Journal of Physical Chemistry A, Vol.103, No.43, 8733-8737, 1999
G2 and G3 calculations of enthalpies of hydrogenation, isomerization, and formation of bi-, tri-, and tetracyclic C-7 hydrocarbons: The norbornadiene cycle
We have calculated the standard enthalpies of isomerization, hydrogenation, and formation (Delta(hyd)H(298), Delta(isom)H(298), and Delta(f)H(298)) of norbornadiene, quadricyclane, norbornene, nortricyclane, and norbornane by the G2, G2(MP2), G2(MP2,SVP), G3(MP2), and B3LYP/6-311+(3df,2p) procedures. Comparison with combustion and hydrogenation thermochemical results shows that agreement between G-n theory and experiment remains within the target interval of 1 to 2 kcal mol(-1) for these C-7 hydrocarbons, but that B3LYP/6-311 +(3df,2p) results do not fall within this range.