Germanium‐Bridged 2‐Phenylbenzoheteroles as Luminophores Exhibiting Highly Efficient Solid‐State Fluorescence

Abstract

[1]Benzogermolo[3,2-b]indoles, [1]benzogermolo[3,2-b]benzofuran, [1]benzogermolo[3,2-b]benzothiophene, and [1]benzogermolo[3,2-b]benzothiophene-S,S-dioxide were synthesized from the corresponding 3-bromo-2-(2-bromophenyl)benzoheteroles and characterized. A comparison of the absorption spectra of the Ph Ge- and Ph Si-bridged 2-phenylindoles reveals that the Ge bridge has the effect of slightly widening the HOMO-LUMO energy gap of the bridged 2-phenylindole π-system with regard to the Si-bridged system. Replacement of the indole ring by benzofuran or benzothiophene rings induces blueshifts in the absorption spectrum, whereas the absorption spectrum of the benzothiophene-S,S-dioxide derivative was redshifted with respect to the indole derivative. These results are consistent with the changes in the HOMO-LUMO energy gaps calculated by using density functional theory. The Ph Ge-bridged indole, benzofuran, and benzothiophene-S,S-dioxide derivatives exhibit brilliant fluorescence in the violet-to-blue region with good-to-excellent quantum yields in toluene (λ =376-439 nm, Φ=0.62-0.99) and powder form (λ =401-451 nm, Φ=0.64-0.80).

Preparation of Near‐Infrared Emissive π‐Conjugated Polymer Films Based on Boron‐Fused Azobenzene Complexes with Perpendicularly Protruded Aryl Substituents

“…[39][40][41] By employing unique properties of heteroatoms, various types of luminescent dyes and polymers have been developed. [42][43][44][45][46][47][48][49][50][51][52][53][54] As a luminescent "element-block", we focused on the complexes having a tetracoordinated boron atom. [55] Boron complexation has been used for reinforcing molecular rigidity and planarity.…”

Novel Germoles and Their Ladder-Type Derivatives: Modular Synthesis, Luminescence Tuning, and Electroluminescence

“…Supporting Information is available and includes general materials, methods and instruments, synthesis routes, 1 H NMR, 13 C NMR spectra, additional spectra, characterization data, TD-DFT calculations, and electroluminescence performance.…”

Synthesis of Pyridinothienogermoles as Unsymmetrically Condensed Germoles

“…Viologen derivatives were also prepared by treating diphenyldipyridinogermole with methyl iodide, and these compounds showed stable electrochromic properties . However, most of the condensed siloles and germoles reported so far possess symmetrical tricyclic systems, and studies of unsymmetrical tricyclic systems have been limited to rather simple cases, including siloles and germoles condensed with phenylpyridine (BPyS), phenylthiophene (BTS), phenylcarbazole (BCzS), phenylindole (BInS and BInG), , phenylbenzofuran (BBFS and BBFG), phenylbenzothiophene (BBTS and BBTG), , and benzofuranylbenzothiophene (BFBTS and BFBTG), as shown in Chart .…”