Abstract
The folding of a series of donor-acceptor oligorotaxanes is studied by means of molecular dynamics simulations. The oligorotaxanes consist of tetracationic cyclobis(paraquat-p-phenylene) rings threaded onto oligomers of 1,5-dioxynaphthalene linked by polyethers. Minimum energy structures are isolated using simulated annealing from which insights into the interactions responsible for the folding are extracted. The folding in vacuum is primarily driven by Coulombic interactions between the ionic species. In turn, in a high dielectric medium, the folding is the result of a series of conflicting interactions primarily orchestrated by the rings. In both cases, folded globular structures result. The observed secondary structures extend a previously proposed pleated π-stacked model for the folding that has been, in fact, observed in crystal samples of a [3]Rotaxane, the smallest of the oligorotaxanes considered. Simulations using two different force fields in the crystal environment, in vacuum, and in explicit solvent indicate that the π-stacked conformation adopted by the [3]Rotaxane is stable due to crystal packing effects rather than intracomplex interactions. The π-stacked conformation is also shown to be thermodynamically improbable in longer oligomers.
| Original language | English |
|---|---|
| Pages (from-to) | 2477-2484 |
| Number of pages | 8 |
| Journal | Journal of Physical Chemistry B |
| Volume | 115 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - Mar 24 2011 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Materials Chemistry
- Surfaces, Coatings and Films
Cite this
Coulombic interactions and crystal packing effects in the folding of donor-acceptor oligorotaxanes. / Franco, Ignacio; Ratner, Mark A; Schatz, George C.
In: Journal of Physical Chemistry B, Vol. 115, No. 11, 24.03.2011, p. 2477-2484.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Coulombic interactions and crystal packing effects in the folding of donor-acceptor oligorotaxanes
AU - Franco, Ignacio
AU - Ratner, Mark A
AU - Schatz, George C
PY - 2011/3/24
Y1 - 2011/3/24
N2 - The folding of a series of donor-acceptor oligorotaxanes is studied by means of molecular dynamics simulations. The oligorotaxanes consist of tetracationic cyclobis(paraquat-p-phenylene) rings threaded onto oligomers of 1,5-dioxynaphthalene linked by polyethers. Minimum energy structures are isolated using simulated annealing from which insights into the interactions responsible for the folding are extracted. The folding in vacuum is primarily driven by Coulombic interactions between the ionic species. In turn, in a high dielectric medium, the folding is the result of a series of conflicting interactions primarily orchestrated by the rings. In both cases, folded globular structures result. The observed secondary structures extend a previously proposed pleated π-stacked model for the folding that has been, in fact, observed in crystal samples of a [3]Rotaxane, the smallest of the oligorotaxanes considered. Simulations using two different force fields in the crystal environment, in vacuum, and in explicit solvent indicate that the π-stacked conformation adopted by the [3]Rotaxane is stable due to crystal packing effects rather than intracomplex interactions. The π-stacked conformation is also shown to be thermodynamically improbable in longer oligomers.
AB - The folding of a series of donor-acceptor oligorotaxanes is studied by means of molecular dynamics simulations. The oligorotaxanes consist of tetracationic cyclobis(paraquat-p-phenylene) rings threaded onto oligomers of 1,5-dioxynaphthalene linked by polyethers. Minimum energy structures are isolated using simulated annealing from which insights into the interactions responsible for the folding are extracted. The folding in vacuum is primarily driven by Coulombic interactions between the ionic species. In turn, in a high dielectric medium, the folding is the result of a series of conflicting interactions primarily orchestrated by the rings. In both cases, folded globular structures result. The observed secondary structures extend a previously proposed pleated π-stacked model for the folding that has been, in fact, observed in crystal samples of a [3]Rotaxane, the smallest of the oligorotaxanes considered. Simulations using two different force fields in the crystal environment, in vacuum, and in explicit solvent indicate that the π-stacked conformation adopted by the [3]Rotaxane is stable due to crystal packing effects rather than intracomplex interactions. The π-stacked conformation is also shown to be thermodynamically improbable in longer oligomers.
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U2 - 10.1021/jp108913s
DO - 10.1021/jp108913s
M3 - Article
VL - 115
SP - 2477
EP - 2484
JO - Journal of Physical Chemistry B Materials
JF - Journal of Physical Chemistry B Materials
SN - 1520-6106
IS - 11
ER -