Experimental and Computational Thermochemical Study of the Three Monoiodophenol Isomers

The present work reports the values of the standard (p degrees = 0.1 MPa) molar enthalpies of formation in the condensed phase of the three isomers of monoiodophenol derived from the standard molar energies of combustion, in oxygen, to yield CO(2)(g), I(2)(cr)., and H(2)O(1), at T = 298.15 K, measured by rotating-bomb combustion calorimetry, as well as the values of the standard molar enthalpies of sublimation, at T = 298.15 K, determined using high-temperature Calvet microcalorimetry. Combining the former two experimental quantities, the standard molar enthalpies of formation in the gaseous phase were derived, at T = 298.15 K: Delta(f)H(m)degrees (2-iodophenol, g) = -(15.3 +/- 2.0) kJ.mol(-1) Delta(f)H(m)degrees(3-iodophenol, g) = -(7.2 +/- 2.1) kJ.mol(-1), and Delta(f)H(m)degrees(4-iodophenol, g) = -(14.3 +/- 2.3) kJ.mol(-1). The experimental values of the gas-phase enthalpies of formation of each compound were compared with estimates using the empirical scheme developed by Cox and with the calculated values based on high-level density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional at the 6-311G(d,p) basis set.