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Harding DJ Gruene P Haertelt M Meijer G Fielicke A Hamilton SM Hopkins WS Mackenzie SR Neville SP Walsh TR 《The Journal of chemical physics》2010,133(21):214304
The geometric structures of small cationic rhodium clusters Rh(n)(+) (n = 6-12) are investigated by comparison of experimental far-infrared multiple photon dissociation spectra with spectra calculated using density functional theory. The clusters are found to favor structures based on octahedral and tetrahedral motifs for most of the sizes considered, in contrast to previous theoretical predictions that rhodium clusters should favor cubic motifs. Our findings highlight the need for further development of theoretical and computational methods to treat these high-spin transition metal clusters. 相似文献
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Jarrod J. M. Amoore Dr. Suzanne M. Neville Dr. Boujemaa Moubaraki Dr. Simon S. Iremonger Dr. Keith S. Murray Prof. Jean‐François Létard Dr. Cameron J. Kepert Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(6):1973-1982
We previously reported the dinuclear material [FeII2(ddpp)2(NCS)4] ? 4 CH2Cl2 ( 1? 4 CH2Cl2; ddpp=2,5‐di(2′,2′′‐dipyridylamino)pyridine) and its partially desolvated analogue ( 1? CH2Cl2), which undergo two‐ and one‐step spin‐crossover (SCO) transitions, respectively. Here, we manipulate the type and degree of solvation in this system and find that either a one‐ or two‐step spin transition can be specifically targeted. The chloroform clathrate 1? 4 CHCl3 undergoes a relatively abrupt one‐step SCO, in which the two equivalent FeII sites within the dinuclear molecule crossover simultaneously. Partial desolvation of 1? 4 CHCl3 to form 1? 3 CHCl3 and 1? CHCl3 occurs through single‐crystal‐to‐single‐crystal processes (monoclinic C2/c to P21/n to P21/n) in which the two equivalent FeII sites become inequivalent sites within the dinuclear molecule of each phase. Both 1? 3 CHCl3 and 1? CHCl3 undergo one‐step spin transitions, with the former having a significantly higher SCO temperature than 1? 4 CHCl3 and the latter, and each has a broader SCO transition than 1? 4 CHCl3, attributable to the overlap of two SCO steps in each case. Further magnetic manipulation can be carried out on these materials through reversibly resolvating the partially desolvated material with chloroform to produce the original one‐step SCO, or with dichloromethane to produce a two‐step SCO reminiscent of that seen for 1? 4 CH2Cl2. Furthermore, we investigate the light‐induced excited spin state trapping (LIESST) effect on 1? 4 CH2Cl2 and 1? CH2Cl2 and observe partial LIESST activity for the former and no activity for the latter. 相似文献
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Self-consistent field theory investigation of directed self-assembly in cylindrical confinement
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Neville J. McLeanAxel Gansmuller Maria ConcistreLynda J. Brown Malcom H. LevittRichard C.D. Brown 《Tetrahedron》2011,67(43):8404-8410
To enable solid-state NMR investigations of the rhodopsin chromophore and its photointermediates, a series of 11Z-retinal isotopomers have been synthesised containing pairs of adjacent 13C labels at C9/C10, C10/C11 or C11/C12, respectively. The C9 labelled carbon atom was introduced through the Heck reaction of a 13C-labelled Weinreb acrylamide derivative, and the label at the C12 position derived from a 13C-containing ethoxy Bestmann-Ohira reagent. The 13C labels at C10 and C11 were introduced through the reaction of β-ionone with labelled triethyl phosphonoacetate. 相似文献
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Neville F Broderick MJ Gibson T Millner PA 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):279-285
In nature, some peptides induce precipitation of silicic acid into silica nanoparticles such as is found in marine algae called diatoms. However, polybasic polymers can act as peptide mimics; one such polymer, polyethyleneimine (PEI), has the advantage that it is stable at room temperature and is inexpensive, in comparison with synthetic peptides. We describe the fabrication and characterization of biosilicate nanoparticles formed by mimicking the peptides using PEI. Brownian motion nanoparticle tracking analysis and field emission gun scanning electron microscopy have been used for the first time to characterize nanoparticles made with tetramethyl orthosilicate (TMOS) and PEI to investigate the fundamental factors that affect particle properties. These factors include the effect of phosphate concentration, PEI molecular weight, TMOS concentration, and species of alkoxy-silane used. The properties of the particles are compared with other particles made with polymers that induce silication. Our results show that using PEI gives differences in particle size compared with previous work using other polymers that induce silication. The entrapment of enzymes during the silication process, rationale for using nonphosphate and phosphate buffers during enzyme entrapment, and the analysis of enzyme activity are also presented. Because enzymes can be entrapped during fabrication, it means that there are many future possibilities for the use of silicate nanoparticles containing enzymes, such as biosensors and biocatalytic reactors. 相似文献