Aromaticity, a cornerstone of chemical stability, is governed by Hückel’s and Baird’s rules for the ground (S0) and triplet excited (T1) states, respectively, yet these canonical rules are challenged by two-state aromaticity (adaptive aromaticity)—a burgeoning frontier in aromaticity research.
Molecular topology plays a key role in controlling the aromatic or antiaromatic character of cyclic π-conjugated systems. Herein we report synthesis of triply twisted [54]dodecaphyrin(2.1.0.1.2.1.0.1.2.1.0.1) tri-NiII complex 4Ni via reductive cyclization of cyclic tris(dipyrrin) NiII complex 3, which was synthesized by a tri-NiII templation. 4Ni was converted into free base 4H and CuII complex 4Cu.
In this study, we report the aromatic C─C bond cleavage of cyclopentadienide by transient imino(metallophosphino)silylenes through the reaction of silylene equivalents with CpCo(CO)2, enabling the transformation of cyclopentadienides into silicon-bridged homocyclopentadienides. The presence of homoaromaticity in these species is substantiated by NICS and ACID analyses.
B,N-doped organic analogues can be widely used in photoelectronic materials, medicine and other fields. However, B,N-doped cyclo[n]carbons have not yet been developed. Herein, we report a systematic investigation of the thermodynamic stability and aromaticity of mono B,N-doped cyclo[10]carbon isomers via density functional theory (DFT). Several rules for thermodynamic stability have been proposed. Specifically, rule 1: isomers with B,N atoms separated by an even number of C atoms are more stable than those separated by an odd number of C atoms.
Open-shell species are central to spintronics and infrared optoelectronics, but remain challenging to stabilize in discrete molecular systems. Herein, we report that electron injection into pillar-shaped, radially π-conjugated [4]cyclonaphthodithiophene diimides ([4]C-NDTIs) triggers global aromaticity, yielding radical species with notable stability and optical properties.
The stabilization of 4π-electron systems remains a fundamental challenge in chemistry, stemming from their intrinsic antiaromaticity and thermodynamic instability as dictated by Hückel’s rule. A recent experimental study has demonstrated that rational molecular design using N-heterocyclic carbenes (NHCs) can surmount these limitations by inducing aromaticity. However, the issue of T1 aromaticity in such systems remains unresolved. Elucidating the substituent-modulated behavior of T1 (anti)aromaticity is crucial for deciphering the physicochemical properties of these systems.
Single-component organic photovoltaics (SC-OPVs) offer an innovative approach to the traditional bulk-heterojunction organic photovoltaics (BHJ-OPVs) by chemically bonding the donor and acceptor materials within a single molecule. This approach has the potential not only to reduce the manufacturing costs but also to stabilize the photoactive layer against common morphological degradation processes typically observed in BHJ-OPVs.
While triplet carbenes have been stabilized through spin delocalization, capturing triplet aluminyl anions─isoelectronic counterparts of carbenes─has remained an unsolved challenge in main-group chemistry. All previously reported aluminyl anions exhibit a singlet ground state, despite the use of diverse ligand frameworks. Herein, we report the first example of formally triplet aluminyl anions within bimetallic clusters, [((CH3)2C(CH2NPiPr2)2)2Al2Pd2]M2 (M = Li, Na, K).
Aryl and vinyl boron reagents are widely employed in modern organic synthesis. However, the direct coupling of nucleophilic vinyl boron reagents to construct conjugated 1,4-diarylbutadiene dianionic (DABDA) motifs in the absence of additives remains a significant challenge. Here, we report for the first time the direct coupling of various β-aryl vinyl boron reagents, initiated by the rare-earth metal monoalkyl complexes for the synthesis of a number of rare-earth metal complexes featuring inverse sandwich DABDA motifs.
The photoisomerism of azo switches using light in the near-IR region (NIR, 780-1400 nm) is highly preferable for the applications to biomedical and pharmacological fields. The common chemical modifications of azobenzene only enables the E ⇆ Z photoswitching wavelengths of azobenzene derivatives close to the red limit of near-infrared light.