Relative energies for different multiplets of trimethylenemethane and methylenecyclopropane are calculated at MCSCF, CASPT2N, and DFT levels of theory. Comparison to the experimentally measured heat of formation for the A2′ state and to the experimentally measured A2′-A1 gap permits analysis of the relative importance of active space and basis set selection in the multiconfigurational methods. ...

Dynamic behaviors of chemical concepts in density functional theory such as frontier orbitals (HOMO/LUMO), chemical potential, hardness, and electrophilicity index have been investigated in this work in the context of Bohn-Oppenheimer quantum molecular dynamics in association with molecular conformation changes. Exemplary molecular systems like CH5 , Cl (H2O)30 and Ca 2+ (H2O)15 are studied at ...

Semiempirical CNDO/2 calculations of the electronic and molecular structures have been carried out for six antitumor anthracycline antibiotics. The strong correlation between their biological activity and such molecular properties as chromophore dipole moment, energy of frontier orbitals, and steric volumes was found and the proper QSAR equations were constructed. The molecular mechanics model ...

The electronic and redox properties of a series of cyclometalated Pd complexes with oxidation states of +2, +3 and +4 were examined using a range of currently available spectroscopic and electrochemical techniques. Changes in metal-ligand bond lengths were established by X-ray crystallography and correctly predicted by DFT calculations, from which the frontier orbitals and partial atomic charge...

A fluorescent and colorimetric molecular probe containing phenol groups has been designed and synthesized. The anion binding ability was evaluated for biolgically important anions (F-, Cl-, Br-, I-, AcO- and H2PO4-) by theoretical investigation, UV-Vis and fluorescence spectroscopy and 1H-NMR titration experiments. Results indicated the probe showed strong binding ability for H2PO4- without the...

A number of hexaarylbenzene compounds were studied theoretically, in order to compare energy changes as a result of the toroidal delocalization effect that is characteristic of all these species. The energy was studied taking advantage of locally designed isodesmic reactions. Results indicate that the amount of aromaticity manifested by each substituent is a factor that should be considered whe...

Complexes of the general formula W[SNS]2M(dppe) (M = Pd, Pt; [SNS]H3 = bis(2-mercapto-p-tolyl)amine; dppe = 1,2-bis(diphenylphosphino)ethane) were prepared by combining the corresponding (dppe)MCl2 synthon with W[SNS]2 under reducing conditions. X-ray diffraction studies revealed the formation of a heterobimetallic complex supported by a single thiolate bridging ligand and a short metal-metal b...

the n-(2-benzoyl-phenyl) oxalyl derivatives are important models for studying of three-centered intramolecular hydrogen bonding in organic molecules. the quantum theoretical calculations for two crystal structures of n-(2-benzoyl-phenyl) oxalyl (compounds i and ii) were performed by density functional theory (b3lyp method and 6-311+g* basis set). from the optimized structures, geometric paramet...

The adsorption properties of thin silica films on Mo(112) have been tailored by embedding single Pd atoms into the nanopores of the oxide material. The embedded Pd is able to anchor metal adatoms that would not bind to the inert silica surface otherwise. Several adsorption structures, e.g., Pd-Pd, Ag-Pd, and Au-Pd complexes, have been prepared in this way and analyzed with the STM and density f...

The frontier orbital sequence of individual dicyanovinyl-substituted oligothiophene molecules is studied by means of scanning tunneling microscopy. On NaCl/Cu(111), the molecules are neutral, and the two lowest unoccupied molecular states are observed in the expected order of increasing energy. On NaCl/Cu(311), where the molecules are negatively charged, the sequence of two observed molecular o...