Radical-substituted dihydrophenazine radical cation salts: Molecular packing structure and bulk magnetic property

Masuda, Yuki; Takeda, Hirotaka; Kuratsu, Masato; Suzuki, Shuichi; Kozaki, Masatoshi; Shiomi, Daisuke; Sato, Kazunobu; Takui, Takeji; Okada, Keiji

doi:10.1351/pac-con-09-10-04

Cited by 12 publications

(1 citation statement)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Herein we report the photophysical studies of a series of N , N ′-disubstituted-dihydrophenazines analogues exhibiting anomalous spectral properties. Owing to highly electron-rich and redox-active properties, dihydrophenazines have been widely investigated for application in organic electronics as p-type materials. , Meanwhile, the phenanthrene substitutes also serve as useful building blocks to develop novel optoelectronic architectures . It is therefore demanding to develop new N , N ′-disubstituted-dihydrophenazine derivatives comprising phenanthrene (as a fused ring) and to explore their associated physical and chemical properties from both fundamental and application perspectives.…”

Section: Introductionmentioning

confidence: 99%

Excited-State Conformational/Electronic Responses of Saddle-ShapedN,N′-Disubstituted-Dihydrodibenzo[a,c]phenazines: Wide-Tuning Emission from Red to Deep Blue and White Light Combination

et al. 2015

View full text Add to dashboard Cite

A tailored strategy is utilized to modify 5,10-dimethylphenazine (DMP) to donor-acceptor type N,N'-disubstituted-dihydrodibenzo[a,c]phenazines. The representative compounds DMAC (N,N'-dimethyl), DPAC (N,N'-diphenyl), and FlPAC (N-phenyl-N'-fluorenyl) reveal significant nonplanar distortions (i.e., a saddle shape) and remarkably large Stokes-shifted emission independent of the solvent polarity. For DPAC and FlPAC with higher steric hindrance on the N,N'-substituents, normal Stokes-shifted emission also appears, for which the peak wavelength reveals solvent-polarity dependence. These unique photophysical behaviors are rationalized by electronic configuration coupled conformation changes en route to the geometry planarization in the excited state. This proposed mechanism is different from the symmetry rule imposed to explain the anomalously long-wavelength emission for DMP and is firmly supported by polarity-, viscosity-, and temperature-dependent steady-state and nanosecond time-resolved spectroscopy. Together with femtosecond early dynamics and computational simulation of the reaction energy surfaces, the results lead us to establish a sequential, three-step kinetics. Upon electronic excitation of N,N'-disubstituted-dihydrodibenzo[a,c]phenazines, intramolecular charge-transfer takes place, followed by the combination of polarization stabilization and skeletal motion toward the planarization, i.e., elongation of the π-delocalization over the benzo[a,c]phenazines moiety. Along the planarization, DPAC and FlPAC encounter steric hindrance raised by the N,N'-disubstitutes, resulting in a local minimum state, i.e., the intermediate. The combination of initial charge-transfer state, intermediate, and the final planarization state renders the full spectrum of interest and significance in their anomalous photophysics. Depending on rigidity, the N,N'-disubstituted-dihydrodibenzo[a,c]phenazines exhibit multiple emissions, which can be widely tuned from red to deep blue and even to white light generation upon optimization of the surrounding media.

show abstract

Section: Introductionmentioning

confidence: 99%

Excited-State Conformational/Electronic Responses of Saddle-ShapedN,N′-Disubstituted-Dihydrodibenzo[a,c]phenazines: Wide-Tuning Emission from Red to Deep Blue and White Light Combination

et al. 2015

View full text Add to dashboard Cite

show abstract

Syntheses and Properties of (Nitronyl nitroxide)‐substituted Tri‐phenylamine ortho‐Bridged by Two Oxygen and Sulfur Atoms

Yokoyama

Tanaka

Fujimoto

et al. 2020

Chemistry An Asian Journal

Self Cite

View full text Add to dashboard Cite

A nitronyl nitroxide unit (NN) was linked with a triphenylamine‐based condensed polycyclic skeleton DOTT to form a radical substituted donor NN‐DOTT. X‐ray crystal structure analysis demonstrated a flat bowl shape of the DOTT unit. EPR spectra showed the localization of electron spin on the NN unit. Chemical oxidation of the DOTT unit produced radical‐substituted radical cation salts NN‐DOTT+ ⋅ SbF6− and NN‐DOTT+ ⋅ FeBr4− that are stable under ambient conditions. The magnetic behavior of NN‐DOTT+ ⋅ SbF6− is characterized by the strong intramolecular ferromagnetic interaction between NN and DOTT+. The X‐ray structural analysis of NN‐DOTT+ ⋅ FeBr4− shows planar structure of DOTT and 1D mixed‐stack column of NN‐DOTT+ and FeBr4−. Magnetic measurements established that NN‐DOTT+ ⋅ FeBr4− undergoes magnetic phase transition into a weak ferromagnet at 7 K.

show abstract

Triplet Diradical‐Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide

Tahara

Suzuki

Kozaki

et al. 2019

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

The spin–spin and magnetic properties of two (nitronyl nitroxide)‐(di‐p‐anisylamine‐phenothiazine) diradical cation salts, (DAA‐PTZ)+‐NN⋅MBr4− (M=Ga, Fe), have been investigated. These diradical‐cation species were prepared by the cross‐coupling of iodophenothiazine DAA‐PTZ‐I with NN‐AuPPh3 followed by oxidation with the thianthrenium radical cation (TA+⋅MBr4−). These salts were found to be highly stable under aerobic conditions. For the GaBr4 salt, large ferromagnetic intramolecular and small antiferromagnetic intermolecular interactions (J1/kB=+320 K and J2/kB=−2 K, respectively) were observed. The magnetic property of the Fe3+ salt was analyzed by using a six‐spin model assuming identical intramolecular exchange interaction (J3/kB=+320 K) and the other exchange interactions (J4/kB=−7 K and J5/kB=−4 K). A significant color change was observed in the UV/Vis/NIR absorption spectra upon electrochemical oxidation of the doublet DAA‐PTZ‐NN to the triplet (DAA‐PTZ)+‐NN.

show abstract

Radical-substituted dihydrophenazine radical cation salts: Molecular packing structure and bulk magnetic property

Cited by 12 publications

References 18 publications

Excited-State Conformational/Electronic Responses of Saddle-ShapedN,N′-Disubstituted-Dihydrodibenzo[a,c]phenazines: Wide-Tuning Emission from Red to Deep Blue and White Light Combination

Excited-State Conformational/Electronic Responses of Saddle-ShapedN,N′-Disubstituted-Dihydrodibenzo[a,c]phenazines: Wide-Tuning Emission from Red to Deep Blue and White Light Combination

Syntheses and Properties of (Nitronyl nitroxide)‐substituted Tri‐phenylamine ortho‐Bridged by Two Oxygen and Sulfur Atoms

Triplet Diradical‐Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide

Contact Info

Product

Resources

About