Xuhong Qian

Novel highly efficient fluoroionophores with a peri-effect and strong electron-donating receptors: TICT-promoted PET and signaling response to transition metal cations with low background emission

Novel fluoroionophores with piperazine frameworks as receptors for transition metal cations have been designed with the aid of calculation and synthesized. They exhibited low background emission and highly efficient fluorescence enhancements upon complexation with different transition metal cations, which could be ascribed to the special contribution of the TICT-promoted PET processes caused by the peri-effect and strong electron-donating receptors.

4-Amino-1,8-dicyanonaphthalene derivatives as novel fluorophore and fluorescence switches: efficient synthesis and fluorescence enhancement induced by transition metal ions and protons

A new electronic push–pull fluorophore, 4-amino-1,8-dicyanonaphthalene, and its derivatives have been synthesized efficiently. They can be used as photo-induced electron transfer fluorescence switches which exhibit considerable fluorescence enhancement induced by transition metal ions Cr3+ and Fe3+ and also respond to pH values very sensitively.

Novel and highly efficient DNA photocleavers: hydroperoxides of heterocyclic-fused naphthalimides

Abstract A series of novel hydroperoxides of heterocyclic-fused naphthalimides were designed, synthesized and exhibited excellent DNA photonicking activities. Among these compounds, the benzothiophenonaphthalimide-type reagent proved to be the most efficient, it can induce single-strand nicks in duplex DNA at micromolar concentration upon illumination. The relationship between the molecular structure and cleaving activities was discussed.

Promoting effects of the hydroxymethyl group on the fluorescent signaling recognition of anions by thioureas

Abstract A series of novel fluorescent naphthylthioureas 1 – 4 with hydroxymethyl groups was designed and synthesized. Upon complexation with anions, 1 – 4 showed strong fluorescence enhancements in the order: 1 > 2 > 3 ≈ 4 , which is consistent with the number of hydroxymethyl groups contained in their structures. Hydroxymethyl groups have an important influence on the compounds’ trans – trans or trans – cis conformations, and their action to promote the fluorescence signaling recognition of the thioureas for anions might be caused by their preorganizing the intramolecular protons of the receptor in favor of sites of the trans – trans conformation ready for hydrogen bond formation with the anions. Thioureas 1 to 4 had favorable selectivities for certain anions, which relied on the net charge and Brφnsted basicity of the anions.

Synthesis and properties of benzothioxanthene dicarboximide hydroperoxide: an efficient ‘time-resolved’ DNA photocleaver with long-wavelength

Abstract A novel hydroperoxide of benzothioxanthene dicarboximide B4 was synthesized through naphthyl radical-induced aromatic 1,5-hydrogen transfer in an unusual Pschorr cyclization and photooxygenation. It was evaluated as an excellent ‘time-resolved’ DNA photocleaver with long-wavelength absorption, which can photonick the duplex DNA at a micromolar concentration of 5 μM upon irradiation at 450 nm.

N-Aroyloxynaphthalimides as novel highly efficient DNA photocleavers: substituent effects

Abstract A novel DNA photocleaver family of N -benzoyloxythioxonaphthalimides, which show improved DNA intercalation and photocleaving activity compared with their oxo- counterparts, were synthesized and evaluated. The substituents on the benzene ring of the benzoyloxy moiety have an important and unusual influence on the DNA photocleaving activity. N -( p -Methoxylbenzoyloxy)thioxonaphthalimide is able to photocleave DNA at low concentration (5 μM) with ‘time-resolved’ and pH independent properties.

Benzothioxanthene dyes as fluorescent label for DNA hybridization: synthesis and application

Abstract With naphthalimide as starting material, a new fluorescent benzothioxanthene dye with application for labeling oligodeoxynucleotide was prepared through imidation, deprotection and iodoacetylation. The benzothioanthene derivatives have DNA intercalation action and displayed a large Stokes’ shift in Tris–HCl–H 2 O buffer. The fluorescence intensity of the dye-labeled oligodeoxynucleotide, which was obtained through the connection of the dye to the sulphydryl functions of phosphate, was found to be sensitive to nucleobase mismatch in DNA sequence during hybridization, and so could be used as novel heterogeneous hybridization probes.

Synthesis and peroxidase-staining properties of novel water soluble polyhydroxylalkyl benzidine dyes

Abstract A series of water soluble N-polyhydroxyalkyl benzidine derivatives was synthesized. The oxidation of glucose–benzidine and fructose–benzidine by iodide was faster than that of benzidine, while N-substituted hydroxylethyl and N-mercaptoethyl benzidines were almost the same as benzidine. It was found that these compounds were able to stain peroxidase well, and compound 2 (fructose–benzidine conjugate) gave the best visualization, which was as good as benzidine.