Department of Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi, 221005, India.
Department of Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi, 221005, India.
Mater Sci Eng C Mater Biol Appl. 2017 Oct 1;79:45-54. doi: 10.1016/j.msec.2017.05.009. Epub 2017 May 4.
The effect of acetone on 3-aminopropyltrimethoxysilane (3-APTMS) mediated synthesis of gold nanoparticles (AuNPs) in polar protic, polar aprotic and non polar solvents specifically water, acetone and chloroform has been studied. The findings revealed that acetone promotes the formation of siloxane polymer in chloroform and acetone solvents, but not in water, while AuNPs are formed in all cases. The bifunctional nature of 3-APTMS [NH(CH)Si(OMe)] controls the formation of siloxane polymer through hydrolysis and condensation of trimethoxysilyl group whereas the amine moieties are likely to form imine linkage, which are involved in the synthesis of gold nanoparticles. The siloxane polymer with imine linkage can be formed both in absence and the presence of gold precursor (i.e. HAuCl). Accordingly, siloxane-gold nanoparticles can be made in different morphology, through control over the process, in three ways; (i) all precursors (Au, 3-APTMS and acetone) mixed simultaneously yielding [(siloxane-Au)], (ii) polymer made first followed by sequential reduction of Au in homogenous suspension forming (Au-siloxane) and (iii) polymer made into thin film followed by sequential reduction of Au in the heterogeneous system yielding (Au-siloxane). The AuNPs produced with the use of water as solvent is different from the three described above as discrete spherical AuNPs are formed as [(AuNPs)] and in this case siloxane polymer is not formed. The results based on AFM and SEM characterizations revealed porous morphology of NPs fabricated in chloroform/acetone, due to the formation of siloxane polymer, and non-porous morphology for the same in water. The "(Au-siloxane)" efficiently promote the reduction of p-nitrophenol with good operational stability, justifying its interest for heterogeneous catalysis. On the other hand, (siloxane-Au) and (Au-siloxane) can be also deposited onto glassy carbon surfaces to yield polymer modified electrodes for subsequent electroanalytical applications. The cyclic voltammetry response of such modified electrodes to a redox probe (i.e., Fe(CN)) was characteristic of diffusion controlled and thin-layer electrochemical behaviour respectively as a function of non-porous and porous nature of the polymer. The as made nanomaterial shows excellent biocatalyst for dopamine sensing based on peroxidase mimetic activity. The typical result on dopamine sensing is reported.
丙酮对 3-氨丙基三甲氧基硅烷（3-APTMS）在极性质子、极性非质子和非极性溶剂（特别是水、丙酮和氯仿）中介导的金纳米粒子（AuNPs）合成的影响进行了研究。研究结果表明，丙酮在氯仿和丙酮溶剂中促进硅氧烷聚合物的形成，但在水中则不会，而在所有情况下都形成 AuNPs。3-APTMS 的双官能性质[NH(CH)Si(OMe)]通过三甲氧基硅烷基的水解和缩合控制硅氧烷聚合物的形成，而胺部分可能形成亚胺键，这参与了金纳米粒子的合成。硅氧烷聚合物与亚胺键可以在没有和存在金前体（即 HAuCl）的情况下形成。因此，可以通过控制过程，以三种方式形成不同形态的硅氧烷-金纳米粒子；（i）同时混合所有前体（Au、3-APTMS 和丙酮），生成[(siloxane-Au)]，（ii）首先形成聚合物，然后在均相悬浮液中顺序还原 Au，生成(Au-siloxane)，（iii）将聚合物制成薄膜，然后在非均相体系中顺序还原 Au，生成(Au-siloxane)。使用水作为溶剂制备的 AuNPs 与上述三种情况不同，因为形成了离散的球形 AuNPs 作为[(AuNPs)]，并且在这种情况下不形成硅氧烷聚合物。基于 AFM 和 SEM 特性的结果表明，在氯仿/丙酮中制备的 NPs 具有多孔形态，这是由于硅氧烷聚合物的形成，而在水中则具有非多孔形态。"(Au-siloxane)"有效地促进了对 p-硝基苯酚的还原，具有良好的操作稳定性，证明了其在多相催化中的应用价值。另一方面，(siloxane-Au)和(Au-siloxane)也可以沉积到玻璃碳表面上，以制备用于后续电分析应用的聚合物修饰电极。这种修饰电极对氧化还原探针（即 Fe(CN)）的循环伏安响应分别是扩散控制和薄层电化学行为的特征，这取决于聚合物的非多孔和多孔性质。所制备的纳米材料在基于过氧化物酶模拟活性的多巴胺传感方面表现出优异的生物催化剂性能。报道了多巴胺传感的典型结果。
