Group 8 metal alkynyl complexes for nonlinear optics

Studies of the nonlinear optical (NLO) properties of Group 8 metal alkynyl complexes are summarized, with particular focus on results since 2003; structure–NLO property relationships are developed, optical nonlinearities of multipolar alkynyl complexes are described, and switching of the NLO response of molecules and molecular materials derived from Group 8 metal alkynyl complexes is discussed.