Diamond-type nanogrids (DGs), can helically expand to form spiro-linked polymers. Herein, we designed and synthesized two types of DGs, DGs-1 (A1B1 mode) in 44–50% yields, and DGs-2 (A2 + B2 mode) in 64% yield.
Organic science & technology (OST) become the frontier horizon after nanotechnology, information technology as well as biotechnology toward the era of consciousness. Organic nanogridarenes (ONGAs) are becoming robust nanoscaffolds for next-generation multifunctional/intelligent semiconductors with tunable cross-scale features. However, the prerequisite of trans-dimensional & intelligent design is to clarify the gridization rules for the discovery of the powerful molecular gridization protocols. Here, we report an efficient and multiselective Csp2-Csp3 gridization based on dual halogen bonding (X···π and X···S, X = Br, I) self-activated electrophilic substitution of halogenated electron-rich molecular blocks under supersonic conditions. Windmill-type nanogrids of cyclopenta[1,2-b:5,4-b']dithiophene (WG4) were obtained with the maximum path selectivity (96%), nanogrid-size selectivity (67%), site-selectivity (>99%) and moderate diastereoselectivity (WG4-1-6:WG4-2-6:WG4-3-6:WG4-4-6 =1:3.3:5.3:0), superior to the previous Friedel-Crafts gridization. Mechanistic studies have revealed the roles of XBs where the X···S bonding accelerates dehalogenation after electrophilic attack, and the X···π bonding leads to the multiselectivity of WG4. Impressively, C2-symmetric WG4-1-6 (21×21×15 Å) crystallizes into a Fd3̄c space group as the 16th pure organic molecules in CCDC library and hierarchically self-assemble into a complex 3D porous superstructure.
Bulky conjugated molecules with high stability are the prerequisite for the overall improvement of performance in wide-bandgap semiconductors. Herein, a chiral difluorenol, 2,2′-(9,9′-spirobi[fluorene]-2,2′-diyl)bis(9-(4-(octyloxy)phenyl)-9H-fluoren-9-ol) (DOHSBF), is set as a desirable model to reveal the stereoisomeric effects of wide-bandgap molecules toward controlling photophysical behavior and improving thermal and optical stability. Three diastereomers are obtained and elucidated by NMR spectra. Interestingly, the effect of modifying the stereo-centers is not observed on optical properties in solutions, pristine films, or post-treated film states. All three diastereomers as well as the mixture exhibit excellent spectral stability without undesirable green emission. Therefore, this stereoisomer-independent blue-emitting difluorenol will be a promising candidate for next-generation wide-bandgap semiconductors that would have extensive application in organic photonics.
Strained nanogrids are the hybrids between nanogrids and nanorings with high strain like CPPs, offering state-of-the-art models and versatile nanobricks for advanced materials. Herein, we reported the unique blue-emitting strained triangle windmill-type nanogrids (TWGs) with π-interrupted backbones and delta-stacked motifs that have two diastereoisomers with different strains (cis-trans-TWG 15.60 kcal/mol, cis-cis-TWG 13.31 kcal/mol). They are synthesized by Pd-PPh3-assisted C-H gridization with size-selectivity of TWGs in 35 % yield and diastereoselectivity of cis-trans-TWG/cis-cis-TWG (80:20). Single-crystal X-ray diffraction and non-covalent index reveal both diastereoisomers exhibit the unique angle, bending, torsion as well as steric strains. Among those, torsion strain of cis-trans-TWG is much greater than that of cis-cis-TWG. Furthermore, strain-induced red shift of 25 nm in cis-trans-TWG than cis-cis-TWG was confirmed by TDDFT and photophysics charaterization. Interestingly, aggregates-induced emission switching and enhancement was observed in cis-trans-TWG skeleton with concentration from 10-5 to 10-1.
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