Reaction of N,N′‐(cyclohexane‐1,2‐diylidene)bis(4‐fluorobenzohydrazide), C20H18F2N4O2, ( LF ), with zinc chloride and mercury(II) chloride produced different types and shapes of neutral coordination complexes, namely, dichlorido[N,N′‐(cyclohexane‐1,2‐diylidene)bis(4‐fluorobenzohydrazide)‐κ2N,O]zinc(II), [ZnCl2(C20H18F2N4O2)], ( 1 ), and dichlorido[N,N′‐(cyclohexane‐1,2‐diylidene)bis(4‐fluorobenzohydrazide)‐κ4O,N,N′,O′]mercury(II), [HgCl2(C20H18F2N4O2)], ( 2 ). The organic ligand and its metal complexes are characterized using various techniques: IR, UV–Vis and nuclear magnetic resonance (NMR) spectroscopies, in addition to powder X‐ray diffraction (PXRD), single‐crystal X‐ray crystallography and microelemental analysis. Depending upon the data from these analyses and measurements, a typical tetrahedral geometry was confirmed for zinc complex ( 1 ), in which the ZnII atom is located outside the bis(benzhydrazone) core. The HgII atom in ( 2 ) is found within the core and has a common octahedral structure. The in vitro antibacterial activities of the prepared compounds were evaluated against two different bacterial strains, i.e. gram positive Bacillus subtilis and gram negative Pseudomonas aeruginosa bacteria. The prepared compounds exhibited differentiated growth‐inhibitory activities against these two bacterial strains based on the difference in their lipophilic nature and structural features. 相似文献
While collisionally activated dissociation (CAD) pathways for peptides are well characterized, those of intact proteins are
not. We systematically assigned CAD product ions of ubiquitin, myoglobin, and bovine serum albumin generated using high-yield,
in-source fragmentation. Assignment of >98% of hundreds of product ions implies that the fragmentation pathways described
are representative of the major pathways. Protein dissociation mechanisms were found to be modulated by both source declustering
potential and precursor ion charge state. Like peptides, higher charge states of proteins fragmented at lower energies next
to Pro, via mobile protons, while lower charge states fragmented at higher energies after Asp and Glu, via localized protons.
Unlike peptides, however, predominant fragmentation channels of proteins occurred at intermediate charge states via non-canonical
mechanisms and produced extensive internal fragmentation. The non-canonical mechanisms include prominent cleavages C-terminal
to Pro and Asn, and N-terminal to Ile, Leu, and Ser; these cleavages, along with internal fragments, led to a 45% increase
in sequence coverage, improving the specificity of top-down protein identification. Three applications take advantage of the
different mechanisms of protein fragmentation. First, modulation of declustering potential selectively fragments different
charge states, allowing the source region to be used as the first stage of a low-resolution tandem mass spectrometer, facilitating
pseudo-MS3 of product ions with known parent charge states. Second, development and integration of automated modulation of
ion funnel declustering potential allows users access to a particular fragmentation mechanism, yielding facile cleavage on
a liquid chromatography timescale. Third, augmentation of a top-down search engine improved protein characterization. 相似文献
Understanding pore-scale flow and transport processes is important for understanding flow and transport within rocks on a larger scale. Flow experiments on small-scale micromodels can be used to experimentally investigate pore-scale flow. Current manufacturing methods of micromodels are costly and time consuming. 3D printing is an alternative method for the production of micromodels. We have been able to visualise small-scale, single-phase flow and transport processes within a 3D printed micromodel using a custom-built visualisation cell. Results have been compared with the same experiments run on a micromodel with the same geometry made from polymethyl methacrylate (PMMA, also known as Perspex). Numerical simulations of the experiments indicate that differences in experimental results between the 3D printed micromodel and the Perspex micromodel may be due to variability in print geometry and surface properties between the samples. 3D printing technology looks promising as a micromodel manufacturing method; however, further work is needed to improve the accuracy and quality of 3D printed models in terms of geometry and surface roughness.