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Title: Investigation of the Nanoscale Self-Assembly of Donor-sigma-Acceptor Molecules

Abstract

Electronic structure calculations are used to explore the nature of the interactions that lead to the self-assembly of a new class of functionalized donor-sigma-acceptor molecules, 1-aza-adamantanetriones (AATs), and the consequences of molecular structure on the resulting supramolecular systems. The results show how the self-assembly process originates from the saturated core of the molecules that underlies their shape, conformational preferences, and dipole-directed one-dimensional assembly. The solvation properties of the monomers are explored and 1H NMR chemical shift values are determined and compared to experimental trends. A theoretical understanding of this class of supramolecular structures coupled with their molecular-level tunability introduces the possibility to design novel functional materials for specific electronic and optoelectronic applications.

Authors:
 [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Nanophase Materials Sciences; Center for Computational Sciences
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
966079
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Quantum Chemistry; Journal Volume: 107
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ORGANIC COMPOUNDS; ELECTRONIC STRUCTURE; MOLECULAR STRUCTURE; MONOMERS; SOLVATION; NUCLEAR MAGNETIC RESONANCE; SYNTHESIS

Citation Formats

Sumpter, Bobby G, Meunier, Vincent, Vazquez-Mayagoitia, Alvaro, and Castellano, Ronald K. Investigation of the Nanoscale Self-Assembly of Donor-sigma-Acceptor Molecules. United States: N. p., 2007. Web. doi:10.1002/qua.21411.
Sumpter, Bobby G, Meunier, Vincent, Vazquez-Mayagoitia, Alvaro, & Castellano, Ronald K. Investigation of the Nanoscale Self-Assembly of Donor-sigma-Acceptor Molecules. United States. doi:10.1002/qua.21411.
Sumpter, Bobby G, Meunier, Vincent, Vazquez-Mayagoitia, Alvaro, and Castellano, Ronald K. Mon . "Investigation of the Nanoscale Self-Assembly of Donor-sigma-Acceptor Molecules". United States. doi:10.1002/qua.21411.
@article{osti_966079,
title = {Investigation of the Nanoscale Self-Assembly of Donor-sigma-Acceptor Molecules},
author = {Sumpter, Bobby G and Meunier, Vincent and Vazquez-Mayagoitia, Alvaro and Castellano, Ronald K},
abstractNote = {Electronic structure calculations are used to explore the nature of the interactions that lead to the self-assembly of a new class of functionalized donor-sigma-acceptor molecules, 1-aza-adamantanetriones (AATs), and the consequences of molecular structure on the resulting supramolecular systems. The results show how the self-assembly process originates from the saturated core of the molecules that underlies their shape, conformational preferences, and dipole-directed one-dimensional assembly. The solvation properties of the monomers are explored and 1H NMR chemical shift values are determined and compared to experimental trends. A theoretical understanding of this class of supramolecular structures coupled with their molecular-level tunability introduces the possibility to design novel functional materials for specific electronic and optoelectronic applications.},
doi = {10.1002/qua.21411},
journal = {International Journal of Quantum Chemistry},
number = ,
volume = 107,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Pockels-Langmuir and Langmuir-Blodgett monolayer films have been found for the 2-(4-nitrophenyl)ethyl esters of N-(4-dodecoxyphenyl)carbamic acid (DDOP-C-ENP, 7) and N-(3,4,5-tridodecoxyphenyl)carbamic acid (TDDOP-C-ENP, 9) and also for the (2-hydroxyethoxy)-7,7,8,8-tetracyanoquinodimethane ester of N-(3,4,5-tridodecoxyphenyl)carbamic acid (TDDOP-C-HETCNQ, 10). The pressure-area isotherms vary greatly depending on the number of dodecoxy groups attached to these donor-{sigma}-acceptor molecules. The film strength improves dramatically by lowering the subphase temperature.
  • Tetrakis ((2,4,6-trimethylphenyl)porphyrinato)rhodium(II) ((TMP)Rh) and tetrakis((2,4,6-trilsopropylphenyl)-porphyrinato)rhodium(II) ((TTiPP)Rh) occur as low-spin d{sup 7} complexes with EPR parameters associated with a(d{sub xy}){sup 2}-(d{sub xz,yz}){sup 4}(d,2){sup 1} ground configuration. (por)Rh{sup II} species typically react as metalloradicals with a wide variety of substrates to give diamagnetic products; however, the use of increased porphyrin or substrate steric demands has permitted observation of paramagnetic 1:1 adducts. EPR spectra were used in examining features related to the electronic structure for a series of 1:1 five-coordinate complexes with nitrogen, phosphorus, arsenic, and carbon donor ligands. Each of the five-coordinate species is a low-spin d{sup 7} complex with the unpairedmore » electron occupying a d{sub z}2 MO (d{sub xy}d{sub xz}d{sub yz}){sup 6}-(d{sub z}{sup 2}){sup 1} ground configuration. The ligands form 1:1 adducts that have effective axial symmetry with the exceptions of CO, which has as a bent Rh-CO unit, and ethene, which has a symmetrical {pi} complex structure. Donor atom spin densities are estimated from ligand hyperfine coupling. Rhodium-103 hyperfine coupling is used in evaluating the rhodium 4d{sub x}2 (0.67) and Ss (0.02) spin density in the ethene {pi} complex, which combined with the total ethene C{sub 2p} (0.278) and C{sub 2s} (0.008) spin densities, determined from the ligand hyperfine coupling, accounts for most of the unpaired electron. Estimates of the d{sub z}2 to d{sub xz} and d{sub yz} energy separations for the series of 1:1 complexes illustrate the elevation of d{sub z}2 by {sigma} donor ligands and the combined lowering of d{sub xz}, d{sub yz}, and d{sub z}2 elevation by ligands with {pi} acceptor ability. 26 refs., 2 figs., 2 tabs.« less
  • Luminescence lifetimes ([tau][sub m]) of the [sigma]-bond-to-ligand charge-transfer (SBLCT) excited states of two diastereomers of fac-tris[(8-quinolyl)phenylmethylsilyl]iridium(III) differ by about a factor of 2 and are strongly solvent dependent. The [tau][sub m] values of the more symmetric [Delta]RRR, [Lambda]SSS diastereomer (A) are generally longer than those of the less symmetric [Delta]RRS, [Lambda]SSR diastereomer (B); [tau][sub m]'s of both diastereomers are substantially shortened relative to their values in aliphatic hydrocarbons by exciplex formation with a variety of weakly coordinating solvents including aromatic hydrocarbons, olefins, ethers, ketones, alcohols, and nitriles. Quenching constants (k[sub q]) due to exciplex formation are found to be muchmore » larger for B than they are for A in the [sigma]-donor solvents (cyclic ethers, ketones, alcohols, and nitriles); however, k[sub q] values of B are slightly smaller than those of A in [pi]-acceptor solvents (aromatic hydrocarbons, olefins). The results suggest that [sigma]-donor solvents form exciplexes by binding at the metal center, whereas [pi]-acceptor solvents bind at a quinolyl radical anion ligand site. A and B may prove useful as luminescent environmental probes which can distinguish between [sigma]-donor and [pi]-acceptor binding sites. 19 refs., 1 fig., 1 tab.« less
  • Ab initio calculations demonstrate that specific zwitterionic molecules which have a {sigma}-bonded donor-acceptor system show an enhanced hyperpolarizability ({beta}) value when the effects of electron correlations are considered. Ab initio second-order Moeller-Plesset perturbation theory (MP2) through-space (TS)-through-bond (TB) interaction (TB denotes orbital interactions through directly bonded atoms in a molecule, and TS denotes all interactions other than TB interactions) analysis proposes that the {sigma} conjugation between acceptor and donor through bonds causes the dependence of the perturbation term between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (and their vicinal molecular orbitals) in MP2 calculations on electricmore » fields, making the hyperpolarizability ({beta}) value remarkably large.« less
  • Liquid crystalline composite materials have been prepared that are strongly photorefractive. Nematic liquid crystals were doped with both electron donor and electron acceptor molecules that undergo facile, photoinduced, electron transfer reactions to yield mobile ions. A photorefractive gain ratio of 1.88 was observed. This gain ratio was achieved with low applied electric fields (0.4 kilovolts per centimeter) requiring only a 1.5-volt battery and low light intensities (100 milliwatts per square centimeter) in samples 37 to 88 micrometers thick that showed no loss in gain over a 6-month period. 20 refs., 4 figs.