Evaluation of the Heats of Formation of Corannulene and C₆₀ by Means of High-Level Theoretical Procedures

Abstract

In this study, we address the issues associated with predicting usefully accurate heats of formation for moderately-sized molecules such as corannulene and C(60). We obtain a high-level theoretical heat of formation for corannulene through the use of reaction schemes that conserve increasingly larger molecular fragments between the reactants and products. The reaction enthalpies are obtained by means of the high-level, ab initio W1h thermochemical protocol, while accurate experimental enthalpies of formation for the other molecules involved in the reactions are obtained from the Active Thermochemical Tables (ATcT) network. Our best theoretical heat of formation for corannulene (Δ(f)H°(298)[C(20)H(10)(g)] = 485.2 ± 7.9 kJ mol(-1)) differs significantly from the currently accepted experimental value (Δ(f)H°(298)[C(20)H(10)(g)] = 458.5 ± 9.2 kJ mol(-1)), and this suggests that re-examination of the experimental data may be in order. We have used our theoretical heat of formation for corannulene to obtain a predicted heat of formation of C(60) through reactions that involve only corannulene and planar polyacenes. Current experimental values span a range of ~200 kJ mol(-1). Our reaction enthalpies are obtained by means of double-hybrid density functional theory in conjunction with a large quadruple-ζ basis set, while accurate experimental heats of formation (or our theoretical value in the case of corannulene) are used for the other molecules involved. Our best theoretical heat of formation for C(60) (Δ(f)H°(298)[C(60)(g)] = 2521.6 kJ mol(-1)) suggests that the experimental value adopted by the NIST thermochemical database (Δ(f)H°(298)[C(60)(g)] = 2560 ± 100 kJ mol(-1)) should be revised downward.

From small fullerenes to the graphene limit: A harmonic force‐field method for fullerenes and a comparison to density functional calculations for Goldberg–Coxeter fullerenes up to C980

“…Isodesmic reaction energies compared with C 60 ‐ I h for Goldberg–Coxeter fullerenes were used to extrapolate to the graphene limit. The extrapolated graphene value was used to obtain the heat of formation of C 60 , which is in very good agreement with the more accurate value published by Radom and coworkers . The force constants of the general force field were adjusted to the vibrational spectrum of three selected fullerenes, which gives rather accurate values for the zero‐point vibrational contribution .…”

“…In a recent paper by Radom and coworkers, the heat of formation for C 60 was calculated accurately to be 602.7 kcal/mol, which translates into 10.0 kcal/mol per carbon atom. This value is already in very good agreement with our PBE or B3LYP graphene limit value (mean value between both levels of theory is 8.9 ± 0.3 kcal/mol which is in the range of values listed in Table ).…”

Heats of formation of platonic hydrocarbon cages by means of high‐level thermochemical procedures

“…The DBOC contributions at the HF/cc‐pVTZ level of theory range between 0.23 ( 1 ) and 0.78 ( 3 ) kcal mol −1 . We note the sizeable DBOC contribution for 3 : for comparison, the DBOC contributions to the TAE (at the HF level) for other medium‐sized organic systems are: 0.63 (corannulene, C 20 H 10 ), 0.59 (naphthacene, C 18 H 12 ), 0.61 (triphenylene, C 18 H 12 ), 0.60 (lysine, C 6 H 14 N 2 O 2 ), and 0.72 (arginine, C 6 H 14 N 4 O 2 ) kcal mol −1 . It is also worth pointing out that the HF/cc‐pVDZ level of theory gives essentially the same results at a much lower computational cost, namely the differences amount to less than 0.03 kcal mol −1 (Table ).…”

W4‐17: A diverse and high‐confidence dataset of atomization energies for benchmarking high‐level electronic structure methods

“…[60] Thus, W1-F12 has been applied to large hydrocarbons (e.g., sumanene, [100] corannulene, [102] and even dodecahedrane) [4] as well as to systems of biological relevance (e.g., guanine [60] and arginine). [60] Thus, W1-F12 has been applied to large hydrocarbons (e.g., sumanene, [100] corannulene, [102] and even dodecahedrane) [4] as well as to systems of biological relevance (e.g., guanine [60] and arginine).…”