their physicochemical properties revealed that bis(N,N′-diisopropylformamidinato
一氧化锡 (SnO) 是一种很有前途的氧化物半导体,具有广泛的应用前景,从 p 型场效应晶体管 (FET) 中的沟道材料到用于下一代电池的电极材料。为了在低温下控制 SnO 薄膜的生长,本研究采用原子层沉积 (ALD),其中前体的选择起着重要作用。对四种不同的脒基锡 ( II ) 前体进行比较热评估以及配体球对其物理化学性质的影响表明,双 ( N , N '-二异丙基甲脒基锡 ( II ) ( 1) 具有所需的挥发性、良好的热稳定性和对水的足够反应性,可用作 ALD 前体。水辅助 ALD 工艺在低至 140 °C 的温度下在 Si 衬底上产生晶体 SnO 薄膜,每循环生长 (GPC) 为 0.82 Å。通过采用互补的分析工具,即 X 射线衍射 (XRD)、原子力显微镜 (AFM)、X 射线反射率 (XRR)、卢瑟福背散射光谱/核反应分析 (RBS/NRA) 和 X 射线光电子能谱 ( XP