Tetrathiafulvalene–Polychlorotriphenylmethyl Dyads: Influence of Bridge and Open‐Shell Characteristics on Linear and Nonlinear Optical Properties

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Single-component conductors based on neutral organic radicals have received a lot of attention due to the possibility that the unpaired electron can serve as a charge carrier without the need of a previous doping process. Although most of these systems are based on delocalized planar radicals, we present here a nonplanar and spin localized radical based on a tetrathiafulvalene (TTF) moiety, linked to a perchlorotriphenylmethyl (PTM) radical by a conjugated bridge, which exhibits a semiconducting behavior upon application of high pressure. The synthesis, electronic properties, and crystal structure of this neutral radical TTF-Ph-PTM derivative (1) are reported and implications of its crystalline structure on its electrical properties are discussed. On the other hand, the non-radical derivative (2), which is isostructural with the radical 1, shows an insulating behavior at all measured pressures. The different electronic structures of these two isostructural systems have a direct influence on the conducting properties, as demonstrated by band structure DFT calculations.

Section: Methodsmentioning

confidence: 99%

Role of the Open‐Shell Character on the Pressure‐Induced Conductivity of an Organic Donor–Acceptor Radical Dyad

Souto

Gullo

Cui

et al. 2018

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“…[59] TTF derivatives have also been exploited for the design of supramolecular switches, sensors, [60] rectifiers, [61] and for nonlinear optics (NLO). [62] In view of the unique electronic properties and functional versatility of the TTF electroactiveu nit, its derivatives have been extensively explored as molecular building blocks for constructing electroactiveM OFs and COFs. [63] The main reason for incorporating TTFu nits into frameworks lies in the fact that TTFs can form p-p stacking columns with relativelys hort S•••S interactions, providing efficient charge-transport pathways.…”

Section: Tetrathiafulvalene(ttf)mentioning

confidence: 99%

Electroactive Organic Building Blocks for the Chemical Design of Functional Porous Frameworks (MOFs and COFs) in Electronics

Souto

Strutyński

Melle‐Franco

et al. 2020

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Electroactive organic molecules have received a lot of attention in the field of electronics because of their fascinating electronic properties, easy functionalization and potential low cost towards their implementation in electronic devices. In recent years, electroactive organic molecules have also emerged as promising building blocks for the design and construction of crystalline porous frameworks such as metal–organic frameworks (MOFs) and covalent‐organic frameworks (COFs) for applications in electronics. Such porous materials present certain additional advantages such as, for example, an immense structural and functional versatility, combination of porosity with multiple electronic properties and the possibility of tuning their physical properties by post‐synthetic modifications. In this Review, we summarize the main electroactive organic building blocks used in the past few years for the design and construction of functional porous materials (MOFs and COFs) for electronics with special emphasis on their electronic structure and function relationships. The different building blocks have been classified based on the electronic nature and main function of the resulting porous frameworks. The design and synthesis of novel electroactive organic molecules is encouraged towards the construction of functional porous frameworks exhibiting new functions and applications in electronics.

“…[1,2] Amongt he organic emittersw ith unpaired electrons, particular attention has been devoted to triphenylmethyl( trityl) radicalbased chlorinatedd erivatives. [3] In additiont ot heir remarkable persistence and chemical stability,t hey also present:( i) high valueso fl uminescence quantum yield (LQY) at long wavelengths, especially when dispersed in rigid hosts; [4][5][6] and (ii)non-linear opticala ctivity, [7] such as high two-photon absorption( 2PA) cross-sections. [8] Even thought hey were first reporteds everald ecades ago, they are, indeed, far from an extinct research field.I nt his sense, different synthetic approachesa re currently being pursued aimingt oo btain higher photostabilitya nd LQY values or red-shifted emissions.…”

Section: Introductionmentioning

confidence: 99%

An Enantiopure Propeller‐Like Trityl‐Brominated Radical: Bringing Together a High Racemization Barrier and an Efficient Circularly Polarized Luminescent Magnetic Emitter

Mayorga‐Burrezo

Jiménez

Blasi

et al. 2020

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A new persistent organic free radical has been synthetized with Br atoms occupying the ortho‐ and para‐positions of a trityl core. After the isolation of its two propeller‐like atropisomers, Plus (P) and minus (M), their absolute configurations were assigned by a combination of theoretical and experimental data. Remarkably, no hints of racemization were observed up to 60 °C for more than two hours, due to the higher steric hindrance imposed by the bulky Br atoms. Therefore, when compared to its chlorinated homologue (t1/2=18 s at 60 °C), an outstanding stability against racemization was achieved. A circularly polarized luminescence (CPL) response of both enantiomers was detected. This free radical shows a satisfactory luminescent dissymmetry factor (|glum(592 nm)|≈0.7×10−3) despite its pure organic nature and low luminescence quantum yield (LQY). Improved organic magnetic CPL emitters derived from the reported structure can be envisaged thanks to the wide possibilities that Br atoms at para‐positions offer for further functionalization.