5‐(2‐Thienyl)tetrazolates as Ligands for Ru<sup>II</sup>–Polypyridyl Complexes: Synthesis, Electrochemistry and Photophysical Properties

Stagni, Stefano; Palazzi, Antonio; Brulatti, Pierpaolo; Salmi, Mauro; Muzzioli, Sara; Zacchini, Stefano; Marcaccio, Massimo; Paolucci, Francesco

doi:10.1002/ejic.201000405

Cited by 12 publications

(12 citation statements)

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“…Intermediates 1, 3, and 8 were synthesized following literature procedures. 51,52 Intermediates 2, 4, and 9, although reported in the literature, [53][54][55] were synthesized following modified routes. For the synthesis of PH targets, intermediates 12 and 14 were synthesized following literature procedures, with modifications.…”

Section: Resultsmentioning

confidence: 99%

Structure–Assembly–Property Relationships of Simple Ditopic Hydrogen-Bonding-Capable π-Conjugated Oligomers

Weldeab

Kornman

et al. 2021

Organic Materials

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A series of simple ditopic hydrogen bonding capable molecules functionalized with 2,4-diamino-1,3,5-triazine (DAT), barbiturate (B), and phthalhydrazide (PH) on both termini of a 2,2′-bithiophene linker were designed and synthesized. The intrinsic electronic structures of the ditopic DAT, PH, and B molecules were investigated with ground-state DFT calculations. Their solution absorbance was investigated with UV-vis, where it was found that increasing size of R group substituent on the bithiophene linker resulted in a general blue-shift in solution absorbance maximum. The solid-state optical properties of ditopic DAT and B thin films were evaluated by UV-vis, and it was found that the solid-state absorbance was red-shifted with respect to solution absorbance in all cases. The three DAT molecules were vacuum thermal deposited onto Au(111) substrates and the morphologies were examined using STM. (DAT-T)2 was observed to organize into six-membered rosettes on the surface, whereas (DAT-TMe)2 formed linear assemblies before and after thermal annealing. For (DAT-Toct)2 , an irregular arrangement was observed, while (B-TMe)2 showed several co-existent assembly patterns. The work presented here provides fundamental molecular-supramolecular relationships useful for semiconductive materials design based on ditopic hydrogen bonding capable building blocks.

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Section: Resultsmentioning

confidence: 99%

Structure–Assembly–Property Relationships of Simple Ditopic Hydrogen-Bonding-Capable π-Conjugated Oligomers

Weldeab

Kornman

et al. 2021

Organic Materials

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“…The Ru(PTA) complexes emit in the yellow-red region of the electromagnetic spectrum at room temperature, with the maximum photoluminescence (PL) wavelength (λ max ) in the 560–615 nm region. In all Ru(PTA) cases, the PL emission originates from 3 MLCT states involving the charge transfer from polypyridyl and tetrazole ligands to t 2g of the ruthenium center, as demonstrated by the shape and position of the emission band in the 550–700 nm region, and by the lifetime values, which are in the expected range for Ru–tetrazole complexes, e.g., 100–500 ns in degassed acetonitrile . The PL emission quantum yields are calculated by comparison with the known [Ru(bpy) 3 ] 2+ one (Φ std = 9.5%) in acetonitrile solution at room temperature with an excitation wavelength of 405 nm (see Figure S1).…”

Section: Resultsmentioning

confidence: 99%

“… a Complex 7 is obtained from neutral RuTz [Ru(phen) 2 (TzBA) 2 ] at 20 or 16 V . fwhm = full width at half-maximum. b At 20 V. c At 16 V. …”

Section: Resultsmentioning

confidence: 99%

“…In all Ru(PTA) cases, the PL emission originates from 3 MLCT states involving the charge transfer from polypyridyl and tetrazole ligands to t 2g of the ruthenium center, as demonstrated by the shape and position of the emission band in the 550−700 nm region, and by the lifetime values, which are in the expected range for Ru−tetrazole complexes, e.g., 100−500 ns in degassed acetonitrile. 37 The PL emission quantum yields are calculated by comparison with the known [Ru(bpy) 3 ] 2+ one (Φ std = 9.5%) in acetonitrile solution at room temperature with an excitation wavelength of 405 nm (see Figure S1). 38,39 The absorption spectra of the Ru(PTA) complexes, measured in acetonitrile solution at room temperature, are shown in Figure 3, and their data are summarized in Table 1.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Ruthenium Tetrazole Based Electroluminescent Device: Key Role of Counter Ions for Light Emission Properties

et al. 2016

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Light-emitting electrochemical cells (LECs), thanks to their simple device structure and the tunable emission wavelength of the light-emitting layer, are emerging as a class of electrochemical device candidate for the development of next-generation solid-state lighting. The possibility to tune ondemand the energy levels of Ruthenium(II) polypyridyl complexes, makes them ideal candidates as light-emitting layer. However, the optimization of the latter is not trivial and several issues, such as charge injection and electron and hole transport, have still to be solved to enhance the LEC performances. Here, we demonstrate how the exploitation of small counter anion (BF 4 -) enhances the light emission performance of ruthenium tetrazole complexes in light-emitting diodes. In comparison with neutral ruthenium tetrazole complexes, cationic Ru tetrazole ones, containing BF 4 ion, show a reduction of turn-on voltage from7 to 5 V, at high luminous efficiency (1.49 cd/A) and applied voltage of 12 V, and a twofold improvement of the luminance. Moreover, complexes containing BF 4 counter ion show better stability of luminance over time than other complexes without counter ion.sandwiched between two metallic layers ( Figure 1). In fact, the figures of merit (FoM) of OLEDs are influenced by different factors, including electrodes material, emitter, hole-and electron-transport layer, and polymer host, as well as transport layers thickness, purity of emitter and contamination. 5The most important parameters to be tuned for the optimization of OLED performances are the balance in terms of density and mobility of charge carriers, and the matching of energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of light emitting layer, hole and electron transport layers. 6,7 The progress of OLED technology, mainly driven by the search for high performance OLED material, was initiated in 1972, when Tokel and Bard exploited the Ru(bpy) 3 2+ complex as emitter. 8 After many years of development following the Bard's pivotal work, 8 J. K. Lee et al., demonstrated that Ru polypyridyl complexes show luminance as high as 100 cd/m 2 at low turn-on voltage, i.e., in the 2.5-3.5V range. 9 Light-emitting electrochemical cells (LECs) are another class of electroluminescent devices candidate for the development of next-generation SSLs. 10 A LEC consists of an ionic luminescent material, sandwiched between two electrodes, i.e., anode usually made of indium tin oxide (ITO)and cathode based on metals such as aluminum or gold in an ionic environment. 11 The luminescent material is either an ionic transition-metal complex (iTMC) or conjugated light-emitting polymer. 12,13 Lightemitting electrochemical cells are characterized by: (1) turn on voltage close to the optical band gap of the light emitting layer (LEL); (2) weakly dependence of the FoM on the emitter thickness; (3)symmetrical current-voltage characteristic; (4) external quantum efficiency (EQE) independent on the electrode work-function. 14,...

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“…Diaz et al [38] reported a strong absorption at 350 nm for terthiophene and, if these absorptions are compared, it is possible to see how the inclusion of terthiophene into the structure of a ruthenium complex may be generating the overlapping absorption spectrum of terthiophene and, in turn, a shift for both 1 and 2, the latter being higher in energy, probably due to the presence of methyl groups on complex 2 and, therefore, the formation of a complex bearing a more positive charge. This may justify the slight shift of one band relative to the other in the near UV spectrum [25,39]. The molar absorptivity (e) recorded for complexes 1 and 2 was 1.1 Â 10 4 and 1.7 Â 10 4 molÁL À1 Ácm À1 , respectively.…”

Section: Characterization By Uv-vis Spectroscopymentioning

confidence: 94%

Synthesis and electrochemical characterization of new ruthenium–terthiophene complexes

et al. 2015

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5‐(2‐Thienyl)tetrazolates as Ligands for Ru^II–Polypyridyl Complexes: Synthesis, Electrochemistry and Photophysical Properties

Cited by 12 publications

References 60 publications

Structure–Assembly–Property Relationships of Simple Ditopic Hydrogen-Bonding-Capable π-Conjugated Oligomers

Structure–Assembly–Property Relationships of Simple Ditopic Hydrogen-Bonding-Capable π-Conjugated Oligomers

Ruthenium Tetrazole Based Electroluminescent Device: Key Role of Counter Ions for Light Emission Properties

Synthesis and electrochemical characterization of new ruthenium–terthiophene complexes

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5‐(2‐Thienyl)tetrazolates as Ligands for RuII–Polypyridyl Complexes: Synthesis, Electrochemistry and Photophysical Properties

Cited by 12 publications

References 60 publications

Structure–Assembly–Property Relationships of Simple Ditopic Hydrogen-Bonding-Capable π-Conjugated Oligomers

Structure–Assembly–Property Relationships of Simple Ditopic Hydrogen-Bonding-Capable π-Conjugated Oligomers

Ruthenium Tetrazole Based Electroluminescent Device: Key Role of Counter Ions for Light Emission Properties

Synthesis and electrochemical characterization of new ruthenium–terthiophene complexes

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5‐(2‐Thienyl)tetrazolates as Ligands for Ru^II–Polypyridyl Complexes: Synthesis, Electrochemistry and Photophysical Properties