LC-BLYP Calculations of the Structures and Photophysical Properties of [1,3]Thiazolo[4,5-<i>b</i>]pyrazine Derivatives in Cyclohexane and Methanol

Dokmaisrijan, Supaporn; Kungwan, Nawee

doi:10.1021/acs.jpca.9b09074

Cited by 7 publications

(3 citation statements)

References 37 publications

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“…37 We have optimized the starting geometries thoroughly using 24 different DFAs, Hartree−Fock with three corrections (HF-3c), 38 and a wave function-based method, RI-SCS-MP2. 39 The DFAs cover the range from cheaper GGA methods to expensive double hybrid methods PBE0 b,66 M06-2X a, 54,55 ωB97M-D3BJ 67 revPBE c, 68 LC-BLYP 69,70 CAM-B3LYP 71 a DFT-D3 with zero-damping. 49 b DFT-D3 with Becke−Johnson damping.…”

Section: ■ Computational Detailsmentioning

confidence: 99%

Performance of Density Functionals and Semiempirical 3c Methods for Small Gold–Thiolate Clusters

et al. 2023

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In light of the recent surge in computational studies of gold thiolate clusters, we present a comparison of popular density functionals (DFAs) and three-part corrected methods (3c-methods) on their performance by taking a data set named as AuSR18 consisting of 18 isomers of Au n (SCH3) m (m ≤ n = 1–3). We have compared the efficiency and accuracy of the DFAs and 3c-methods in geometry optimization with RI-SCS-MP2 as the reference method. Similarly, the performance for accurate and efficient energy evaluation was compared with DLPNO-CCSD(T) as the reference method. The lowest energy structure among the isomers of the largest stoichiometry from our data set, AuSR18, i.e., Au3(SCH3)3, is considered to evaluate the computational time for SCF and gradient evaluations. Alongside this, the numbers of optimization steps to locate the most stable minima of Au3(SCH3)3 are compared to assess the efficiency of the methods. A comparison of relevant bond lengths with the reference geometries was made to estimate the accuracy in geometry optimization. Some methods, such as LC-BLYP, ωB97M-D3BJ, M06-2X, and PBEh-3c, could not locate many of the minima found by most of the other methods; thus, the versatility in locating various minima is also an important criterion in choosing a method for the given project. To determine the accuracy of the methods, we compared the relative energies of the isomers in each stoichiometry and the interaction energy of the gold core with the ligands. The dependence of basis set size and relativistic effects on energies are also compared. The following are some of the highlights. TPSS has shown accuracy, while mPWPW shows comparable speed and accuracy. For the relative energies of the clusters, the hybrid range-separated DFAs are the best option. CAM-B3LYP excels, whereas B3LYP performs poorly. Overall, LC-BLYP is a balanced performer considering both the geometry and relative stability of the structures, but it lacks diversity. The 3c-methods, although fast, are less impressive in relative stability.

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Section: ■ Computational Detailsmentioning

confidence: 99%

Performance of Density Functionals and Semiempirical 3c Methods for Small Gold–Thiolate Clusters

et al. 2023

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“…To study the effect of the range-separation parameter on the size and quality of the auxiliary basis sets, we use the LC-BLYP functional, as the range-separation parameter in this functional is often varied and optimized for different purposes. − To perform the procedure of the OT-RSH functionals, we add dummy functionals with the respective values for the range-separation parameter to the implementation. Unless stated otherwise, we employ a value of ξ = 0.33 a 0 –1 .…”

Section: Computational Detailsmentioning

confidence: 99%

Automated Generation of Optimized Auxiliary Basis Sets for Long-Range-Corrected TDDFT Using the Cholesky Decomposition

Hellmann

Tölle

Niemeyer

et al. 2022

J. Chem. Theory Comput.

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Range-separated hybrid functionals making use of a smooth separation of the Coulomb operator in terms of the error function and its complement have proven to be a valuable tool for improving Kohn−Sham density functional theory (DFT) calculations. This holds in particular for obtaining accurate excitation energies from linear-response time-dependent DFT. Evaluating the long-range exchange contributions represents one of the most time-consuming tasks in such calculations. Prefitted auxiliary basis sets can be employed to speed up this step. Here, we present a way to generate auxiliary basis sets optimized to fit the long-range exchange contributions only, contrary to the common optimization strategies on the basis of the full Coulomb operator. For this purpose, we use the atomic Cholesky decomposition technique. The basis sets are generated on-the-fly using the specific range-separation parameter defined in the exchange−correlation functional. We obtain excitation energies and oscillator strengths which are of similar or better accuracy than those obtained with conventional resolution-of-the-identity auxiliary basis sets while drastically reducing the number of auxiliary functions required. This is demonstrated for the QUESTDB#5 benchmark set. In addition, we outline the benefits of this approach in sequences of calculations employing varying range-separation parameters, as is the case in the optimally tuned range-separation strategy. Finally, we illustrate the efficiency of this approach for real-world examples, namely, a chlorophyll tetramer from photosystem II and a carotenoid− porphyrin−C 60 triad.

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“…Thiazolo [4,5-b] pyrazines (TPy) are fused ring structures of pyrazines and thiazoles, and more electron deficient than benzothiazols. [11][12][13][14] Therefore, we envisioned that 2-methyl-TPy (MeTPy: 3) could be used as a nucleophile for Knoevenagel condensation, affording PBB3 derivatives such as 1, containing a diene linker between two aromatic groups (Chart 1c). Here, we report the synthesis of compounds 1, 6, 7, and 8 by Knoevenagel condensation between MeTPy and electrondonating aldehydes.…”

Section: Introductionmentioning

confidence: 99%

Knoevenagel Condensation between 2-Methyl-thiazolo[4,5-<i>b</i>]pyrazines and Aldehydes

2022

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Knoevenagel condensation, an olefin-forming reaction from active methyl/methylene-containing compounds and aldehydes, is a fundamental and useful synthetic method. Benzothiazoles are, however, out of the scope of Knoevenagel condensation. Here, we report that Knoevenagel condensation between aldehydes and 2-methyl-thiazolo[4,5-b]pyrazines (MeTPy), a fused ring structure comprising pyrazine and thiazole, proceeded smoothly, despite minor structural differences from benzothiazoles. This finding will be useful for short synthesis of MeTPy-containing functional molecules, such as a tau probe analog 1.

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LC-BLYP Calculations of the Structures and Photophysical Properties of [1,3]Thiazolo[4,5-b]pyrazine Derivatives in Cyclohexane and Methanol

Cited by 7 publications

References 37 publications

Performance of Density Functionals and Semiempirical 3c Methods for Small Gold–Thiolate Clusters

Performance of Density Functionals and Semiempirical 3c Methods for Small Gold–Thiolate Clusters

Automated Generation of Optimized Auxiliary Basis Sets for Long-Range-Corrected TDDFT Using the Cholesky Decomposition

Knoevenagel Condensation between 2-Methyl-thiazolo[4,5-<i>b</i>]pyrazines and Aldehydes

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