o-Carborane-Triphenylamine Dyad: Studies on Its Acceptor-Donor Behavior toward Dual Redox Mediator

Abstract

Novel carborane-triphenylamine dyad 1 was successfully prepared. The dyad exhibited the aggregation-induced emission (AIE) property in a solution of THF/water [1/99 (v/v)]. The cyclic voltammogram of 1 measured in tetrabutylammonium perchlorate (TBAP)/DMF using glassy carbon (GC) disk working electrode showed redox couples both at anodic side and cathodic side derived from redox responses of the triarylamine and the carborane moieties, respectively. The mediatory behavior of 1 for the anodic oxidation of benzyl alcohol was clearly confirmed by cyclic voltammetry in the presence of 2,6-lutidine. The catalytic current of 1 for the cathodic reduction of 1,2-dibromo-1,2-diphenylethane was also observed.

Substituent Effects on the Fluorescence Properties of ortho‐Carbor­anes: Unusual Emission Behaviour in C‐(2′‐Pyridyl)‐ortho‐carboranes

“…Such low-energy emissions have been reported in other diaryl-ortho-carboranes and arise from charge transfer involving both the ring and the carborane cluster. [9,10,13,15,16,18,20,[22][23][24][25][26] The solid-state emission of 1,2-diphenylortho-carborane 16 here is expected as many derivatives containing the diphenyl-ortho-carborane unit emit in the solid state. …”

“…Photoexcitation of such dyads induced a charge transfer from an organic scaffold to the carborane cluster, which either led to luminescence quenching or to charge-transfer (CT) emissions or both -depending on the solvents used and whether the materials were investigated as solids. [7][8][9][10][11][12][13][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Dual fluorescence with CT and local transitions has been observed in some orthocarboranes. [12,13,[15][16][17][18][19][20]28] The ortho-carborane unit plays a role similar to meta-and para-carborane clusters in the photophysical process of a compound if there is a stronger electron acceptor than the cluster in these systems, [5,6,29,30] and if the ortho-carborane group is connected to a donor at one or more boron cluster atoms.…”

“…[33] Also other highly luminescent metal complexes have been reported with the pyridylcarborane unit present. [46] Given that there have been many articles on the observed luminescence of 1-monoalkyl-, 1-monoaryl-and 1,2-diaryl-ortho-carborane derivatives, [7][8][9][10][11][12][13][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] by contrast 1-monomethyl-ortho-carborane 4, 1-monophenyl-ortho-carborane 7 and 1,2-diphenyl-ortho-carborane 16 were quoted to be non-emissive. [20,30] …”

Modulation of the cis‐ and trans‐Conformations in Bis‐o‐carborane Substituted Benzodithiophenes and Emission Enhancement Effect on Luminescent Efficiency by Solidification

“…Even though intense luminescence can be observed in the solution state, optical properties were often spoiled through ACQ by intermolecular interactions in the solid state. [5][6][7] It has been reported that some of the o-carborane [8][9][10][11][12][13] derivatives presented AIE [14][15][16][17][18][19][20][21] and can be applied as a solid-state luminescent material. [1][2][3] Intense solid-state luminescent properties originating from AIE were found and applied for developing the conjugated materials, including polymers.…”

Electrochemical Properties and Reactions of Oxygen‐Containing Organotrifluoroborates and Their Boronic Acid Esters

“…Carboranes are also electroactive and show reversible reduction behavior, and their reduction potential is easily tunable with functional groups on the carbon atoms . We recently found that carboranes act as high‐performance electrocatalysts for the debromination reaction of alkyl halides …”