A systematic study on the first excited-state proton transfer (ESPT) in 2RAI-H2O (R = OH, OCH3, CN, NO2, CHO) complexes in solution were investigated at the TD-M06-2X/6-31 + G(d, p) level. The double proton transfer occurred in an asynchronous but concerted protolysis fashion no matter which substituent R was used at C2 position in pyrrole ring in the 7AI-H2O complex. The specific vibrational-mode of ESPT in the model systems was confirmed and contributed to promote the reaction rate by shortening the reaction path. The substituent effects of different groups on the ESPT thermodynamics and kinetics were discussed. It was obvious that the geometries, barrier height, asynchrony, and specific vibration-mode of excited-state proton transfer changed with the different substituent groups.
Graphical Abstract The distance between two neighboring heavy atoms such as N1-O11 (R1) and O11-N8 (R2) distances played an important role in the proton transfer reaction. The sum of the N1-O11 and O11-N8 distances in the reactant of 2RAI-H2O (R=H, OH, OCH3; CN, CHO, NO2) complexes is in the range of 5.542 Å~5.692 Å and changes along with the substituent group at C2 position in the pyrrole ring. The ESDPT barrier height and the sum of the N1-O11 and O11-N8 distances have a good correlation.
We have developed a first generation of hybrid sparsomycin-linezolid compounds into a new family of orally bioavailable biaryloxazolidinones that have activity against both linezolid-susceptible and -resistant gram-positive bacteria as well as the fastidious gram-negative bacteria Haemophilus influenzae and Moraxella catarrahalis. The convergent synthesis of these new compounds is detailed. 相似文献
Peptoids are versatile peptidomimetic molecules with wide-ranging applications from drug discovery to materials science. An understanding of peptoid sequence features that contribute to both their three-dimensional structures and their interactions with lipids will expand functions of peptoids in varied fields. Furthermore, these topics capture the enthusiasm of undergraduate students who prepare and study diverse peptoids in laboratory coursework and/or in faculty led research. Here, we present the synthesis and study of 21 peptoids with varied functionality, including 19 tripeptoids and 2 longer oligomers. We observed differences in fluorescence spectral features for 10 of the tripeptoids that correlated with peptoid flexibility and relative positioning of chromophores. Interactions of representative peptoids with sonicated glycerophospholipid vesicles were also evaluated using fluorescence spectroscopy. We observed evidence of conformational changes effected by lipids for select peptoids. We also summarize our experiences engaging students in peptoid-based projects to advance both research and undergraduate educational objectives in parallel. 相似文献
Hydrobiologia - Comparing spatio-temporal patterns between planktonic and benthic algae is helpful for understanding their associations and differences. However, such studies are still rare... 相似文献