Update of descriptors for organosilicon compounds compatible with the 2025-WSU compound descriptor database for use...

Descriptors compatible with the calibration models for the WSU-2025 compound descriptor database are assigned for 24 organosilanes of general structure R₄Si, 15 linear organosiloxanes of general structure R₃SiO(R₂SiO)_mSiR₃ with m = 0-4, 11 cyclic organosiloxanes of general structure (R₂SiO)_m with m = 3-6, hexamethyldisilazane, hexamethylcyclotriazane, hexamethyldisilthiane, and heptamethylcyclotetrasiloxanol. The R group for organosiloxanes includes hydrogen, chlorine, methyl, vinyl, ethyl, octyl, and trimethylsiloxy and, in addition, for organosilanes acetate, methoxy, ethoxy, phenyl, nonafluorohexyl, 3-aminopropyl, 3-isocyanatopropyl, 3-glycidoxypropyl, and 3-methacryloxypropyl. Descriptors were assigned using the Solver method from experimental measurements of gas chromatographic retention factors at several temperatures on up to 12 varied stationary phases and liquid-liquid partition constants in a minimum of three totally organic biphasic systems (n-hexane-acetonitrile, n-heptane-N,N-dimethylformamide, and n-heptane-2,2,2-trifluoroethanol). Organosilicon compounds are characterized by weak dispersive interactions compared with organic compounds of a similar size, weak dipole-type interactions unless substituents contain embedded polar functional groups, an absence of hydrogen-bond acidity, except for organosilanes with -NH-, -NH₂ or -OH functional groups (Si-H bond is not hydrogen-bond acidic), and generally relatively large but variable hydrogen-bond basicity moderated for Si-O compounds by the type of substituents co-bonded to the silicon atom. The solvation parameter model provides varied results for the estimation of the octanol-water, octanol-air, and water-air partition constants for six volatile organosiloxanes, likely resulting from the uncertainty in their experimental values since the partition constants fall outside the range for convenient laboratory measurements.