(3 + 2)-Annulation of <i>p</i>-Quinamine and Aryne: A Strategy To Construct the Multisubstituted Hydrocarbazoles

Xu, Deyang; Zhao, Yu‐Long; Song, Dengpeng; Zhong, Zhuliang; Feng, Shangbiao; Xie, Xingang; Wang, Xiaolei; She, Xuegong

doi:10.1021/acs.orglett.7b01578

Cited by 38 publications

(11 citation statements)

References 68 publications

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“…It is useful to point out that Fu et al [49] have attributed a large band gap shift of 0.7 eV to stress; our results here suggest rather that the thickness-dependent band gap is the dominant effect. On a similar note, micro/nanostructure can influence the value of gap extracted from Tauc plots, [50] as microstructure can influence the concentration of impurities, which in turn may have defect states in the gap. Nonetheless, all in all our results highlight the importance of ellipsometry measurements where surface roughness can be taken properly into account.…”

Section: Film Growth and Structural Parametersmentioning

confidence: 99%

Revisiting the Optical Band Gap in Epitaxial BiFeO₃ Thin Films

Sando

Carrétéro

Grisolia

et al. 2017

Advanced Optical Materials

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the pursuit of electric-field-controlled magnetism. [2] BFO is part of a larger family of ferroelectric oxides, important compounds that are relevant in the fields of optical modulation, [3] data storage, [4,5] actuation, [6] and sensing. [7] While many of these established applications are based on bulk samples (either single crystals or ceramics), there has recently been a substantial drive to exploit and enhance the desirable functional properties of ferroelectric oxides in thin film form. [8][9][10] Epitaxial strain [11] is a powerful tool in this context: tuning the structure of thin films by strain can bring about, for example, strong modification of ferroelectric polarization and transition temperatures, [12] spin configurations, [13] and magnetic and magneto-transport properties. [14] A wide range of remarkable functionalities has been shown in BFO thin films, [15] such as a tuneable ferroelectric domain structure, [16] strongly strain-dependent magnetic structure, [17] and electric-field sensitive magnetic functionalities. [18,19] While the bulk parent compound of BFO is rhombohedral (R'), a peculiar aspect of thin film BFO is the formation, under strong (≈4%) compressive strain, of a giant axial ratio tetragonal-like (T') polymorph. [20,21] This change in structure is concomitant with a modification of the oxygen coordination (from octahedral to square pyramidal) and drastic changes in optical [22] and piezoelectric responses, [23] and magnetic properties. [24] From an optical point of view, BFO has a band gap that is rather low for ferroelectric oxides, [25] and it exhibits a significant bulk photovoltaic effect, [26] pushing it into the realm of optical research in the hope of using it in energy harvesting, photocatalysis or optical devices. [22] Given the significant general interest of ferroelectrics for photovoltaic applications, [27] it is important to obtain a stronger understanding of the influence of growth parameters and other factors on the optical properties of BFO thin films. In addition, significant size effects, related to microstrain and oxygen content, have been shown to influence the optical response of BFO nanoparticles. [28] Although a large body of literature regarding optical properties (particularly the band gap) for BFO in the form of thin films exists, there is a large dispersion in the data, with reported values for R' BFO ranging from 2.65 to 2.82 eV. For A detailed structural and optical band gap characterization study for more than 40 epitaxial bismuth ferrite (BiFeO 3 -BFO) thin films, measured by X-ray diffraction, atomic force microscopy, and optical transmission spectroscopy, is reported. The films are grown in different deposition systems to varying thicknesses (10-140 nm), on several substrates, and under different growth and cooling conditions. Using the results and literature data, first it is shown that the band gap measured by transmission is systematically lower than the gap found by ellipsometry, suggesting that sufficient caution must be exercised when comparing...

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Section: Film Growth and Structural Parametersmentioning

confidence: 99%

Revisiting the Optical Band Gap in Epitaxial BiFeO₃ Thin Films

Sando

Carrétéro

Grisolia

et al. 2017

Advanced Optical Materials

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“…A similar work was also reported by Ikawa, Akai, and co-workers . Meanwhile, She and co-workers accomplished an efficient synthesis of indole-fused hydrocarbazoles 6-62 through a formal [3 + 2] annulation reaction of protected p -quinamines 6-61 and o -silylaryl triflates (Scheme b) . Notably, when 4 Å molecular sieves (4 Å MS) were used as the additive, the reaction could reach the highest yield.…”

Section: Nucleophilic Annulation Reactionsmentioning

confidence: 99%

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

2021

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Arynes are among the most active organic intermediates and have found numerous applications in expeditious preparation of substituted arenes. In the past 20 years, chemists have witnessed a resurgence in aryne chemistry, which is mainly attributed by the extensive utilization of Kobayashi's method, a fluoride-induced removal of the TMS group with concomitant departure of its ortho OTf group on o-silylaryl triflates. Nowadays, o-silylaryl triflates are the most frequently employed aryne precursors. This review provides an overview of the history of Kobayashi's method, its methodological achievements, and its applications in the synthesis of natural products, bioactive molecules, and polycyclic aromatic hydrocarbons.

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“…She and group came up with an idea for the synthesis of hydrocarbazole analogues 122 using aryne precursor (Scheme 48). 42 They achieved this interesting transformation via (3+2) annulation of p-quinamines 121 and aryne precursors 1. Various p-quinamines were used to explore the substrate scope for this synthetic protocol.…”

Section: Scheme 47 Synthesis Of Benzo[c]carbazole Amide Derivativesmentioning

confidence: 99%

Aryne Annulations for the Synthesis of Carbocycles and Heterocycles: An Updated Review

2022

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Carbocycles and heterocycles are the most relevant structural moieties, which find boundless applications in interdisciplinary areas. In this regard, the interesting chemistry of aryne is highly embraced by the researchers for the synthesis of structurally different polycyclic systems i.e. carbocycles and heterocycles. In this review, we intended to provide a comprehensive overview on annulative approach considering Kobayashi's aryne intermediate as the key reactive species with diverse nucleo-/electrophilic partners. The review highlights the different aryne annulation reactions adopted for the synthesis of carbocycles and heterocycles (covering articles mainly from middle of 20’s), showcasing their viability towards broad range of substrates bearing diverse functionalities.

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(3 + 2)-Annulation of p-Quinamine and Aryne: A Strategy To Construct the Multisubstituted Hydrocarbazoles

Cited by 38 publications

References 68 publications

Revisiting the Optical Band Gap in Epitaxial BiFeO₃ Thin Films

Revisiting the Optical Band Gap in Epitaxial BiFeO₃ Thin Films

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

Aryne Annulations for the Synthesis of Carbocycles and Heterocycles: An Updated Review

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(3 + 2)-Annulation of p-Quinamine and Aryne: A Strategy To Construct the Multisubstituted Hydrocarbazoles

Cited by 38 publications

References 68 publications

Revisiting the Optical Band Gap in Epitaxial BiFeO3 Thin Films

Revisiting the Optical Band Gap in Epitaxial BiFeO3 Thin Films

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

Aryne Annulations for the Synthesis of Carbocycles and Heterocycles: An Updated Review

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Revisiting the Optical Band Gap in Epitaxial BiFeO₃ Thin Films

Revisiting the Optical Band Gap in Epitaxial BiFeO₃ Thin Films