Lanthanide Sensitization with Ruthenium Carbon-Rich Complexes and Redox Commutation of Near-IR Luminescence

Abstract

International audienceWith the help of associations between Eu3+, Yb3+, and Nd3+ ions and low-potential redox-active ruthenium carbon-rich complexes bearing bipyridine chelating unit(s) of the type trans-[Ph–C≡C–(dppe)2Ru–C≡C–bipy-κ2N,N′–Ln(TTA)3], trans-[(dppe)2Ru(−C≡C–bipy-κ2N,N′–Ln(TTA)3)2], and trans-[Ph–C≡C–(dppe)2Ru–C≡C–C6H4–C≡C–bipy-κ2N,N′–Yb(TTA)3], we built new original d–f heterometallic complexes. Efficient sensitization in the visible range of the Nd3+ and Yb3+ near-infrared (NIR) emitters was achieved with the metal–acetylide antenna, while sensitization of the Eu3+ ion was not efficient owing to the low energy level of the antenna excited state. The redox properties of these groups also allow for low-potential redox modulation of NIR luminescence of the Yb3+ ion and, for the first time, of the Nd3+ ion

Diarylethene-Containing Carbon-Rich Ruthenium Organometallics: Tuning of Electrochromism

“…8,29−51 To this end, group 8 metal acetylide complexes, displaying strong ligand-mediated electronic effects, are attractive redoxswitchable candidates. 52,53 Indeed, they allow modulation of different features such as NLO properties, 29,54 luminescence, 55 magnetic properties, 56 and conductivity 11 or achievement of quantum cell automata. 57 Among them, ruthenium species with a trans ditopic structure are especially attractive (i) owing to their exceptional ability to operate as a connector by allowing electron flow to occur between different elements in multicomponent carbon-rich systems (i.e., provide a strong electronic interaction between two remote redox-active metal centers through a carbon-rich bridge or within a bridge), 52a,58−62 and (ii) for the achievement of efficient molecular wires and junctions.…”

Self-Assembled Monolayers of Redox-Active 4d–4f Heterobimetallic Complexes

“…The complexes were prepared as sketched on scheme 1. First, following a classical procedure, 19 combinations of H-CC-bipy 33 with the vinylidene 34 in the presence of a non-coordinating salt (NaPF 6 ) and a base (Et 3 N), led in good yield (82%) to the adducts 1 bearing one bypiridine function, which was characterized by means of 31 P, 1 H, 13 C NMR, IR spectroscopies and mass spectrometry. As characteristic features, we observed the expected  (C≡C) vibration stretch for the acetylide complexes at 2058 cm -1 in the FTIR spectra, a single resonance peak in the 31 complexes 1Eu and 1Yb.…”

“…As expected, the ruthenium(II) complex 1 shows one main absorption bands above 300 nm at  max = 401 nm ( = 23500 mol -1 .L) due to a charge transfer from Ru(d)/alkynyl based orbitals to a * orbital based on the bipyridine unit. 19 A marked bathochromic shift of this transition to  max  464 nm ( 23000 mol -1 .L  = 59 nm) was The emission properties were first studied on the Yb complex. Excitation in the aforementioned lower energy transition ( ex = 465 nm) results in a characteristic line shape emission profile of Yb(III) at 976 nm ( 2 F 5/2 → 2 F 7/2 ) in the NIR spectral range (Figure 2) due to a straightforward sensitization mechanism from the Ru-acetylide ligand to the Yb ion.…”

“…Indeed, we have previously described molecular compounds based on the association of organometallic ruthenium acetylide moieties with europium, neodymium and ytterbium centers. 19,20 The carbon-rich ruthenium -arylacetylide is a very interesting building block because it exhibits low oxidation potential with stable redox state and promotes strong electronic coupling between the metal and the organic ligands. [20][21][22][23] This organometallic moiety turned out to be an attractive platform in order to achieve redox event [19][20]24 and to introduce grafting groups for building functional redox active surfaces.…”

“…19,20 The carbon-rich ruthenium -arylacetylide is a very interesting building block because it exhibits low oxidation potential with stable redox state and promotes strong electronic coupling between the metal and the organic ligands. [20][21][22][23] This organometallic moiety turned out to be an attractive platform in order to achieve redox event [19][20]24 and to introduce grafting groups for building functional redox active surfaces. [25][26][27] Before forming the SAMs, the organometallic complexes were thoroughly characterized in solution and the redox and optical properties (including NIR emissions) of the heterobimetallic compounds were found to be retained after the introduction of the anchoring hexylthiol chain.…”