排序方式: 共有37条查询结果,搜索用时 31 毫秒
21.
We report the results of a theoretical study of neutral, anionic, and cationic Ga(n)On clusters (n = 4-7), focusing on their ground-state configurations, stability, and electronic properties. The structural motif of these small gallium oxide clusters appears to be a rhombus or a hexagonal ring with alternate gallium and oxygen atoms. With the increase in the cluster size from Ga4O4 to Ga7O7, the ground-state configurations show a transition from planar to quasi-planar to three-dimensional structure that maximizes the number of ionic metal-oxygen bonds in the cluster. The ionization-induced distortions in the ground state of the respective neutral clusters are small. However, the nature of the LUMO orbital of the neutral isomers is found to be a key factor in determining the ordering of the low-lying isomers of the corresponding anionic clusters. A sequential addition of a GaO unit to the GaO monomer initially increases the binding energy, though values of the ionization potential and the electron affinity do not show any systematic variation in these clusters. 相似文献
22.
Marudachalam Shanmugasundaram Mrinalini Puranik 《Journal of Raman spectroscopy : JRS》2009,40(12):1726-1748
Purines, pyrimidines, and the corresponding ribose monophosphates are ubiquitous biomolecules involved in several cellular processes–in DNA and RNA, signaling, and energy transactions. In the new and exciting field of DNA‐inspired nanostructures, they are used as fundamental building blocks. Unique features of the nucleobases are that several tautomeric states are close in energy and the tautomeric equilibria are sensitive to exocyclic substitution and pH. Knowing the exact structure and tautomer(s) at physiological conditions is crucial to understand the substrate specificities and catalytic mechanisms of the many enzymes for which these nucleobases are substrates. Very few spectroscopic methods can distinguish between tautomers and provide solution structures. Vibrational spectroscopy has long been known to be an excellent tool to obtain reliable information on nucleic acids. However, even when good‐quality spectra are available, isotope editing is required to make reliable band assignments and identify structures unequivocally. Density functional theoretical (DFT) methods have become indispensible in assisting the assignment of observed spectra to normal modes, identification of tautomers, and modeling of spectra of isotope‐edited molecules. We review the performance of DFT methods in the prediction of nucleobases and their analogs. We find that even with modest basis sets, trends in vibrational spectra can be predicted adequately and guide assignments to normal modes of the molecule. Shifts in band positions induced upon isotope labeling are reproduced more reliably than the band positions. Scaling considerably improves the agreement between the computed and experimental spectra, but accurate prediction of vibrations of exocyclic groups like CO requires that solvent effects are taken into account. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
23.
24.
Thipanni Anitha Madoori Mrinalini Damera Vani Seelam Prasanthkumar Kallu Rajender Reddy Lingamallu Giribabu 《Photochemistry and photobiology》2020,96(6):1182-1190
Herein, we report the versatile synthetic strategy and opto-electronic properties for the phosphorylation of BODIPY derivatives 5aa - 5ak by substituting with an electron-donating/withdrawing group at the ortho position. Nevertheless, this new methodology relatively promotes the tolerance of the aldehyde moiety and the high yield for the synthesis of BODIPY o-OPhos derivatives. The photophysical studies suggest improved optical properties due to the inductive effect of various electron-donating/withdrawing groups. The UV-visible and the emission data suggest that BODIPY o-OPhos derivatives emphasize the property of the excited states with an increase in fluorescence intensity and high quantum yields due to the presence of bulky phospsho-triester at the meso- position which hinders the free rotation around the C-Ar bond and facilitates the development of OLEDs and various organophosphorus warfare agents. Electrochemical studies reveal 5ak depicts the ease of redox activity amongst the 5aa - 5ak derivatives. The density functional theory indicates the highest occupied molecular orbital on the BODIPY moiety whereas the lowest unoccupied molecular orbital delocalized on BODIPY and the phospho-triester moieties. Thus, the unique development of the novel BODIPY derivatives with improved optical and redox properties pave the way for fluorescent probes and bioimaging techniques. 相似文献
25.
Unprecedented Charge‐Transfer Complex of Fused Diporphyrin as Near‐Infrared Absorption‐Induced High‐Aspect‐Ratio Nanorods
下载免费PDF全文
![点击此处可从《化学:亚洲杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
B. Shivaprasad Achary Dr. Sabapathi Gokulnath Samrat Ghosh Madoori Mrinalini Dr. Seelam Prasanthkumar Dr. Lingamallu Giribabu 《化学:亚洲杂志》2016,11(24):3498-3502
Charge‐transfer (CT) complexes of near‐infrared absorbing systems have been unknown until now. Consequently, structural similarities between donor and acceptor are rather important to achieve this phenomenon. Herein, we report electron donors such as non‐fused diporphyrin‐anthracene (DP), zinc diporphyrin‐anthracene (ZnDP) and fused zinc diporphyrin‐anthracene (FZnDP) in which FZnDP absorbs in NIR region and permits a CT complex with the electron acceptor, perylene diimide (PDI ) in CHCl3 exclusively. UV/Vis‐NIR absorption, 1H NMR, NOESY and powder X‐ray diffraction analysis demonstrated that the CT complex formation occurs by π–π stacking between perylene units in FZnDP and PDI upon mixing together in a 1:1 molar concentration in CHCl3, unlike non‐fused ZnDP and DP. TEM and AFM images revealed that the CT complex initially forms nanospheres leading to nanorods by diffusion of CH3OH vapors into the CHCl3 solution of FZnDP/PDI (1:1 molar ratio). Therefore, these CT nanorods could lead to significant advances in optical, biological and ferroelectric applications. 相似文献
26.
For ease of detection, soluble forms of phage-displayed scFv antibodies are usually expressed with a tag, e.g., c-myc or His
(Histidine). The binding is then assayed by a monoclonal antibody to the tag. In this article, we describe the use of biotinylated
antigen for detecting soluble scFv antibodies without utilizing the peptide tag detection system. The scFv antibodies were
against the oncoplacental antigen heat-stable alkaline phosphatase (HSAP). The method essentially consisted of either reverse
Western or antigen capture enzyme-linked immunosorbent assay (ELISA). In the reverse Western, periplasmic extract was electrophoresed,
and binding to biotinylated antigen was detected by the detection system based on streptavidin-horseradish peroxidase. The
antigen capture ELISA utilized the binding of periplasmic extract to a polystyrene plate. We have also demonstrated the use
of antigen capture ELISA for studying specificity and affinity of the selected clones. Although these techniques have been
developed for antibodies to HSAP, they have general utility for phage expression systems without a peptide tag. 相似文献
27.
Potale Laxman V. Khodke Amol S. Patole Shangiresh S. Damle Mrinalini C. 《平面色谱法杂志一现代薄层色谱法》2012,25(1):72-76
JPC – Journal of Planar Chromatography – Modern TLC - Asensitive, selective, precise, and stability-indicating (in accordance with ICH guidelines) high-performance thin-layer... 相似文献
28.
Sensing Characteristics of a Graphene‐like Boron Carbide Monolayer towards Selected Toxic Gases
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Manasi S. Mahabal Dr. Mrinalini D. Deshpande Dr. Tanveer Hussain Prof. Rajeev Ahuja 《Chemphyschem》2015,16(16):3511-3517
By using first‐principles calculations based on density functional theory, we study the adsorption efficiency of a BC3 sheet for various gases, such as CO, CO2, NO, NO2, and NH3. The optimal adsorption position and orientation of these gas molecules on the BC3 surface is determined and the adsorption energies are calculated. Among the gas molecules, CO2 is predicted to be weakly adsorbed on the graphene‐like BC3 sheet, whereas the NH3 gas molecule shows a strong interaction with the BC3 sheet. The charge transfer between the molecules and the sheet is discussed in terms of Bader charge analysis and density of states. The calculated work function of BC3 in the presence of CO, CO2, and NO is greater than that of a bare BC3 sheet. The decrease in the work function of BC3 sheets in the presence of NO2 and NH3 further explains the affinity of the sheet towards the gas molecules. The energy gap of the BC3 sheets is sensitive to the adsorption of the gas molecules, which implies possible future applications in gas sensors. 相似文献
29.
30.