One-dimensionality and neutral-to-ionic transition of some mixed-stack charge-transfer complexes

2002 ◽  
Vol 12 (9) ◽  
pp. 357-360
Author(s):  
M. Buron ◽  
E. Collet ◽  
M. H. Lemée-Cailleau ◽  
H. Cailleau ◽  
T. Luty ◽  
...  
Keyword(s):  
Phase Transition ◽  
Charge Transfer ◽  
Charge Transfer Complexes ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
Giant Dielectric ◽  
Ionic Transition ◽  
The One ◽  
Ct Complexes ◽  
Dimerization Process

Mixed-stack charge-transfer (CT) complexes undergoing the neutral-ionic (N-I) phase transition are molecular materials formed of stacks where electron donor (D) and acceptor (A) molecules regularly alternate. In the N phase, the CT is low and molecules are situated on inversion centers, while in the I phase, the increase of CT is accompanied by a lattice distortion (dimerization process and symmetry breaking). The one-dimensional (1D) architecture triggers the chain multistability by stabilizing lattice-relaxed (LR)-CT excitations ...D° A° D° A° $(D^+A^-)(D^+A^-)(D^+A^-)$ Do A" D° A° D°... These 1D nano-scale objects are at the heart of the equilibrium N-I phase transition and govern the fascinating physical properties such as giant dielectric response or photo-induced phase transformations. In this contribution, the 1D character of these critical excitations will be demonstrated by direct observation using high resolution X-Ray diffraction.

scholarly journals Charge Transfer Complexes of Ketotifen with 2,3-Dichloro-5,6-dicyano-p-benzoquinone and 7,7,8,8-Tetracyanoquodimethane: Spectroscopic Characterization Studies

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2039
Author(s):  
Gamal A. E. Mostafa ◽  
Ahmed Bakheit ◽  
Najla AlMasoud ◽  
Haitham AlRabiah
Keyword(s):  
Charge Transfer ◽  
Spectroscopic Characterization ◽  
Molar Ratio ◽  
Charge Transfer Complexes ◽  
Physical Parameters ◽  
Spectrophotometric Methods ◽  
Theoretical Approaches ◽  
The Stability ◽  
Ct Complexes

The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job’s method, which was compatible with the results obtained using the Benesi–Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.

Neutron-Scattering Study of the Structural Phase Transition in the One-Dimensional ConductorK2Pt(CN)4Br0.3·3D2O

1974 ◽  
Vol 32 (15) ◽  
pp. 836-839 ◽  
Author(s):  
B. Renker ◽  
L. Pintschovius ◽  
W. Gläser ◽  
H. Rietschel ◽  
R. Comès ◽  
...  
Keyword(s):  
Phase Transition ◽  
Neutron Scattering ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
One Dimensional ◽  
Scattering Study ◽  
Neutron Scattering Study ◽  
The One

Polysulfonylamine, CXXV [1]. Neue Komplexe von Disulfonylaminen mit Kronenethern - im voraus entworfen oder zufällig entdeckt / Polysulfonylamines, CXXV [1]. New Complexes of Disulfonylam ines with Crown Ethers - Preconceived or Discovered by Serendipity

2000 ◽  
Vol 55 (3-4) ◽  
pp. 299-316 ◽  
Author(s):  
Dagmar Henschel ◽  
Karna Wijaya ◽  
Oliver Moers ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Hydrogen Bonds ◽  
X Ray Diffraction ◽  
Ladder Structure ◽  
Triclinic Space Group ◽  
One Dimensional ◽  
X Ray ◽  
Bonding System ◽  
Supramolecular Aggregate ◽  
Guest Species ◽  
The One

Abstract In a study aim ed at the „deconstruction“ of the supramolecular aggregate 3(18C6) · 2HN( SO2Me)2 (1,18C6 = 18-crown-6), which is known to display a ladder structure with two isotactic [18C6 - Me SO2N(H)SO2Me···)∞ polymers forming the uprights and symmetrically N - H···O bonded 18C6 rings providing the rungs, the following crystalline complexes were isolated and (except for 2b) characterized by low-temperature X-ray diffraction: 18C6-ClN (SO2Me)2 (2a, triclinic, space group P1̅, Z = 2), 18C6-PhN (SO2Me)2 (2b), 18C6 -MeN(SO2Me)2 (3, monoclinic, P21/c, Z = 8), Bz18C6-HN(SO2Me)2 (4, Bz18C6 = benzo-18-crown-6, monoclinic, P21/n, Z = 4), 18C6-2 MeN (SO2Me)2 (5, triclinic, P1̅, Z = 1), 18C6-Me2SO- HN( SO2Me) (SO2Ph) (13, triclinic, P1̅, Z = 2), and 18C6-H2OMe2SO·2HN(SO2Me)2 (14, triclinic, P1̅, Z = 2). Each of the one-dimensional polymers 2a (syndiotactic), 3 (disyndiotactic) and 4 (isotactic) mimics a single upright of 1; in contrast to 1 and 2a, where the intra-catemer connectivity solely relies on S - Me ··· crow n and crown ··· O = S hydrogen bonds, this bonding system is reinforced in 3 by N -Me ··· crown and in 4 by N - H ··· crown hydrogen bonds. Complex 5 is monomeric and matches a fragment formally extruded from the catemer 3; moreover, 3 and 5 represent a rare case of two structurally characterized 18C6 complexes containing the same uncharged guest species in distinct molecular ratios. The surprising structure of the quaternary adduct 14 exhibits an [18C6 ··· MeSO2N(H)SO2Me ··· ]∞ chain, which can be regarded both as an isolated, though unmodified upright from the ladder 1 and, being syndiotactic, as a stereochemical analogue of 2a; the potentially rung-forming *NH functions in the chain are blocked by hydrogenbonded side chains of the type * N - H ··· water ··· sulfoxide ··· H - N (SO2Me)2. The ternary complex 13 consists of chains [18C6 ··· Me2SO ··· H - N (SO2Ph)SO2Me···]∞ and is not closely related to the other structures

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