Narrow Results

Standard enthalpies of formation (ΔH_f) were calculated with models developed using the computer program SPARC. SPARC uses computational algorithms based on chemical structure theory to calculate the ΔH_f. Molecular structures are broken into simple functional units (reactophores) with intrinsic properties. Each reactophore is analyzed and the effects of appended molecular structures are quantified through perturbation theory. The ΔH_f models have been developed using all known data for saturated and unsaturated hydrocarbons. The structures of these compounds vary from chains to conjugated rings to poly-benzoic aromatic hydrocarbons. The SPARC calculated RMS deviation of these 587 compounds is 4.50 kJ mol^-1.

Three endohedral fullerenes C₂H₂–C₆₀, C₂H₄–C₆₀, and C₂H₆–C₆₀ are investigated theoretically using density functional theory. Their electronic and structural properties are studied. The calculations suggest that the formations of these complexes are endothermic; the dopant and C₆₀ cage affect each other rarely except for the slight distortion of C₆₀ cage and compression of the hydrocarbon molecules. A small quantity of electron transfer from C₆₀ to the hydrocarbon molecule was also observed. Accordingly, C₆₀ could theoretically be a good container for some small hydrocarbon molecules.