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Title: Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

Journal Article · · Beilstein Journal of Organic Chemistry
DOI:https://doi.org/10.3762/bjoc.19.121· OSTI ID:2204445

1,3-Dimethyl-2,3-dihydrobenzo[ d ]imidazoles, 1H , and 1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[ d ]imidazoles, 1 2 , are of interest as n-dopants for organic electron-transport materials. Salts of 2-(4-(dimethylamino)phenyl)-4,7-dimethoxy-, 2-cyclohexyl-4,7-dimethoxy-, and 2-(5-(dimethylamino)thiophen-2-yl)benzo[ d ]imidazolium ( 1g–i + , respectively) have been synthesized and reduced with NaBH 4 to 1gH , 1hH , and 1iH , and with Na:Hg to 1g 2 and 1h 2 . Their electrochemistry and reactivity were compared to those derived from 2-(4-(dimethylamino)phenyl)- ( 1b + ) and 2-cyclohexylbenzo[ d ]imidazolium ( 1e + ) salts. E ( 1 + / 1 ) values for 2-aryl species are less reducing than for 2-alkyl analogues, i.e., the radicals are stabilized more by aryl groups than the cations, while 4,7-dimethoxy substitution leads to more reducing E ( 1 + / 1 ) values, as well as cathodic shifts in E ( 1 2 •+ / 1 2 ) and E ( 1H •+ / 1H ) values. Both the use of 3,4-dimethoxy and 2-aryl substituents accelerates the reaction of the 1H species with PC 61 BM. Because 2-aryl groups stabilize radicals, 1b 2 and 1g 2 exhibit weaker bonds than 1e 2 and 1h 2 and thus react with 6,13-bis(triisopropylsilylethynyl)pentacene ( VII ) via a “cleavage-first” pathway, while 1e 2 and 1h 2 react only via “electron-transfer-first”. 1h 2 exhibits the most cathodic E ( 1 2 •+ / 1 2 ) value of the dimers considered here and, therefore, reacts more rapidly than any of the other dimers with VII via “electron-transfer-first”. Crystal structures show rather long central C–C bonds for 1b 2 (1.5899(11) and 1.6194(8) Å) and 1h 2 (1.6299(13) Å).

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Laboratory Directed Research and Development (LDRD) Program; National Science Foundation (NSF); United States-India Educational Foundation (USIEF)
Grant/Contract Number:
LDRD Program; AC36-08GO28308; DMR-1807797/2216857; DMR-2122108; 2266/FNPDR/2017
OSTI ID:
2204445
Alternate ID(s):
OSTI ID: 2204446; OSTI ID: 2222411
Report Number(s):
NREL/JA-5900-86656; BJOCBH
Journal Information:
Beilstein Journal of Organic Chemistry, Journal Name: Beilstein Journal of Organic Chemistry Vol. 19; ISSN 1860-5397
Publisher:
Beilstein InstitutCopyright Statement
Country of Publication:
Germany
Language:
English

References (57)

Electron transport in a sequentially doped naphthalene diimide polymer journal January 2020
Dimers of Nineteen-Electron Sandwich Compounds: An Electrochemical Study of the Kinetics of Their Formation journal July 2015
A survey of Hammett substituent constants and resonance and field parameters journal March 1991
Benzimidazolines Convert Sulfur Dioxide to Bisulfate at Room Temperature and Atmospheric Pressure Utilizing Aerial Oxygen journal June 2017
Organic thermoelectric materials for energy harvesting and temperature control journal August 2016
Role of Polymer Structure on the Conductivity of N-Doped Polymers journal March 2016
n-Dopants Based on Dimers of Benzimidazoline Radicals: Structures and Mechanism of Redox Reactions journal June 2015
Molecular parameters responsible for thermally activated transport in doped organic semiconductors journal January 2019
Reductively Induced Dimerization of the Ligated Benzene in [Mn(η6-C6H6)(CO)3]+:  Formation of the Initial C−C Bond by Anion/Cation Addition journal January 1996
Direct detection of molecular hydrogen upon p- and n-doping of organic semiconductors with complex oxidants or reductants journal January 2023
Revisiting doping mechanisms of n-type organic materials with N-DMBI for thermoelectric applications: Photo-activation, thermal activation, and air stability journal May 2021
Crystal and molecular structure of the photoreductive dimer of 5,6-dihydro-3,5,5-trimethyl-1,4-oxazin-2-one journal September 1977
Doping mechanisms of N-DMBI-H for organic thermoelectrics: hydrogen removal vs. hydride transfer journal January 2020
Electricity-driven recycling of ester plastics using one-electron electro-organocatalysis journal August 2023
Unexpected Enhancement of Molecular n-Doping Efficiency in Polymer Thin Films by a Degradation Product journal January 2022
Dimers of Nineteen-Electron Sandwich Compounds: Crystal and Electronic Structures, and Comparison of Reducing Strengths journal October 2014
Reactivity of an air-stable dihydrobenzoimidazole n-dopant with organic semiconductor molecules journal April 2021
10,10'-Dimethyl-9,10,9',10'-tetrahydro-9,9'-biacridinyl journal July 1977
On the mechanism of the reduction of .alpha.-haloketones by 1,3-dimethyl-2-phenylbenzimidazoline. Reduction by a SET (single electron transfer)-hydrogen atom abstraction chain mechanism journal August 1989
Organometallic and Organic Dimers: Moderately Air-Stable, Yet Highly Reducing, n-Dopants journal January 2022
Electrochemical generation of triplet states journal December 1984
Mono- and dinuclear molybdenum complexes with sterically demanding cycloheptatrienyl ligands journal January 2004
Poly(phenylene) and m -Terphenyl as Powerful Protecting Groups for the Preparation of Stable Organic Hydroxides journal March 2016
Impact of Singly Occupied Molecular Orbital Energy on the n-Doping Efficiency of Benzimidazole Derivatives journal September 2019
Benzimidazoles as Metal-Free and Recyclable Hydrides for CO 2 Reduction to Formate journal November 2018
Structure of 2-(2,3-dihydro-1,3-dimethylbenzimidazol-2-yl)phenol journal August 1987
Doped Organic Transistors journal October 2016
Aromatic Amines:  A Comparison of Electron-Donor Strengths journal September 2005
Thermolabile Kohlenwasserstoffe, XX. Synthese, Struktur und Spannung symmetrischer Tetraalkyldiarylethane journal September 1983
Synthetic applications of trialkylaluminum reagents: alkylation and reduction of transition-metal-complexed .pi.-hydrocarbon ligands journal February 1989
Synthesis, structures, and reactivity of isomers of [RuCp*(1,4-(Me2N)2C6H4)]2 journal January 2021
Efficient Solution-Processed n-Type Small-Molecule Thermoelectric Materials Achieved by Precisely Regulating Energy Level of Organic Dopants journal August 2017
Kinetics and mechanism of oxidation of N,N′-dimethyl-9,9′-biacridanyl by some π acceptors and a one-electron oxidant journal February 1985
Doped Charge-Transporting Layers in Planar Perovskite Solar Cells journal June 2018
Use of a 1 H -Benzoimidazole Derivative as an n -Type Dopant and To Enable Air-Stable Solution-Processed n -Channel Organic Thin-Film Transistors journal July 2010
Understanding the Effects of Molecular Dopant on n‐Type Organic Thermoelectric Properties journal May 2019
Cyclodehydrogenation of N-benzylidene-o-phenylenediamines to 2,2'-diaryl-1,1'-bibenzimidazoles with dioxygen catalyzed by copper(I) chloride in pyridine. A structural study of 2,2'-bis(3,4,5-trimethoxyphenyl)-1,1'-bibenzimidazole journal January 1986
Effective Solution- and Vacuum-Processed n-Doping by Dimers of Benzimidazoline Radicals journal April 2014
Conformational Control of Ultrafast Molecular Rotor Property: Tuning Viscosity Sensing Efficiency by Twist Angle Variation journal September 2017
n-Doping of Organic Electronic Materials using Air-Stable Organometallics journal November 2011
Reductive Dimerization and Thermal Rearrangement of Biphenylene Coordinated to Tricarbonylmanganese journal December 1998
A dendritic oligoarylamine-substituted benzimidazole derivative as a useful n-type dopant journal January 2018
Highly Efficient Organic Devices Based on Electrically Doped Transport Layers journal April 2007
Reactions of Electron-Rich Olefins with Proton-Active Compounds journal December 1997
Spectral Signatures of a Negative Polaron in a Doped Polymer Semiconductor: Energy Levels and Hubbard U Interactions journal June 2023
Transition metal-catalysed molecular n-doping of organic semiconductors journal November 2021
Structure moléculaire de la bis(diméthyl-2,3 benzothiazoline) journal May 1973
The First Crystalline Alkali Metal Salt of a Benzenoid Radical Anion without a Stabilizing Substituent and of a Related Dimer:  X-ray Structures of the Toluene Radical Anion and of the Benzene Radical Anion Dimer Potassium-Crown Ether Salts journal December 2000
Mechanistic Study on the Solution-Phase n-Doping of 1,3-Dimethyl-2-aryl-2,3-dihydro-1 H -benzoimidazole Derivatives journal September 2013
Hydride, Hydrogen Atom, Proton, and Electron Transfer Driving Forces of Various Five-Membered Heterocyclic Organic Hydrides and Their Reaction Intermediates in Acetonitrile journal February 2008
Synthesis, characterization, and X-ray analysis of new N,N′-disubstituted-1,4-diazepanes journal October 2012
Organometallic hydride-transfer agents as reductants for organic semiconductor molecules journal April 2019
[2 + 2] Cross Coupling of Benzene and Tropylium Ligands in Reductively Activated Piano Stool Complexes of Mn, Cr, and W journal November 2002
n-Doping of Organic Electronic Materials Using Air-Stable Organometallics: A Mechanistic Study of Reduction by Dimeric Sandwich Compounds journal October 2012
Formation kinetics of an amino carboxy type merostabilized free radical journal March 1980
Two photochromic iodoargentate hybrids with adjustable photoresponsive mechanism journal January 2018
Carbene Complexes of Rhodium and Iridium from Tripodal N-Heterocyclic Carbene Ligands:  Synthesis and Catalytic Properties journal February 2004