We investigated the symmetry breaking mechanism in cubic octa-tert-butyl silsesquioxane and octachloro silsesquioxane monocations (Si8O12(C(CH3)3)8(+) and Si8O12Cl8(+)) using density functional theory (DFT) and group theory. Under Oh symmetry, these ions possess (2)T2g and (2)Eg electronic states and undergo different symmetry breaking mechanisms. The ground states of Si8O12(C(CH3)3)8(+) and Si...

The hexanuclear thioguanidine mixed-valent copper complex cation [Cu6 (NGuaS)6 ]+2 (NGuaS = o-SC6 H4 NC(NMe2 )2 ) and its oxidized/reduced states are theoretically analyzed by means of density functional theory (DFT) (TPSSh + D3BJ/def2-TZV (p)). A detailed bonding analysis using overlap populations is performed. We find that a delocalized Cu-based ring orbital serves as an acceptor for donated ...

The novel steroidal conjugates [M(η(5)-C(5)Me(5))Cl(LEV-ppy)] (M = Rh (1) and Ir (2)) bearing the lipophilic levonorgestrel group 17-α-[2-phenylpyridyl-4-ethynyl]-19-nortestosterone (LEV-ppy), where the chelating ligand is N and C-bound, have been prepared and characterized. Both compounds are more active than cisplatin (about 6-fold) in T47D (breast cancer) at 48 h incubation time. On the othe...

In 2- und 5-Position einer Phenylenbrücke eines schwach koppelnden gemischtvalenten [{Cp*(dppe)RuC≡C}2(μ-1,3-C6H4)]+ Komplexes hat ein OMe-Substituent nur geringen Einfluss auf dessen Elektronenstruktur. 4-Position hingegen erhöht dieser die elektronische Delokalisation im Grundzustand sowie Intensität des IVCT-Überganges. Schwingungsfrequenzen TDDFT-Berechnungen (LH20t-D3(BJ), def2-SVP, COSMO ...

A new approach is presented to improve the performance of semiempirical quantum mechanical (SQM) methods in description noncovalent interactions. To show strategy, PM6 Hamiltonian was selected, although, general, procedure can be applied other Hamiltonians and different methodologies. set small molecules were selected as representative various functional groups, intermolecular potential energy ...

A new approach for obtaining interacting quantum atoms-defined components of binding energy intermolecular interactions, which bypasses the use standard six-dimensional integrals and two-particle reduced density matrix (2-RDM) reconstruction, is proposed. To examine this approach, three datasets calculated within functional theory framework using def2-TZVP basis have been explored. The first tw...

Complexes of glutamine (Gln) cationized with Zn(2+) and Cd(2+) were examined by infrared multiple photon dissociation (IRMPD) action spectroscopy using light generated from a free-electron laser. Electrospray ionization yielded complexes of deprotonated Gln with Zn(2+), [Zn(Gln-H)](+), and intact Gln with CdCl(+), CdCl(+)(Gln). For each complex, the spectra obtained were compared with those for...

In this manuscript, we combined a search in the Cambridge Structural Database (CSD) and ab initio calculations (RI-MP2/def2-TZVPD level of theory) to analyze the ability of trisulphide and triselenide moieties to establish chalcogen 'like-like' interactions. A preliminary CSD inspection revealed two predominant structural patterns, depending on the anti or syn conformation adopted by the substi...

The fully propagated real time-dependent density functional theory method has been applied to study the laser-molecule interaction in 5- and 6-benzyluracil (5BU and 6BU). The molecular geometry optimization and the time-dependent electronic dynamics propagation were carried out using the M11-L local meta-NGA (nonseparable gradient approximations) exchange-correlation functional together with th...

One for all – a unified Brønsted acidity scale...! On the basis of the absolute chemical potential of the proton a unified absolute pH scale universally applicable in the gas phase, in solution and the solid state is introduced [1]. This scale allows to directly compare acidities in different media and to give a thermodynamically meaningful definition of superacidity and can be used in all area...