Energies and isomerizations of (CH)12 hydrocarbons

Reactivity of acenes: mechanisms and dependence on acene length

“…with scantily available experimental data shows excellent agreement regarding the thermodynamics of anthracene dimerization and the activation energy for the dissociation of the anthracene dimer. Both the experimental and computational results agree that the thermal dissociation of the anthracene dimer is a stepwise C–C bond breaking process, however, the computational results disagree with previous findings that predict the presence of a biradical intermediate in the dissociation of the benzene dimer …”

Preparation and Reactivity of [D3d]‐Octahedrane: The Most Stable (CH)12 Hydrocarbon

“…The organic extracts were washed with water (3 3 mL) and dried over Na 2 SO 4 ; the solvents were removed in vacuo. Column chromatography on silica gel (50 g; pentane) gave the starting hydrocarbon 1 (31 mg), 1-bromooctahedrane (31; 64 mg, 43 %) and 10,12-dibromohexacyclo[6.4.0.0 2,6 .0 3,11 .0 4,9 .0 5,7 ]dodecane (32; 24 mg, 12 %). Bromination of 2,4-dehydroadamantane (33): A mixture of hydrocarbon 33 (130 mg, 0.97 mmol), CBr 4 (0.6 g, 1.81 mmol), CH 2 Cl 2 , (3 mL), 50 % aqueous NaOH (2 mL), and tetrabutylammonium bromide (16 mg, 0.05 mmol) was stirred at room temperature for 120 h, then diluted with water (10 mL) and extracted with CH 2 Cl 2 (3 5 mL).…”

“…[2,4] This is in line with the ease of selective adamantane functionalizations under ionic (bromination, nitroxylation) and free-radical (chlorination, hydroxylation) conditions. Herein we present and discuss the preparation, structural and energetic features as well as the reactivity of [D 3d ]-octaAbstract: The synthesis of the (CH) 12 hydrocarbon [D 3d ]-octahedrane (heptacyclo[6.4.0.0 2,4 .0 3,7 .0 5,12 .0 6,10 .0 9,11 ]dodecane) 1 and its selective functionalization retaining the hydrocarbon cage is described. The B3LYP/6-311+G* strain energy of 1 is 83.7 kcal mol À1 (4.7 kcal mol À1 per CÀC bond) which is significantly higher than that of the structurally related (CH) 16 [D 4d ]-decahedrane 2 (75.4 kcal mol À1 ; 3.1 kcal mol À1 per CÀC bond) and (CH) 20 [I h ]-dodecahedrane 3 (51.5 kcal mol À1 ; 1.7 kcal mol À1 per CÀC bond); the heats of formation for 1-3 computed according to homodesmotic equations are 52, 35, and 4 kcal mol…”

“…Keywords: density functional calculations · halogenation · heats of formation · phase-transfer catalysis · polycycles · small rings hedrane (1), which has been suggested [5] to be the most stable of all (CH) 12 hydrocarbons. [6] For comparison, the structurally related higher (CH) n polyhedranes, that is [D 4d ]-decahedrane (2, n = 16) and [I h ]-dodecahedrane (3, n = 20) (Figure 1) will also be evaluated.…”

Synthesis, structure, and photoreactions of fluorinated 2,11‐diaza[32]paracyclophane: Photochemical formation of cage‐diene type benzene dimer

“…Benzene dimers, (CH) 12 hydrocarbons, have attracted much attention because they have highly strained and fascinating molecular structures and are generally unstable and difficult to access through conventional thermal or catalytic reactions. [1,2] It has been established that benzenes display variety of photoreaction pathways such as valence isomerizations, cycloadditions with alkenes, and substitution reactions (Scheme 1A). However, they rarely undergo photochemical dimerization.…”