Chemistry Reference
In-Depth Information
6 Concluding Remarks
In the present chapter, the syntheses, X-ray structures (geometries), and optical
properties of phosphine-coordinated molecular gold clusters (PGCs) have been
summarized. The inspection of the optical properties in the context of the geomet-
rical structures reveals a strong molecular character of PGCs. In addition to the
conventional clusters discovered more than 30 years ago, several new families with
unique geometrical and optical features have now been identified, thereby
expanding the scope of this class of compounds. Among them, unusual optical
properties of a series of [core+exo]-type clusters are quite interesting, which
demonstrates that the attachment of only one or two gold atoms to polyhedral
cores dramatically changes the electronic structures of total metal entities. This
principle would be applicable to the colloidal system, which will benefit the rational
design of functional colloids. It has been demonstrated that the use of bidentate
ligands occasionally allows the generation of unusual cluster species, but it is still at
a phenomenological level. The computer-aided design of multidentate phosphines
would promote the emergence of unique PGCs. Finally, as shown in the last topic,
the electronic structures (optical properties) of PGCs can be altered not only by the
geometrical parameters but also by the electronic perturbation by the external
stimuli. The combination with appropriate organic units as well as the design/
discovery of novel skeletons would lead to the evolution of PGCs to functional
materials.
Acknowledgments The author is grateful to Professor Michael Mingos for reading the drafts of
this chapter and providing useful comments, and to Dr. Yutaro Kamei for his help in preparing
graphics and also checking the structural and spectral data.
References
1. Daniel M-C, Astruc D (2004) Gold nanoparticles: assembly, supramolecular chemistry,
quantum-size-related properties, and applications toward biology, catalysis, and nanotechno-
logy. Chem Rev 104(1):293-346
2. Fernandez EJ, Monge M (2008) Gold nanomaterials. In: Laguna A (ed) Modern
supra molecular gold chemistry: gold-metal interactions and applications. WILEY-VCH,
Weinheim, pp 131-179. doi:10.1002/9783527623778.ch3
3. Sardar R, Funston A, Mulvaney P, Murray R (2009) Gold nanoparticles: past, present, and
future. Langmuir 25(24):13840-13851
4. Giljohann D, Seferos D, Daniel W, Massich M, Patel P, Mirkin C (2010) Gold nanoparticles
for biology and medicine. Angew Chem Int Ed 49(19):3280-3294
5. Takei T, Akita T, Nakamura I, Fujitani T, Okumura M, Okazaki K, Huang J, Ishida T,
Haruta M (2012) Heterogeneous catalysis by gold. Adv Catal 55:1-126
6. Hutchings GJ, Edwards JK (2012) Application of gold nanoparticles in catalysis. Metal
nanoparticles and nanoalloys. In: Johnstone RL, Wilcoxon JP (eds) Frontiers of nanoscience,
vol 3. Elsevier, Oxford, pp 249-293
