The polarity of XH and XM bonds in compounds of the ArXH and ArXM (X = O, S, NR; M = Hg, Sn, Pb, Sb) types and their capacity for coordination and dissociation

The relationship between the values of the σR+ constants of the XMRn and XH groups, reflecting the polarity of the XM and XH bonds, and the capacity of these bonds for heterolytic dissociation in DMSO have been analysed. Linear relations have been established between σR+ and log Kd. The factors responsible for the abnormal stability of the SHg and SPb bonds are discussed. It has been shown that the capacity of the XM and XH bonds for dissociation is not determined by the force of the coordination interactions (Kc) between the M or H atoms and DMSO. The parallel pattern of variations in σR+ and Kc is observed only in the case of XH acids and their SnPh3 and PbPh3 derivatives.