New [2,2]Fluorenophanes Give Insights into Asymmetric Charge Transfer‐Mediated Exciton Delocalization along the π‐π Packing Direction

Wang, Chi Shin; Wei, Yu Chen; Pan, Ming Lun; Wu, Cheng Ham; Chou, Pi‐Tai; Wu, Yao Ting

doi:10.1002/chem.202100234

Cited by 4 publications

(2 citation statements)

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“…We hypothesized that connecting conjugated moieties to different phenyl units on the ring would give rise to fundamentally different conjugation pathways. Promisingly, through-space electronic , and charge transfer properties of substituted paracyclophanes can be tuned according to the substitution pattern on the benzene. Through-bond electronic properties in CPPs should be similarly changeable.…”

Section: Introductionmentioning

confidence: 99%

Splitting the Ring: Impact of Ortho and Meta Pi Conjugation Pathways through Disjointed [8]Cycloparaphenylene Electronic Materials

et al. 2022

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In this report, we describe the synthesis and electronic properties of small-molecule and polymeric [8]cycloparaphenylenes ([8]CPPs) with disjointed pi-conjugated substituents. Arylene-ethynylene linkers were installed on opposite sides of the [8]CPP nanohoop as separated by three phenyl units on either side such that the monomer systems have syn (C2 symmetry) and anti (C1 symmetry) conformers with a small energy gap (0.1–0.6 kcal/mol). This disjoined substitution pattern necessarily forces delocalization through and around the CPP radial structure. We demonstrate new electronic states from this radial/linear mixing in both the small molecules and the pi extended polymers. Quantum chemical calculations reveal that these electronic processes arise from multiple operative radial/linear conjugation pathways, as the disjoint pattern results in both ortho and meta connections to the CPP ring. These results affirm the unique nature of hybrid radial and linear pi electron delocalization operative in these new conjugation pathways.

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Section: Introductionmentioning

confidence: 99%

Splitting the Ring: Impact of Ortho and Meta Pi Conjugation Pathways through Disjointed [8]Cycloparaphenylene Electronic Materials

et al. 2022

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“…Recent applications of the NTO method have been primarily in photochemistry and -physics and studies of excited states. A small selection of available studies is presented by refs − . Visualization of NTOs has been particularly useful for systems for which the descriptions of an electronic transition of interest involve a considerable number of pairs of occupied and unoccupied MOs with relatively low weights, which renders the assignment of the excitation difficult.…”

Section: Introductionmentioning

confidence: 99%

Spin–Orbit Natural Transition Orbitals and Spin-Forbidden Transitions

Feng

Autschbach

2021

J. Chem. Theory Comput.

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Natural transition orbitals (NTOs) are in widespread use for visualizing and analyzing electronic transitions. The present work introduces the analysis of formally spin-forbidden transitions with the help of complex-valued spin−orbit (SO) NTOs. The analysis specifically focuses on the components in such transitions that cause their intensity to be nonzero because of SO coupling. Transition properties such as transition dipole moments are partitioned into SO-NTO hole−particle pairs, such that contributions to the intensity from specific occupied and unoccupied orbitals are obtained. The method has been implemented within the restricted active space (RAS) self-consistent field wave function theory framework, with SO coupling treated by RAS state interaction. SO-NTOs have a broad range of potential applications, which is illustrated by the T 2 −S 1 state mixing in pyrazine, spin-forbidden versus spin-allowed 4f−5d transitions in the Tb 3+ ion, and the phosphorescence of tris(2-phenylpyridine) iridium [Ir(ppy) 3 ].

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Molecular Insights into [2.2]Paracyclophane‐Based Functional Materials: Chemical Aspects Behind Functions

Hassan

2024

Adv Funct Materials

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Many of the functions and features of practically useful materials are the province of molecular‐level chemistry and their modulation at different length‐scale. This report illustrates the molecular‐level chemistry behind functions and features of the [2.2]paracyclophane‐based materials with a particular focus on the most recent explorations on through‐space conjugated small‐molecule organic emitters, π‐stacked macrocyclic molecules and polymers, poly(p‐phenylenevinylene)s featuring well‐defined donor‐acceptors sequence control, and surface engineering of technologically‐relevant parylenes that finds broad applications across the field of chemical science and technology. This report largely deals with the potential and opportunities associated with molecular features and functions of planar chirality, conformational behaviors, strain‐induced non‐planarity of the aromatics, the profound impacts of through‐space conjugation and π‐electron interactions/delocalization on optoelectronic properties of the π‐conjugated organic emitters, polymers and extended structures consisting of cyclophanes. A special focus is put on the concept of supramolecular polymers using chemically‐programmed chiral cyclophanes via non‐covalent stacking and controlled conformational arrangements. Illustrating cyclophane as precursors/monomers and fabrication strategies for their incorporation in structurally‐controlled (poly(p‐xylylene)s formed via chemical vapor deposition polymerization and post‐deposition fabrication for interface engineering is described. Demonstrating a rather different approach of electronically‐dictated ring‐opening metathesis polymerization employing strained cyclophane‐diene precursors that generate conjugated poly(p‐phenylenevinylene)s with well‐defined (i.e., low dispersity) and donor‐acceptor sequence control is also discussed. This report will serve as an indispensable one‐stop reference for organic, and polymer chemists, as well as material scientists working with cyclophanes for research innovations.

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New [2,2]Fluorenophanes Give Insights into Asymmetric Charge Transfer‐Mediated Exciton Delocalization along the π‐π Packing Direction

Cited by 4 publications

References 46 publications

Splitting the Ring: Impact of Ortho and Meta Pi Conjugation Pathways through Disjointed [8]Cycloparaphenylene Electronic Materials

Splitting the Ring: Impact of Ortho and Meta Pi Conjugation Pathways through Disjointed [8]Cycloparaphenylene Electronic Materials

Spin–Orbit Natural Transition Orbitals and Spin-Forbidden Transitions

Molecular Insights into [2.2]Paracyclophane‐Based Functional Materials: Chemical Aspects Behind Functions

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