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41.
42.
Dr. Eddy W. T. Yemeli Dr. Graeme R. Blake Dr. Alexios P. Douvalis Prof. Thomas Bakas Gert O. R. Alberda van Ekenstein Dr. Petra J. van Koningsbruggen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(72):16766-16776
The iron(III) spin-crossover compounds [Fe(Hthsa)(thsa)] ⋅ H2O ( 1 ), [Fe(Hth5Clsa)(th5Clsa)2] ⋅ H2O ( 2 ), and [Fe(Hth5Brsa)(th5Brsa)2] ⋅ H2O ( 3 ) (H2thsa=salicylaldehyde thiosemicarbazone, H2th5Clsa=5-chlorosalicylaldehyde thiosemicarbazone, and H2th5Brsa=5-bromosalicylaldehyde thiosemicarbazone) have been synthesized and their spin-transition properties investigated by magnetic susceptibility, Mössbauer spectroscopy, and differential scanning calorimetry measurements. The three compounds exhibit an abrupt spin transition with a thermal hysteresis effect. The more polarizable the substituent on the salicylaldehyde moiety, the more complete is the transition at room temperature with an increased degree of cooperativity. The molecular structures of 1 and 2 in the high-spin state are revealed. The occurrence of the light-induced excited-spin-state trapping phenomenon appears to be dependent on the substituent incorporated into the 5-position of the salicylaldehyde subunit. Whereas the compounds with an electron-withdrawing group (-Br or -Cl) exhibit light-induced trapped excited high-spin states with great longevity of metastability, the halogen-free compound does not, even though strong intermolecular interactions (such as hydrogen-bonding networks and π stacking) operate in the system. For compound 2 , the surface level of photoconversion is less than 35 %. In contrast, compound 3 displays full photoexcitation. 相似文献
43.
D. Chiladze J. Carbonell S. Dymov V. Glagolev M. Hartmann V. Hejny A. Kacharava I. Keshelashvili A. Khoukaz H.R. Koch V. Komarov P. Kulessa A. Kulikov G. Macharashvili Y. Maeda T. Mersmann S. Merzliakov S. Mikirtytchiants A. Mussgiller M. Nioradze H. Ohm F. Rathmann R. Schleichert H.J. Stein H. Ströher Yu. Uzikov S. Yaschenko C. Wilkin 《Physics letters. [Part B]》2006
44.
The existing experimental data on the d(n, p)nn and d(p, n)pp cross-sections in the forward direction are reviewed in terms of the Dean sum rule. It is shown that the measurement of the
ratio of the charge exchange on the deuteron to that on the proton might, if taken together with other experimental data,
allow a direct construction of the np → np scattering amplitude in the backward direction with few ambiguities.
Communicated by T. Hennino 相似文献
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47.
Graeme Butt N. Pirzada Ronald D. Topsom William Adcock Anil N. Abeywickrema 《Tetrahedron letters》1982,23(21):2161-2162
The carbon-13 substituent chemical shifts of 4-substituted bicyclo[2.2.2]oct-1-yl cyanides are a linear function of the substituent inductive parameters. 相似文献
48.
Kemmitt T Al-Salim NI Gainsford GJ Bubendorfer A Waterland M 《Inorganic chemistry》2004,43(20):6300-6306
Aqueous titanium citrate solutions were prepared from the reaction of citric acid with titanium 2-propoxide in a range of molar ratios. Solutions containing two or fewer citrates per titanium resulted in the slow crystallization of an insoluble titanium oxo-citrate complex. Single-crystal X-ray analysis identified the species as Ti(8)O(10)(citrate)(4)(H(2)O)(12).14H(2)O.3HOPr(i)(), crystallized in the tetragonal space group I4(1)/a, with a = 30.775(7) A, c = 14.528(7) A, V = 13 759(8) A(3), and Z = 8. The trianionic citrate ligands supply both carboxylate and alkoxide coordination and stabilize the structure using simultaneous chelating and bridging modes of attachment. The compound is a neutral species, exhibiting titanium in three contrasting environments. Laser Raman microscopy and (13)C CPMAS solid-state NMR data were consistent with those of the X-ray crystal structure. When exposed to air, the crystals rapidly lost water and became a powder. The dehydrated powder was noncrystalline to X-rays and insoluble, but (13)C NMR results demonstrated retention of the carboxylate linkages. 相似文献
49.
Phenanthrenequinone undergoes highly efficient proton transfer processes in the presence of a thiourea-functionalised polystyrene copolymer whereas interactions with a similar benzyl-thiourea monomer show strong redox modulation of the quinone without proton transfer. 相似文献
50.
A method for extending atomistic computer simulations of solids beyond the nanosecond time scale was used to simulate metal crystal growth on the time scale of laboratory experiments. Transitions involving concerted motion of multiple atoms on the crystal surface are found to lead to remarkably smooth growth of pure Al(100). Cu(100) is found to grow with a rougher surface, consistent with experiments. Not only is the activation energy of the multiatom Al processes surprisingly low, but vibrational entropy also favors processes where many atoms are displaced. 相似文献