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631.
Alves GA Amato S Anjos JC Appel JA Astorga J Bracker SB Cremaldi LM Dagenhart WD Darling CL Dixon RL Errede D Fenker HC Gay C Green DR Jedicke R Karchin PE Kennedy C Kwan S Lueking LH de Mello Neto JR Metheny J Milburn RH de Miranda JM da Motta Filho H Napier A Passmore D Rafatian A dos Reis AC Ross WR Santoro AF Sheaff M Souza MH Spalding WJ Stoughton C Streetman ME Summers DJ Takach SF Wallace A Wu Z 《Physical review letters》1996,77(12):2392-2395
632.
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634.
H. Stobbe E. Müller und J. Mc. C. Sanders 《Fresenius' Journal of Analytical Chemistry》1907,46(6-7):426-428
Ohne Zusammenfassung 相似文献
635.
636.
J. Mc. Connell Sanders 《Fresenius' Journal of Analytical Chemistry》1908,47(6-7):420
Ohne Zusammenfassung 相似文献
637.
Marc Harris Kenneth Houser Johanna Scarino Scott Wallace Brandon Arndt Amy Smith Gary Romberger Allix Sanders 《Journal of inclusion phenomena and macrocyclic chemistry》2008,60(1-2):153-161
Two novel ethylene oxide-bridged bipyridine oligomers were synthesized that contain host pockets with four (1) or six (2) oxygen donor atoms and a pyridyl nitrogen donor. The alkali picrate extracting ability and selectivity of these free ligands
was investigated using a liquid–liquid dichloromethane–water extraction study. Both open-chain oligomer frameworks display
unexpectedly high extraction efficiency (EE) values for specific guest ions (EE = 57% Na+ extracted by 1, and EE = 39% Cs+ extracted by 2). These extraction values are comparable to macrocyclic analogues and their ion selectivities follow the ‘same-fit’ concept
that has been extensively reported for fixed pocket systems. The shorter chain oligomer (1) binds ions in the series (Na+ > K+ > Cs+), while the larger oligomer (2) binds ions in the reverse order (Cs+ > K+ > Na+). Formation of the host–guest ligand–ion complexes were verified by 1H NMR spectroscopy and MALDI-TOF mass spectrometry experiments. A Job’s plot analysis based on UV spectral data also supported
the 1:1 (oligomer to ion) complexation observed in the MALDI mass spectra. 相似文献
638.
639.
We use a grating spectrometer with a time resolution of 17.4 μs and a spectral resolution of 5 GHz to analyze a superluminescent
source operating near 1350 nm. Polychromatic beating noise is shown to dominate single-shot measurements of the source spectrum;
the observed noise level is within 19% of the theoretical beating noise level. By adopting a delayed pulse referencing scheme
used previously with wavelength-swept sources, the beating noise is virtually eliminated, allowing spectral measurements limited
only by shot noise and camera read noise. 相似文献
640.
C C Mak N Bampos S L Darling M Montalti L Prodi J K Sanders 《The Journal of organic chemistry》2001,66(13):4476-4486
An approach which employs pentameric porphyrin arrays as building blocks toward larger porphyrin arrays is described. Two flexible, and one relatively rigid, Ru-centered porphyrin pentamers (1-3) were synthesized and fully characterized. Their potential as building blocks toward larger porphyrin arrays has been studied via their coordination chemistry using bidentate and tetradentate ligands. DABCO (diazabicyclo[2.2.2]octane) can bind two monomeric porphyrins but was found to be too small to allow the complete formation of a 10-porphyrin array. On the other hand, titration of a larger bridging dipyridyl porphyrin ligand 17 (0.5 equiv) with 1 or 2 and tetrapyridyl ligand 18 (0.25 equiv) with 3 results in the formation of the 11-porphyrin and 21-porphyrin arrays, respectively, with the 21-porphyrin array containing porphyrins in three different metalation states. Changes in the chemical shift of the inner NH protons as well as the ortho- and meso-protons of the pyridyl groups of the porphyrin ligand clearly indicate the formation of large multiple porphyrin complexes. These studies demonstrate that by use of carefully designed building blocks and suitable bridging ligands, porphyrin arrays can be constructed with a dramatic increase in size in relatively few steps. Exploiting the fact that the strength of binding of pyridyl ligands is Ru > Zn > Ni, intra- vs intermolecular competition has been used to investigate aspects of the folding of the array. The photophysical properties of 3 are also described. 相似文献