Bonding in Organometallic Complexes

Abstract

Neutral ligands (:L) and monoanionic ligands (X–) donate a pair of electrons or a lone-pair to a vacant orbital in a transition metal centre (M) to form a covalent σ-bond between them. Ligands such as :C≡O, :C≡NR (isonitrile or isocyanide) and :PR3 (tertiary phosphine or phosphite) can donate a pair of electrons to a metal centre to form a σ-bond. These ligands are considered as σ-donors.