Physical Properties Relative to dp-π Bonding

Abstract

The question of d–π bonding has long been an area of controversy in organic compounds containing sulfur, phosphorus or silicon. Although the involvement of d-orbitals in valence-shell-expanded compounds (d—σ bonding) is commonly accepted (although no longer required — see theoretical discussion in preceding section), dp—π bonding is on a much more questionable experimental basis and has usually been invoked to explain the “unexplainable”. Most cases where dp—π bonding has been invoked have been concerned with physical and spectroscopic properties, since the effect on chemical properties is generally smaller and complicated by other factors.