⁹⁹Tc NMR as a promising technique for structural investigation of biomolecules: theoretical studies on the solvent and thermal effects of phenylbenzothiazole complex

Abstract

The phenylbenzothiazole compounds show antitumor properties and are highly selective. In this paper, the (99)Tc chemical shifts based on the ((99m)Tc)(CO)3 (NNO) complex conjugated to the antitumor agent 2-(4'-aminophenyl)benzothiazole are reported. Thermal and solvent effects were studied computationally by quantum-chemical methods, using the density functional theory (DFT) (DFT level BPW91/aug-cc-pVTZ for the Tc and BPW91/IGLO-II for the other atoms) to compute the NMR parameters for the complex. We have calculated the (99)Tc NMR chemical shifts of the complex in gas phase and solution using different solvation models (polarizable continuum model and explicit solvation). To evaluate the thermal effect, molecular dynamics simulations were carried, using the atom-centered density matrix propagation method at the DFT level (BP86/LanL2dz). The results highlight that the (99)Tc NMR spectroscopy can be a promising technique for structural investigation of biomolecules, at the molecular level, in different environments.

Probing long‐range spin–spin coupling constants in 2‐halo‐substituted cyclohexanones and cyclohexanethiones: The role of solvent and stereoelectronic effects

“…After the classical molecular dynamics, the last conformation was selected and quantum dynamics calculations were performed using the Gaussian09 program, at 298 K, because it is not a compound with biological activity. Additionally, with the aim of exploring the relativistic effects, including scalar and spin‐orbit, for the compounds with bromine, relativistic DFT calculations were employed using the ADF software …”

6-Benzothiazolyl Ureas, Thioureas and Guanidines are Potent Inhibitors of ABAD/17β-HSD10 and Potential Drugs for Alzheimer"s Disease Treatment: Design, Synthesis and in vitro Evaluation

“…Reactions were monitored by TLC performed on aluminium sheets precoated with silica gel 60 F254 (Merck, Czech Republic) using mobile phase CHCl3/ C spectra are reported in ppm (δ) relative to solvent peak dimethylsulfoxide-d6 (δ 39.52) [19].…”

Exploring EPR Parameters of 99Tc Complexes for Designing New MRI Probes: Coordination Environment, Solvent, and Thermal Effects on the Spectroscopic Properties

“…Using the last configuration from classical MD as the starting point, we subsequently started quantum MD simulations using the ADMP method at the DFT level [25] (BP86/LanL2dz). These procedures have been employed with success in previous studies [11].…”

“…After an equilibrium time of 1 ps, in which a temperature of 310 K was maintained via velocity rescaling, statistical averages and snapshots for hyperfine coupling constant (HFCC) calculations were collected from subsequent unconstrained micro canonical runs of 1 ps, obtaining a total of 1000 conformations. Snapshots were taken every 25 fs generating a total of 40 conformations [11] for use in HFCC calculations. A new method of selecting structures has been successfully used, OWSCA; this method uses the wavelet transform to decompose the DM signal; the signal decomposed by the transform is able to represent well and with a minimum error the entire DM signal [30].…”

“…Based on this context, it is necessary to understand the relaxation mechanisms of water molecules and the influence of paramagnetic effects on the 1 H and 17 O hyperfine coupling constant ( iso ) values [7]. More recently, radioisotopes of technetium (Tc) have been considered promising nuclei for the NMR (Nuclear Magnetic Resonance) and MRI techniques [9][10][11]. Based on this context, in 2006 Tzanopoulou et al synthesized the ( 99m Tc)(CO) 3 (NNO) complex conjugated to the antitumor agent 2-(4 -aminophenyl)benzothiazole [ABT; see Complex 1, Figure 1] [12].…”