Organometallic Complexes for Nonlinear Optics. 24. Reversible Electrochemical Switching of Nonlinear Absorption

Abstract

The molecular inorganic compounds 1,3,5-{trans-[RuCl(dppe)2]C⋮C-4-C6H4C⋮C}3C6H3 (1), trans-[Ru(C⋮C-4-C6H4C⋮CPh)Cl(dppe)2] (2), and trans-[Ru(C⋮CPh)Cl(dppm)2] (3) exhibit reversible oxidation in solution, assigned to the metal-centered RuII/III processes. Complexes 1−3 are essentially transparent at frequencies below 20 × 103 cm-1, whereas the green complexes 1 + −3 + have a strong absorption band centered near 11−12 × 103 cm-1. These absorption bands have been utilized to demonstrate facile NLO switching utilizing an optically transparent thin-layer electrochemical cell, a procedure which has applicability to evaluating the switching capability of a range of materials. This procedure has been applied to switch cubic nonlinearities, the first electrochromic switching of molecular nonlinear absorption. Oxidation of the molecules results in changes, including changes of sign, of both the imaginary (absorptive) part of the third-order nonlinearity and the real (refractive) part. Cycling between the two forms of the molecules is facile. The sign of the nonlinearity is reversed on oxidation of 1 and 2, whereas 3, a complex with negligible third-order nonlinearity in the resting state, has third-order nonlinearity switched on upon oxidation to 3 + .

Multistate Redox‐Active Metalated Triarylamines

“…The vinylidene salt 5 was then deprotonated to yield the tris-alkynyl complex trans, trans,trans-[{(dppe) 2 ClRu(CϵC-4-C 6 H 4 )} 3 N] (6); complex 6 had previously been prepared from tris(4-ethynylphenyl)-amine and 1 without isolation of the trivinylidene complex. [16] There was no difference in the reactivity of 5 or 6 towards ethynylferrocene, both of which afforded trans, trans,trans-[{(η 5 [17] All complexes were characterized by IR and 1 H and 31 P NMR spectroscopy, high-resolution mass spectrometry, and satisfactory microanalyses; the structures of complexes 2 (Figure 1), 3 (Figure 2), and 4 ( Figure 3) were confirmed by single-crystal X-ray diffraction studies. The IR spectra of the alkynyl complexes contain a ν CϵC band at around 2060 cm -1 due to the metal-bonded alkynyl group, whereas the spectra of the vinylidene complexes show a ν C=C band at around 1630 cm -1 together with a strong band at 839 cm -1 that corresponds to the PF 6 -counterion.…”

“…Theoretical Methods: Density functional theory calculations were executed in this study using the Amsterdam Density Functional (ADF) program, version ADF 2010.01, [55] developed by Baerends et al [56,57] Calculations were performed in parallel mode with the VAYU supercomputer housed at the ANU Supercomputer Facility and operated under the National Computational Infrastructure Scheme. Calculations in C s symmetry were pursued on the structure [trans-(η 5 In all calculations and for all atoms, the all-electron Slater-type orbital basis sets used were of triple-ζ-plus-polarization quality (TZP). Geometry optimizations employed the gradient algorithm of Versluis and Ziegler.…”

“…[4] One reason is because oxidation of such compounds can "switch on" absorptions at low energy, thus significantly affecting the third-order NLO behavior. [5][6][7][8][9] We have reported carbonrich organometallics with three accessible redox states as possible multistate linear optical and NLO switches; in particular, we described the introduction of [(η 5 -C 5 Me 5 )(dppe)-Fe(CϵC-4-C 6 H 4 CϵC)Ru(dppe) 2 ] [dppe = 1,2-bis(diphenylphosphanyl)ethane] fragments into both linear and threefold symmetric branched aryleneethynylene architectures; the heterodinuclear fragment permits switching between three states. [10,11] As a continuation of these studies, we now report (i) replacement of the organoiron [Fe(dppe)(η 5 -C 5 HCϵC-4-C 6 H 4 NPh 2 and (HCϵC-4-C 6 H 4 ) 3 N are irreversible processes.…”

Nitrile ligands for controlled synthesis of alkynyl-ruthenium based homo and hetero bimetallic systems

“…Alkynylmetal complexes constitute a particularly important class of organometallic complexes with p-conjugated bridges both on account of their intrinsic interest and, more recently, their potential as components or models of nanoscale electronic [16][17][18] and optical devices [19][20][21][22][23][24][25], related to the fact that the metal atom lies in the same plane as the p-system and can participate to the extension of the pconjugated path. From a design perspective, the metal acetylide linkage is appealing because of the rigid nature of the alkyne ligands and the defined directionality in the case of trans substituted metal centers [26][27][28][29].…”

Electron‐Rich Iron/Ruthenium Arylalkynyl Complexes for Third‐Order Nonlinear Optics: Redox‐Switching between Three States

“…This observation is consistent with the previous study of 1 a, which revealed a very weak communication between the various metallic centers connected by this type of central organic core. [15,16] Spectroelectrochemistry: Once the oxidation potentials were known, the oxidized states of these compounds could be readily generated in situ by using an optically transparent thin-layer electrochemical (OTTLE) cell. The optical properties of 2, 3-H, 3-NO 2 , and 4, and of their oxidized states were thus investigated by UV/Vis/NIR spectroelectrochemistry ( Figure 1).…”