A description of the bonding of π-conjugated ligands
to a transition metal which involves a synergic process with donation of electrons
from the filled π-orbital or lone electron pair orbital of the ligand into an empty
orbital of the metal (donor–acceptor bond), together with release (back donation)
of electrons from an n
d orbital of the metal (which is of π-symmetry with respect to the metal–ligand axis)
into the empty π*-antibonding orbital of the ligand.
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook