Results 81 to 90 of about 23,422 (216)

M\"obius and twisted graphene nanoribbons: stability, geometry and electronic properties

, 2009
Results of classical force field geometry optimizations for twisted graphene nanoribbons with a number of twists $N_t$ varying from 0 to 7 (the case $N_t$=1 corresponds to a half-twist M\"obius nanoribbon) are presented in this work.
Caetano, Ewerton W. S., Freire, Valder N., Galvao, Douglas S., Santos, Sergio G. dos, Sato, Fernando   +4 more
core   +1 more source

Leveraging the Bias‐Variance Tradeoff in Quantum Chemistry for Accurate Negative Singlet‐Triplet Gap Predictions: A Case for Double‐Hybrid DFT

Journal of Computational Chemistry, Volume 46, Issue 25, September 30, 2025.
Flexibility in the parameter space of double‐hybrid DFT methods can be exploited to correct a parameterization with high bias but low variance using an internal reference parameterization with high variance but low bias. ABSTRACT Molecules that have been suggested to violate the Hund's rule, having a first excited singlet state (S1$$ {\mathrm{S}}_1 $$)
Atreyee Majumdar, Raghunathan Ramakrishnan   +1 more
wiley   +1 more source

Magnetic circular dichroism spectra from resonant and damped coupled cluster response theory

, 2020
A computational expression for the Faraday A term of magnetic circular dichroism (MCD) is derived within coupled cluster response theory and alternative computational expressions for the B term are discussed.
Barron L. D., C. Hättig, Mason W. R., Piepho S. B., R. Faber, S. Coriani, S. Ghidinelli   +6 more
core   +1 more source

Enlarged‐TriQuinoline (Enl‐TQ): Disparity in Chemical Behaviors by Geometric Scaling of the Trimeric Quinoline Ring System

Chemistry – An Asian Journal, Volume 20, Issue 17, September 4, 2025.
TriQuinoline (TQ), a quasi‐planar cyclic quinoline trimer in a head‐to‐tail arrangement, strongly captures a proton and exhibits unusual physicochemical properties. In this study, we designed and synthesized its expanded analog, Enlarged‐TriQuinoline (Enl‐TQ), in which three alkyne units are embedded between three quinoline units to acquire an expanded
Mai Yamashita, Ryosuke Tsutsumi, Toi Kobayashi, Naoya Kumagai   +3 more
wiley   +1 more source

Design, synthesis and spectroscopic properties of crown ether-capped dibenzotetraaza[14]annulenes

Beilstein Journal of Organic Chemistry, 2019
The first crown ether-capped dibenzotetraaza[14]annulenes (DBTAAs), featuring two macrocyclic binding sites fixed in a face-to-face orientation, were synthesized in satisfactory 26–28% isolated yields.
Krzysztof M. Zwoliński, Julita Eilmes
doaj   +1 more source

Conjugation and optoelectronic properties of acetylenic scaffolds and charge-transfer chromophores [PDF]

, 2017
Our group started a research program in acetylene chemistry in 1987; since then, an intense research effort led to a fascinating journey into acetylenic scaffolding, aimed at exploring conjugative and optoelectronic properties of acetylenic chromophores.
Diederich, François, Kivala, Milan
core  

Spin states of zigzag-edged Mobius graphene nanoribbons from first principles

, 2008
Mobius graphene nanoribbons have only one edge topologically. How the magnetic structures, previously associated with the two edges of zigzag-edged flat nanoribbons or cyclic nanorings, would change for their Mobius counterparts is an intriguing question.
Ajami D., Ajami D., Andre J. M., Barone V., Blöchl P. E., Borden W. T., Castro C., Castro C., Chen Z., Cohen A. J., De-en Jiang, Fujita M., Grimme S., Hachmann J., Harigaya K., Herges R., Hod O., Jiang D. E., Jiang D. E., Jiang D. E., Kawase T., Kresse G., Kresse G., Kresse G., Martin-Santamaria S., Moll J. F., Nakada K., Perdew J. P., Pople J. A., Rzepa H. S., Schreiner P. R., Sheng Dai, Slipchenko L. V., Son Y.-W., Son Y.-W., Stepien M., Wakabayashi K., Warner P. M., Wodrich M. D., Yang L.   +39 more
core   +1 more source

Photocatalytic reactions of a nickel(II) annulene complex incorporated in polymeric structures [PDF]

, 2014
The photochemical reactions of the Ni(II) annulene complex, [NiII([5,7,12,14]-tetra methyl dibenzo[2,3- b:2,3-b,i][1,4,8,11]tetraaza[14]annulenate)], grafted into a poly(isobutylene-alt-maleate) backbone were investigated in aqueous media. The grafted Ni(
Costamagna, J., Estiu, G., Ferraudi, G., Lappin, A. G., Ruiz, Gustavo Teodosio, Vericat, Carolina, Villagrán, M.   +6 more
core   +1 more source

Energetics of Baird aromaticity supported by inversion of photoexcited chiral [4n]annulene derivatives

Nature Communications, 2017
Baird’s rule applies to cyclic π-conjugated molecules in their excited state, yet a quantification of the involved energetics is elusive. Here, the authors show the ring inversion kinetics of two nonplanar and chiral [4n]annulenes to support Baird’s rule
Michihisa Ueda, Kjell Jorner, Young Mo Sung, Tadashi Mori, Qi Xiao, Dongho Kim, Henrik Ottosson, Takuzo Aida, Yoshimitsu Itoh   +8 more
doaj   +1 more source

A Cheap Metal for a "Noble" Task: Preparative and Mechanistic Aspects of Cycloisomerization and Cycloaddition Reactions Catalyzed by Low-Valent Iron Complexes

, 2008
Reaction of ferrocene with lithium in the presence of either ethylene or COD allows the Fe(0)-ate complexes 1 and 4 to be prepared on a large scale, which turned out to be excellent catalysts for a variety of Alder-ene, [4+2], [5+2], and [2+2+2 ...
Fürstner, A., Goddard, R., Kattnig, E., Krause, H., Lehmann, C., Majima, K., Martín, R.   +6 more
core   +1 more source