Magnetic properties of a doped linear polyarylamine bearing a high concentration of coupled spins (S = 1)

Abstract

Magnetic properties of a doped linear polyarylamine (PA2), whose chain includes alternating para-phenylene and meta-phenylene groups, and of two cyclic and linear model compounds (C2 and D2) were explored by pulsed-EPR nutation spectroscopy, SQUID magnetometry and DFT calculations. Stoichiometrically doped PA2 samples exhibit a pure S = 1 state (exchange coupling constant J = 18 K) with a high spin concentration (0.65) corresponding to 65% of mers bearing holes. Such properties were already observed for doped reticulated polyarylamines but are quite unusual for doped linear polyarylamines. In order to better understand the properties of PA2, model compounds C2 and D2 were also investigated: pure S = 1 spin states could also be obtained, but with higher J (respectively 57 K and 35 K) and, surprisingly, with high but still limited spin concentrations (respectively 0.77 and 0.65).

Linear Oligoarylamines: Electrochemical, EPR, and Computational Studies of Their Oxidative States

“…The Supporting Information contains calculated energy results of compounds N2-N6, 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60…”

“…Although straight-chain compounds possessing the same or similar moieties (N1-N4 and N6) have been studied before, 2,22 we reinvestigated them to exploit their electronic properties systematically and in detail, and compared their electrochemical properties with those of N5. 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 Synthesis of N4. To a solution of N 1 ,N 4 -bis(4-aminophenyl)-N 1 ,N 4 -diphenylbenzene -1,4-diamine (N2-(NH 2 ) 2 , 0.111 g, 0.25 mmol) in 1,2-dichlorobenzene (5 mL) was added Cu (0.191 g, 3 mmol), K 2 CO 3 (0.346 g, 2.5 mmol), 18-crown-6 (0.10 g), iodobenzene (0.17 mL, 1.5 mmol).…”

“…Some investigations are typical examples of studies of organic mixed-valence molecules as hole transport materials to examine the intramolecular charge transfer (ICT) process, [11][12] and some are those of high-spin organic polyradicals to elucidate their stable multiredox properties of the magnetic triarylamine derivatives. [13][14][15][16][17][18][19][20][21] In comparison with the above, both these two cases incorporated "branching points" within dendrimers to link each triarylamine unit.…”

On‐Surface Driven Formal Michael Addition Produces m‐Polyaniline Oligomers on Pt(111)

“…Additionally, there is growing recent interest in PANI chains polymerized in the meta ‐position ( m ‐PANI), since its well‐known room‐temperature ferromagnetic behaviour [9, 10] has become of interest for tuning electronic and magnetic states, spin transport and spin interactions that may have important implications for applications in organic conductors and spintronics [11] and as possible precursor materials for the development of carbon magnets [12] . Albeit there are several synthetic routes to m ‐PANI homopolymers [13–16] or m ‐PANI/ p ‐PANI copolymer‐like structures, [17, 18] these reactions can be challenging, requiring multistep processes to obtain adequately pure materials.…”

On‐Surface Driven Formal Michael Addition Produces m‐Polyaniline Oligomers on Pt(111)

“…[8] Additionally, there is growing recent interest in PA NI chains polymerized in the meta-position (m-PANI), since its well-known roomtemperature ferromagnetic behaviour [9,10] has become of interest for tuning electronic and magnetic states,s pin transport and spin interactions that may have important implications for applications in organic conductors and spintronics [11] and as possible precursor materials for the development of carbon magnets. [12] Albeit there are several synthetic routes to m-PANI homopolymers [13][14][15][16] or m-PANI/ p-PANI copolymer-like structures, [17,18] these reactions can be challenging,r equiring multistep processes to obtain adequately pure materials.…”