Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090, Vienna, Austria.
Published: November 2021
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Article Abstract
A density matrix renormalization group-self consistent field (DMRG-SCF) study has been carried out to calculate the low-lying excited states of CpMo(CO) NO, a molybdenum complex containing NO and CO ligands. In order to automatically select an appropriate active space, a novel procedure employing the maximum single-orbital entropy for several states has been introduced and shown to be efficient and easy-to-implement when several electronic states are simultaneously considered. The analysis of the resulting natural transition orbitals and charge-transfer numbers shows that the lowest five excited electronic states are excitation into metal-NO antibonding orbitals, which offer the possibility for nitric oxide (NO) photorelease after excitation with visible light. Higher excited states are metal-centered excitations with contributions of metal-CO antibonding orbitals, which may serve as a gateway for carbon monoxide (CO) delivery. Time-dependent density functional theory calculations done for comparison, show that the state characters agree remarkably well with those from DMRG-SCF, while excitation energies are 0.4-1.0 eV red-shifted with respect to the DMRG-SCF ones.
High-level quantum chemical calculations are performed for the (NH)MO and (NH)MO species (M = Ti-Cu), extending our previous work on the bare MO ions. The potential energy curves along the M-O distance are constructed for the ground and multiple excited electronic states of (NH)MO and are compared to those of MO. We see that ammonia stabilizes the oxo states (MO) over the oxyl (MO) ones.
The synthesis, electrochemical, spectroelectrochemical, photophysical and light induced electron transfer reactions in two new anthanthrene quinodimethanes have been studied and analyzed in the context of dynamic electrochemistry. Their properties are dependent on the interconversion between folded and twisted forms, which are separated by a relatively small energy range, thus allowing to explore their interconversion by variable temperature measurements. The photophysics of these molecules is mediated by a diradical excited state with a twisted structure that habilitates rapid intersystem crossing.
Spike-wave-discharges (SWD) are the electrophysiological hallmark of absence epilepsy. SWD are generated in the thalamo-cortical network and a seizure onset zone was identified in the somatosensory cortex (S1). We have shown before that inhibition of the centromedian thalamic nucleus (CM) in GAERS rats resulted in a selective suppression of the spike component while rhythmic cortical 5-9 Hz oscillations remained present.
The two-dimensional (2D) refocused INADEQUATE NMR experiment, which correlates double-quantum (DQ) and single-quantum (SQ) coherences, is widely used to probe the chemical connectivities in solids. Nevertheless, the multiplets along the F dimension reduce the resolution and sensitivity of this experiment. The Composite-Refocusing (CR) technique with two excitation pulses has been proposed to suppress these multiplets in 2D INADEQUATE spectra of liquids.
Type-I photosensitizers (PSs) are among the most potential candidates for photodynamic therapy (PDT), as their low dependence on oxygen endow them with many advantages for treating hypoxic tumor. However, most of the reported type-I PSs have a contingency of molecular design, because electron transfer (ET) reaction is more difficult to achieve than energy transfer (EET) process. Therefore, it is urgent to understand molecular design mechanisms for type-I PSs.
