Ground-State Electronic Structure in Charge-Transfer Complexes Based on Carbazole and Diarylamine Donors

The geometries, binding energies, and amounts of charge transferred in the ground state for a series of donor/acceptor organic π–π complexes have been characterized at the density functional theory level. We find that these compounds exhibit important changes in geometry upon complexation that is accompanied by a large binding energy. The amount of charge transferred from the donor to the acceptor depends highly on the substitution of the donor and can be roughly described by the electron donating or withdrawing ability of the substituent. Interestingly, there is a significant difference in the behavior of carbazoles and diarylamines upon substitution

Prediction of Soil Sorption Coefficients Using a Universal Solvation Model

Using a database of 440 molecules, we develop a set of effective solvent descriptors that characterize the organic carbon component of soil and thereby allow quantum mechanical SM5 universal solvation models to be applied to partitioning of solutes between soil and air. Combining this set of effective solvent descriptors with solute atomic surface tension parameters already developed for water/air and organic solvent/air partitioning allows one to predict the partitioning of any solutes composed of H, C, N, O, F, P, S, Cl, Br, and I between soil and water. We also present linear correlations of soil/water partitioning with 1-octanol/water partition coefficients using the same database. The quantum mechanical calculations have the advantages that they require no experimental input and should be robust for a wide range of solute functionality. The quantitative effective solvent descriptors can be used for a better understanding (than with previously available models) of the sources of different partitioning phenomena in cases where the results exhibit significant fragment interactions. We anticipate that the model will be useful for understanding the partitioning of organic chemicals in the environment between water and soil or, more generally, between water and soil or sediments (geosorbents)

Prediction of Soil Sorption Coefficients Using a Universal Solvation Model

Using a database of 440 molecules, we develop a set of effective solvent descriptors that characterize the organic carbon component of soil and thereby allow quantum mechanical SM5 universal solvation models to be applied to partitioning of solutes between soil and air. Combining this set of effective solvent descriptors with solute atomic surface tension parameters already developed for water/air and organic solvent/air partitioning allows one to predict the partitioning of any solutes composed of H, C, N, O, F, P, S, Cl, Br, and I between soil and water. We also present linear correlations of soil/water partitioning with 1-octanol/water partition coefficients using the same database. The quantum mechanical calculations have the advantages that they require no experimental input and should be robust for a wide range of solute functionality. The quantitative effective solvent descriptors can be used for a better understanding (than with previously available models) of the sources of different partitioning phenomena in cases where the results exhibit significant fragment interactions. We anticipate that the model will be useful for understanding the partitioning of organic chemicals in the environment between water and soil or, more generally, between water and soil or sediments (geosorbents)

Prediction of Soil Sorption Coefficients Using a Universal Solvation Model

Using a database of 440 molecules, we develop a set of effective solvent descriptors that characterize the organic carbon component of soil and thereby allow quantum mechanical SM5 universal solvation models to be applied to partitioning of solutes between soil and air. Combining this set of effective solvent descriptors with solute atomic surface tension parameters already developed for water/air and organic solvent/air partitioning allows one to predict the partitioning of any solutes composed of H, C, N, O, F, P, S, Cl, Br, and I between soil and water. We also present linear correlations of soil/water partitioning with 1-octanol/water partition coefficients using the same database. The quantum mechanical calculations have the advantages that they require no experimental input and should be robust for a wide range of solute functionality. The quantitative effective solvent descriptors can be used for a better understanding (than with previously available models) of the sources of different partitioning phenomena in cases where the results exhibit significant fragment interactions. We anticipate that the model will be useful for understanding the partitioning of organic chemicals in the environment between water and soil or, more generally, between water and soil or sediments (geosorbents)

Prediction of Soil Sorption Coefficients Using a Universal Solvation Model

Using a database of 440 molecules, we develop a set of effective solvent descriptors that characterize the organic carbon component of soil and thereby allow quantum mechanical SM5 universal solvation models to be applied to partitioning of solutes between soil and air. Combining this set of effective solvent descriptors with solute atomic surface tension parameters already developed for water/air and organic solvent/air partitioning allows one to predict the partitioning of any solutes composed of H, C, N, O, F, P, S, Cl, Br, and I between soil and water. We also present linear correlations of soil/water partitioning with 1-octanol/water partition coefficients using the same database. The quantum mechanical calculations have the advantages that they require no experimental input and should be robust for a wide range of solute functionality. The quantitative effective solvent descriptors can be used for a better understanding (than with previously available models) of the sources of different partitioning phenomena in cases where the results exhibit significant fragment interactions. We anticipate that the model will be useful for understanding the partitioning of organic chemicals in the environment between water and soil or, more generally, between water and soil or sediments (geosorbents)

Prediction of Soil Sorption Coefficients Using a Universal Solvation Model

Using a database of 440 molecules, we develop a set of effective solvent descriptors that characterize the organic carbon component of soil and thereby allow quantum mechanical SM5 universal solvation models to be applied to partitioning of solutes between soil and air. Combining this set of effective solvent descriptors with solute atomic surface tension parameters already developed for water/air and organic solvent/air partitioning allows one to predict the partitioning of any solutes composed of H, C, N, O, F, P, S, Cl, Br, and I between soil and water. We also present linear correlations of soil/water partitioning with 1-octanol/water partition coefficients using the same database. The quantum mechanical calculations have the advantages that they require no experimental input and should be robust for a wide range of solute functionality. The quantitative effective solvent descriptors can be used for a better understanding (than with previously available models) of the sources of different partitioning phenomena in cases where the results exhibit significant fragment interactions. We anticipate that the model will be useful for understanding the partitioning of organic chemicals in the environment between water and soil or, more generally, between water and soil or sediments (geosorbents)

Prediction of Soil Sorption Coefficients Using a Universal Solvation Model

Using a database of 440 molecules, we develop a set of effective solvent descriptors that characterize the organic carbon component of soil and thereby allow quantum mechanical SM5 universal solvation models to be applied to partitioning of solutes between soil and air. Combining this set of effective solvent descriptors with solute atomic surface tension parameters already developed for water/air and organic solvent/air partitioning allows one to predict the partitioning of any solutes composed of H, C, N, O, F, P, S, Cl, Br, and I between soil and water. We also present linear correlations of soil/water partitioning with 1-octanol/water partition coefficients using the same database. The quantum mechanical calculations have the advantages that they require no experimental input and should be robust for a wide range of solute functionality. The quantitative effective solvent descriptors can be used for a better understanding (than with previously available models) of the sources of different partitioning phenomena in cases where the results exhibit significant fragment interactions. We anticipate that the model will be useful for understanding the partitioning of organic chemicals in the environment between water and soil or, more generally, between water and soil or sediments (geosorbents)

Effect of Substituents on the Electronic Structure and Degradation Process in Carbazole Derivatives for Blue OLED Host Materials

We investigate the dissociation mechanism of the C–N bond between carbazole and dibenzothiophene in carbazole-dibenzothiophene (Cz-DBT) positional isomers, selected as representative systems for blue host materials in organic light-emitting diodes (OLEDs). The C–N bond dissociation energies, calculated at the density functional theory level, are found to depend strongly on the charge states of the parental molecules. In particular, the anionic C–N bond dissociations resulting in a carbazole anion can have low dissociation energies (∼1.6 eV) with respect to blue emission energy. These low values are attributed to the large electron affinity of the carbazole radical, a feature that importantly can be modulated via substitution. Substitution also impacts the energies of the first excited electronic states of the Cz-DBT molecules since these states have an intramolecular charge-transfer nature due to the spatially localized character of the frontier molecular orbitals within the carbazole moiety (for the HOMO) and the dibenzothiophene moiety (for the LUMO). The implications of these results must be considered when designing blue OLED hosts since these materials must combine chemical stability and high triplet energy

Electronic Structure of the Perylene–Zinc Oxide Interface: Computational Study of Photoinduced Electron Transfer and Impact of Surface Defects

The electronic properties of dye-sensitized semiconductor surfaces consisting of perylene chromophores chemisorbed on zinc oxide via different spacer-anchor groups have been studied at the density-functional-theory level. The energy distributions of the donor states and the rates of photoinduced electron transfer from dye to surface are predicted. We evaluate in particular the impact of saturated versus unsaturated aliphatic spacer groups inserted between the perylene chromophore and the semiconductor as well as the influence of surface defects on the electron-injection rates

Parametrization of a Universal Solvation Model for Molecules Containing Silicon

The SM5.42 solvation model is extended to include compounds containing Si. The new parameters are based on a data set of 13 octanol/water partition coefficients (which we convert into 13 differential free energies of solvation), three absolute solvation energies, and one pKa. The data set includes compounds containing C, H, O, and Si. We carried out parametrizations using compounds in the data set that do not contain bonds between Si and O (i.e., eight differential free energies of solvation and three absolute free energies of solvation for nine compounds) at the HF/MIDI!, HF/MIDI!6D, HF/6-31G*, HF/6-31+G*, HF/cc-pVDZ, BPW91/MIDI!, BPW91/MIDI!6D, BPW91/DVZP, B3LYP/MIDI!, AM1, and PM3 levels of theory. The mean unsigned errors over the eight differential free energies of solvation and three absolute solvation energies for these levels of theory are in the range of 0.48−0.53 kcal/mol. We used five additional differential free energies of solvation for five compounds that do contain O−Si bonds to parametrize the BPW91/6-31G* level of theory. The resulting mean unsigned error over all 13 differential free energies of solvation and absolute free energies of solvation is 0.44 kcal/mol for this level of theory