Journal ArticleDOI
Triplet State Aromaticity: NICS Criterion, Hyperconjugation, and Charge Effects.
Hong-Chao Sun,Ke An,Jun Zhu +2 more
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TLDR
Results indicate that among the various computationally available NICS indices, NICS(1)zz is the best for the triplet state, and calculations suggest that five-membered cyclic species with "hyperconjugative" aromaticity in the S0 state will become antiaromatic (and aromatic) in the T1 state, indicating an important role of hyperconjugation.Abstract:
Aromaticity, one of the most important concepts in organic chemistry, has attracted considerable interest from both experimentalists and theoreticians. It remains unclear which NICS index is best to evaluate the triplet-state aromaticity. Here, we carry out thorough density functional theory (DFT) calculations to examine this issue. Our results indicate that among the various computationally available NICS indices, NICS(1)zz is the best for the triplet state. The correlations can be improved from 0.840 to 0.938 when only neutral species are considered, demonstrating the significant effect of the charge on the triplet-state aromaticity. In addition, calculations suggest that five-membered cyclic species with "hyperconjugative" aromaticity (and antiaromaticity) in the S0 state will become antiaromatic (and aromatic) in the T1 state, indicating an important role of hyperconjugation. Finally, a moderate correlation (r(2) =0.708) is identified between the NICS(1)zz values and spin distributions.read more
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Unconventional Aromaticity in Organometallics: The Power of Transition Metals.
Dandan Chen,Qiong Xie,Jun Zhu +2 more
TL;DR: The concepts and examples presented here show the importance of interplay and union between experiment and theory in developing novel aromatic systems and, especially, the indispensable role of computational study in rationalization of unconventional aromaticity.
Journal ArticleDOI
Singlet Fission in a Pyrrole-Fused Cross-Conjugated Skeleton with Adaptive Aromaticity.
Long Wang,Lu Lin,Jingjing Yang,Yishi Wu,Hua Wang,Jun Zhu,Jiannian Yao,Hongbing Fu,Hongbing Fu +8 more
TL;DR: In this article, Singlet fission (SF) materials hold the potential to increase the power conversion efficiency of solar cells by reducing the thermalization of high-energy excited states.
Journal ArticleDOI
Dual Aromaticity in Both the T0 and S1 States: Osmapyridinium with Phosphonium Substituents
TL;DR: These findings highlight the importance of a transition metal and phosphoniums in achieving adaptive aromaticity and the triplet ground state and may aid the design of organometallics for photochemical and molecular magnetism applications.
Journal ArticleDOI
Rational Design of a Carbon‐Boron Frustrated Lewis Pair for Metal‐free Dinitrogen Activation
TL;DR: This work demonstrates that a metal-free N2 activation could be favorable both thermodynamically and kinetically (with an activation energy as low as 9.1 kcal mol-1 ) by using a carbon-boron formal frustrated Lewis pair, which is supported by high-level coupled cluster calculations.
Journal ArticleDOI
An Energetic Guide for Estimating Trifluoromethyl Cation Donor Abilities of Electrophilic Trifluoromethylating Reagents: Computations of X–CF3 Bond Heterolytic Dissociation Enthalpies
TL;DR: A good correspondence has been identified between the computed TC(+)DA values and the experimentally observed relative trifluoromethylating capabilities of the reagents and all the information disclosed in this work would contribute to future rational exploration of the electrophilic tr ifluorometrichylation chemistry.
References
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P. Jeffrey Hay,Willard R. Wadt +1 more
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Results obtained with the correlation energy density functionals of becke and Lee, Yang and Parr
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