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Vasiļevska A, Slanina T. Structure-property-function relationships of stabilized and persistent C- and N-based triaryl radicals. Chem Commun (Camb) 2024; 60:252-264. [PMID: 38086625 DOI: 10.1039/d3cc05706b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Structurally similar C- and N-based triaryl radicals are among the most commonly used structural motifs in stable, open-shell, organic molecules. The application of such species is associated with their stability, properties and structural design. This study summarizes the basic stabilization and persistence principles of C- and N-based triaryl radicals and highlights recent advances in design strategies of radicals tailored for specific applications.
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Affiliation(s)
- Anna Vasiļevska
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 166 10 Prague 6, Czech Republic.
- Department of Organic Chemistry, Charles University, 128 00 Prague 2, Czech Republic
| | - Tomáš Slanina
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 166 10 Prague 6, Czech Republic.
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2
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Heuer A, Coste SC, Singh G, Mercado BQ, Mayer JM. A Guide to Tris(4-Substituted)-triphenylmethyl Radicals. J Org Chem 2023; 88:9893-9901. [PMID: 37403939 PMCID: PMC10367072 DOI: 10.1021/acs.joc.3c00658] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Indexed: 07/06/2023]
Abstract
Triphenylmethyl (trityl, Ph3C•) radicals have been considered the prototypical carbon-centered radical since their discovery in 1900. Tris(4-substituted)-trityls [(4-R-Ph)3C•] have since been used in many ways due to their stability, persistence, and spectroscopic activity. Despite their widespread use, existing synthetic routes toward tris(4-substituted)-trityl radicals are not reproducible and often lead to impure materials. We report here robust syntheses of six electronically varied (4-RPh)3C•, where R = NMe2, OCH3, tBu, Ph, Cl, and CF3. The characterization reported for the radicals and related compounds includes five X-ray crystal structures, electrochemical potentials, and optical spectra. Each radical is best accessed using a stepwise approach from the trityl halide, (RPh)3CCl or (RPh)3CBr, by controllably removing the halide with subsequent 1e- reduction of the trityl cation, (RPh)3C+. These syntheses afford consistently crystalline trityl radicals of high purity for further studies.
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Affiliation(s)
| | | | - Gurjot Singh
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Brandon Q. Mercado
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - James M. Mayer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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3
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Stekovic D, Bag P, Shankhari P, Fokwa BPT, Itkis ME. Effect of Substitution on the Hysteretic Phase Transition in a Bistable Phenalenyl-Based Neutral Radical Molecular Conductor. Chemistry 2019; 25:4166-4174. [PMID: 30588670 DOI: 10.1002/chem.201805816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Indexed: 11/10/2022]
Abstract
The ability to tune the physical properties of bistable organic functional materials by means of chemistry can facilitate their development for molecular electronic switching components. The butylamine-containing biphenalenyl boron neutral radical, [Bu]2 B, crystalline compound has recently attracted significant attention by displaying a hysteretic phase transition accompanied by simultaneous bistability in magnetic, electrical, and optical properties close to room temperature. In this report, substitutional doping was applied to [Bu]2 B by crystallizing solid solutions of bistable [Bu]2 B and its non-radical-containing counterpart [Bu]2 Be. With increasing doping degree, the hysteretic phase transition is gradually suppressed in terms of reducing the height, but conserves the width of the hysteresis loop as observed through magnetic susceptibility and electrical conductivity measurements. At the critical doping level of about 6 %, the abrupt transformation of the crystal structure to that of the pure [Bu]2 Be crystal packing was observed, accompanied by a complete collapse of the hysteresis loop. Further study of the structure-properties relationships of bistable neutral radical conductors based on the [Bu]2 B host can be conducted utilizing a variety of biphenalenyl-based molecular conductors.
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Affiliation(s)
- Dejan Stekovic
- Department of Chemistry, University of California, Riverside, Riverside, CA, 92521, USA.,Center for Nanoscale Science and Engineering, University of California, Riverside, Riverside, CA, 92521, USA
| | - Pradip Bag
- Department of Chemistry, University of California, Riverside, Riverside, CA, 92521, USA.,Center for Nanoscale Science and Engineering, University of California, Riverside, Riverside, CA, 92521, USA
| | - Pritam Shankhari
- Department of Chemistry, University of California, Riverside, Riverside, CA, 92521, USA
| | - Boniface P T Fokwa
- Department of Chemistry, University of California, Riverside, Riverside, CA, 92521, USA.,Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA, 92521, USA
| | - Mikhail E Itkis
- Department of Chemistry, University of California, Riverside, Riverside, CA, 92521, USA.,Center for Nanoscale Science and Engineering, University of California, Riverside, Riverside, CA, 92521, USA.,Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA, 92521, USA
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Chen L, Lim KJC, Babra TS, Taylor JO, PiŽl M, Evans R, Chippindale AM, Hartl F, Colquhoun HM, Greenland BW. A macrocyclic receptor containing two viologen species connected by conjugated terphenyl groups. Org Biomol Chem 2018; 16:5006-5015. [PMID: 29946600 DOI: 10.1039/c8ob00919h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A macrocyclic receptor molecule containing two viologen species connected by conjugated terphenyl groups has been designed and synthesised. The single-crystal X-ray structure shows that the two viologen residues have a transannular NN separation of ca. 7.4 Å. Thus, the internal cavity dimensions are suitable for the inclusion of π-electron-rich species. The macrocycle is redox active, and can accept electrons from suitable donor species including triethylamine, resulting in a dramatic colour change from pale yellow to dark green as a consequence of the formation of a paramagnetic bis(radical cationic) species. Cyclic voltammetry shows that the macrocycle can undergo two sequential and reversible reduction processes (E1/2 = -0.65 and -0.97 V vs. Fc/Fc+). DFT and TD-DFT studies accurately replicate the structure of the tetracationic macrocycle and the electronic absorption spectra of the three major redox states of the system. These calculations also showed that during electrochemical reduction, the unpaired electron density of the radical cations remained relatively localised within the heterocyclic rings. The ability of the macrocycle to form supramolecular complexes was confirmed by the formation of a pseudorotaxane with a guest molecule containing a π-electron-rich 1,5-dihydroxynaphthalene derivative. Threading and dethreading of the pseudorotaxane was fast on the NMR timescale, and the complex exhibited an association constant of 150 M-1 (±30 M-1) as calculated from 1H NMR titration studies.
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Affiliation(s)
- Long Chen
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, UK.
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Abstract
Organic field-effect transistors hold the promise of enabling low-cost and flexible electronics. Following its success in organic optoelectronics, the organic doping technology is also used increasingly in organic field-effect transistors. Doping not only increases device performance, but it also provides a way to fine-control the transistor behavior, to develop new transistor concepts, and even improve the stability of organic transistors. This Review summarizes the latest progress made in the understanding of the doping technology and its application to organic transistors. It presents the most successful doping models and an overview of the wide variety of materials used as dopants. Further, the influence of doping on charge transport in the most relevant polycrystalline organic semiconductors is reviewed, and a concise overview on the influence of doping on transistor behavior and performance is given. In particular, recent progress in the understanding of contact doping and channel doping is summarized.
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Affiliation(s)
- Björn Lüssem
- Department of Physics, Kent State University , Kent, Ohio 44242, United States
| | - Chang-Min Keum
- Department of Physics, Kent State University , Kent, Ohio 44242, United States
| | - Daniel Kasemann
- Institut für Angewandte Photophysik, TU Dresden , 01069 Dresden, Germany
| | - Ben Naab
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Zhenan Bao
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Karl Leo
- Institut für Angewandte Photophysik, TU Dresden , 01069 Dresden, Germany
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Stoler E, Warner JC. Non-Covalent Derivatives: Cocrystals and Eutectics. Molecules 2015; 20:14833-48. [PMID: 26287141 PMCID: PMC6332263 DOI: 10.3390/molecules200814833] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/05/2015] [Indexed: 12/31/2022] Open
Abstract
Non-covalent derivatives (NCDs) are formed by incorporating one (or more) coformer molecule(s) into the matrix of a parent molecule via non-covalent forces. These forces can include ionic forces, Van der Waals forces, hydrogen bonding, lipophilic-lipophilic interactions and pi-pi interactions. NCDs, in both cocrystal and eutectic forms, possess properties that are unique to their supramolecular matrix. These properties include critical product performance factors such as solubility, stability and bioavailability. NCDs have been used to tailor materials for a variety of applications and have the potential to be used in an even broader range of materials and processes. NCDs can be prepared using little or no solvent and none of the reagents typical to synthetic modifications. Thus, NCDs represent a powerfully versatile, environmentally-friendly and cost-effective opportunity.
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Affiliation(s)
- Emily Stoler
- The Warner Babcock Institute for Green Chemistry, 100 Research Drive, Wilmington, MA 01887, USA.
| | - John C Warner
- The Warner Babcock Institute for Green Chemistry, 100 Research Drive, Wilmington, MA 01887, USA.
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Mebrouk K, Kaddour W, Auban-Senzier P, Pasquier C, Jeannin O, Camerel F, Fourmigué M. Molecular Alloys of Neutral Gold/Nickel Dithiolene Complexes in Single-Component Semiconductors. Inorg Chem 2015; 54:7454-60. [PMID: 26186238 DOI: 10.1021/acs.inorgchem.5b01059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Control of band filling or doping of molecular (semi)conductors can be performed by substitutional insertion of molecules with a similar shape but a different electron count, with one more or one less electron. This strategy has been explored here within the semiconducting, single-component, radical gold dithiolene complex [AuOC4] bearing para-butoxyphenyl substituents. Alloying with the corresponding neutral nickel dithiolene complex [NiOC4] lacking one electron afforded a complete isostructural series [NiOC4]1-x[AuOC4]x, spanning the whole composition range from x = 0 to x = 1 by 0.1 increments, further characterized by X-ray diffraction and EDX analyses. Magnetic susceptibility data confirm the antiferromagnetic interactions between neighboring radical gold dithiolene complexes. The electrical conductivity increases exponentially with the x gold fraction, while the activation energy remains constant in the more conducting, gold-rich samples. This behavior is tentatively assigned to the tunneling barriers of variable width (with x) but of constant height, separating more conducting gold-rich segments. Comparison of redox potentials for the 1e(-) oxidation and reduction of both [NiOC4] and [AuOC4] dithiolene complexes indicates that the [NiOC4] nickel complex does not act as a dopant for the radical [AuOC4] complex.
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Affiliation(s)
- Kenny Mebrouk
- †Institut des Sciences Chimiques de Rennes (ISCR), Université Rennes 1, UMR CNRS 6226, Campus de Beaulieu, 35042 Rennes, France
| | - Wafa Kaddour
- ‡Laboratoire de Physique des Solides (LPS), Université Paris-Sud, UMR CNRS 8502, Bât. 510, 91405 Orsay, France
| | - Pascale Auban-Senzier
- ‡Laboratoire de Physique des Solides (LPS), Université Paris-Sud, UMR CNRS 8502, Bât. 510, 91405 Orsay, France
| | - Claude Pasquier
- ‡Laboratoire de Physique des Solides (LPS), Université Paris-Sud, UMR CNRS 8502, Bât. 510, 91405 Orsay, France
| | - Olivier Jeannin
- †Institut des Sciences Chimiques de Rennes (ISCR), Université Rennes 1, UMR CNRS 6226, Campus de Beaulieu, 35042 Rennes, France
| | - Franck Camerel
- †Institut des Sciences Chimiques de Rennes (ISCR), Université Rennes 1, UMR CNRS 6226, Campus de Beaulieu, 35042 Rennes, France
| | - Marc Fourmigué
- †Institut des Sciences Chimiques de Rennes (ISCR), Université Rennes 1, UMR CNRS 6226, Campus de Beaulieu, 35042 Rennes, France
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Bag P, Itkis ME, Stekovic D, Pal SK, Tham FS, Haddon RC. Band Structure Engineering by Substitutional Doping in Solid-State Solutions of [5-Me-PLY(O,O)]2B(1-x)Be(x) Radical Crystals. J Am Chem Soc 2015; 137:10000-8. [PMID: 26235568 DOI: 10.1021/jacs.5b06145] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the substitutional doping of solid-state spiro-bis(5-methyl-1,9-oxido-phenalenyl)boron radical ([2]2B) by co-crystallization of this radical with the corresponding spiro-bis(5-methyl-1,9-oxido-phenalenyl)beryllium compound ([2]2Be). The pure compounds crystallize in different space groups ([2]2B, P1̅, Z = 2; [2]2Be, P2₁/c, Z = 4) with distinct packing arrangements, yet we are able to isolate crystals of composition [2]2B(1-x)Be(x), where x = 0-0.59. The phase transition from the P1̅ to the P2₁/c space group occurs at x = 0.1, but the conductivities of the solid solutions are enhanced and the activation energies reduced for values of x = 0-0.25. The molecular packing is driven by the relative concentration of the spin-bearing ([2]2B) and spin-free ([2]2Be) molecules in the crystals, and the extended Hückel theory band structures show that the progressive incorporation of spin-free [2]2Be in the lattice of the [2]2B radical (overall bandwidth, W = 1.4 eV, in the pure compound) leads to very strong narrowing of the bandwidth, which reaches a minimum at [2]2Be (W = 0.3 eV). The results provide a graphic picture of the structural transformations undergone by the lattice, and at certain compositions we are able to identify distinct structures for the [2]2B and [2]2Be molecules in a single crystalline phase.
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Pal SK, Bag P, Itkis ME, Tham FS, Haddon RC. Enhanced Electrical Conductivity in a Substitutionally Doped Spiro-bis(phenalenyl)boron Radical Molecular Solid. J Am Chem Soc 2014; 136:14738-41. [DOI: 10.1021/ja508903z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Sushanta K. Pal
- Department of Chemistry and Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
| | - Pradip Bag
- Department of Chemistry and Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
| | - Mikhail E. Itkis
- Department of Chemistry and Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
| | - Fook S. Tham
- Department of Chemistry and Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
| | - Robert C. Haddon
- Department of Chemistry and Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
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Liu Y, Lin J, Chen M, Song L. Investigation on the interaction of the toxicant, gentian violet, with bovine hemoglobin. Food Chem Toxicol 2013; 58:264-72. [DOI: 10.1016/j.fct.2013.04.048] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 04/26/2013] [Accepted: 04/28/2013] [Indexed: 11/30/2022]
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Huang L, Liu C, Qiao X, Tian H, Geng Y, Yan D. Tunable field-effect mobility utilizing mixed crystals of organic molecules. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:3455-3459. [PMID: 21721054 DOI: 10.1002/adma.201101353] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 05/20/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Lizhen Huang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, PR China
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