Facile Preparation Methods for Triarylmethyl‐Type Stable Luminescent Diradicals and Higher Multiradicals

High-performance luminescent radicals featuring donor-radical (D-R) charge-transfer (CT) excited states have emerged as promising candidates for optoelectronic applications. However, prior studies have predominantly focused on through-bond charge-transfer (TBCT) mechanisms. In this work, we report the first examples of luminescent radicals based on TTM (tris(2,4,6-trichlorophenyl)methyl radical) with through-space charge-transfer (TSCT) excited states, represented by TPA-FR-TTM and CZP-FR-TTM. Spatial separation and non-bonding character between the donor and radical units minimizes electron-vibrational coupling and effectively suppresses non-radiative decay. As a result, CZP-FR-TTM exhibits an outstanding photoluminescence quantum efficiency (PLQE) of 64.3% and an ultralow non-radiative decay rate of 1.3×106 s-1, among the lowest ever reported for luminescent radicals. Furthermore, the reduced electronic coupling leads to non-Aufbau electronic structures, enhancing radical stability. These findings establish TSCT as a powerful design strategy for high-performance and stable luminescent radicals, opening new avenues for open-shell optoelectronic materials.

The influence of the intermolecular magnetic dipole-dipole interaction on the free induction decay (FID) as well as on the Hahn-echo of proton spins in polymer melts is investigated. It is shown that for isotropic models of polymer dynamics, when polymer segment displacements do not correlate with an initial chain conformation, the influence of the intermolecular magnetic dipole-dipole interactions to the FID and Hahn echo is increasing more rapidly with evolution time than the corresponding influence of the intramolecular magnetic dipole-dipole interactions. On the other hand, the situation is inverted for the tube-reptation model: here the influence of the intramolecular magnetic dipole-dipole interactions to the FID and Hahn echo is increasing faster with time than the contribution from intermolecular interactions. A simple expression for the relative mean squared displacements of polymer segments from different chains is obtained from the intermolecular contribution to the FID. A modified Anderson-Weiss approximation, taking into account flip-flop transitions between different spins, is proposed and on that basis, the conditions for extracting the relative intermolecular mean squared displacements of polymer segments from the intermolecular contribution to the proton FID is established. Systematic investigations of intermolecular contributions, which were considered as an unimportant factor for FID and Hahn echo in polymer systems by most previous works, actually cannot be considered as negligible and opens a new dimension for obtaining information about polymer dynamics in the millisecond regime.

Proton spin dynamics in polymer melts: New perspectives for experimental investigations of polymer dynamics

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModerately strong intramolecular magnetic exchange interaction between the copper(II) ions separated by 11.25 .ANG. in [L2Cu2(OH2)2(.eta.-terephthalato)](ClO4)2 (L = 1,4,7-trimethyl-1,4,7-triazacyclononane)Phalguni. Chaudhuri, Karen. Oder, Karl. Wieghardt, Stefan. Gehring, Wolfgang. Haase, Bernhard. Nuber, and Johannes. WeissCite this: J. Am. Chem. Soc. 1988, 110, 11, 3657–3658Publication Date (Print):May 1, 1988Publication History Published online1 May 2002Published inissue 1 May 1988https://doi.org/10.1021/ja00219a051RIGHTS & PERMISSIONSArticle Views350Altmetric-Citations130LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

High electron mobilities and suppressed π–π aggregation for perylenediimides can be achieved at the same time by properly tailoring the dimerization and alkylation modes to enhance both intermolecular and intramolecular electronic interactions.

Intramolecular electronic interactions were investigated in five series of 12-, 10-, and 6-vertex closo-boranes and hydrocarbons (benzene, acetylene, bicyclo[2.2.2]octane, and cubane) substituted with triple-bonded groups Y≡Z (C≡CR, C≡N, C≡O, and N≡N). Structural data (single crystal X-ray crystallography), spectroscopic properties (UV, IR, and NMR), chemical behavior (dediazoniation reactions), and electronic structure calculations (hybridization and π bond order) are all in agreement that the degree of electronic conjugation between the cluster and the Y≡Z substituent is lowest for the 12-vertex closo-borane and highest for the 6-vertex analog.

Synthesis, characterization and some properties of S-bridged polynuclear complexes composed of fac(S)-[Cr(aet) 3] units (aet=2-aminoethanethiolate (aet). Crystal structures of [Ni{Cr(aet) 3} 2] 2+ and [{Cr(aet) 3} 4Zn 4O] 6+

Intramolecular Magnetic Interaction Controlled by Redox Reaction of Tetraphenylethylene-Based Spin System

A family of pyridine, 2,2′-bipyridine, 1,10-phenanthroline, 3,6-bis(2-pyridyl)pyridazine ligands bearing two nitronyl nitroxide radicals was synthesized and characterized. The pincer ligands having two radicals in ortho positions relative to the nitrogen atoms form stable nickel(II) and copper(II) complexes. The pyridine based 2,6- and 2,5-biradicals crystallized in the monoclinic space group P2 1 /c while the bipyridine 5,5′-biradical crystallized in the monoclinic space group P2 1 /n (radical is 4,4,5,5-tetramethylimidazoline 3-oxide 1-oxyl). The highest dihedral angle between the radicals and the pyridine ring is found in the pyridine 2,6-biradical (ca. 47°), followed by the 2,5-biradical (ca. 38°) and then by the bipyridine 6,6′- (ca. 27°) and 5,5′-biradicals (ca. 24°). All the biradicals exhibit similar EPR spectra, in solution and at room temperature, with nine lines due to coupling of the unpaired electrons with four equivalent nitrogen nuclei (hyperfine coupling constant A N 3.3-3.8 G). In some cases these nine lines are reduced to five lines (A N 7.5-7.6 G) at low temperature due to a weakening of the spin-spin exchange interaction J which becomes smaller than the isotropic coupling constant. The χT product for all radicals measured at 300 K lies in the range of 0.70-0.77 emu K mol –1 . For the pyridine 2,6- and 2,5-biradicals, magneto-structural correlation reveals through bond ferro- and antiferro-magnetic interaction (J/k B =+9.4 and –39 K, respectively) due to a favorable spin polarization effect. These intramolecular interactions persist when the radicals are dispersed in a polystyrene matrix. For the bipyridine 6,6′- and 5,5′-biradicals, the experimental data were fitted using a Bleaney-Bowers expression for two interacting spins and the values of J/k B =–24 to –1.9 K, respectively, are representative of an antiferromagnetic through-space interaction between two neighboring radicals. No intramolecular magnetic interactions were found in the oligopyridine based compounds. In all of these biradicals, both nitroxides are oxidized at the same potential (ca. +0.45 V vs. Ag/Ag + ) by a two-electron quasi-reversible process to the nitrosonium dication and irreversibly reduced to the dianions between –1.80 and –1.40 V. In the Cu(II) and Ni(II) complexes of the bipyridine-6,6′- and phenanthroline-2,9-biradical reduction of the nitroxides to the hydroxylamine anions is quasi-reversible and is facilitated by ca. 1.20 V versus the

In this paper, a D–A polymer (PIB) containing carbazole as the donor group in the main chain and benzimidazole benzisoindolinone as the acceptor group was synthesized by Suzuki reaction. The Suzuki reaction, also known as the Suzuki coupling reaction, is a relatively new organic coupling reaction in which aryl or alkenyl boronic acids or boronic acid esters react with chlorine, bromine, iodoaromatic hydrocarbons or alkenes under the catalysis of zerovalent palladium complexes cross-coupling. A series of devices were fabricated by a spin-coating approach, and the devices all exhibited ternary resistance switching storage behavior. Among them, the composite device with the mass fraction of SnO2 NPs of 5 wt% has the best storage performance, with a threshold voltage of −0.4 V and a switching current ratio of 1:101.5:104.5. At the same time, the current of the device remained stable after a 3-h test. Furthermore, after 103 cycles, the current has no obvious attenuation. The device has good stability and continuity. Moreover, the conduction mechanism is further revealed. Inorganic nanoparticle composite devices have splendid memory performances and exhibit underlying application significance in storing data.

The reduction of hexachloroacetone in CH2Cl2 or CHCl3 was much enhanced in the presence of 1,6-bis(1-benzyl-1,4-dihydronicotinamido)hexane owing to an intramolecular electronic interaction of charge transfer character.

Chemical oxidation of a TTF-based NiII complex with I2 produces the corresponding radical cation salt1, [Ni2Cl2(L)2](I3)2(I5)2(I2)(H2O)2(C4H8O)3, (L=4,5-bis(2-pyridylmethylsulfanyl)-4′,5′-ethylenedithiotetrathiafulvalene). The results of magnetic susceptibility measurements show the occurrence of intramolecular magnetic exchange interactions in1. The lack of close S…S contacts, confirmed by crystal structure analysis, results in an insulating behavior.

A theory has been constructed for the ${\mathrm{CH}}_{3}$F molecule's nuclear-spin conversion induced by the intramolecular magnetic dipole-dipole nuclei interaction. It is shown that for $^{13}\mathrm{CH}_{3}$F molecules this mechanism leads to the rate of spin conversion (0.71\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}2}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$/Torr, which is approximately one-half of the experimentally registered value.

Spin-lattice relaxation times of proton and fluorine nuclei in solid CHF3 were measured by the pulsed magnetic resonance technique between 7 and 116K. In 1H resonance, non-exponential recovery of magnetization was clearly observed. T1 data as well as magnetization recoveries were interpreted in terms of intramolecular magnetic dipole interactions between like spins and also between unlike spins, which are modulated by the isotropic reorientation of a whole molecule. A calculation of the temperature dependence of T1 was made by using an activation energy of 17kJ mol−1 and a pre-exponential factor of 1.0×10−16 s for the motion, yielding results in agreement with the present experimental results.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIntramolecular Magnetic and Electrostatic Interactions in Stepwise Stacked Trinuclear Paramagnetic Metallocenes with the Metal Sequences FeM'Fe and NiM'Ni (M' = V, Cr, Co, Ni) and CoCrCoHermann Atzkern, Pierre Bergerat, Holger Beruda, Monika Fritz, Johann Hiermeier, Peter Hudeczek, Olivier Kahn, Frank H. Koehler, Martin Paul, and Bernd WeberCite this: J. Am. Chem. Soc. 1995, 117, 3, 997–1011Publication Date (Print):January 1, 1995Publication History Published online1 May 2002Published inissue 1 January 1995https://pubs.acs.org/doi/10.1021/ja00108a016https://doi.org/10.1021/ja00108a016research-articleACS PublicationsRequest reuse permissionsArticle Views260Altmetric-Citations33LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (2)»Supporting Information Supporting Information Get e-Alerts