Guest–host interactions between dichroic dyes and anisotropic hosts

Pålsson, Lars‐Olof; Vaughan, Helen L.; Smith, A. B.; Szablewski, Marek; Cross, Graham H.; Roberts, Tony; Masutani, Akira; Yasuda, Akio; Beeby, Andrew; Bloor, D.

doi:10.1016/j.jlumin.2005.03.017

Cited by 13 publications

(14 citation statements)

References 26 publications

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“…Diaminodicyanoquinodimethanes (DADQs) with formulas 4-(R 1 R 2 C)-1-[(NC) 2 C]-C 6 H 4 such as 1 – 3 (Chart ) are conveniently synthesized from reactions of 7,7,8,8-tetracyanoquinodimethane (TCNQ, 1,4-[(NC) 2 C] 2 -C 6 H 4 ) with amines. − Such compounds with varied functional groups can be easily modified into molecules designed for specific interactions with the surrounding media. DADQs have been investigated mainly for applications including nonlinear optics , but also for electroluminescent devices, dye doped liquid crystal displays, through to environmentally sensitive optical probes. − …”

Section: Introductionmentioning

confidence: 99%

“…Although the parent disubstituted dicyanoquinodimethane, in which two nitrile moieties are substituted with NH 2 groups, (Chart , structure 1 ), was first reported in 1962, its optical properties and NMR spectroscopic data are presented here for the first time. The optical and electronic properties of functionalized DADQ adducts 2 and 3 , (Chart ) mainly in the condensed phase, have been investigated in our laboratory. − ,− Studies of such TCNQ substitution products have demonstrated their potential in, for instance, sensing applications, as the local environment strongly modulates the excited state and thereby the fluorescence. ,,− The motivation for considering DADQ adducts for these applications arises from the ease, by which DADQ can be modified through variations of functional groups. The prospect of design and definition of adducts with specific covalent or electrostatic interaction to almost any material is an attractive feature in itself worthy of exploration.…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast Dynamics and Computational Studies on Diaminodicyanoquinodimethanes (DADQs)

et al. 2014

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Three diaminodicyanoquinodimethanes, 4-(R(1)R(2)C)-1-[(NC)2C]-C6H4 (R(1),R(2) = H2N, 1; R(1) = 3,5-Me2-4-OCH4H6N-, R(2) = H2N, 2; R(1) = 3,5-Me2-4-OCH4H6N-, R(2) = 4-Me-C5H9N, 3), were investigated using carbon-13 NMR, steady-state, and ultrafast transient absorption and ultrafast fluorescence spectroscopies to unravel the unusual characteristics of this class of chromophores. Computed (GIAO)B3LYP/6-31G* data for the zwitterions 1-3 using necessary solvation (PCM) models were shown to be in excellent agreement with observed structural and carbon-13 NMR data. The ground-state geometries of 1-3 contain a cationic methine group R(1)R(2)C- twisted from the C6H4 ring and an anionic methine group (NC)2C- in plane with the C6H4 ring in solution and solid state. The (13)C chemical shifts of the peak corresponding to the methine carbon at the (NC)2C- group of 1-3 are observed at 32.5-34.7 ppm, which are some 55 ppm upfield compared with the (13)C chemical shift for the methine carbons in TCNQ, 1,4-[(NC)2C]2-C6H4. The decay of the excited state in diaminodicyanoquinodimethanes is fast and dominated by nonradiative processes on the picosecond time scale, which depends on the viscosity of the medium. The dynamics of the excited-state decay is therefore limited by conformational changes through an intramolecular twisting motion. This twisting motion is hindered by friction, which, in turn, also depends on the functional group size of the system. The dominant nonradiative pathways after excitation are due to twisted excited-state conformers according to TD-DFT computations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultrafast Dynamics and Computational Studies on Diaminodicyanoquinodimethanes (DADQs)

et al. 2014

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“…One example is a nematic liquid crystal doped with chiral molecules [19] that induce the well-known macroscopic cholesteric ordering [19]. Moreover, nowadays an intensive investigation of thermodynamics [20][21][22][23] and physical chemistry [24] of a nematic liquid crystal doped with a great variety of different solute molecules and micelles [25] is under way. A very special example comprises dye-doped nematic liquid crystals: under the action Mathematically, the similarity between the director-mediated and electrostatic interaction lies in the massless nature of the both theories and the Coulomb-like behavior of the Green functions which derives from it.…”

Section: Introductionmentioning

confidence: 99%

Colloidal nematostatics

Pergamenshchik¹,

Uzunova²

2010

Condens. Matter Phys.

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We give a review of the theory of large distance colloidal interaction via the nematic director field. The new area of nematic colloidal systems (or nematic emulsions) has been guided by the analogy between the colloidal nematostatics and electrostatics. The elastic charge density representation of the colloidal nematostatics [V.M. Pergamenshchik, V.O. Uzunova, Eur. Phys. J. E, 2007, 23, 161; Phys. Rev. E, 2007, 76, 011707] develops this analogy at the level of charge density and Coulomb interaction. The analogy is shown to lie in common mathematics based on the solutions of Laplace equation. However, the 3d colloidal nematostatics substantially differs from electrostatics both in its mathematical structure and physical implications. The elastic charge is a vector fully determined by the torque exerted upon colloid, the role of Gauss' theorem is played by conservation of the torque components. Elastic multipoles consist of two tensors (dyads). Formulas for the elastic multipoles, the Coulomb-like, dipole-dipole, and quadrupole-quadrupole pair interaction potentials are derived and illustrated by particular examples. Based on the tensorial structure, we list possible types of elastic dipoles and quadrupoles. An elastic dipole is characterized by its isotropic strength, anisotropy, chirality, and its longitudinal component. An elastic quadrupole can be uniaxial and biaxial. Relation between the multipole type and its symmetry is discussed, sketches of some types of multipoles are given. Using the mirror image method of electrostatics as a guiding idea, we develop the mirror image method in nematostatics for arbitrary director tilt at the wall. The method is applied to the charge-wall and dipole-wall interaction. : 61.30.Dk, 61.30.Jf, 82.70Dd, 01.55.+b 1. The intrigue of nematic colloids: similarity to the electrostatics, its origin, and how it is developed in this article. Key words: nematic colloid, electrostatic analogy, elastic charge and multipoles PACSIsotropic liquids doped with colloidal particles or just colloids are the classical many-particle systems which, over many decades , have been studied using the methods of molecular and statistical physics, electrolyte theory, physical chemistry, and so on [1,2]. Colloidal particles can be of different physical and chemical origin, but in all cases their interaction via isotropic liquid is of a short range [3], even if the colloids are charged since their electric field is rapidly screened by a numerous couterions. The nematic colloids, that have become widely known just over the last 15 years, are fundamentally different: interaction of colloids mediated by distortions of the nematic director is of a long range. That is why nematic colloids are usually compared not with standard isotropic colloids, but with a system of electric charges. The similarity with the electrostatics has always been a powerful, if not dominating, factor of the development of the field of nematic colloids. But what is the origin of this similarity?The interaction of particles in a ne...

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“…Although, luminophores should be, in principle, capable of emitting electromagnetic radiation independently of their physical state, most of the practical applications require luminophores to be synthesized as solid-films, aggregates, or crystals [ 5 , 6 ]. For example, solid-state organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs) [ 3 , 7 ] are considered essential components in optoelectronic or sensing applications for ecosystem monitoring and biomedical research [ 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

A Theoretical and Experimental Study on the Potential Luminescent and Biological Activities of Diaminodicyanoquinodimethane Derivatives

Jiménez

Caetano

Santiago

et al. 2021

IJMS

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Recently, several studies have demonstrated that diaminodicyanoquinone derivatives (DADQs) could present interesting fluorescence properties. Furthermore, some DADQs under the solid state are capable of showing quantum yields that can reach values of 90%. Besides, the diaminodiacyanoquinone core represents a versatile building block propense either to modification or integration into different systems to obtain and provide them unique photophysical features. Herein, we carried out a theoretical study on the fluorescence properties of three different diaminodicyanoquinodimethane systems. Therefore, time-dependent density functional theory (TD-DFT) was used to obtain the values associated with the dipole moments, oscillator strengths, and the conformational energies between the ground and the first excited states of each molecule. The results suggest that only two of the three studied systems possess significant luminescent properties. In a further stage, the theoretical insights were confirmed by means of experimental measurements, which not only retrieved the photoluminescence of the DADQs, but also suggest a preliminary and promising antibacterial activity of these systems.

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Guest–host interactions between dichroic dyes and anisotropic hosts

Cited by 13 publications

References 26 publications

Ultrafast Dynamics and Computational Studies on Diaminodicyanoquinodimethanes (DADQs)

Ultrafast Dynamics and Computational Studies on Diaminodicyanoquinodimethanes (DADQs)

Colloidal nematostatics

A Theoretical and Experimental Study on the Potential Luminescent and Biological Activities of Diaminodicyanoquinodimethane Derivatives

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