Thermochemical stabilities of giant fullerenes using density functional tight binding theory and isodesmic‐type reactions

Abstract

We present a systematic assessment of the density functional tight binding (DFTB) method for calculating heats of formation of fullerenes with isodesmic-type reaction schemes. We show that DFTB3-D/3ob can accurately predict Δ f H values of the 1812 structural isomers of C 60 , reproduce subtle trends in Δ f H values for 24 isolated pentagon rule (IPR) isomers of C 84 , and predict Δ f H values of giant fullerenes that are in effectively exact agreement with benchmark DSD-PBEP86/def2-QZVPP calculations. For fullerenes up to C 320 , DFTB Δ f H values are within 1.0 kJ mol −1 of DSD-PBEP86/def2-QZVPP values per carbon atom, and on a per carbon atom basis DFTB3-D/3ob yields exactly the same numerical trend of (Δ f H [per carbon] = 722n −0.72 + 5.2 kJ mol −1). DFTB3-D/3ob is therefore an accurate replacement for high-level DHDFT and composite thermochemical methods in predicting of thermochemical stabilities of giant fullerenes and analogous nanocarbon architectures.

Assessment of DLPNO‐CCSD(T)‐F12 and its use for the formulation of the low‐cost and reliable L‐W1X composite method

“…For some properties such as atomization energies, the deviations for direct calculations often scale with the system size, such that large species are often associated with large deviations. In such cases, the use of isodesmic‐type reactions can usually reduce the deviations by error cancellation, 51 such that reasonably accurate atomization energies can be obtained for, for example, medium‐sized fullerenes 52–54 . In the present study, we examined two sets of systems, namely platonic hydrocarbons 36 and polycyclic aromatic hydrocarbons; 37 for each of these, we use two different approaches to investigate how the use of isodesmic‐type reactions influence the accuracy in the DLPNO‐CCSD(T)‐F12 computations.…”

Theoretical Study on the Structure and Spectral Properties of Several Classical C84 Isomers and Their Newly Synthesized Derivatives

“…C 2 (13)-C 84 acts as a chiral cage, and its derivative YCN@ C 2 (13)-C 84 is an enantiomer like other chiral cage-based endohedral fullerenes. The research on fullerenes mainly focuses on the synthesis method, stability, and reaction mechanism of fullerenes. ,− Therefore, further theoretical studies on the electronic structure and spectral properties of the newly synthesized fullerenes and their derivatives were carried out.…”

Computational insights into the singlet–triplet energy gaps, ionization energies, and electron affinities for a diverse set of 812 small fullerenes (C20–C50)

“…A series of density functional theory studies examined the fundamental properties of fullerene isomers, with the focus being thermochemical stability. [11][12][13][14][15][16][17][18][19][20][21][22][23][24] Indeed, these studies revealed an intricate interplay between several underlying factors, which leads to structurally dependent variations in not only their thermochemical stability but also kinetic liability. Our fullerenestability model predicts the regioselectivity of fullerene reactions that are consistent with experimental findings.…”