Na Liu

Bio: Na Liu is an academic researcher from Zhanjiang Normal University. The author has contributed to research in topics: Chemistry & Conjugated system. The author has an hindex of 1, co-authored 2 publications receiving 31 citations.

Resonance-assisted intramolecular triel bonds.

Abstract: The possibility that the intramolecular Tr⋯S triel bond is strengthened by resonance is examined by quantum chemical calculations within the planar five-membered ring of TrH2-CRCR-CRS (Tr = Al, Ga, In; R = NO2, CH3). This internal bond is found to be rather short (2.4-2.7 Å) with a large bond energy between 12 and 21 kcal mol-1. The pattern of bond length alternation and atomic charges within the ring is consistent with resonance involving the conjugated double bonds. This resonance enhances the triel bond strength by some 25%. The electron-withdrawing NO2 group weakens the bond, but it is strengthened by the electron-donating CH3 substituent. NICS analysis suggests the presence of a certain degree of aromaticity within the ring.

Noncovalent interactions in model molecular clusters containing the tetrel atoms Si and Ge

Abstract: An MP2 computational study was undertaken for the XF···LiF-TF3CN (X = Li, H, Cl: T = Si, Ge) and LiF-TF3CN···XF (T = Si, Ge; XF = BeF2, BF3, SF2, PH2F, SiH3F, LiF, HF, ClF) series of complexes involving a strongly bound LiF-TF3CN molecular subunit, characterised by a strong bonding motif with an Si-F (or Ge-F) bond perpendicular to the LiF molecule. The effect of attachment of XF, to either the LiF or the CN end of the LiF-TF3CN moiety, was investigated and rationalised with the aid of the natural bond orbital (NBO) analyses and localised molecular orbital-energy decomposition analyses (LMO-EDA). These analyses allow for a comparison of the bonding features in these complexes and the relative strengths of the noncovalent interactions introduced by the model Lewis acids XF. GRAPHICAL ABSTRACT

Crystal structure of 2-((tert-butyldimethylsilyl)oxy)-5-methylisophthalaldehyde, C15H22O3Si

Abstract: Abstract C15H22O3Si, monoclinic, P21/n (no. 14), a = 10.0187(5) Å, b = 11.9948(5) Å, c = 13.6259(7) Å, β = 102.521(5)°, V = 1598.51(14) Å3, Z = 4, Rgt(F) = 0.0485, wRref(F2) = 0.1273, T = 293 K.

A novel N-nitrosation-based ratiometric fluorescent probe for highly selective imaging endogenous nitric oxide in living cells and zebrafish

Abstract: Nitric oxide (NO), a widespread signaling transduction molecule in organism, plays key roles in lots of pathophysiological processes. Aberrant level of NO is closely related to tumors, cardiovascular and cerebrovascular diseases, neurodegenerative diseases and many other diseases. Therefore, sensing NO in cells and in vivo is of great significance for the study of the chemical biology of related diseases. Herein, a novel ratiometric fluorescence probe (AC-SA), in which anthracene carboximide used as fluorophore and secondary amines at the 6th position of the fluorophore severed as recognition moiety is rationally designed to detect NO. The AC-SA can capture NO via N-nitrosation reaction to give obvious fluorescence signal change from red to green based on the intramolecular charge transfer (ICT) mechanism. The AC-SA features striking ratiometric signal (I525/I625), good sensitivity (4.05 nM), high selectivity for sensing NO over various interferents in physiological pH. More important, the AC-SA can be applied to image endogenous NO in Raw 264.7 macrophage cells as well as zebrafish in a ratiometric manner.

Fluorescent Chemosensor for Dual-Channel Discrimination between Phosgene and Triphosgene

Abstract: As highly toxic and accessible chemical reagents, phosgene and triphosgene have become a serious threat to public safety. So, it is highly desirable to develop facile methods to detect and recognize them. In this article, a novel fluorescent chemosensor, Phos-4, has been constructed with 1,8-naphthalimide as the fluorophore and 2-(2-aminophenyl)imidazol as the recognition sites for discrimination between phosgene and triphosgene in a dual-channel mode for the first time. Owing to the difference in electrophilicity between chlorocarbonyl and trichloromethoxycarbonyl, the sensing reaction of Phos-4 with phosgene undergoes two carbamylations to afford a cyclic product with green fluorescence, and only one carbamylation occurs for triphosgene to form a noncyclic product with blue fluorescence. The sensor Phos-4 exhibits high sensitivity (the limit of detection, 3.2 nM, for phosgene, and 1.9 nM, for triphosgene) and high selectivity in solutions. Furthermore, facile test papers containing Phos-4-embedded nanofibrous membrane have been fabricated by the electrospinning technology. The test papers can provide visual and selective detection of phosgene with a lower limit of detection (42 ppb) and a faster response (≤10 s) in the gas phase over those in solutions. The test paper with Phos-4 is promising to be a practical detection tool of gaseous phosgene.