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291.
Gilad Golub Israel Zilbermann Haim Cohen Dan Meyerstein 《Supramolecular chemistry》2013,25(3-4):275-279
Abstract Tertiary-amine ligands are known to be poorer [sgrave] donor ligands than the corresponding primary- or secondary-amine ligands. They are known to shift the redox potentials of given couples to the anodic direction relative to the corresponding complexes with primary- or secondary-amine ligands. A review of data in the literature and of recent results on nickel complexes with tetra-aza-macrocyclic ligands and copper complexes with open chain polyamine ligands suggests that the major source for these effects is the poorer solvation of the complexes with the tertiary-amine complexes due to the lack of hydrogen bonding between the complexes and the solvent, or the counter ions. Thus the stabilisation of low valent transition metal complexes by tertiary-amine ligands is due to thermodynamic reasons. On the other hand, tertiary-amine-macrocyclic ligands stabilise high valent complexes because the route to the formation of imine groups is kinetically inhibited in these complexes. 相似文献
292.
Xiao-Hui Li Yi-Xuan Guo Yujie Ren Jia-Jun Peng Ji-Shu Liu Cong Wang Han Zhang 《Frontiers of Physics》2022,17(1):12302-33
Narrow-bandgap materials possess the intriguing optical-electric properties and unique structures,which can be widely applied in the field of photonics,energy optoelectronic sensing and biomedicine,etc.Nowadays,the researches on nonlinear optical properties of narrow-bandgap materials have attracted extensive attention worldwide.In this paper,we review the progress of narrow-bandgap materials from many aspects,such as background,nonlinear optical properties,energy band structure,methods of preparation,and applications.These materials have obvious nonlinear optical characteristics and the interaction with the short pulse laser excitation shows the extremely strong nonlinear absorption characteristics,which leads to the optical limiting or saturable absorption related to Pauli blocking and excited state absorption.Especially,some of these novel narrow-bandgap materials have been utilized for the generation of ultrashort pulse that covers the range from the visible to mid-infrared wavelength regions.Hence,the study on these materials paves a new way for the advancement of optoelctronics devices. 相似文献
293.
Designed Enclosure Enables Guest Binding Within the 4200 Å3 Cavity of a Self‐Assembled Cube
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William J. Ramsay Filip T. Szczypiński Dr. Haim Weissman Dr. Tanya K. Ronson Dr. Maarten M. J. Smulders Prof. Boris Rybtchinski Prof. Jonathan R. Nitschke 《Angewandte Chemie (International ed. in English)》2015,54(19):5636-5640
Metal–organic self‐assembly has proven to be of great use in constructing structures of increasing size and intricacy, but the largest assemblies lack the functions associated with the ability to bind guests. Here we demonstrate the self‐assembly of two simple organic molecules with CdII and PtII into a giant heterometallic supramolecular cube which is capable of binding a variety of mono‐ and dianionic guests within an enclosed cavity greater than 4200 Å3. Its structure was established by X‐ray crystallography and cryogenic transmission electron microscopy. This cube is the largest discrete abiological assembly that has been observed to bind guests in solution; cavity enclosure and coulombic effects appear to be crucial drivers of host–guest chemistry at this scale. The degree of cavity occupancy, however, appears less important: the largest guest studied, bound the most weakly, occupying only 11 % of the host cavity. 相似文献
294.
Kanda S Olsen SL Ueno K Kirk P Cheng CP Ye MH Abashian A Gotow K Haim D Mattson ME Piilonen L Sterner KL Choi SK Lusin S Rosenfeld C Wilson S Zheng LY Fry CA Tanaka R Chinitz LM Ko W Lander RL Rowe J Smith JR Stuart D Abe K Breedon RE Fujii Y Kurihara Y Liu F Maki A Nozaki T Omori T Sagawa H Sakai Y Sasaki T Sugimoto Y Takaiwa Y Terada S Kajino F Aso T Miyano K Miyata H Ohkubo K Oyoshi M Shirai M Takashimizu N Yamashita Y Schnetzer S Vinson J Walker RC Bodek A Kim BJ Kumita T Velissaris C 《Physical review D: Particles and fields》1995,52(9):4872-4876
295.
Silver and gold nanoparticles are very efficient catalysts for the dimerization of methyl-radicals in aqueous solutions. The rate constants for the reaction of methyl-radicals with the gold and silver nanoparticles were measured and found to be 3.7 x 10(8) M(-1) s(-1) and 1.4 x 10(9) M(-1) s(-1), respectively. The results thus suggest that alkyl-radicals, also not reducing ones, are scavenged by these nanoparticles. This might explain the role, if such a role exists, of these nanoparticles in medical applications. 相似文献
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