Systematic High‐Accuracy Prediction of Electron Affinities for Biological Quinones

Abstract

Quinones play vital roles as electron carriers in fundamental biological processes; therefore, the ability to accurately predict their electron affinities is crucial for understanding their properties and function. The increasing availability of cost-effective implementations of correlated wave function methods for both closed-shell and open-shell systems offers an alternative to density functional theory approaches that have traditionally dominated the field despite their shortcomings. Here, we define a benchmark set of quinones with experimentally available electron affinities and evaluate a range of electronic structure methods, setting a target accuracy of 0.1 eV. Among wave function methods, we test various implementations of coupled cluster (CC) theory, including local pair natural orbital (LPNO) approaches to canonical and parameterized CCSD, the domainbased DLPNO approximation, and the equations-of-motion approach for electron affinities, EA-EOM-CCSD. In addition, several variants of canonical, spin-component-scaled, orbital-optimized, and explicitly correlated (F12) Møller-Plesset perturbation theory are benchmarked. Achieving systematically the target level of accuracy is challenging and a composite scheme that combines canonical CCSD(T) with large basis set LPNObased extrapolation of correlation energy proves to be the most accurate approach. Methods that offer comparable performance are the parameterized LPNO-pCCSD, the DLPNO-CCSD(T 0 ), and the orbital optimized OO-SCS-MP2. Among DFT methods, viable practical alternatives are only the M06 and the double hybrids, but the latter should be employed with caution because of significant basis set sensitivity. A highly accurate yet cost-effective DLPNO-based coupled cluster approach is used to investigate the methoxy conformation effect on the electron affinities of ubiquinones found in photosynthetic bacterial reaction centers.

Single‐reference coupled cluster methods for computing excitation energies in large molecules: The efficiency and accuracy of approximations

“…Similar conclusions hold for the state‐specific PNO implementation as well as for the state averaged PNO EOM implementation of Valeev . Our own STEOM implementation depends on ground state PNOs, for which standardized parameter sets guaranteeing a certain accuracy are available, and it has been shown that the error in the ground state computation and in the subsequent IP/EA calculations can also be kept below similar limits . The question of accuracy is most complicated for multilayer embedding methods.…”

“…121 Our own STEOM implementation depends on ground state PNOs, for which standardized parameter sets guaranteeing a certain accuracy are available, 205 and it has been shown that the error in the ground state computation and in the subsequent IP/EA calculations can also be kept below similar limits. 74,[132][133][134]206 The question of accuracy is most complicated for multilayer embedding methods. Here, the size of the various layers and whether the excitation crosses the layer boundaries are the factors that determine accuracy.…”

Unveiling the Photophysical Properties of Boron-dipyrromethene Dyes Using a New Accurate Excited State Coupled Cluster Method

“…For this reason, the T CutPNOSingles threshold plays a crucial role in determining the accuracy of the method. More information on the equations can be found in the literature. , As the active space selection is also in the canonical basis, the constructed unit vector guess can be used directly without further transformation.…”

<p>Pharmacological Activity and Mechanism of Tanshinone IIA in Related Diseases</p>

“…The terpenoids are easily reduced to diphenol derivatives, 16 which are then oxidized 17 and easily converted. 18 Quinone compounds play a role in the transmission of electrons, 19 as a product of metabolism of organisms, 20,21 exhibits a variety of biological activities by promoting or interfering with various biochemical reactions of organisms, 22 and promotes certain biochemical reactions as coenzymes 23 for biological reactions. 22 Or interfere with the action, 24 thus showing a variety of pharmacological effects, such as anti-atherosclerosis, 25 anti-myocardial ischemia, 26 anti-arrhythmia, 27 repair of vascular endothelial cells, 28 improve coronary blood circulation, 29 anticardiac hypertrophy, and anti-tumor (as shown in Figure 2).…”