Homeotropic alignment through charge-transfer-induced columnar mesophase formation in an unsymmetrically substituted triphenylene derivative

2010 ◽  
Vol 82 (11) ◽  
pp. 1993-2003 ◽  
Author(s):  
Juanjuan Li ◽  
Zhiqun He ◽  
Huan Zhao ◽  
Hemant Gopee ◽  
Xiangfei Kong ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complex ◽  
X Ray Diffraction ◽  
Hexagonal Symmetry ◽  
X Ray ◽  
Mesophase Formation ◽  
Homeotropic Orientation ◽  
Donor Acceptor ◽  
Homeotropic Alignment ◽  
Spectroscopy Optical

An unsymmetrically substituted triphenylene, with two adjacent chloroethoxyethyl lateral flexible chains, was synthesized and characterized. Although this compound showed no mesomorphic behavior, it formed a donor–acceptor charge-transfer complex with 2,4,7-trinitrofluorenone (TNF). The resulting 1:1 complex has been investigated using UV–vis and IR spectroscopy, optical microscopy, thermal analysis, and X-ray diffraction. A columnar mesophase with hexagonal symmetry was found. More interestingly, this charge-transfer complex can be easily aligned on a glass surface in a homeotropic orientation, which is stable at room temperature (RT) and over a wide temperature range.

Radikal-markierte Metallocene (M = Fe, Co). Metallocenylen verbrückte Bis(3-imidazolin-l-oxyle) / Radical Labeled M etallocenes (M = Fe, Co). M etallocenylene B ridged B is(3-im idazolin-l-oxyls)

2001 ◽  
Vol 56 (7) ◽  
pp. 563-570
Author(s):  
Harald Dialer ◽  
Kurt Polbom ◽  
Wolfgang Beck
Keyword(s):  
Charge Transfer ◽  
Radical Anion ◽  
Room Temperature ◽  
Lithium Salt ◽  
Charge Transfer Complex ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Charge ◽  
Different Sources

Abstract Radical Labeled M etallocenes (M = Fe, Co). M etallocenylene B ridged B is(3-im idazolin-l-oxyls) The addition of the lithium salt of the silyl protected hydroxylamine 1-hydroxy-2,2,4,5,5-pentamethyl-3-imidazoline (1) to 6 ,6 -dimethylfulvalene gives the lithium cyclopentadienide 2 from which the 1,1 '-substituted ferrocene and cobaltocinium derivatives 3 and 4 were obtained. Deprotection and oxidation of 3 and 4 afford the metallocenylene bridged bis(3-imidazolin-l-oxyls) 5 and 7. The ferrocene bridged diradical 5 forms with DDQ a charge transfer complex 8 . The complexes 5 and 7 were characterized by X-ray diffraction and by their EPR spectra. Magnetic measurements show at room temperature two independent spins for 5 and 7 and four unpaired electrons for 8 , the latter arising from three different sources [Fe(III) low spin d5, two nitroxides and DDQ- radical anion].

scholarly journals Intermolecular interactions and charge transfer in the 2:1 tetrathiafulvalene bromanil complex, (TTF)2-BA

2011 ◽  
Vol 67 (3) ◽  
pp. 244-249 ◽  
Author(s):  
Pilar García-Orduña ◽  
Slimane Dahaoui ◽  
Claude Lecomte
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Charge Transfer ◽  
Room Temperature ◽  
Charge Transfer Complex ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Donor And Acceptor ◽  
A Charge

The crystal structure of the 2:1 charge-transfer complex of tetrathiafulvalene [2,2′-bis(1,3-dithiolylidene)] and bromanil (tetrabromo-1,4-benzoquinone) [(TTF)2-BA, (C6H4S4)2–C6Br4O2] has been determined by X-ray diffraction at room temperature, 100 and 25 K. No structural phase transition occurs in the temperature range studied. The crystal is made of TTF–BA–TTF sandwich trimers. A charge-transfer estimation between donor and acceptor (0.2 e) molecules is proposed in comparison to the molecular geometries of TTF–BA and TTF and BA isolated molecules. Displacement parameters of the molecules have been modeled with the TLS formalism.

Donor/Akzeptor-Komplexe aus 1,3,5-Tris(dimethylamino)benzol und 1,2,3,4,5,6-Hexacyanobenzol/Donor/Acceptor Complexes from 1,3,5-Tris(dimethylamino)benzene with 1,2,3,4,5,6-Hexacyanobenzene

1989 ◽  
Vol 44 (3) ◽  
pp. 327-332 ◽  
Author(s):  
◽  
R. Niebl ◽  
G. Renner ◽  
D. von der Ruhr ◽  
A. K. Kilic ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Single Crystal ◽  
Room Temperature ◽  
Charge Transfer Complex ◽  
Acetonitrile Solution ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Crystallization Method ◽  
Donor Acceptor

Reaction of 1,3,5-tris(dimethylamino)benzene (TDMAB ) with 1,2,3,4,5,6-hexacyanobenzene (HCNB) in acetonitrile solution gives - depending on the crystallization method - two different products: dark needles of a 1:1 (1) and black compact crystals with a metallic lustre of a 2:1 (2) charge transfer complex. 2 crystallizes in the triclinic space group P1 , Z = 1, a = 9.9489(22), b = 10.0555(21), c = 10.1418(20) Å , α = 115.006(16)°, β = 102.820(17)°, γ = 93.647(18)°, V = 882.3 Å3, dc = 1.2 g cm-3, measured at room temperature, R = 0.053 for 2670 observed independent reflections and 301 parameters. The structure contains isolated “trimers” of one HCNB acceptor which is “pancaked” by two TDMAB neighbors. The arrangement of these trimers in the lattice results in alternating HCNB and TDMAB sheets. The solid is diamagnetic.1 could not be obtained in crystals suitable for a single crystal X-ray investigation. Its paramagnetism which is observed immediately after preparation disappears in the course of several days.

A quinoxaline-fused tetrathiafulvalene derivative and its semiconducting charge-transfer salt: synthesis, crystal structures and physical properties

2014 ◽  
Vol 38 (5) ◽  
pp. 2052-2057 ◽  
Author(s):  
Yan Geng ◽  
Christoph Fiolka ◽  
Karl Krämer ◽  
Jürg Hauser ◽  
Vladimir Laukhin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Charge Transfer ◽  
Physical Properties ◽  
Single Crystal ◽  
Crystal Structures ◽  
Single Crystal Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Donor Acceptor ◽  
Tetrathiafulvalene Derivative

A quinoxaline-fused tetrathiafulvalene (TTF) derivative 1 has been synthesized to form a compact and planar π-conjugated donor–acceptor (D–π–A) ensemble, and its single crystal structure has been determined by X-ray diffraction.

Effect of conjugated system extension on structural features and electron-density distribution in charge–transfer difluoroborates

2021 ◽  
Vol 77 (12) ◽  
Author(s):  
Borys Ośmiałowski ◽  
Błażej Dziuk ◽  
Krzysztof Ejsmont ◽  
Lilianna Chęcińska ◽  
Liliana Dobrzańska
Keyword(s):  
Charge Transfer ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Dimethylamino Group ◽  
X Ray ◽  
Transfer Path ◽  
Donor Acceptor ◽  
Related Donor ◽  
System Extension ◽  
Bearing Rings

A comparative structural study of two related donor–acceptor pyridine-based BF2 complexes, namely, 3-(dimethylamino)-1,1-difluoro-1H-pyrido[1,2-c][1,3,5,2]oxadiazaborinin-9-ium-1-uide, C8H10BF2N3O (1), and 3-{(1E,3E)-4-[4-(dimethylamino)phenyl]buta-1,3-dien-1-yl}-1,1-difluoro-1H-pyrido[1,2-c][1,3,5,2]oxadiazaborinin-9-ium-1-uide, C18H18BF2N3O (2), containing a dimethylamino group and either the shortest (in 1) or the longest (in 2) charge-transfer path known until now in this family of compounds, is presented. Single-crystal X-ray diffraction analysis supported by computational investigations shed more light on these systems, indicating, among other aspects, the predominance of C—H...F contacts in 1, the formation of antiparallel dimers held together by π–π interactions in both compounds, and the involvement of fused BF2-bearing rings in the charge-transfer process.

scholarly journals Isolation and X-ray Crystal Structure of an Electrogenerated TEMPO–N3 Charge-Transfer Complex

2021 ◽  
Author(s):  
Hosea M. Nelson ◽  
Juno C. Siu ◽  
Ambarneil Saha ◽  
Duilio Cascio ◽  
Samantha N. MacMillan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Charge Transfer ◽  
Charge Transfer Complex ◽  
X Ray

Synthese und Kristallstrukturen einiger Tetramethylstibonium-Hydrogendicarboxylate / Synthesis and Crystal Structures of Some Tetramethylstibonium Hydrogendicarboxylates

1982 ◽  
Vol 37 (11) ◽  
pp. 1393-1401 ◽  
Author(s):  
Beatrix Milewski-Mahrla ◽  
Hubert Schmidbaur
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Spectroscopic Data ◽  
Molar Ratio ◽  
Ionic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylate Oxygen ◽  
Donor Acceptor ◽  
New Compounds

Reactions of pentamethylantimony (CH3)5Sb with carboxylic acids in the molar ratio 1:2 afford one equivalent of methane and essentially quantitative yields of crystalline tetramothylstibonium hydrogendicarboxylates. Six new compounds of this series have been synthesized using benzoic, o-phthalic, salicylic, 4-ethoxy-salicylic, oxalic, and malic acid, and characterized by analytical and spectroscopic data. An ionic structure with strong hydrogen bonds in the anionic components is proposed.The crystal structures of the hydrogen-dibenzoato (1), hydrogen-ortho-plithalato (2) and 4-ethoxy-hydrogen-salicylate (3) were determined by single crystal X-ray diffraction. The compounds can be described as having ionic lattices with some donor-acceptor inter­actions between the stibonium centers and the carboxylate oxygen atoms. The anions are characterized by strong hydrogen bonds O...H...O. Thus, the (CH3)4Sb-tetrahedron in 1 is distorted by two benzoate oxygon atoms (at 304(2) and 340(2) pin). The cation in 2 is largely undistorted and the anion has a hydrogenphthalate hydrogen bond of d(O...H...O) = 232 pm. The cation-anion contact in 3 is as short as d(Sb-O) = 289 pm rendering the Sb atom pentacoordinate.

scholarly journals Isolation and X-ray Crystal Structure of an Electrogenerated TEMPO–N3 Charge-Transfer Complex

2020 ◽  
Author(s):  
Hosea Nelson ◽  
Juno Siu ◽  
Ambarniel Saha ◽  
Duilio Cascio ◽  
Song-Bai Wu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Charge Transfer ◽  
Theoretical Analysis ◽  
Charge Transfer Complex ◽  
Reactive Intermediates ◽  
Structural Elucidation ◽  
Catalytic Reactions ◽  
X Ray ◽  
Increasing Demand ◽  
Computational Predictions

Recent advances in radical-based catalytic reactions have created an increasing demand for the understanding of their mechanistic underpinnings. Structural elucidation of transient reactive intermediates via diffraction techniques, though rarely possible, is one of the most decisive ways to support such mechanistic hypotheses. Here we present the isolation, structural elucidation, and theoretical analysis of an electrochemically generated and catalytically relevant charge-transfer species formed between the azidyl radical and (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO). The unusual bent N–N–N angle and the pancake bonding between these two fragments highlight the weak bonding interactions present in this complex. This X-ray structure validates computational predictions as well as mechanistic proposals of TEMPO-mediated radical azidation reactions.

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