Developing functional
porous materials as a platform for the heterogeneous
catalytic oxidation reaction provides a good way to solve the high
environmental issues resulted by traditional oxidation processes in
the industry. This article reported a design and facile synthesis
of N-rich functional porous organic polymers with mesopores such as
Azo-POP-4, Azo-POP-5, and Azo-POP-6 based on the triaminotriphenylazobenzene
subunit for the first time. The nitrogen-rich POPs with the triaminotriphenylazobenzene
subunit was found to remove 85% of copper ions from water within 30
min. The as-synthesized Cu@Azo-POP-4 demonstrated high catalytic reactivity
and selectivity in aerobic C–H bond oxidation to afford the
desired ketones in high yield. In addition, the catalyst could be
reused easily five times without decreasing the reactivity, which
will help to design catalysts reducing environmental pollution and
advance the chemical technology.
Irreversible tautomerization could lead to fascinating functional porous organic polymers such as TKH-POPs comprising tris(β-keto-hydrazo)-cyclohexane subunit.
Background: Extant indices for distinguishing between iron deficiency anemia (IDA) and thalassemia (Thal) have substantial practical limitations. The aim of this pilot study was to assess the predictive value of red blood cell lifespan (RBCLS), as determined by an automated CO breath test analysis approach, in the differential diagnosis of these two common forms of microcytic hypochromic anemia (MHA). Methods: RBCLS measurements were conducted in 35 healthy controls (HCs) and 114 patients diagnosed with MHA (IDA, N = 59; and Thal, N = 55) with ELS TESTER that provides a direct RBCLS value read-out. RBCLS between IDA and Thal was compared and evaluated by referring to normal cut-off from the instrument. Results: Compared with that in HCs, RBCLS in IDA and Thal groups was shortened; and median RBCLS was shorter in the Thal group than that in IDA group (33 d versus 79 d, p < 0.001). The median RBCLS in IDA patients with chronic gastrointestinal (GI) bleeding was shorter than that those without GI bleeding (38 d versus 100 d, p < 0.001). Using 75 d as a cut-off, RBCLS had a sensitivity of 96.4% and a specificity of 50.8% for detecting Thal. When GI bleeding patients were excluded from the IDA group, discriminant efficiency of RBCLS was further improved. Conclusions: MHA with a normal RBCLS is suggestive of IDA, whereas MHA with a significantly shortened RBCLS without signs of chronic GI bleeding is suggestive of Thal.
The usefulness of 14 N NMR spectroscopy was highly underestimated compared with 15 N NMR, which usually required tedious and expensive 15 N-labeling manipulations. It is of great significance to make the 14 N NMR spectroscopy convenient and useful considering 14 N nuclei's high natural abundance of 99.6%. Herein, lots of efforts have been made to generalize routine 14 N NMR to characterize nitrogen-containing species by tuning the balance between the solubility and viscosity of the samples. Satisfactory 14 N NMR spectra of more than 60 nitrogen-containing compounds have been recorded, and the chemical shifts and the peaks' full width at half-maxima of more than 10 nitrogenbased functionalities have been summarized. Successful monitoring of the orthoselective nitration of aniline has been demonstrated using the 14 N NMR protocol developed in this paper, which will help realize the visualization of nitration processes in the industry.
Porous organic polymers (POPs) have
aroused great and wide attention
from the materials community, while the identification of their precise
structures is still very challenging. The well-defined structures
are of great importance in understanding the relationship between
the structure and function of the polymer materials, though they are
sometimes ignored and do not receive enough attention. In this letter,
an efficient 15N labeling technique and 15N
solid-state NMR (15N-SSNMR) were combined to obtain strong
evidence for the presence of the azo bond and keto-hydrazone structure
in the solid state. Thus, the structure of tris(β-hydroxyl-azo)-benzene
in previously proposed hydroxylazobenzene polymers was revised
to tris(β-keto-hydrazo)-cyclohexane in TKH-POPs for the first
time. In contrast, similar tautomerization did not occur in the azo
coupling polymerization of 1,3,5-triaminobenzene and diazonium salts,
i.e., tris(β-amino-azo)-benzene remained in Azo-POPs. This work
will open up a window to develop innovative porous organic polymers
more efficiently with the aid of 15N-SSNMR.
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