Structures and stabilities of alkanethiolate monolayers on palladium clusters as studied by gel permeation chromatography

Haruno Murayama, Takashi Narushima, Yuichi Negishi, Tatsuya Tsukuda

研究成果: Contribution to journalArticle査読

30 被引用数 (Scopus)

抄録

Palladium clusters protected by a series of n-alkanethiolates, Pd:SCn (SCn = n-CnH2n+1S, n = 10, 12, 14, 16, and 18), were prepared by a ligand exchange approach: Pd clusters protected by poly (N-vinyl-2-pyrrolidone) (PVP) were transferred from the aqueous phase to the toluene phase containing the thiols. The structures and stabilities of the thiolate monolayers of the Pd:SCn clusters were investigated by gel permeation chromatography (GPC) together with TEM, XPS, and FT-IR. The thicknesses of the thiolate layers formed on the Pd clusters were evaluated from the differences between the hydrodynamic diameters and core diameters of the Pd:SCn clusters, determined by GPC and TEM, respectively. The thicknesses thus obtained are in good agreement with the lengths of the corresponding thiolates in the all-trans conformations, illustrating that the alkanethiolates in nearly straight configurations are aligned almost perpendicularly to the core surfaces. Fractionation of the Pd:SC18 clusters by GPC yielded a series of the purified samples: the clusters in each fraction are different in their core sizes. The GPC measurements on the Pd:SCn clusters with small n revealed the decomposition of the monolayers through spontaneous etching and their reconstruction by heat treatment in the presence of the free thiols. The mechanism of these processes is discussed. The present study demonstrates that the GPC provides an elemental and versatile means to characterize and purify the monolayer-protected clusters.

本文言語英語
ページ(範囲)3496-3503
ページ数8
ジャーナルJournal of Physical Chemistry B
108
11
DOI
出版ステータス出版済み - 3 18 2004

All Science Journal Classification (ASJC) codes

  • 物理化学および理論化学
  • 表面、皮膜および薄膜
  • 材料化学

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