title: Stabilization of gold nanowires inside nanoaggregates of cyclo[8]thiophene, cyclo[8]selenophene, and cyclo[8]tellurophene: a theoretical study.
abstract: The stabilities and electronic properties of gold clusters containing up to six atoms trapped inside cyclo[8]thiophene (CS8), cyclo[8]selenophene (CSe8), and cyclo[8]tellurophene (CTe8) nanoaggregates have been studied using the M06 functional. The 6-31G(d) basis set was used for all atoms except Au and Te, for which the LANL2DZ(d,p) pseudopotential basis set was applied. Single-point energy calculations were performed with the 6-311G(d,p) basis set for all atoms except for Au and Te, for which the cc-TZVP-pp pseudopotential basis set was used. Among the three studied macrocycles, only CS8 and CSe8 were found to be capable of nanoaggregate formation. In the lowest-energy conformer of CTe8, the tellurophene fragments adopt an anti orientation, thus impeding a tubular arrangement of the macrocycles. The formation of gold clusters inside the CS8 and CSe8 nanoaggregates is a thermodynamically favorable process, and could represent a potentially useful method of stabilizing metal nanowires. The binding energy between the nanoaggregate and the gold cluster is always higher for selenium-containing complexes than for sulfur-containing ones because Se has a higher affinity than S for Au in such complexes. Interactions of the gold cluster with the nanoaggregate walls can change the geometry of the most stable isomer for the cluster. The relative energies of different isomers are rather similar, suggesting that they coexist. For nanoaggregates containing Au6 clusters, the cluster geometry when it is inside a nanoaggregate is different from the geometry of the cluster when it is not inside the nanoaggregate, due to the geometric restrictions imposed by the nanoaggregate cavity. The reorganization energy needed to change the geometry leads to lower binding energies for these complexes compared to those of some smaller systems, although the formation of a complex between Au₆ and a nanoaggregate with six CS8 or CSe8 macrocycles is still thermodynamically viable.
authors: Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Apartado Postal 70-360, CU, Coyoacán, DF CP 04510, México.
authors: Xiaomin
authors: X
authors: Huang
authors: Serguei
authors: S
authors: Fomine
references: Nature. 2009 Dec 24;462(7276):1039-43
references: 20033044
references: Nature. 2005 Aug 4;436(7051):677-80
references: 16079841
references: J Am Chem Soc. 2006 Jan 11;128(1):278-90
references: 16390158
references: Angew Chem Int Ed Engl. 2002 Dec 2;41(23):4378-400
references: 12458501
references: Nano Lett. 2006 Jun;6(6):1136-40
references: 16771568
references: Science. 2000 Jul 28;289(5479):606-8
references: 10915620
references: Acc Chem Res. 2000 Nov;33(11):791-804
references: 11087316
references: Chem Soc Rev. 2012 Jul 21;41(14):4827-59
references: 22648395
references: J Org Chem. 2006 Apr 14;71(8):2972-81
references: 16599590
references: Chem Commun (Camb). 2003 Apr 21;(8):948-9
references: 12744313
references: Acc Chem Res. 2010 Dec 21;43(12):1509-18
references: 20949977
references: J Phys Chem A. 2008 May 1;112(17):3996-4003
references: 18345652