Can azobenzene photoisomerize when chemisorbed on a gold surface? An analysis of steric effects based on nonadiabatic dynamics simulations

Enrico Benassi, Giovanni Granucci, Maurizio Persico, Stefano Corni

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Through a combined quantum mechanics/molecular mechanics (QM/MM) approach, we evaluate the photodynamics of the mono- and dithiolated azobenzenes when they are chemisorbed on a gold surface. The analysis of steric effects suggests that the presence of the surface influences the photoisomerization process of the chemisorbed monothiolated azobenzene. In particular, the trans → cis quantum yields decrease, and the nπ∗ state lifetimes become longer. The approach to the twisted conical intersection needed for the isomerization is hindered when the molecule is attached to a substrate because of the van der Waals interactions with the surface. For the cis isomer, the cis → trans photoisomerization quantum yield is almost unaffected, since this isomer is not flat, and thus the interaction with the surface is less remarkable. Dithiolated azobenzene can photoisomerize both trans → cis and cis → trans, also when doubly linked to the surface, preserving the two bonds with the gold atoms: the flexibility of the central azo-moiety enables the molecule to photoisomerize without any bond breaking. The quantum yields in this case are even higher than in the monothiolated case, probably because of the strained initial conformation, which must adapt to the available distances between the anchoring sites.

Original languageEnglish
Pages (from-to)5962-5974
Number of pages13
JournalJournal of Physical Chemistry C
Volume119
Issue number11
DOIs
Publication statusPublished - 1 Jan 2015
Externally publishedYes

Fingerprint

Azobenzene
Gold
gold
Quantum yield
Computer simulation
Photoisomerization
simulation
Isomers
isomers
Molecular mechanics
Molecules
Quantum theory
Isomerization
intersections
preserving
isomerization
Conformations
quantum mechanics
molecules
flexibility

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Can azobenzene photoisomerize when chemisorbed on a gold surface? An analysis of steric effects based on nonadiabatic dynamics simulations. / Benassi, Enrico; Granucci, Giovanni; Persico, Maurizio; Corni, Stefano.

In: Journal of Physical Chemistry C, Vol. 119, No. 11, 01.01.2015, p. 5962-5974.

Research output: Contribution to journalArticle

@article{38e5b73a6bf4419099d228472f5dba58,
title = "Can azobenzene photoisomerize when chemisorbed on a gold surface? An analysis of steric effects based on nonadiabatic dynamics simulations",
abstract = "Through a combined quantum mechanics/molecular mechanics (QM/MM) approach, we evaluate the photodynamics of the mono- and dithiolated azobenzenes when they are chemisorbed on a gold surface. The analysis of steric effects suggests that the presence of the surface influences the photoisomerization process of the chemisorbed monothiolated azobenzene. In particular, the trans → cis quantum yields decrease, and the nπ∗ state lifetimes become longer. The approach to the twisted conical intersection needed for the isomerization is hindered when the molecule is attached to a substrate because of the van der Waals interactions with the surface. For the cis isomer, the cis → trans photoisomerization quantum yield is almost unaffected, since this isomer is not flat, and thus the interaction with the surface is less remarkable. Dithiolated azobenzene can photoisomerize both trans → cis and cis → trans, also when doubly linked to the surface, preserving the two bonds with the gold atoms: the flexibility of the central azo-moiety enables the molecule to photoisomerize without any bond breaking. The quantum yields in this case are even higher than in the monothiolated case, probably because of the strained initial conformation, which must adapt to the available distances between the anchoring sites.",
author = "Enrico Benassi and Giovanni Granucci and Maurizio Persico and Stefano Corni",
year = "2015",
month = "1",
day = "1",
doi = "10.1021/jp511269p",
language = "English",
volume = "119",
pages = "5962--5974",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "11",

}

TY - JOUR

T1 - Can azobenzene photoisomerize when chemisorbed on a gold surface? An analysis of steric effects based on nonadiabatic dynamics simulations

AU - Benassi, Enrico

AU - Granucci, Giovanni

AU - Persico, Maurizio

AU - Corni, Stefano

PY - 2015/1/1

Y1 - 2015/1/1

N2 - Through a combined quantum mechanics/molecular mechanics (QM/MM) approach, we evaluate the photodynamics of the mono- and dithiolated azobenzenes when they are chemisorbed on a gold surface. The analysis of steric effects suggests that the presence of the surface influences the photoisomerization process of the chemisorbed monothiolated azobenzene. In particular, the trans → cis quantum yields decrease, and the nπ∗ state lifetimes become longer. The approach to the twisted conical intersection needed for the isomerization is hindered when the molecule is attached to a substrate because of the van der Waals interactions with the surface. For the cis isomer, the cis → trans photoisomerization quantum yield is almost unaffected, since this isomer is not flat, and thus the interaction with the surface is less remarkable. Dithiolated azobenzene can photoisomerize both trans → cis and cis → trans, also when doubly linked to the surface, preserving the two bonds with the gold atoms: the flexibility of the central azo-moiety enables the molecule to photoisomerize without any bond breaking. The quantum yields in this case are even higher than in the monothiolated case, probably because of the strained initial conformation, which must adapt to the available distances between the anchoring sites.

AB - Through a combined quantum mechanics/molecular mechanics (QM/MM) approach, we evaluate the photodynamics of the mono- and dithiolated azobenzenes when they are chemisorbed on a gold surface. The analysis of steric effects suggests that the presence of the surface influences the photoisomerization process of the chemisorbed monothiolated azobenzene. In particular, the trans → cis quantum yields decrease, and the nπ∗ state lifetimes become longer. The approach to the twisted conical intersection needed for the isomerization is hindered when the molecule is attached to a substrate because of the van der Waals interactions with the surface. For the cis isomer, the cis → trans photoisomerization quantum yield is almost unaffected, since this isomer is not flat, and thus the interaction with the surface is less remarkable. Dithiolated azobenzene can photoisomerize both trans → cis and cis → trans, also when doubly linked to the surface, preserving the two bonds with the gold atoms: the flexibility of the central azo-moiety enables the molecule to photoisomerize without any bond breaking. The quantum yields in this case are even higher than in the monothiolated case, probably because of the strained initial conformation, which must adapt to the available distances between the anchoring sites.

UR - http://www.scopus.com/inward/record.url?scp=84925240137&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84925240137&partnerID=8YFLogxK

U2 - 10.1021/jp511269p

DO - 10.1021/jp511269p

M3 - Article

VL - 119

SP - 5962

EP - 5974

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 11

ER -