Ma Hengchang

A self-assembled triphenylamine-based fluorescent chemosensor for selective detection of Fe3+ and Cu2+ ions in aqueous solution

A novel triphenylamine-based fluorescent sensor tris((4-amino)phenylduryl)amine (m-TAPA) for Fe3+/Cu2+ ion has been developed. m-TAPA shows high selectivity and sensitivity toward Fe3+/Cu2+ over alkali and transition metal ions in aqueous solution. The possible mechanism of fluorescence quenching was that Fe3+/Cu2+ can be captured by the NH2 groups of m-TAPA to form non-fluorescent complexes, resulting in strong quenching. The detection limits of Fe3+ and Cu2+ were calculated to be 230 nM and 620 nM, respectively. Furthermore, fluorescent test strips have been prepared for convenient detection of Fe3+ and Cu2+ ions in environmental water samples, even in drinking water.

Self-assembled triphenylamine derivative for trace detection of picric acid

Detection of explosives is of utmost importance due to the threat to human security as a result of illegal transport and terrorist activities. Picric acid (PA) is widely used in the industrial and military fields, and is inadvertently able to contaminate the environment and groundwater, posing a threat to human health. Achieving the detection of explosives at the parts per billion (ppb) level using chemosensors is a great challenge. Herein, we demonstrate that triphenylamine based fluorescent chemosensors tris(4′-carbethoxybiphenyl) amine (TCEPA) and tris(4′-carboxybiphenyl) amine (TCPA) exhibit superior detection capability for PA in solution state at the ppb level (40 ppb and 5 ppb respectively) and efficient quenching behaviours in the vapor phase at room temperature. In addition, fluorescent test strips have been prepared by dip-coating Thin Layer Chromatography (TCL) for trace detection of PA at the attogram level.

Triphenylamine-decorated BODIPY fluorescent probe for trace detection of picric acid

Triphenylamine-decorated BODIPY derivative TBMA was designed and synthesized. Luminogen aggregation was developed by taking advantage of twisted intramolecular charge transfer (TICT) and aggregation-induced emission (AIE) processes. In non-polar solvents, the locally excited (LE) states of BODIPY luminogens emitted intense yellow light. Increasing solvent polarity brought the luminogens from an LE to a TICT state, causing a large bathochromic shift in the emission color and a dramatic decrease in emission efficiency. The red emission was greatly boosted by aggregate formation or AIE effect. We also discovered that TBMA could be applied as an efficient chemical sensor for picric acid (PA) detection. The detection limit and quenching constant (KSV) were determined as 30 ppb and 2.1 × 10−6 M−1 respectively. 19F NMR and 1H NMR titration analysis verified that F⋯H hydrogen bonding is demonstrated as the mode of interaction, which possibly facilitates effective exciton migration.

Preparation and Characterization of Wool-Pd(0)Catalyst and Its Catalytic Performance for Oxidation of Alcohol in Water

Wool-Pd(0) catalyst was prepared successfully using nature biopolymer wool as stabilizer and supporter. The structure of the palladium catalyst was characterized by field emission scanning electron microscopy and X-ray photoelectron spectroscopy, and the results showed that Pd(0) particles are well dispersed on the surface of wool. Applying wool-Pd(0) catalyst in the oxidation of alcohol under optimized conditions, several parameters such as catalyst amount, base, reaction temperature, and reaction time were screened. It was found that 35 mg wool-Pd(0) catalyst is available for the oxidation of 0.2 mmol alcohol to corresponding aldehyde or ketone with higher conversion and selectivity in the presence of 0.2 mmol K 2 CO 3 and using water as reaction medium. The heterogeneous catalyst is of good reusability in this reaction system.Wool-Pd(0)catalyst was prepared successfully using nature biopolymer wool as stabilizer and supporter.The structure of the palladium catalyst was characterized by field emission scanning electron microscopy and X-ray photoelectron spectroscopy,and the results showed that Pd(0)particles are well dispersed on the surface of wool.Applying wool-Pd(0)catalyst in the oxidation of alcohol under optimized conditions,several parameters such as catalyst amount,base,reaction temperature,and reaction time were screened.It was found that 35 mg wool-Pd(0)catalyst is available for the oxidation of 0.2mmol alcohol to corresponding aldehyde or ketone with higher conversion and selectivity in the presence of0.2mmol K2CO3 and using water as reaction medium.The heterogeneous catalyst is of good reusability in this reaction system.

SO 4 2- /SnO 2 -Fe 2 O 3 固体酸催化下的环酮Baeyer-Villiger氧化反应及缩合反应

采用共沉淀的方法制备了不同Fe掺杂量的SO42-／SnO2·Fe2O3固体超强酸催化剂．利用傅里叶变换红外（FTIR）光谱，粉末X射线衍射（XRD），N2吸附-脱附实验（BET），热重（TG）分析和扫描电镜（SEM）等方法对样品进行了表征．考察了所得催化剂对4-叔丁基环己酮与乙二醇缩合反应的催化性能．实验结果表明，与未经过掺杂改性的SO4 2-／SnO2固体酸催化剂相比，改性后催化剂的催化性能得到了改善．研究了以Fe／Sn摩尔比为0．5的SO4 2-／SnO2-Fe2O3固体酸为催化剂，部分醛酮类化合物与乙二醇及1，2-丙二醇的缩合反应．考察了反应时间、催化剂用量等因素对反应的影响．同时，将所得催化剂应用于环酮Baeyer-Villiger氧化反应中，催化剂表现出良好的催化活性。且催化剂具有一定的循环使用性．

Baeyer-Villiger Oxidation of Cyclohexanone Catalyzed by SBA-15 Supported Silicotungstic Acid

Silicotungstic acid (H4O40SiW12) was supported on SBA-15 with the content of 20% by impregnation. The structure and proper-ties of the catalyst were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption-desorption, and transmis-sion electron microscopy. H4O40SiW12 was highly dispersed on SBA-15 without structural change. The material was applied as an efficient catalyst for the Baeyer-Villiger oxidation of cyclohexanone under different conditions such as the catalyst amount, reaction temperature, and reaction time. When 10 mg of catalyst was used, the cyclohexanone conversion and selectivity for lactone were up to 86% and 99%, respec-tively, at 70 oC for 8 h. The catalyst had moderate reusability in the oxidation system.

The soft interactions of aminated SiO2 nanoparticles with fluorescent partners: a multi-functional sensing platform with a signal amplification effect

Signal amplification, known as the “molecular wire” effect, is greatly desirable and achieved by the electrostatic interactions of aminated SiO2 nanoparticles (SiO2–NH2) with acidic fluorescent partners (NBTA). This explored sensing platform exhibited a multi-responsive capability toward external stimuli, including that of TFA/Et3N, chloroauric acid, as well as the explosive compound PA.

Preparation and Application of SO 4 2– /SnO 2 /SBA-15 Solid Acid Catalyst for Acetalization of Cyclic Ketones: Preparation and Application of SO 4 2– /SnO 2 /SBA-15 Solid Acid Catalyst for Acetalization of Cyclic Ketones

SO42-/SnO2/SBA-15 catalyst samples with different amounts of SnO2 were prepared by a wetness impregnation method and characterized by X-ray diffraction,N2 adsorption-desorption,and transmission electron microscopy.Their catalytic performance for the acetalization of 4-tert-butylcyclohexanone with glycol was investigated.The results showed that SBA-15 supported SO42-/SnO2 improved the catalytic activity markedly,which was caused by the increasing surface area of the sulfated tin oxide.The catalytic performance of SO42-/20%SnO2/SBA-15 for acetalization of several cyclic ketones with diols was also explored.Under the optimum conditions,a series of cyclic ketones such as cyclohexanone,4-methylcyclohexanone,and 4-tert-butylcyclohexanone were well transformed into the corresponding products.The catalyst can be reused for several times without any significant loss in catalytic activity.