Gas-Phase Heat of Formation Values for Buckminsterfullerene (C₆₀), C70 Fullerene (C₇₀), Corannulene, Coronene, Sumanene, and Other Polycyclic Aromatic Hydrocarbons Calculated Using Density Functional Theory (M06 2X) Coupled with a Versatile Inexpensive Group-Equivalent Approach

Abstract

A straightforward procedure using density functional theory (M06 2X) coupled with a group-equivalent approach is described that was used to calculate gas-phase heat of formation (Δ H°) values for buckminsterfullerene (C), C70 fullerene (C), corannulene, coronene, and sumanene. This procedure was also used to calculate exceptionally accurate Δ H° values for a variety of single-ring aromatic and 2-7 ring polycyclic aromatic hydrocarbons (PAHs) as well as a large selection of other hydrocarbons and phenols. The approach described herein is internally consistent, and results for C, C, corannulene, coronene, and sumanene are in very close agreement with results reported by others who used higher-level computational theory. Statistical analysis of a test set containing benzene and 18 two to seven ring PAHs demonstrated that by using this approach a mean absolute deviation (MAD) and a root-mean-square deviation (RMSD) of 0.8 and 1.3 kJ/mol, respectively, were achieved for reference/experimental Δ H° values versus calculated/predicted Δ H° values. For statistical analysis of a larger test set containing 235 aromatic and aliphatic hydrocarbons and phenols, a MAD and a RMSD of 1.2 and 1.9 kJ/mol, respectively, were achieved for reference/experimental Δ H° values versus calculated/predicted Δ H° values.

Applications of isodesmic‐type reactions for computational thermochemistry

“…This value (2,520.0 ± 20.7 kJ mol −1 ) is in good agreement with the one in Reference 52. In other subsequent studies, 60,61 similar values ranged in ~2,510–2,530 kJ mol −1 have been proposed. They all suggest that the existing literature value of 2,560 kJ mol −1 is somewhat too positive, by ~40 kJ mol −1 .…”

Gas-phase thermochemistry of polycyclic aromatic hydrocarbons: an approach integrating the quantum chemistry composite scheme and reaction generator

“…[B3LYP] and [G3MP2B3] are the group-based empirical correction B3LYP and G3MP2B3 values of Allison and Burgess; 20,21 [AT,HC] and [AT,B,I] are the ATOMIC HC and ATOMIC HC best estimate values of Bakowies, see Table 3 in ref. 44; [M06-2X] are the group equivalent M06-2X values of Bumpus; 22 [DLPNO] are our previous 48 DLPNO-CCSD(T) estimates obtained on the B3LYP wave function and using only the small ATcT species as references; [W1-F12] are the W1-F12 estimates of Karton and Martin; 25 [W1h] are the W1h estimates of Radom and co-workers; 37 eExperimental values available in the literature. Reliable values employed for benchmarking our predictions are given in bold.…”

“…While in some instances the deviations can be explained by the deficiencies in the computational scheme, it is not unlikely that some experimental data have to be revised, especially in the cases when the predictions of Allison and Burgess are confirmed by other theoretical schemes. With the help of the M06-2X-based group-equivalent approach, Bumpus 22 detected that experimental enthalpies of formation of coronene and corannulene derived in the review of Roux et al 23 and incorporated in the NIST webbook are overestimated by 14.2 and underestimated by 28.5 kJ mol −1 , respectively.…”

All Hands on Deck: Accelerating Ab Initio Thermochemistry via Wavefunction Approximations

“…The latest experimental reference for C 60 's ∆H • f (298 K) is given by NIST 27 as 610 ± 30 kcal/mol, a value determined by averaging over 6 experimental estimations. The large experimental uncertainty compelled many to provide theoretical support for bracketing the NIST value [28][29][30][31][32] . However, ∆H • f (298 K) of C 60 has thus far been determined at the composite wavefunction level only by depending on group-additivity/isodesmic reaction schemes that may introduce non-negligible uncertainties.…”