THE STANDARD ENTHALPIES OF FORMATION OF SOME DIBENZOANNELATED CYCLOALKANOLS

The heats of combustion of s-9,10-bis-hydroxymethyl-9,10-dihydrophenan threne, ethyl-5,6-dihydro-7H-dibenzo[a,c]cyclohepten-6-ol, xymethyl-5, 6-dihydro-7H-di-benzo[a,c]cycloheptene, oxymethyl-5,6-dihydro-7H-diben zo[a,c]cycloheptene, 5H-dibenzo-[a,d]cyclohepten-5-ol and 5H-10,11 -di hydrodibenzo[a,d]cyclohepten-5-ol were measured by means of a Gallenka mp adiabatic bomb calorimeter. Uncertainties in the determination of t he heats of combustion ranged between 0.2 and 0.3%. The enthalpies of formation and atomization for the six compounds were derived. The expe rimental values of the heats of atomization were compared with those c alculated using the Allen-Skinner bond energy scheme. Conclusions abou t energetic contributions which stabilize the structure of the investi gated compounds were drawn. (C) 1998 Elsevier Science B.V.