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81.
New Experimental Insight into the Nature of Metal−Metal Bonds in Digallium Compounds: J Coupling between Quadrupolar Nuclei 下载免费PDF全文
Dr. Libor Kobera Scott A. Southern Dr. Gyandshwar Kumar Rao Prof. Dr. Darrin S. Richeson Prof. Dr. David L. Bryce 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(28):9565-9573
Multiple bonding between atoms is of ongoing fundamental and applied interest. Here, we report a multinuclear (1H, 13C, and 71Ga) solid‐state magnetic resonance spectroscopic study of digallium compounds which have been proposed, albeit somewhat controversially, to contain single, double, and triple Ga?Ga bonds. Of particular relevance to the nature of these bonds, we have carried out two‐dimensional 71Ga J/D‐resolved NMR experiments which provide a direct measurement of J(71Ga,71Ga) spin–spin coupling constants across the gallium?gallium bonds. When placed in the context of clear‐cut experimental data for analogous singly, doubly, and triply bonded carbon spin pairs or boron spin pairs, the 71Ga NMR data clearly support the notion of a different bonding paradigm in the gallium systems. Our findings are consistent with an increasing role across the purported gallane–gallene–gallyne series for classical and/or slipped π‐type bonding orbitals. 相似文献
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A novel fiber-optic sensor structure fabricated by cascading two optical microfiber knot resonators (MKRs) is proposed and demonstrated in this paper. A theoretical model for describing the principle of the sensing structure is given and its temperature responses are characterized experimentally. Experimental results show that high-precision and simultaneous multi-point temperature sensing in micro-scale can be achieved. Such a sensing structure also has the potential for achieving dual-parameter measurement to eliminate the cross-talk between two parameters in micro-scale. 相似文献
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Rama Raju Baadhe Naveen Kumar Mekala Satwik Reddy Palagiri Sreenivasa Rao Parcha 《Applied biochemistry and biotechnology》2012,167(5):1172-1182
In this case study, we designed a farnesyl pyrophosphate (FPP) biosynthetic network using hybrid functional Petri net with extension (HFPNe) which is derived from traditional Petri net theory and allows easy modeling with graphical approach of various types of entities in the networks together. Our main objective is to improve the production of FPP in yeast, which is further converted to amorphadiene (AD), a precursor of artemisinin (antimalarial drug). Natively, mevalonate (MEV) pathway is present in yeast. Methyl erythritol phosphate pathways (MEP) are present only in higher plant plastids and eubacteria, but not present in yeast. IPP and DAMP are common isomeric intermediate in these two pathways, which immediately yields FPP. By integrating these two pathways in yeast, we augmented the FPP synthesis approximately two folds higher (431.16 U/pt) than in MEV pathway alone (259.91 U/pt) by using HFPNe technique. Further enhanced FPP levels converted to AD by amorphadiene synthase gene yielding 436.5 U/pt of AD which approximately two folds higher compared to the AD (258.5 U/pt) synthesized by MEV pathway exclusively. Simulation and validation processes performed using these models are reliable with identified biological information and data. 相似文献
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Abstract In this study, the molecular weights of the polymer from vinyl benzoate has been reported for different dose rates and different temperatures. The mol.wt. remains around 4000. With increasing dose, the molecular weight increases to about 14,000. The degrees of polymerization and the kinetic chain lengths calculated from the experimentally determined G R values have been compared which show that the kinetic chain length is larger than the D ? Pn. From a plot of the (D ? Pn)?1 vs. R p , an intercept is obtained which is equal to 3.25 × 10?2 which is higher than obtained in conventional polymerization. By examining the effect of temperature on mol.wt., the dependence of R p on dose rate and the absence of induction period it has been concluded that chain transfer occurs to impurities that are generated during radiolysis. 相似文献