Synthesis and Magnetic Properties of Orthogonally Linked Phenothiazine Cation Radical Dimer and Tetramer

Abstract

A 3,3'-orthogonally linked phenothiazine cation radical dimer with methyl substituents at the 2, 2', 4, and 4' positions was synthesized. The dimer was isolated as a stable product which exists in a triplet state due to a torsion angle of ca. 80 degrees between the two phenothiazine units. The tetramer was also synthesized by linking the dimers using a 1,4-phenylene spacer.

A double hetero[4]helicene composed of two phenothiazines: synthesis, structural properties, and cationic states

“…[1][2][3][4] In particular, directly connected phenothiazine oligomers, which are the simplest multi-redox systems consisting of phenothiazines, have been of interest in the studies of electronic and magnetic interactions among the phenothiazine units. [5][6][7][8][9][10][11] Another important feature of phenothiazines is the controllability of the structure by redox stimuli. Phenothiazine derivatives possess a bent structure along the S-N axis with the bending angle (denoted as y b ) of typically 150-1601, and upon oxidation, the phenothiazine skeleton transforms to the more planar structure.…”

Oxidation State Tuning of Room Temperature Phosphorescence and Delayed Fluorescence in Phenothiazine and Phenothiazine‐5,5‐dioxide Dimers

“…It is able to undergo a fully reversible single-electron oxidation at low applied potentials to form stable radical cation species which gives it intriguing electrochemical and magnetic properties. [5][6][7][8][9][10] These reliable electrochemical properties of PTZ derivatives have led to their study in a variety of organic electronic technologies, [11] most notably organic dyesensitized, [12][13][14][15][16][17] bulk heterojunction [18][19][20][21] and perovskite solar cells. [22] In contrast, the emissive properties of PTZ are complex, often involving an interplay between triplet-mediated luminescence processes and conformational changes associated with the butterfly geometry.…”

The 3,5‐dinitroanilide anion: a singlet anilide anion with evidence for a thermally accessible triplet state

“…Organic molecules having unusual electronic properties, such as low-lying high-spin electronic states, have been of interest for several decades. [1][2][3][4][5][6][7][8][9][10] Although the long-term aspiration of designing commercially interesting organic magnetic materials remains elusive, fundamental studies have identified several families of organic species that are either ground state triplets or have low-energy triplet states. [11][12][13][14][15][16][17][18] These include carbenes, [19][20][21] nitrenes, [22][23][24][25] diradicals, [1,[26][27][28][29][30][31][32] nitrenium ions, [33,34] certain aryl cations, [35][36][37][38][39] , and antiaromatic cations such as cyclopentadiene.…”

“…Organic molecules having unusual electronic properties, such as low‐lying high‐spin electronic states, have been of interest for several decades . Although the long‐term aspiration of designing commercially interesting organic magnetic materials remains elusive, fundamental studies have identified several families of organic species that are either ground state triplets or have low‐energy triplet states .…”