Orientation in Polyalkylation of Polycyclic Aromatic Hydrocarbons. Structure Determination by NMR Spectroscopy.

Berg, Arne; Jakobsen, Hans J.; Johansen, Steffen Radich; Smidsrød, Olav; Lindberg, Alf A.; Jansen, Gert; Lamm, Bo; Samuelsson, Benny

doi:10.3891/acta.chem.scand.23-0567

Cited by 14 publications

(10 citation statements)

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“…General Experimental Methods for Synthesis: All reagents were obtained from commercial sources and used as received, with the exception of [Ir(COD)(μ-OMe)]2, 46 2,7-di-(tert-butyl)pyrene, 47 4-bromo-2,7-di-(tert-butyl)pyrene, 31 4,9-dibromopyrene, 34 1,2,3,6,7,8-hexahydropyrene, 33 and dimesitylboron fluoride (Mes2BF) 48 which were synthesized as reported previously. Solvents were HPLC grade, and were treated to remove trace water using a commercial solvent purification system and deoxygenated using the freeze−pump−thaw method.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, Photophysical, and Electrochemical Properties of Pyrenes Substituted with Donors or Acceptors at the 4- or 4,9-Positions

Krummenacher

Friedrich

et al. 2018

J. Org. Chem.

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We report herein an efficient and direct functionalization of the 4,9-positions of pyrene by Ir-catalyzed borylation. Three pinacol boronates (-Bpin), including 4-(Bpin)-2,7-di( tert-butyl)pyrene (5), 4,9- bis(Bpin)-2,7-di( tert-butyl)pyrene (6), and 4,10- bis(Bpin)-2,7-di( tert-butyl)pyrene (7), were synthesized. The structures of 6 and 7 have been confirmed by single-crystal X-ray diffraction. To demonstrate the utility of these compounds, donor (NPh)-substituted compounds 4-diphenylamino-2,7-di( tert-butyl)pyrene (1) and 4,9- bis(diphenylamino)-2,7-di( tert-butyl)pyrene (2) have been synthesized on a gram scale. Acceptor (BMes)-substituted compounds 4,9- bis(BMes)pyrene (3) and 4,9- bis(BMes)-1,2,3,6,7,8-hexahydropyrene (4) were synthesized for comparison. The photophysical and electrochemical properties of compounds 1-4 have been studied both experimentally and theoretically. The S → S transitions of the 4- or 4,9-disubstituted pyrenes, 1-3, are allowed, with moderate fluorescence quantum yields and radiative decay rates. The photophysical and electrochemical properties of 1-3 were compared with the 2,6-naphthalenylene-cored compound 4 as well as the previously reported 2,7- and 1,6- pyrenylene-cored compounds.

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Section: Methodsmentioning

confidence: 99%

Synthesis, Photophysical, and Electrochemical Properties of Pyrenes Substituted with Donors or Acceptors at the 4- or 4,9-Positions

Krummenacher

Friedrich

et al. 2018

J. Org. Chem.

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“…The positions of the substituents were not known, although by analogy with the other known products of electrophilic substitution reactions Buu-Hoi & Cagniant (1944) thought the compound to be the 1,6-derivative (I). Recent nuclear magnetic resonance studies by Berg, Jakobsen & Johansen (1969) show the compound to be the 2,7-derivative (II).…”

Section: Introductionmentioning

confidence: 99%

The crystal structure of 2,7-di-t-butylpyrene

Hazell¹,

Lomborg²

1972

Acta Crystallogr Sect B

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“…The 1-, 3-, 6-, and 8-positions of pyrene are the sites of maximum contributions of the highest occupied molecular orbital (HOMO) and hence favorable for electrophilic aromatic substitution, such as direct bromination or formylation . Most pyrene derivatives result from reactions at these “common sites.” In contrast, the 2- and 7-positions of pyrene lie on a nodal plane of both the HOMO and lowest unoccupied molecular orbital (LUMO), but are the least hindered sites and are thus favorable for sterically controlled reactions, such as Ir-catalyzed direct borylation − or tert -butylation . The 4-, 5-, 9-, and 10-positions of pyrene, also known as the K-region, lack either steric or electronic advantages.…”

Section: Introductionmentioning

confidence: 99%

Comparison Study of the Site-Effect on Regioisomeric Pyridyl–Pyrene Conjugates: Synthesis, Structures, and Photophysical Properties

et al. 2020

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To investigate the "site effect" of pyridyl substituents on a pyrene core, four regioisomeric monopyridyl-pyrene (1−4) and five regioisomeric dipyridyl-pyrene (5−9) conjugates were synthesized and characterized and their structures confirmed by single-crystal X-ray diffraction. The photophysical properties and related frontier orbital features of these compounds have been studied both experimentally and theoretically and demonstrate the dependence of the properties of the compounds on the position of substitution of the pyridyl moieties connecting to the pyrene core. It was found that the absorption spectra of 2-and 4substituted pyrene derivatives display similar and weak influence on the S 2 ← S 0 excitations, whereas they are quite different from those of 1-substituted isomers. The emission spectra of 1and 4-substituted pyrenes are quite similar, whereas those of 2-substituted isomers display the largest bathochromic shift. The 1,6-disubstituted compound 5 exhibits a near-unity emission quantum yield in solution, which is nearly three times higher than those of other regioisomeric dipyridyl-pyrenes. In addition, the tetrasubstituted 1,6-dipyridyl-3,8-di-n-butyl-pyrene (10) exhibits the highest solid-state quantum yield of 0.24 among all of the 10 pyridyl-pyrenes prepared in this study.

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Orientation in Polyalkylation of Polycyclic Aromatic Hydrocarbons. Structure Determination by NMR Spectroscopy.

Cited by 14 publications

References 0 publications

Synthesis, Photophysical, and Electrochemical Properties of Pyrenes Substituted with Donors or Acceptors at the 4- or 4,9-Positions

Synthesis, Photophysical, and Electrochemical Properties of Pyrenes Substituted with Donors or Acceptors at the 4- or 4,9-Positions

The crystal structure of 2,7-di-t-butylpyrene

Comparison Study of the Site-Effect on Regioisomeric Pyridyl–Pyrene Conjugates: Synthesis, Structures, and Photophysical Properties

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