Fluorenylporphyrins functionalized by electrochromic ruthenium units as redox-triggered fluorescence switches

Abstract

The electrofluorochromic behaviour of two ruthenium-appended porphyrin dyads has been investigated. Differences in response according to the nature of the interposed aryl linker are rationalised with the aid of electrochemistry and TD-DFT calculations.

Platinum(II) Complexes of Tridentate ‐Coordinating Ligands Based on Imides, Amides, and Hydrazides: Synthesis and Luminescence Properties

“…Neither of these bimetallic complexes shows detectable luminescence at room temperature. For the Ru−Pt complex, this observation is in line with other studies where low‐energy absorbing RuL 4 X 2 units efficiently quench the excited states of covalently linked higher‐energy emitters [30] . Whilst many Ir(ppy) 2 ( )‐based complexes are brightly emissive, those with ancillary ligands having low‐energy excited states associated with them are often not so.…”

Nonlinear optical properties of meso-Tetra(fluorenyl)porphyrins peripherally functionalized with one to four ruthenium alkynyl substituents

“…Cyclic voltammetry (CV) studies of the porphyrins 5a-5d and 6 were carried out in dichloromethane, with [NBu 4 ][PF 6 ] (0.1 M) as supporting electrolyte (Table 1). In line with published data for 5a 24 and the related molecules 1b and 12, 17 the organometallic compounds 5b-5d show the classic ringcentered oxidations and reduction of the H 2 TFP free-base porphyrin, as modelled by 6, plus a Ru-centered oxidation at ca. 0.42 V, at nearly the same potential as that measured for the 2-fluorenylalkynyl Ru(II) complex 13 36 and close to that for the Ru-centered oxidation of 12 24 (Table 1).…”

“…In line with published data for 5a 24 and the related molecules 1b and 12, 17 the organometallic compounds 5b-5d show the classic ringcentered oxidations and reduction of the H 2 TFP free-base porphyrin, as modelled by 6, plus a Ru-centered oxidation at ca. 0.42 V, at nearly the same potential as that measured for the 2-fluorenylalkynyl Ru(II) complex 13 36 and close to that for the Ru-centered oxidation of 12 24 (Table 1). Upon progressing from 5a to 5d, the intensity of this redox process increases relative to the porphyrin-based processes, consistent with the increasing number of ruthenium atoms in the molecule (Figure S11, ESI).…”

“…Because the butyl groups in 5b-5d do not contribute significantly to the important frontier orbitals, they were replaced with hydrogens (affording the models 5b′-5d′), which reduces the computational expense for these large molecules during geometry optimizations (this replacement was previously carried out successfully with 5a/5a′). 24 Under these conditions, the Ru…Ru and Cl…Cl distances in 5b are estimated to be 32.8 and 37.8 Å, respectively, whereas the Ru…Ru through-space distances between the two Ru centers in 5c and 5d are in the region 22-26 Å.…”

“…Similar NMR signatures have previously been observed for the related organometallic compounds 12 17 and 13 36 (Figure 4). 24 .…”