Qinglei Liu

Selective fluorescence sensor for Cu2+ with a novel triazole Schiff-base derivative with coumarin units

Abstract Novel triazole Schiff-base derivative 3 bearing a coumarin unit was synthesized by the reaction of 4-formylbenzocoumarin (1) with 3,5-diphenyl-4-amino-1,2,4-triazole (2). The structure of the product was characterized by means of IR, MS, 1H NMR, 13C NMR, and elemental analysis. The UV-vis absorption and fluorescence emission spectra of compound 3 exhibit blue-shifted absorption and fluorescent enhancement upon chelation to cupric ion. Fluorometric titration revealed a 2:1 ligand to metal ratio in the complex and the binding constant of 4.62×106 m-1.

2-[(3-Propyl-sulfanyl-5-p-tolyl-4H-1,2,4-triazol-4-yl)imino-meth-yl]phenol.

In the title molecule, C19H20N4OS, the two benzene rings form dihedral angles of 16.2 (1) and 12.0 (1)°, respectively, with the central triazole ring. In the crystal, intermolecular O—H⋯N hydrogen bonds link molecules into chains in the [010] direction.

Selective Zn 2+ recognition of novel triazole Schiff-base derivatives bearing the coumarin group

Three novel triazole Schiff-bases derivatives bearing coumarin units have been synthesised from 3,5-diaryl-4-amino-1,2,4-triazole with three kinds of coumarin aldehydes. The UV-Vis absorption and fluorescence emission spectra of (E)-4-((3,5-diphenyl-4H-1,2,4-triazol-4-ylimino)methyl)-7-methoxy-2H-chromen-2-one exhibited blue-shifted absorption and fluorescent enhancement upon chelation to zinc ion as a 2: 1 ligand-to-metal complex with a binding constant of 3.29 × 106 M−1.

Synthesis and Fe 3+ recognition of novel triazole Schiff-base derivatives bearing fluorogenic naphthalene and anthracene units

Novel triazole Schiff-bases derivatives have been synthesised from 3,5-diaryl-4-amino-1,2,4-triazole with naphthaldehyde and anthraldehyde. The emission spectrum of 3,5-diphenyl-4-(anthrylmethyleneamino)-1,2,4-triazole exhibited fluorescent quenching upon chelation to Fe3+ ions.

3-[4-(2-Chloro-benzyl-idene-amino)-3-methyl-5-sulfanyl-idene-4,5-dihydro-1H-1,2,4-triazol-1-yl]-1,3-diphenyl-propan-1-one.

In the title molecule, C25H21ClN4OS, the triazole ring forms dihedral angles of 47.9 (2), 84.5 (2) and 3.9 (2)° with the two phenyl rings and the chlorophenyl ring, respectively. The chlorophenyl ring, the triazole ring and the conjugative linker between the two aromatic rings are nearly coplanar with an r.m.s. deviation of 0.0483 (2) Å and a maximum deviation of 0.0911 (2) Å.

rac-3-{4-[(Furan-2-ylmethyl­idene)­amino]-3-methyl-5-sulfanyl­idene-4,5-dihydro-1H-1,2,4-triazol-1-yl}-1,3-diphenyl­propan-1-one

In the title molecule, C23H20N4O2S, the triazole ring forms dihedral angles of 150.3 (2), 77.3 (2) and 77.6 (2)°, respectively, with the furan ring and the phenyl rings. The furan ring is almost perpendicular to the central phenyl ring, making a dihedral angle of 86.0 (3)°.

3-(4-Amino-3-ethyl-5-sulfanyl-idene-4,5-dihydro-1H-1,2,4-triazol-1-yl)-3-(2-chloro-phen-yl)-1-phenyl-propan-1-one.

In the title molecule, C19H19ClN4OS, the 1,2,4-triazole ring forms dihedral angles of 86.0 (2) and 65.6 (2)° with the phenyl and chlorophenyl rings, respectively. In the crystal, intermolecular N—H⋯S and N—H⋯O hydrogen bonds link molecules into centrosymmetric dimers, which are further linked into chains in [001] via weak C—H⋯π interactions.

3-[3-Methyl-4-(4-nitro­benzyl­idene­amino)-5-sulfanyl­idene-4,5-dihydro-1H-1,2,4-triazol-1-yl]-1,3-diphenyl­propan-1-one dichloro­methane monosolvate

In the title compound, C25H21N5O3S·CH2Cl2, the dichloromethane solvent molecule is disordered over four positions, with an occupancy ratio of 0.271 (3):0.3884 (18):0.298 (2):0.0424 (15). The 1,2,4-triazole ring makes dihedral angles of 47.3 (2)/87.3 (2) and 3.6 (2)° with the phenyl and nitrophenyl rings, respectively. An intramolecular C—H⋯S hydrogen bond results in the formation of an almost planar six-membered ring [r.m.s. derivation = 0.0051 (2) Å]. Intermolecular C—H⋯O hydrogen bonding consolidates the structure.

1,4-Bis{[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]sulfan-yl}butane.

In the centrosymmetric title compound, C18H16N6O2S2, the 1,3,4-oxadiazole and the attached pyridinyl ring are twisted by 5.3 (3)°.