One-electron bonds as intermolecular bonds for molecular complexes involving Mulliken n-electron donors and as-electron acceptors

Abstract

For 1 : 1 molecular complexes involving an n-type electron donor and an aσ-type electron acceptor, it is proved that the simplest Mulliken description, Ψ_N ≈ Ψ(D,A)+λΨ(D⁺-A^-), is equivalent to using a one-electron bond as the intermolecular bond between the donor (D) and the acceptor (A). The theory is illustrated with reference to the Hassel compound Me₃N...I₂, and the charge-transfer aspects of hydrogen bonding for the water dimer.