It is well-known that the small non-IPR fullerenes C (n < 60) are highly unstable and that is why they cannot be obtained as empty cages. However, they become stable as exohedral or endohedral derivatives. In this report, the molecular structures of non-IPR isomers 29 (C) and 40 (T) of fullerene C are investigated using a semiempirical approach developed earlier for higher fullerenes. Quantum-chemical calculations (DFT) show that isomers 29 (C) and 40 (T) have open-shell structures. The distributions of single, double, and delocalized π-bonds in the isomer molecules in question are presented for the first time as well as their molecular formulas. It is found unusual for higher fullerenes chain of π-bonds passing through some cycles. Identified features in the structures of small fullerene molecules can be predictive of the ability to their synthesis as derivatives and will assist in their structure determination.
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http://dx.doi.org/10.1007/s00894-020-04625-9 | DOI Listing |
J Chem Phys
January 2025
Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830, USA.
The linear scaling divide-expand-consolidate (DEC) framework is expanded to include unrestricted Hartree-Fock references. By partitioning the orbital space and employing local molecular orbitals, the full molecular calculation can be performed as independent calculations on individual fragments, making the method well-suited for massively parallel implementations. This approach also incorporates error control through the fragment optimization threshold (FOT), which maintains precision and consistency throughout the calculations.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
Theoretical simulations of electron detachment processes are vital for understanding chemical redox reactions, semiconductor and electrochemical properties, and high-energy radiation damage. However, accurate calculations of ionized electronic states are very challenging due to their open-shell nature, importance of electron correlation effects, and strong interactions with chemical environment. In this work, we present an efficient approach based on algebraic diagrammatic construction theory with polarizable embedding that allows to accurately simulate ionized electronic states in condensed-phase or biochemical environments (PE-IP-ADC).
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Nadia, Mohanpur 741246, WB, India.
In this paper, we demonstrate the performance of several density-based methods in predicting the inversion of S1 and T1 states of a few N-heterocyclic triangulene based fused ring molecules (popularly known as INVEST molecules) with an eye to identify a well performing but cost-effective preliminary screening method. Both conventional linear-response time-dependent density functional theory (LR-TDDFT) and ΔSCF methods (namely maximum overlap method, square-gradient minimization method, and restricted open-shell Kohn-Sham) are considered for excited state computations using exchange-correlation (XC) functionals from different rungs of Jacob's ladder. A well-justified systematism is observed in the performance of the functionals when compared against fully internally contracted multireference configuration interaction singles and doubles and/or equation of motion coupled-cluster singles and doubles (EOM-CCSD), with the most important feature being the capture of spin-polarization in the presence of correlation.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, United States.
Diffusion-limited kinetics is a key mechanistic debate when consecutive photoelectron transfer (conPET) is discussed in photoredox catalysis. In situ generated organic photoactive radicals can access catalytic systems as reducing as alkaline metals that can activate remarkably stable bonds. However, in many cases, the extremely short-lived transient nature of these doublet state open-shell species has led to debatable mechanistic studies, hindering adoption and development.
View Article and Find Full Text PDFNat Commun
January 2025
School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan, China.
[n]Peri-acenes ([n]PA) have attracted great interest as promising candidates for nanoelectronics and spintronics. However, the synthesis of large [n]PA (n > 4) is extremely challenging due to their intrinsic open-shell radical character and high reactivity. Herein, we report the successful synthesis and isolation of a derivative (1) of peri-hexacene in crystalline form.
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