Controllable Photophysical and Nonlinear Properties in Conformation Isomerization of Macrocyclic [32]Octaphyrin(1.0.1.0.1.0.1.0) Involving Hückel and Möbius Topologies

Abstract

The conversions of photophysical and nonlinear optical (NLO) properties in [32]octaphyrins(1.0.1.0.1.0.1.0) following macrocyclic isomerization between Huckel and Mobius topologies have been studied in detail by means of quantum chemistry calculations. Compared to their quasi-planar analogues, the twisted Mobius and the figure-eight Huckel conformers exhibit red-and blue-shifted absorptions, respectively. The fluorescence emissions of Huckel topological molecules are likely to be from the second excited state, while the Mobius ones should emit photons from the first excited state by following Kasha's rule. The average polarizabilities of octaphyrins reveal certain regularity with regard to their topologies, but is not particularly large; with the π-conjugation enhanced, the polarizability value increased moderately. The static firstand second-order hyperpolarizabilities of Mobius conformations are almost all much higher than those of Huckel conformers, and the figureeight Huckel structures exhibit relatively high values than the quasi-planar Huckel ones. Regarding the frequency dispersions under the incident light, the strong optical resonance effects were found on the firstand second-order hyperpolarizability of molecules, which contrast with the fact that it has modest influences on the average polarizability. The primary cause of the performance differences in optical properties of the octaphyrins has also been probed from different perspectives by various methods of electronic wavefunction analysis. Generally, we confirm that the topological transformation of expanded porphyrins can be used as a special switch to trigger various optical properties.

Tuning Electronic Structure and Optical Properties of Li@cyclo[18]carbon Complex via Switching Doping Position of Lithium Atom

“…There is no significant difference between the α iso of Li@C 18 in and Li@C 18 out , which is similar to the law of polarizability between the analogues of many other types of compounds we have studied [41][42][43][44]. However, the change in the way of binding of Li atom not only causes the magnitude of β vec to vary, but also alters the sign of it.…”

“…The (hyper)polarizability density analysis, which graphically exhibits the spatial contribution of electrons in a molecule to electric response properties, is helpful to gain a deep insight into the physical nature of molecular (hyper)polarizability [17,[41][42][43][44]. The (hyper)polarizability densities, namely the local contributions to the respectively, for comparison.…”

Remarkable Size Effect on Photophysical and Nonlinear Optical Properties of All‐Carboatomic Rings, Cyclo[18]carbon and Its Analogues

“…However, C 10 shows a distinctive difference with significantly large gap. The HOMO‐LUMO gap of a molecular ring has a close relationship with its aromaticity, [30] and it is notable that the aromaticity of C 10 as distinct from that of other carbon rings has been reported, [18] and some works have revealed that molecular aromaticity can serve as a fingerprint of optical properties in organic macrocycles [31–33] . With these facts in mind, the large gap of C 10 is not unexpected.…”

Remarkable Size Effect on Photophysical and Nonlinear Optical Properties of All-Carboatomic Rings, Cyclo[18]carbon and Its Analogues

“…However, C10 shows a distinctive difference with significantly large gap. It is notable that the aromaticity of C10 as distinct from that of other carbon rings has been reported [18], and some works have revealed that molecular aromaticity can serve as a fingerprint of optical properties in organic macrocycles [40][41][42], which jointly explain its anomaly. Oscillator strength (f) of an excited state is proportional to the square of transition dipole moment (μ T ) corresponding to this state, while transition dipole moment density is able to intuitively reveal the contribution of different spatial positions to μ T [43].…”