Organometallic complexes for nonlinear optics: Part 25. Quadratic and cubic hyperpolarizabilities of some dipolar and quadrupolar gold and ruthenium complexes

Abstract

The complexes [Au(4-CCC 6H 4NO 2)(L)] [L=PCy 3 ( 1), PMe 3 ( 2)], [(L)Au(μ-4-CCRCC)Au(L)] [R=C 6H 4, L=PCy 3 ( 4), PPh 3 ( 5); R=C 6H 4-4-C 6H 4, L=PCy 3 ( 7), PPh 3 ( 8)], trans,trans-[RuCl(dppm) 2(μ-4,4′-CCC 6H 4C 6H 4CC)RuCl(dppm) 2] ( 11), trans-[Ru(X)(Y)(dppe) 2] [X=Cl, Y=4-CCC 6H 4I ( 12), 4-CCC 6H 4CCSiMe 3 ( 13); X=CCPh, 4-CCC 6H 4CCH ( 14)] and { trans-[Ru(CCPh)(dppe) 2]} 2(μ-4,4′-CCC 6H 4CCCCC 6H 4CC) ( 15) have been prepared and their electrochemical (Ru complexes) and nonlinear optical properties assessed. Electronic communication between the metal centers in 10, 11 and 15 diminishes as the π-delocalizable bridge is lengthened. Quadratic nonlinear optical (NLO) merit increases on replacing triarylphosphine by trialkylphosphine, the relative β values Au(4-CCC 6H 4NO 2)(PPh 3)< 1< 3 being observed. Cubic NLO values are small for the gold complexes and much larger for the ruthenium examples. Complex 15 has the largest σ 2/MWt (two-photon absorption cross-section/molecular weight) value observed thus far for an organometallic complex.