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排序方式: 共有153条查询结果,搜索用时 218 毫秒
91.
Llewellyn SA Green ML Green JC Cowley AR 《Dalton transactions (Cambridge, England : 2003)》2006,(21):2535-2541
The compound [Fe(eta-C5H5)(CO)2(Me)] reacts thermally with N-heterocyclic carbenes (L) to give both alkyl, [Fe(eta-C5H5)(L)(CO)(Me)], and acyl, [Fe(eta-C5H5)(L)(CO)(COMe)], derivatives. The reaction temperature has been shown to affect the product distribution. The alkyl and acyl derivatives exist in an equilibrium that is more easily perturbed than in the tertiary phosphine analogues. DFT studies on the reactivity of [Fe(eta-C5H5)(CO)2(Me)] with PH3 and dihydroimidazole-2-ylidene (IH) have shown that CO exchange is energetically favoured for IH, and energetically disfavoured for PH3. The products of CO-induced migratory insertion, [Fe(eta-C5H5)(L)(CO)(COMe)], are more stable than the parent alkyl, [Fe(eta-C5H5)(L)(CO)(Me)], compounds. This stabilisation is larger when L = IH than when L = PH3. Stabilisation of the transition state by agostic interactions was seen in both instances, but this was significantly more pronounced for L = IH. 相似文献
92.
93.
Prof. Qingyuan Yang Dr. Sébastien Vaesen Florence Ragon Dr. Andrew D. Wiersum Dong Wu Dr. Ana Lago Dr. Thomas Devic Dr. Charlotte Martineau Dr. Francis Taulelle Dr. Philip L. Llewellyn Dr. Hervé Jobic Prof. Chongli Zhong Dr. Christian Serre Prof. Guy De Weireld Prof. Guillaume Maurin 《Angewandte Chemie (International ed. in English)》2013,52(39):10316-10320
94.
Stefan G. Llewellyn Smith Y. Hattori 《Communications in Nonlinear Science & Numerical Simulation》2012,17(5):2101-2107
New solutions for compact vortex rings and vortices in the presence of swirl and toroidal magnetic field are presented. Steady solutions are found for thin-core vortex rings, generalizing the classical results of Kelvin and Hicks. An exact family of steady spherical solutions is found in the case when the underlying governing equation, originally due to Hicks, is linear. Proper matching of the pressure is critical in obtaining these solutions, for which another 19th century equation proves key. Contour dynamics simulations show the existence of counter-propagating dipolar structures when both swirl and magnetic fields are present. 相似文献
95.
Yang Q Wiersum AD Llewellyn PL Guillerm V Serre C Maurin G 《Chemical communications (Cambridge, England)》2011,47(34):9603-9605
The ligand functionalization effect on the CO(2)/CH(4) separation performance of the MOF type UiO-66(Zr) was explored computationally. The -SO(3)H and -CO(2)H functionalized forms show the highest selectivity, good working capacity and medium ranged CO(2) adsorption enthalpy that make these materials very promising for physisorption-based processes. 相似文献
96.
Khalid Kiani David J. T. Hill Firas Rasoul Michael Whittaker Llewellyn Rintoul 《Journal of polymer science. Part A, Polymer chemistry》2007,45(6):1074-1083
RAFT mediated grafting of poly(t‐butyl acrylate) onto the surface of a commercial poly(ethylene‐co‐propylene), Elpro, has been carried out using initiation by 60Co γ‐radiation at 298 and 273 K. The polymerizations were in bulk monomer and using the RAFT agent 1‐phenylethyl phenyldithioacetate. The rates of homopolymerization and grafting were found to decrease with increasing RAFT agent concentration, indicating that both polymerization processes involve participation of the RAFT agent. There was good agreement between the predicted and experimental molecular weights of the homopolymer that had a narrow polydispersity. The poly(t‐butyl acrylate) grafts were hydrolyzed by trifluoroacetic acid to form poly(acrylic acid) grafts, which could either be further functionalized or used to control the surface polarity of the Elpro. ATR‐FTIR spectroscopy was used to characterize the grafts and Raman spectroscopy was used to assess the depth of the grafts. The water contact angle for the Elpro surface grafted with poly(acrylic acid) was found to be linearly dependent on the amount of the graft present. The living nature of the grafted chains was demonstrated by the addition of a second block of polystyrene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1074–1083, 2007 相似文献
97.
F. Gomez P. Vast Ph. Llewellyn F. Rouquerol 《Journal of Thermal Analysis and Calorimetry》1997,49(3):1171-1178
We used CRTA for the study of both the elaboration and characterization of several polyphosphate glasses. We show that controlled transformation rate thermal analysis is able to remove a systematic error present in classical thermal analysis, in the study of the precursor of the phosphate glass. We show too that in CRTA, water release in the phosphate glasses can take place by diffusion phenomena at low temperature and that it is not due to the crystallization. These two examples illustrate some interests of this inverse method in the study of the decomposition of inorganic compounds with water release. 相似文献
98.
Hua Chen Ying Chen Yun Liu Lan Fu Cheng Huang David Llewellyn 《Chemical physics letters》2008,463(1-3):130-133
Over 1.0 mm boron nitride nanotubes (BNNTs) were successfully synthesized by an optimized ball milling and annealing method. The annealing temperature of 1100 °C is crucial for the growth of the long BNNTs because at this temperature there is a fast nitrogen dissolution rate in Fe and the B/N ratio in Fe is 1. Such long BNNTs enable a reliable single tube configuration for electrical property characterization and consequently the average resistivity of the long BNNTs is determined to be 7.1 ± 0.9 × 104 Ω cm. Therefore, these BNNTs are promising insulators for three dimensional microelectromechanical system. 相似文献
99.
100.
Dr. Julien Rodriguez Dr. Isabelle Beurroies Dr. Thierry Loiseau Dr. Renaud Denoyel Dr. Philip L. Llewellyn 《Angewandte Chemie (International ed. in English)》2015,54(15):4626-4630
In any process, the heat exchanged is an essential property required in its development. Whilst the work related to structural transitions of some flexible metal–organic frameworks (MOFs) has been quantified and linked with potential applications such as molecular springs or shock absorbers, the heat related to such transitions has never been directly measured. This has now been carried out with MIL‐53(Al) using specifically devised calorimetry experiments. We project the importance of these heats in devices such as molecular springs or dampers. 相似文献