[Cu(bpdo)2·2H2O]2+-supported SBA-15 nanocatalyst for efficient one-pot synthesis of benzoxanthenone and benzochromene derivatives

A novel [Cu(bpdo)₂·2H₂O]²⁺-supported SBA-15 catalyst (bpdo = 2,2′-bipyridine,1,1′-dioxide) was prepared by the impregnation method. The catalyst was characterized by XRD, TEM, and BET nitrogen adsorption–desorption method, FT-IR, UV–vis, and chemical analysis. XRD patterns and TEM analysis of [Cu(bpdo)₂·2H₂O]²⁺/SBA-15 showed highly ordered hexagonal mesoporous silica, even after immobilization. Also, nitrogen adsorption–desorption isotherms exhibited type-IV isotherms and H1 hysteresis loops according to the IUPAC classification of mesoporous materials. This green support was tested for the synthesis of benzoxanthenone and benzochromene derivatives under solvent-free conditions, with high yield of products via a simple experimental and work-up procedure.     

Application of Nanosized Cu0.5Co0.5Fe2O4 Spinel Ferrite as a Nanocatalyst in the Synthesis of 14‐Aryl‐14H‐dibenzo[a,j]xanthene Derivatives under Solvent‐free Conditions

Copper and cobalt substituted spinel ferrites Cu_1‐xCo_xFe₂O₄ (0≤X≤1) have been synthesized by using hydrothermal method. The resultant spinel ferrites were systematically characterized by different techniques such as X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FT‐IR). It was indicated that all the resultant spinel ferrites obtained by the hydrothermal method had the single‐phase crystalline. The resultant spinel ferrites were employed in the synthesis of 14‐aryl‐14‐H‐dibenzo[a,j]xanthene derivatives. It was found that the nanocatalyst Cu_0.5Co_0.5Fe₂O₄ displays the best performance in the synthesis of 14‐aryl‐14H‐dibenzo[a,j]xanthenes. The catalyst was reused several times without significant loss of its activity for the preparation of desired product. In addition high yields of the products, solvent‐free conditions and reusability of the catalyst are other worthwhile advantages of the present study.     

ZnO: An Ecofriendly,Green Nano‐catalyst for the Synthesis of Pyrazole Derivatives under Aqueous Media

An efficient nano ZnO catalyzed green protocol for the synthesis of pyrazol derivatives by condensation of different substituted phenyl hydrazines/semicarbazide/thiosemicarbazide with 1,3‐diketone/ketoester at ambient temperature has been achieved. ZnO nanocatalyst was prepared by low temperature solution combustion method. From the Scherrer method the crystallite size of ZnO was estimated and found to be in the range of 30–50 nm. The main advantage of this protocol is an excellent yield, short reaction time and easy work up procedure. The catalyst was found to be reusable up to five catalytic cycles without any appreciable loss in activity of the catalyst.     

磺酸官能化的磁性核壳结构的纳米材料用于果糖脱水制备5-羟甲基糠醛(英)

通过反相微乳液法制备了以Fe₃O₄为核,磺酸官能化的硅基材料为壳层的磁性酸性催化剂.首先制备纳米Fe₃O₄磁核,然后涂层包覆苯基修饰的纳米级硅层,最后进行苯基磺化修饰,制得固体酸催化剂Fe₃O₄@Si/Ph-SO₃H.在果糖脱水制备5-羟甲基糠醛反应中,该催化剂表现出较好的催化活性,优于传统催化剂A-15,且与均相无机酸催化活性相当.当采用二甲基亚砜作溶剂,在110℃下反应3 h,果糖转化率达到99%,5-羟甲基糠醛收率为82%.另外,该催化剂经磁法回收后可多次重复使用.     

Efficient One‐Pot Synthesis of Bis(4‐hydroxycoumarin)methanes in the Presence of Sulfonic Acid Functionalized Nanoporous Silica (SBA‐Pr‐SO3H)

An efficient and simple method for the synthesis of bis(4‐hydroxycoumarin)methanes has been achieved through a one‐pot condensation of aryl aldehydes and 4‐hydroxycoumarin in the presence of nanoporous solid acid catalyst of SBA‐Pr‐SO₃H with pore size of 6 nm. Excellent yields, short reaction times, reusability of the catalyst and simple workup are advantages of this synthetic procedure.     

原位合成无表面活性剂纳米钯用于催化氢转移反应合成偶氮类化合物及对不饱和双键的还原

以乙酰丙酮钯作为催化剂前体, 异丙醇作为氢源, 在碱性的反应过程中原位得到纳米尺度的钯纳米颗粒, 并进一步得到钯-氢活性结构, 实现硝基的还原及氮氮键的偶联. 该催化体系还可以实现C=C和C=O键的有效还原. 这类原位得到的钯纳米催化材料表面裸露, 因而具有更高的催化活性.     

Aluminatesulfonic acid: Novel and recyclable nanocatalyst for efficient synthesis of aminoalkyl naphthols and amidoalkyl naphthols

In this study, an efficient, mild, and eco-friendly procedure is developed for the preparation of 1-amidoalkyl-2-naphthols and Betti bases from one-pot three-component condensation of aldehydes, 2-naphthol, and nitrogen sources (amides for amidoalkyl naphthols and amine for Betti bases) in the presence of aluminatesulfonic acid nanoparticles (ASA NPs) as recoverable catalyst under solvent-free conditions. ASA NPs were prepared by a simple reaction of net chlorosulfonic acid and sodium aluminate in high purity. ASA NPs were characterized by Fourier transform IR, X-ray powder diffraction, transmission electron microscopy, energy-dispersive X-ray, thermal gravimetric analysis, and UV diffusion/reflectance techniques. On the basis of the thermal gravimetric analysis and some activation parameters evaluated from decomposition thermal steps using Coats–Redfern model, the catalyst showed high thermal stability. High yields, short reaction time, easy workup, inexpensive, and reusability of the catalyst are advantages of this method.     

细胞内原位纳米催化在疾病诊断与治疗中的应用

纳米催化剂因其经济、 稳定以及可量产等优势, 实现了细胞内原位催化反应, 为分子水平人工调控细胞功能提供了可能. 人工纳米催化剂优异的催化性能使其在不同生理和病理条件下成功用于诊断成像和治疗. 本文综合评述了具有天然酶活性的纳米催化剂在癌症和氧化应激治疗以及基于纳米催化剂介导的细胞内原位催化反应的精准诊断成像方面的主要研究进展, 并对纳米催化剂在未来生物医药领域应用中面临的挑战和机遇进行了展望.     

Synthesis of Pyranopyrazoles Using Magnetically Recyclable Heterogeneous Iron Oxide‐silica Core‐shell Nanocatalyst

The Fe₃O₄@SiO₂ core‐shell nanocatalyst were prepared and efficiently used for four‐component coupling reaction of aromatic aldehydes, malononitrile, ethyl acetoacetate and hydrazine hydrate in water/ethanol mixture. Various aromatic aldehydes possessing electron‐withdrawing and electron‐donating groups in different positions on the ring were successfully transformed to substituted pyranopyrazoles in high yields in short time. The nanocatalyst was easily recovered, and reused five times without significant loss in cata‐ lytic activity and performance. The structure, size and morphology of the nanosized catalyst were studied by various techniques such as Fourier transform infrared spectroscopy, powder X‐ray diffraction, dynamic light scattering and transmission electron microscopy.     

Rational Design of Highly Efficient One-pot Synthesis of Ternary PtNiCo/FTO Nanocatalyst for Hydroquinone and Catechol Sensing

In this work, we present a simple and efficient method for preparation of widely dispersed PtNiCo nanocatalyst on FTO without the use of any heavy complex structure. The proposed nanocatalyst enhances the chemical interaction of PtNiCo/FTO and increases its catalytic activity, which was used for electrochemical sensing of catechol and hydroquinone. The surface morphology was characterized by TEM, HRTEM, and XRD. The size of the PtNiCo/FTO octahedrons nanocatalyst was about 0.35–4 nm. Gradual increase of concentration exhibited linearity in oxidation peak response up to 1100 μM with a low detection limit of 0.79 μM for HQ and 1.05 μM for CC. The sensitivity is 1035 μAmM⁻¹ cm⁻² for catechol and 1197 μAmM⁻¹ cm⁻² for hydroquinone. The prepared nanomaterial/sensor applied to real water samples with good reproducibility (98–99 %).