Gas–solvent and water–solvent partition coefficients of the tetraphenyl compounds of group (IV)

Abstract

Literature data on solubilities in organic solvents and vapor pressures at 298 K have been used to obtain gas to solvent partition coefficients for Ph₄M (M = C, Si, Ge, Sn, Pb). These partition coefficients together with known equations that relate partition coefficients to Abraham descriptors have been used to calculate the Abraham descriptors E, S, A, B, V and L. It is shown that for tetraphenylmethane the dipolarity/polarizability descriptor, S, is much smaller than anticipated. From the descriptors it is possible to calculate partition coefficients from water to the organic solvents, and from these together with solubilities in organic solvents finally to deduce the aqueous solubility, C_w in mol dm⁻³, of the Ph₄M compounds. The solubilities we calculate for Ph₄C and Ph₄Ge, log C_w = −10.93 ± 0.58 and −11.12 ± 0.58 respectively, are far smaller than those obtained previously by experiment, log C_w = −7.8 and −7.77, so that our values for water–solvent partition coefficients are much larger than previously suggested. A number of important physico-chemical properties of the Ph₄M compounds are also calculated.