Aggregation-Induced Emission in Group 14 Metalloles (Siloles, Germoles, and Stannoles): Spectroscopic Considerations, Substituent Effects, and Applications

Mullin, Jerome L.; Tracy, Henry J.

doi:10.1002/9781118735183.ch02

Cited by 3 publications

(3 citation statements)

References 127 publications

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“…This observation results in efficient interactions of the σ* and π* orbitals of the butadiene moiety (strong σ*−π* conjugation) compared to the negligibly small σ*−π* conjugation in cyclopentadiene. This strong σ*−π* conjugation leads to a remarkable lowering of E LUMO . , A complementary electronic analysis has been provided by Ottosson and co-workers on the related siloles . In this view, the group 14 heteroles can be depicted in several mesomeric forms including ionic forms, where the substituent on the Sn atom can be anionic or cationic combined with a cationic or anionic heterole counterpart.…”

Section: Introductionmentioning

confidence: 96%

Tuning the Optoelectronic Properties of Stannoles by the Judicious Choice of the Organic Substituents

et al. 2018

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1 Stannoles are organometallic rings in which the heteroatom is involved in a form of conjugation that involves excited states (σ*-π*-conjugation). Only little is known about how the substituents on the tin atom or substituents on the stannole ring determine the optoelectronic properties of these heterocycles. In this work, this has been studied experimentally and theoretically. Calculations of optimized equilibrium geometries, energy gaps between the HOMOs and LUMOs, and of the absorption spectra of a wide range of compounds were performed. The computational data showed that the substituents on the tin atom influence the optoelectronic properties to a lower extent than the substituents in the 2-and 5-positions of the ring. These substituents in the plane of the stannole ring can also have a strong influence on the overall planarity of the structure, in which mesomeric effects can play a substantial role only if the structure is planar. Thus, only structures with a planar backbone are of interest in the context of tuning optoelectronic properties. These were selected for the experimental studies. Based on this information, a series of six novel stannoles was synthesized by formation of a zirconium intermediate and subsequent transmetalation to obtain the tin compound. The calculated electronic HOMO-LUMO gaps varied between 2.94 eV and 2.68 eV.The measured absorption maxima were located between 415 nm and 448 nm as compared to theoretically calculated values ranging from 447 nm (2.77 eV) to 482 nm (2.57 eV). In addition to these optical measurements, cyclic voltammetry data could be obtained, which show two reversible oxidation processes for three of six stannoles. With this study, it could be demonstrated how the judicious choice of substituents can lead to large and predictable bathochromic shifts in the absorption spectra. ASSOCIATED CONTENT Supporting InformationThe Supporting Information is available free of charge on the ACS Publications website. It includes experimental and analytical details, NMR spectra, cyclic voltammetry and absorption spectra (PDF), crystal structure information (CIF) and all computational data (TXT).

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Section: Introductionmentioning

confidence: 96%

Tuning the Optoelectronic Properties of Stannoles by the Judicious Choice of the Organic Substituents

et al. 2018

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“…[5][6][7][8] In addition, the discovery of the aggregation induced emission (AIE) effect of aryl-substituted siloles by Tang and coworker provided a new impetus to this field and had significant impact on materials chemistry. [9][10][11] The interest of our group in silole and germole chemistry was directed to their use as starting materials for new silicon and germanium heterocycles with unprecedented structures and properties. 12 During these investigations, we studied the synthesis and properties of classical reactive intermediates such as the heterolyl radicals 2, heterolyl anions 3 and of more uncommon intermediates such as heterolyl dianions 4 (Fig.…”

Section: Introductionmentioning

confidence: 99%

Covalent triflates as synthons for silolyl- and germolyl cations

2022

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“…[ 5 , 6 , 7 , 8 ] The discovery of the aggregation induced emission effect in perarylated siloles additionally fueled the interest in this class of compounds. [ 9 , 10 , 11 , 12 ] The second mainspring for the development of the chemistry of tetroles was the possible occurrence of aromaticity in the negatively charged ions, II and III , and their applications as ligands in transition metal chemistry. [ 13 , 14 , 15 , 16 ] During the last years, the group of Saito and the Oldenburg team contributed to this field by demonstrating that tetrole dianions III are suitable precursors for a wide variety of novel compounds with the tetrel element in unusual coordination environments.…”

Section: Introductionmentioning

confidence: 99%

Radicals and Anions of Siloles and Germoles

Reinhold

Schmidtmann

Tumanskii

et al. 2021

Chemistry A European J

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The synthesis of persistent sila‐ and germacyclopentadienyl (silolyl‐ and germolyl‐) radicals by careful stoichiometric reduction of the corresponding halides with potassium is reported. The radicals were characterized by EPR spectroscopy and trapping reactions. The reduction of tris(trimethylsilyl)silyl‐substituted halides was successful while smaller substituents (i. e., t‐Butyl, Ph) gave the corresponding dimers. The EPR spectroscopic parameter of the synthesized tetrolyl radicals indicate only small spin delocalization to the butadiene unit due to cross‐hyperconjugation. Silolyl‐ and germolyl anions are unavoidable byproducts and are isolated in the form of their potassium salts and characterized by X‐ray crystallography. The comparison of the molecular structures of two closely related potassium silolides provided an example for different coordination of the potassium cation to the silolyl anion (η1 vs. η5 coordination) that triggers the switch between delocalized and localized states.

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Aggregation-Induced Emission in Group 14 Metalloles (Siloles, Germoles, and Stannoles): Spectroscopic Considerations, Substituent Effects, and Applications

Cited by 3 publications

References 127 publications

Tuning the Optoelectronic Properties of Stannoles by the Judicious Choice of the Organic Substituents

Tuning the Optoelectronic Properties of Stannoles by the Judicious Choice of the Organic Substituents

Covalent triflates as synthons for silolyl- and germolyl cations

Radicals and Anions of Siloles and Germoles

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