Abstract The formation and subsequent fragmentation of spirocyclodiphosph(V)azanes (II-III) has been studied by mass spectrometry using the link-field scan technique and structural inferencies are drawn from these data. 31P nmr measurements for compound (III) are also described. 相似文献
Dynorphin A 1–17 (DYN A) is an endogenous neuropeptide that is of interest due to its diverse roles in analgesia, inflammation and addiction. Upon release, DYN A is subject to metabolism by a range of enzymes and its biotransformation is dependent on the site and environment into which it is released. In this study, we investigated the biotransformation of DYN A in rat inflamed tissue at pH?7.4 and 5.5, in rat serum and in trypsin solution. DYN A-porcine was incubated at 37?°C in each matrix over a range of incubation periods. The resultant fragments were separated using a C4 column and detected by mass spectrometry using total ion current mode. Incubation of DYN A in trypsin solution and in rat serum resulted in 6 and 14 fragments, respectively. Incubation in inflamed rat paw tissue occasioned 21 fragments at pH?7.4 and 31 fragments at pH?5.5. Secondary breakdown of some larger primary fragments was also observed in this study. 相似文献
This study reveals that Fourier transform infrared is an effective analytical tool in probing the extent of hydrolysis of
cerium and gadolinium acetylacetonates dissolved in methanol. It is found that these acetylacetonates have relatively fast
hydrolysis rates at the early stage of hydrolysis (<6 h). However, their hydrolysis rates become very slow beyond 6-h of hydrolysis
and decrease to near zero after 55-h of hydrolysis. As a result, hydrolysis cannot be completed even after 170 h at room temperature.
These phenomena suggest that the first and second acetylacetone ligands chelated to Ce3+ and Gd3+ ions can actually be hydrolyzed with relative ease at room temperature, similar to alkoxide ligands. It is the last acetylacetone
ligand that is very difficult to be hydrolyzed. 相似文献
Abstract Based on its reactions with various nucleophiles both geminal and non-geminal structures have been earlier proposed for N3P3Cl4(NH2)2, although its geminal structure is now considered established. The reactions of this compound with alcohols have been investigated and the products examined by NMR spectroscopy and X-ray crystallography. Evidence for both unrearranged as well as geminal → non-geminal rearranged alcoholysis products is presented. 相似文献
Abstract The reactions of 4-methyl-2-[N-(p-toluidinyl)methyl]aniline with phosphorus oxychloride, thiophosphoryl chloride, and their derivatives yield 1,3,2-benzodiazaphosphorine 2-oxides and 2-sulphides. Their 1H NMR and infrared spectra are discussed. Related 1,3,2-benzodiazophosphorine and 1,3,2-dibenzodiazaphosphocine 2-oxides and 2-sulphides are compared. 相似文献
A fluorescent and colorimetric sensor based on rhodamine 6 g (RD6g) was designed, synthesized, and characterized using microwave irradiation. The sensing behavior of this compound was studied by UV–visible and fluorescence spectroscopy. Sensor RD6g exhibits a high selectivity and an excellent sensitivity and is a dual-responsive colorimetric and fluorescent Hg2+-specific sensor in aqueous buffer solution. Mercury ions give rise to the development of a very fluorescent ring-open amide spirolactam system. The detection limit for Hg2+ was found to be 1.2?×?10?8 M. The binding ratio of RD6g-Hg2+ complex was determined to be 1:1 according to the Job’s plot. The reversibility of RD6g?Hg2+ complex has been achieved with CN? anions. The test strip based on RD6g was developed, which could be used as a suitable and methodical Hg2+ test kit.