نتایج جستجو برای: antiaromaticity
تعداد نتایج: 113 فیلتر نتایج به سال:
Small boron clusters as individual species in the gas phase are reviewed. While the family of known boron compounds is rich and diverse, a large body of hitherto unknown chemistry of boron has been recently identified. Free boron clusters have been recently characterized using photoelectron spectroscopy and ab initio calculations, which have established the planar or quasi-planar shapes of smal...
While boride clusters of alkali and transition metals have been observed and extensively characterized, so far little is known about lanthanide−boron clusters. Lanthanide−boride solids are intriguing, however, and therefore it is of interest to understand the fundamental electronic properties of such systems, also on the subnano scale. We report a joint experimental photoelectron spectroscopic ...
The effects of aromatic stabilization on the rates of [1,5]-hydrogen shifts in a series of carbo- and heterocyclic dihydroaromatic compounds were estimated by B3LYP/6-31G computations. The aromatic stabilization energy of the product is directly translated into increased exothermicity of these reactions. Relative trends for a significant range of endothermic and exothermic [1,5]-shifts with dif...
We performed a joint photoelectron spectroscopy and ab initio study of two carbon-doped boron clusters, CB(9)(-) and C(2)B(8)(-). Unbiased computational searches revealed similar global minimum structures for both clusters. The comparison of the experimentally observed and theoretically calculated vertical detachment energies revealed that only the global minimum structure is responsible for th...
The history and development of pyrazineand pyridine-type heteroacenes and their use in solid-state organic electronics are discussed and reviewed. The larger N-heteroacenes are potential electronor hole-transporting materials and should therefore complement acenes in organic electronics. As they feature electronegative nitrogen ring atoms in their molecular skeleton, issues with oxidation shoul...
3,7,23,27-Tetrabromo[36]octaphyrin 2 was synthesized as a novel octaphyrin bearing two meso-free positions. Surprisingly, its ZnII and NiII complexation reactions produced directly fused porphyrin(2.1.1.1) dimer 6, meso-α N-confused porphyrin (NCP) 7, the first example of NCP tape, respectively, via transannular C−C bond formation. While 6 exhibits diatropic ring-current effect owing to global ...
π-Aromaticity is an important driving force in directing the synthesis of aromatic compounds; contrast, reactions induced by σ-aromaticity are uncommon. Here we report a strategy based on π- and relays to realize structurally defined ring contraction metallacyclobutadiene metallacyclopropene. This reaction involves release π-antiaromaticity afford π-aromatic intermediate, followed reclosure gen...
This Review surveys the experimental and synthetic history of three classic antiaromatic cores: cyclobutadiene, borole, pentalene. The coverage extends from bare molecular cores to fused or substituted variants that impart thermodynamic kinetic stability systems. Recent studies utilize unusual properties these in context advanced electronic materials are discussed.
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