Theoretical Evaluation of Fluorinated Resazurin Derivatives for In Vivo Applications.

Primarily owing to the pronounced fluorescence exhibited by its reduced form, resazurin (also known as alamarBlue®) is widely employed as a redox sensor to assess cell viability in in vitrostudies. In an effort to broaden its applicability for in vivo studies, molecular adjustments are necessary to align optical properties with the near-infrared imaging window while preserving redox properties. This study delves into the theoretical characterisation of a set of fluorinated resazurin derivatives proposed by Kachur et al., 2015 examining the influence of fluorination on structural and electrochemical properties. Assuming that the conductor-like polarisable continuum model mimics the solvent effect, the density functional level of theory combining M06-2X/6-311G* was used to calculate the redox potentials. Furthermore, (TD-)DFT calculations were performed with PBE0/def2-TZVP to evaluate nucleophilic characteristics, transition states for fluorination, relative energies, and fluorescence spectra. With the aim of exploring the potential of resazurin fluorinated derivatives as redox sensors tailored for in vivo applications, acid-base properties and partition coefficients were calculated. The theoretical characterisation has demonstrated its potential for designing novel molecules based on fundamental principles.

Full theoretical protocol for the design of metal-free organic electron donor-spacer-acceptor systems.

A user-friendly (time-dependent) density functional theory based algorithm is proposed to design new donor-spacer-acceptor systems for electron transfer reactions. This algorithm is focused on metal-free organic compounds, most of which contain aromatic or alkene moieties. The oxidation and reduction potentials are calculated, together with the excited-state energy difference including the zero-point energy and the structural properties required to calculate an electron transfer Gibbs free energy change. The proposed algorithm has been tested on well-known systems, while two new compounds are suggested for photoinduced intramolecular electron transfer reactions using this scheme. The methodology here presented is intended to be a tool for synthetic physical-chemists, allowing them to evaluate the properties of hypothetical systems before the synthesis, enabling the study of limitless combinations of donor-spacer-acceptor arrangements.

Quasiclassical trajectory study of the atmospheric reaction N((2)D) + NO(X (2)Π) → O((1)D) + N(2)(X (1)Σ(g)(+)).

Quasiclassical trajectories have been run for the title atmospheric reaction over the range of temperatures 5 ≤ T/K ≤ 3000 on a recently proposed single-sheeted double many-body expansion (DMBE) potential energy surface for ground-state N2O((1)A'). As typical in a capture-like reaction, the rate constant decreases with temperature for 50 ≤ T/K ≤ 800 K, while showing a small dependence at higher temperature regimes. At room temperature, it is predicted to have a value of (20.1 ± 0.2) × 10(-12) cm(3) s(-1). The calculated cross sections show a monotonic decay with temperature and translational energy. Good agreement with the experimental data has been observed, providing more realistic rate constants and hence support of enhanced accuracy for the DMBE potential energy surface with respect to other available forms.

Dynamics study of the atmospheric reaction involving vibrationally excited O(3) with OH.

We investigate the title atmospheric reaction of highly excited O(3) with vibrationally cold OH. Particular attention will be paid to initial vibrational energies of O(3) between 9 and 21 kcal mol(-1). The calculations employ the quasiclassical trajectory method and the realistic double many-body expansion potential energy surface for HO(4)((2)A). Many aspects of the title process are presented. It is found that it may not be possible to ignore this process when studying the stratospheric ozone budget.

Calculation of the rate constant for state-selected recombination of H+O2(nu) as a function of temperature and pressure.

Classical trajectory calculations using the MERCURY/VENUS code have been carried out on the H+O(2) reactive system using the DMBE-IV potential energy surface. The vibrational quantum number and the temperature were selected over the ranges nu=0 to 15, and T=300 to 10 000 K, respectively. All other variables were averaged. Rate constants were determined for the energy transfer process, H+O(2)(nu)-->H+O(2)(nu(")), for the bimolecular exchange process, H+O(2)(nu)-->OH(nu('))+O, and for the dissociative process, H+O(2)(nu)-->H+O+O. The dissociative process appears to be a mere extension of the process of transferring large amounts of energy. State-to-state rate constants are given for the exchange reaction, and they are in reasonable agreement with previous results, while the energy transfer and dissociative rate constants have never been reported previously. The lifetime distributions of the HO(2) complex, calculated as a function of v and temperature, were used as a basis for determining the relative contributions of various vibrational states of O(2) to the thermal rate coefficients for recombination at various pressures. This novel approach, based on the complex's ability to survive until it collides in a secondary process with an inert gas, is used here for the first time. Complete falloff curves for the recombination of H+O(2) are also calculated over a wide range of temperatures and pressures. The combination of the two separate studies results in pressure- and temperature-dependent rate constants for H+O(2)(nu)(+Ar) right arrow over left arrow HO(2)(+Ar). It is found that, unlike the exchange reaction, vibrational and rotational-translational energy are liabilities in promoting recombination.