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

The complexes [Au(4-Cequivalent toCC(6)H(4)NO(2))(L)] [L = PCy3 (1), PMe3 (2)], [(L)Au(mu-4-Cequivalent toCRCequivalent toC)Au(L)] [R = C6H4, L = PCy3 (4), PPh3 (5); R = C6H4-4-C6H4, L = PCy3 (7), PPh3 (8)], trans,trans-[RuCl(dPPM)(2)(p-4,4'-Cequivalent toCC(6)H(4)C(6)H(4)Cequivalent toC)RuCl(dppm)(2)] (11), trans-[Ru(X)(Y)(dppe)(2)] [X = Cl, Y = 4-Cequivalent toCC(6)H(4)I (12), 4-Cequivalent toCC(6)H(4)Cequivalent toCSiMe(3) (13); X = Cequivalent toCPh. 4-Cequivalent toCC(6)H(4)Cequivalent toCH (14)] and {trans-[Ru(Cequivalent toCPh)(dppe)(2)])(2)(mu-4,4'-Cequivalent toCC(6)H(4)Cequivalent toCCequivalent toCC(6)H(4)Cequivalent toC) (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 pi-delocalizable bridge is lengthened. Quadratic nonlinear optical (NLO) merit increases on replacing triarylphosphine by trialkylphosphine, the relative beta values Au(4-Cequivalent toCC(6)H(4)NO(2))(PPh3) < 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 sigma(2)/MWt (two-photon absorption cross-section/molecular weight) value observed thus far for an organometallic complex. (C) 2002 Elsevier Science B.V. All rights reserved.