DWI e.V. and Institute of Technical and Macromolecular Chemistry, RWTH Aachen, Pauwelsstr. 8, D 52056 Aachen, Germany.
Phys Chem Chem Phys. 2011 Aug 14;13(30):13572-8. doi: 10.1039/c1cp20518h. Epub 2011 Jul 12.
The relevance of anion structure on the shape regulating effect of 3-ethyl-1-methylimidazolium-based ionic liquids during the seed-induced growth of gold nanocrystals is evaluated for the particular case of lactate, acetate, methylsulfate, ethylsulfate and tosylsulfonate anion systems. Carboxylate-based anions (lactate and acetate) are found to inhibit the reduction of the gold precursor salt presumably due to the deprotonation of the reducing agent ascorbic acid. The formation of non-uniform, 'head-tail'-type anisotropic particle structures is observed in both methyl- and ethylsulfate anion systems whereas rapid precipitation is observed in the case of tosylsulfonate anions. The particular efficiency of the ethylsulfate solvent system in promoting shape anisotropic growth is interpreted to be a consequence of both reduced anion/cation interactions that act to support the coordination of imidazolium to the metal surface and the enhanced capacity of anions to participate in the particle stabilization process.
评估了 3-乙基-1-甲基咪唑鎓基离子液体在金纳米晶的晶种诱导生长过程中阴离子结构对形状调节效应的相关性，特别针对乳酸盐、醋酸盐、甲基硫酸盐、硫酸乙酯和对甲苯磺酸盐阴离子体系。发现基于羧酸盐的阴离子（乳酸盐和醋酸盐）抑制了金前体盐的还原，这可能是由于还原剂抗坏血酸的去质子化。在甲基硫酸盐和乙基硫酸盐阴离子体系中观察到非均匀的、“头-尾”型各向异性颗粒结构的形成，而在对甲苯磺酸盐阴离子的情况下则观察到快速沉淀。乙基硫酸盐溶剂体系在促进形状各向异性生长方面的特殊效率被解释为减少阴离子/阳离子相互作用的结果，这种相互作用有助于支持咪唑鎓与金属表面的配位，以及阴离子增强参与颗粒稳定化过程的能力。
