0000000000205635

AUTHOR

Joshua E. Barker

0000-0001-6139-8858

showing 22 related works from this author

Molecule Isomerism Modulates the Diradical Properties of Stable Singlet Diradicaloids

2019

Inclusion of quinoidal cores in conjugated hydrocarbons is a common strategy to modulate the properties of diradicaloids formed by aromaticity recovery within the quinoidal unit. Here we describe an alternative approach of tuning of diradical properties in indenoindenodibenzothiophenes upon anti → syn isomerism of the benzothiophene motif. This alters the relationship of the S atom with the radical center from linear to cross conjugation yet retains the same 2,6-naphtho conjugation pattern of the rearomatized core. We conduct a full comparison between the anti and syn derivatives based on structural, spectroscopic, theoretical, and magnetic measurements, showing that these systems are stabl…

ChemistryDiradicalBenzothiopheneAromaticityGeneral ChemistryConjugated system010402 general chemistryPhotochemistry01 natural sciencesBiochemistryCatalysis0104 chemical scienceschemistry.chemical_compoundColloid and Surface ChemistryMoleculeSinglet stateCross-conjugationTriplet stateJournal of the American Chemical Society
researchProduct

Monoradicals and Diradicals of Dibenzofluoreno[3,2-b]fluorene Isomers: Mechanisms of Electronic Delocalization

2020

The preparation of a series of dibenzo- and tetrabenzo-fused fluoreno[3,2-b]fluorenes is disclosed, and the diradicaloid properties of these molecules are compared with those of a similar, previously reported series of anthracene-based diradicaloids. Insights on the diradical mode of delocalization tuning by constitutional isomerism of the external naphthalenes has been explored by means of the physical approach (dissection of the electronic properties in terms of electronic repulsion and transfer integral) of diradicals. This study has also been extended to the redox species of the two series of compounds and found that the radical cations have the same stabilization mode by delocalization…

AnthraceneDiradicalGeneral ChemistryFluoreneCarbocation010402 general chemistry01 natural sciencesBiochemistryCatalysis0104 chemical scienceschemistry.chemical_compoundDelocalized electronColloid and Surface ChemistrychemistryComputational chemistryStructural isomerMoleculeCarbanionJournal of the American Chemical Society
researchProduct

A Tale of Two Isomers: Enhanced Antiaromaticity/Diradical Character versus Deleterious Ring‐Opening of Benzofuran‐fused s ‐Indacenes and Dicyclopenta…

2021

We examine the effects of fusing two benzofurans to s-indacene (indacenodibenzofurans, IDBFs) and dicyclopenta[b,g]naphthalene (indenoindenodibenzofurans, IIDBFs) to control the strong antiaromaticity and diradical character of these core units. Synthesis via 3-functionalized benzofuran yields syn-IDBF and syn-IIDBF. syn-IDBF possesses a high degree of paratropicity, exceeding that of the parent hydrocarbon, which in turn results in strong diradical character for syn-IIDBF. In the case of the anti-isomers, synthesized via 2-substituted benzofurans, these effects are decreased; however, both derivatives undergo an unexpected ring-opening reaction during the final dearomatization step. All th…

ChemistryDiradicalStereochemistryGeneral ChemistryGeneral MedicineRing (chemistry)CatalysisElectronegativityTurn (biochemistry)chemistry.chemical_compoundCharacter (mathematics)BenzofuranAntiaromaticityNaphthaleneAngewandte Chemie
researchProduct

Late-Stage Modification of Electronic Properties of Antiaromatic and Diradicaloid Indeno[1,2-b]fluorene Analogues via Sulfur Oxidation

2020

The ability to alter optoelectronic and magnetic properties of molecules at a late stage in their preparation is in general a nontrivial feat. Here, we report the late-stage oxidation of benzothiop...

010405 organic chemistryChemistryOrganic ChemistryLate stagechemistry.chemical_elementFluoreneequipment and supplies010402 general chemistryPhotochemistry01 natural sciencesSulfur0104 chemical scienceschemistry.chemical_compoundMoleculehuman activitiesAntiaromaticityElectronic propertiesThe Journal of Organic Chemistry
researchProduct

CCDC 2016988: Experimental Crystal Structure Determination

2020

Related Article: Hideki Hayashi, Joshua E. Barker, Abel Cárdenas Valdivia, Ryohei Kishi, Samantha N. MacMillan, Carlos J. Gómez-García, Hidenori Miyauchi, Yosuke Nakamura, Masayoshi Nakano, Shin-ichiro Kato, Michael M. Haley, Juan Casado|2020|J.Am.Chem.Soc.|142|20444|doi:10.1021/jacs.0c09588

Space GroupCrystallography716-bis(4-t-butyl-26-dimethylphenyl)benzo[56]fluoreno[32-b]benzo[g]fluorene unknown solvateCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 1995028: Experimental Crystal Structure Determination

2020

Related Article: Justin J. Dressler, Joshua E. Barker, Lucas J. Karas, Hannah E. Hashimoto, Ryohei Kishi, Lev N. Zakharov, Samantha N. MacMillan, Carlos J. Gomez-Garcia, Masayoshi Nakano, Judy I. Wu, Michael M. Haley|2020|J.Org.Chem.|85|10846|doi:10.1021/acs.joc.0c01387

Space GroupCrystallography714-bis(246-trimethylphenyl)-512-dibenzo[dd']s-indaceno[12-b:56-b']bisthiophene-551212-tetrone chloroform solvateCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 2077070: Experimental Crystal Structure Determination

2021

Related Article: Joshua E. Barker, Tavis W. Price, Lucas J. Karas, Ryohei Kishi, Samantha N. MacMillan, Lev N. Zakharov, Carlos J. G��mez���Garc��a, Judy I. Wu, Masayoshi Nakano, Michael M. Haley|2021|Angew.Chem.,Int.Ed.|60|22385|doi:10.1002/anie.202107855

Space GroupCrystallographyCrystal SystemCrystal StructureCell Parameters26-bis(2-hydroxyphenyl)-37-bis(246-trimethylphenyl)-s-indacene-15-dione chloroform solvateExperimental 3D Coordinates
researchProduct

CCDC 2023797: Experimental Crystal Structure Determination

2020

Related Article: Hideki Hayashi, Joshua E. Barker, Abel Cárdenas Valdivia, Ryohei Kishi, Samantha N. MacMillan, Carlos J. Gómez-García, Hidenori Miyauchi, Yosuke Nakamura, Masayoshi Nakano, Shin-ichiro Kato, Michael M. Haley, Juan Casado|2020|J.Am.Chem.Soc.|142|20444|doi:10.1021/jacs.0c09588

Space GroupCrystallographyCrystal SystemCrystal Structure(716-bis(4-t-butyl-26-dimethylphenyl)-716-dihydrobenzo[56]fluoreno[32-b]benzo[g]fluoren-7-ylium radical) hexachloro-antimonyCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 1949404: Experimental Crystal Structure Determination

2020

Related Article: Joshua E. Barker, Justin J. Dressler, Abel Cárdenas Valdivia, Ryohei Kishi, Eric T. Strand, Lev N. Zakharov, Samantha N. MacMillan, Carlos J. Gómez-García, Masayoshi Nakano, Juan Casado, Michael M. Haley|2019|J.Am.Chem.Soc.|142|1548|doi:10.1021/jacs.9b11898

614-bis(4-t-butyl-26-dimethylphenyl)[1]benzothieno[2''3'':2'3']indeno[5'6':56]indeno[21-b][1]benzothiophene chloroform solvateSpace GroupCrystallographyCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 2016990: Experimental Crystal Structure Determination

2020

Related Article: Hideki Hayashi, Joshua E. Barker, Abel Cárdenas Valdivia, Ryohei Kishi, Samantha N. MacMillan, Carlos J. Gómez-García, Hidenori Miyauchi, Yosuke Nakamura, Masayoshi Nakano, Shin-ichiro Kato, Michael M. Haley, Juan Casado|2020|J.Am.Chem.Soc.|142|20444|doi:10.1021/jacs.0c09588

Space GroupCrystallographyCrystal SystemCrystal StructureCell Parameters918-bis(4-t-butyl-26-dimethylphenyl)benzo[a]benzo[78]fluoreno[23-h]fluorene-514-dione unknown solvateExperimental 3D Coordinates
researchProduct

CCDC 1994473: Experimental Crystal Structure Determination

2020

Related Article: Justin J. Dressler, Joshua E. Barker, Lucas J. Karas, Hannah E. Hashimoto, Ryohei Kishi, Lev N. Zakharov, Samantha N. MacMillan, Carlos J. Gomez-Garcia, Masayoshi Nakano, Judy I. Wu, Michael M. Haley|2020|J.Org.Chem.|85|10846|doi:10.1021/acs.joc.0c01387

614-bis(4-t-butyl-26-dimethylphenyl)-513-[1]benzothieno[2''3'':2'3']indeno[5'6':56]indeno[21-b][1]benzothiophene-551313-tetrone acetonitrile solvateSpace GroupCrystallographyCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 2077067: Experimental Crystal Structure Determination

2021

Related Article: Joshua E. Barker, Tavis W. Price, Lucas J. Karas, Ryohei Kishi, Samantha N. MacMillan, Lev N. Zakharov, Carlos J. G��mez���Garc��a, Judy I. Wu, Masayoshi Nakano, Michael M. Haley|2021|Angew.Chem.,Int.Ed.|60|22385|doi:10.1002/anie.202107855

614-bis(4-t-butyl-26-dimethylphenyl)[1]benzofuro[2''3'':2'3']indeno[5'6':56]indeno[21-b][1]benzofuran chloroform solvateSpace GroupCrystallographyCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 2016987: Experimental Crystal Structure Determination

2020

Related Article: Hideki Hayashi, Joshua E. Barker, Abel Cárdenas Valdivia, Ryohei Kishi, Samantha N. MacMillan, Carlos J. Gómez-García, Hidenori Miyauchi, Yosuke Nakamura, Masayoshi Nakano, Shin-ichiro Kato, Michael M. Haley, Juan Casado|2020|J.Am.Chem.Soc.|142|20444|doi:10.1021/jacs.0c09588

Space GroupCrystallographyCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates817-bis(4-t-butyl-26-dimethylphenyl)-514-dimethoxybenzo[b]benzo[67]fluoreno[23-h]fluorene unknown solvate
researchProduct

CCDC 2016986: Experimental Crystal Structure Determination

2020

Related Article: Hideki Hayashi, Joshua E. Barker, Abel Cárdenas Valdivia, Ryohei Kishi, Samantha N. MacMillan, Carlos J. Gómez-García, Hidenori Miyauchi, Yosuke Nakamura, Masayoshi Nakano, Shin-ichiro Kato, Michael M. Haley, Juan Casado|2020|J.Am.Chem.Soc.|142|20444|doi:10.1021/jacs.0c09588

714-bis(4-t-butyl-26-dimethylphenyl)fluoreno[32-b]fluoreneSpace GroupCrystallographyCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 2016989: Experimental Crystal Structure Determination

2020

Related Article: Hideki Hayashi, Joshua E. Barker, Abel Cárdenas Valdivia, Ryohei Kishi, Samantha N. MacMillan, Carlos J. Gómez-García, Hidenori Miyauchi, Yosuke Nakamura, Masayoshi Nakano, Shin-ichiro Kato, Michael M. Haley, Juan Casado|2020|J.Am.Chem.Soc.|142|20444|doi:10.1021/jacs.0c09588

Space GroupCrystallographyCrystal SystemCrystal StructureCell Parameters918-bis(4-t-butyl-26-dimethylphenyl)benzo[a]benzo[78]fluoreno[23-h]fluorene unknown solvateExperimental 3D Coordinates
researchProduct

CCDC 2076414: Experimental Crystal Structure Determination

2021

Related Article: Joshua E. Barker, Tavis W. Price, Lucas J. Karas, Ryohei Kishi, Samantha N. MacMillan, Lev N. Zakharov, Carlos J. G��mez���Garc��a, Judy I. Wu, Masayoshi Nakano, Michael M. Haley|2021|Angew.Chem.,Int.Ed.|60|22385|doi:10.1002/anie.202107855

Space GroupCrystallography714-bis(246-trimethylphenyl)dibenzo[dd']s-indaceno[12-b:56-b']difuran chloroform solvateCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 1589136: Experimental Crystal Structure Determination

2020

Related Article: Joshua E. Barker, Justin J. Dressler, Abel Cárdenas Valdivia, Ryohei Kishi, Eric T. Strand, Lev N. Zakharov, Samantha N. MacMillan, Carlos J. Gómez-García, Masayoshi Nakano, Juan Casado, Michael M. Haley|2019|J.Am.Chem.Soc.|142|1548|doi:10.1021/jacs.9b11898

Space GroupCrystallography816-bis[246-tri-isopropylphenyl][1]benzothieno[3''2'':2'3']indeno[5'6':56]indeno[12-b][1]benzothiophene acetonitrile solvateCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 2016622: Experimental Crystal Structure Determination

2020

Related Article: Hideki Hayashi, Joshua E. Barker, Abel Cárdenas Valdivia, Ryohei Kishi, Samantha N. MacMillan, Carlos J. Gómez-García, Hidenori Miyauchi, Yosuke Nakamura, Masayoshi Nakano, Shin-ichiro Kato, Michael M. Haley, Juan Casado|2020|J.Am.Chem.Soc.|142|20444|doi:10.1021/jacs.0c09588

Space GroupCrystallographyCrystal SystemCrystal Structure818-bis(4-t-butyl-26-dimethylphenyl)benzo[a]benzo[78]fluoreno[23-h]fluorene-59-dione acetonitrile unknown solvateCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 1995029: Experimental Crystal Structure Determination

2020

Related Article: Justin J. Dressler, Joshua E. Barker, Lucas J. Karas, Hannah E. Hashimoto, Ryohei Kishi, Lev N. Zakharov, Samantha N. MacMillan, Carlos J. Gomez-Garcia, Masayoshi Nakano, Judy I. Wu, Michael M. Haley|2020|J.Org.Chem.|85|10846|doi:10.1021/acs.joc.0c01387

Space GroupCrystallographyCrystal SystemCrystal StructureCell Parameters918-bis(4-t-butyl-26-dimethylphenyl)-514-[12]benzothiazino[4''3'':2'3']indeno[5'6':56]indeno[12-c][12]benzothiazine-551414-tetrone chloroform solvateExperimental 3D Coordinates
researchProduct

CCDC 2077069: Experimental Crystal Structure Determination

2021

Related Article: Joshua E. Barker, Tavis W. Price, Lucas J. Karas, Ryohei Kishi, Samantha N. MacMillan, Lev N. Zakharov, Carlos J. G��mez���Garc��a, Judy I. Wu, Masayoshi Nakano, Michael M. Haley|2021|Angew.Chem.,Int.Ed.|60|22385|doi:10.1002/anie.202107855

Space GroupCrystallographyCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates38-bis(4-t-butyl-26-dimethylphenyl)-27-bis(2-hydroxyphenyl)dicyclopenta[bg]naphthalene-16-dione chloroform methanol solvate
researchProduct

CCDC 2077068: Experimental Crystal Structure Determination

2021

Related Article: Joshua E. Barker, Tavis W. Price, Lucas J. Karas, Ryohei Kishi, Samantha N. MacMillan, Lev N. Zakharov, Carlos J. G��mez���Garc��a, Judy I. Wu, Masayoshi Nakano, Michael M. Haley|2021|Angew.Chem.,Int.Ed.|60|22385|doi:10.1002/anie.202107855

Space GroupCrystallographyCrystal System613-bis(246-trimethylphenyl)dibenzo[dd']s-indaceno[21-b:65-b']difuranCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 1995030: Experimental Crystal Structure Determination

2020

Related Article: Justin J. Dressler, Joshua E. Barker, Lucas J. Karas, Hannah E. Hashimoto, Ryohei Kishi, Lev N. Zakharov, Samantha N. MacMillan, Carlos J. Gomez-Garcia, Masayoshi Nakano, Judy I. Wu, Michael M. Haley|2020|J.Org.Chem.|85|10846|doi:10.1021/acs.joc.0c01387

Space GroupCrystallographyCrystal System613-bis(4-t-butyl-26-dimethylphenyl)-512-dibenzo[dd']s-indaceno[21-b:65-b']bisthiophene-551212-tetrone chloroform dichloromethane acetonitrile solvateCrystal StructureCell ParametersExperimental 3D Coordinates
researchProduct