Self-assembled hybrid tinphosphonate nanoparticles with bimodal porosity: an insight towards the efficient and selective catalytic process for the synthesis of bioactive 1,4-dihydropyridines under solvent-free conditions
作者:Malay Pramanik、Asim Bhaumik
DOI:10.1039/c3ta12476b
日期:——
Self-assembled ordered mesoporous organic–inorganic hybrid tinphosphonate nanomaterial (HSnP-2) with crystalline framework structure has been synthesized through the reaction of benzene-1,3,5-triphosphonic acid (BTPA) and Sn(IV) chloride under hydrothermal conditions at 453 K in the absence of any structure directing agent. Powder XRD, FE-SEM, HR-TEM, N2 sorption, solid state 13C CP-MAS and 31P MAS NMR, TG-DTA analysis and FT-IR spectroscopic techniques are employed to characterize the material. The hexagonal crystal phase of the material is established through REFLEX and CELSIZ unit cell refinement programs. The calculated unit cell parameters of HSnP-2 are a = b = 17.515 Å and c = 10.254 Å. The material is composed of hexagonally ordered tiny nanocrystals of dimensions of ca. 4.0 nm and exhibits high BET surface area (380 m2 g−1), good thermal stability along with uniform supermicropores (ca. 1.3 nm) and an ordered assembly of mesopores. HSnP-2 shows outstanding catalytic activity and high recycling efficiency for the green and efficient one-pot three component coupling reaction for the synthesis of bioactive 1,4-dihydropyridines with excellent yields under solvent-free conditions. The novelty of this eco-friendly catalytic system is further manifested from the mild reaction temperature (333 K) and short reaction time (20 min), together with exclusive selectivity for the desired 1,4-dihydropyridines over 2-arylpyridines or 1,2-dihydopyridines.
自组装有序的介孔有机-无机混合锡膦酸盐纳米材料(HSnP-2)通过苯-1,3,5-三膦酸(BTPA)与Sn(IV)氯化物在无任何结构导向剂的情况下,在453 K的水热条件下反应合成。采用粉末XRD、FE-SEM、HR-TEM、N2吸附、固态13C CP-MAS和31P MAS NMR、TG-DTA分析以及FT-IR光谱技术对该材料进行表征。该材料的六方晶相通过REFLEX和CELSIZ单位晶胞精修程序得到确认。HSnP-2的计算单位晶胞参数为a = b = 17.515 Å,c = 10.254 Å。该材料由尺寸约为4.0 nm的六角有序微小纳米晶体组成,具有高BET表面积(380 m² g⁻¹)、良好的热稳定性,以及均匀的超微孔(约1.3 nm)和有序的介孔排列。HSnP-2表现出卓越的催化活性和高重复利用效率,在无溶剂条件下进行绿色高效的一锅法三组分偶联反应合成生物活性1,4-二氢吡啶,具有优异的产率。这种环保催化系统的创新性体现在温和的反应温度(333 K)和短短的反应时间(20分钟),同时对所需的1,4-二氢吡啶表现出优越的选择性,优于2-芳基吡啶或1,2-二氢吡啶。