The standard molar enthalpies of formation of 5,10,15,20-tetraphenylporphine and 5,10,15,20-tetrakis(4-methoxyphenyl)porphine by oxygen bomb combustion calorimetry

A thermochemical study of 5,10,15,20-tetraphenylporphine zinc(II) by rotating bomb combustion calorimetry and by Knudsen effusion experiments

“…The third column in the same table contains the corresponding quantities for the free ligand TPP, previously reported. (26,27) …”

“…A major research project in this laboratory is the systematic thermochemical study of these molecules, leading to the experimental determination of enthalpies of atomization, which was started some time ago and has produced some results for the free ligands. (26,27) The knowledge of these quantities will permit the calculation of the mean dissociation enthalpy for the four N-metal co-ordination bonds.…”

The enthalpy of sublimation of 5,10,15,20-tetraphenylporphine and 5,10,15,20-tetrakis(4-methoxyphenyl)porphine

“…The source, purification procedure, purity, and spectroscopic characterisation of these compounds have been previously reported. (1) Differential scanning calorimetry (Perkin Elmer DSC 7) in the range of T = (288 to 773) K showed that decomposition of samples of TPP and TMPP occurred at T = 715 K and T = 710 K, respectively.…”

“…After several measurements, the system was opened and samples of the two sublimed substances taken from the quartz crystal surface were analyzed by H n.m.r and u.v. (1) visible spectrophotometry. No impurities or decomposition products were detected for either studied compound.…”

“…The importance of porphyrins has been summarised, and the standard molar enthalpies of formation of 5,10,15,20-tetraphenylporphine (CA registry number 917-23-7, TPP) and 5,10,15,20-tetrakis(4-methoxyphenyl)porphine (CA registry number 22112-78-3, TMPP) in the condensed phase were reported in a previous paper. (1) The enthalpy of sublimation for TPP has been reported in at least three different studies (2)(3)(4) and the obtained values range from 111 kJ · mol −1 to 370 kJ · mol −1 . In this paper, the experimental determination of the enthalpies of sublimation for the above compounds, obtained by the Knudsen effusion method with a quartz-crystal microbalance, are reported.…”