Ailin Yuan

Performances of ramie fiber pretreated with dicationic imidazolium ionic liquid

The chemical structure of a new gemini dicationic imidazolium ionic liquid, 3,3′-[1,2-ethanediylbis (oxy-2,1-ethanediyl)]-bis[1-methyl-imidazolium]-dibromide (PEG150-DIL) was established by 1H-NMR and elemental analyses. Then, PEG150-DIL was applied to pretreat ramie fiber. PEG150-DIL treated ramie fiber was characterized by FT-IR, XRD, DSC-TG and FE-SEM. Finally, the mechanical and dyeing properties of PEG150-DIL pretreated ramie fibers were studied. The optimum condition of PEG150-DIL modification was carried out at 100 °C for 30 min. The color strength increased obviously with the duration time and temperature of the PEG150-DIL. The tensile strength and strength retention of PEG150-DIL -treated ramie fibers decreased with the increase of pretreating time and temperature. The tensile strength retention was 86.20 % under optimal PEG150-DIL pretreating condition (100 °C, 30 min).

3,3′-Dimethyl-1,1′-(butane-1,4-di­yl)diimidazolium bis­(tetra­fluoro­borate)

The title compound, C12H20N4 2+·2BF4 −, was prepared by the anion exchange of a dibromide ionic liquid with sodium tetrafluoroborate. The asymmetric unit contains one half of the imidazolium cation, which lies about an inversion centre at the mid-point of the central C—C bond of the linking butyl chain. The two planar imidazole rings (r.m.s. deviation = 0.0013 Å) are strictly parallel and separated by 2.625 (7) Å [vertical distance between the centroids of two imidazole rings], giving the molecule a stepped appearance. In the crystal structure, intermolecular C—H⋯F hydrogen bonds link the cations and anions, generating a three-dimensional network.

3,3'-Dimethyl-1,1'-[(1,3-dihy-droxy-propane-2,2-di-yl)dimethyl-idene]diimidazolium bis-(hexa-fluoro-phosphate).

The title compound, C13H22N4O2 2+·2PF6 −, was prepared by the anion exchange of the dibromide ionic liquid with potassium hexafluorophosphate. The two imidazole rings are each planar (r.m.s. deviations = 0.0016 and 0.0060 Å) and make a dihedral angle of 45.3 (18)°. Intramolecular O—H⋯F hydrogen bonds occur. Intermolecular C—H⋯F, O—H⋯O and C—H⋯O hydrogen bonds stabilize the crystal structure.

3,3-Dimethyl-1,1-(propane-1,3-di-yl)diimidazol-1-ium tetra-bromido-cadmate(II).

The title compound, (C11H18N4)[CdBr4], was prepared by an anion exchange. The dihedral angle between the two planar imidazolium rings in the cation is 74.4 (4)°. The crystal packing is stabilized by weak intermolecular C—H⋯Br hydrogen bonds between the cation and the tetrahedral anion, building up a three-dimensionnal network.

N-(2-Hydroxy­ethyl)-1,8-naphthalimide

In the molecule of the title compound, C14H11NO3, the naphthalimide ring system is nearly planar (r.m.s. deviation 0.0139 Å). In the crystal structure, intermolecular O—H⋯O hydrogen bonds link the molecules into centrosymmetric dimers forming R 2 2(14) ring motifs. π–π contacts between the naphthalimide rings [centroid–centroid distances = 3.648 (3), 3.783 (3), 3.635 (3), 3.722 (3) and 3.755 (3) Å] may further stabilize the structure.

A fluorescent sensor based on quinazoline ketone derivatives for selectivity of Fe3

In this work, we provided a fluorescent sensor based on a compound containing fluorophore quinazoline ketone for detecting metal ions. 2-Methyl-4(3 H)-quinazoline thione was synthesised as a fluorescent probe for tervalent ferric ion (Fe3+) detection. Fluorescent determination of 2-methyl-4(3 H)-quinazoline thione indicated its maximum emission wavelength of 306.5 nm. The fluorescence interference and titration experiments have shown that the compound has a high selective fluorescence response to Fe3+. With an increase in the Fe3+ ion concentration, the fluorescence emission strength gradually weakened, and a slight red shift appeared. With Job’s method, 2-methyl-4(3 H)-quinazoline thione was proved to form a 1:2 complex with Fe3+. The results revealed that 2-methyl-4(3 H)-quinazoline thione could be used as a fluorescent probe for the recognition of Fe3+ with high selectivity.

1,1'-[(1,3-Dihydroxypropane-2,2-diyl)dimethylene]dipyridinium bis-(hexa-fluoro-phosphate).

The title compound, C15H20N2O2 2+·2PF6 −, was prepared by anion exchange of two bromide ions in the ionic liquid 2,2′-bis-(pyridinium-1-ylmethyl)-propane-1,3-diol dibromide with potassium hexafluorophosphate. The two pyridine rings are planar (r.m.s. deviations = 0.008 and 0.00440 Å) and make a dihedral angle of 44.0 (2)°. Intermolecular O—H⋯F and C—H⋯F interactions occur. The four F atoms in each anion were refined as disordered over two sets of sites with an occupancy ration of 0.700 (19):0.300 (19).