Substituent effects on the electrochemical and spectral characteristics of N,N,N′,N′-tetraaryl-p-phenylenediamine derivatives

Manipulation and Assessment of Charge and Spin Delocalization in Mixed-Valent Triarylamine–Vinylruthenium Conjugates

“…Blending the vinylruthenium and TAA entities together in one compound has led to strongly coupled, intrinsically delocalized MV systems if the vinylruthenium moiety attaches to the phenylene linker in the para position to the amine N atom. , This is opposed to the situation where a redox process (predominantly) involves either the metal ion or a redox-active, noninnocent ligand of the inner coordination sphere with only a little electron delocalization between them but strongly resembles the situation in the other delocalized, unsymmetrical MV systems such as PCT-TAAs, N , N , N ′, N ′-tetraarylphenylenediamines with different aryl substituents at the N and N′ atoms, , a heterobimetallic divinylphenylene-bridged ruthenium/osmium complex, and the alkenyl/alkynyl complexes {Ru}­CHCHC 6 H 4 CCRu­(dppe) 2 (L) (L = Cl or CCPh). , Their associated oxidized forms absorb strongly in the near-infrared (NIR) with stepwise blue shifts of the underlying intervalence charge transfer (IVCT)/π → π* bands upon further oxidation . In particular, the charge and spin density of the MV radical cation of the bis­(anisyl)­amine complex {Ru}­CHCHC 6 H 4 N­(C 6 H 4 -4-OMe) 2 ( 1-OMe of Scheme ) is equally distributed over the TAA and vinylruthenium moieties.…”

Asymmetric redox reactions of C3-symmetric starburst compound with six arylamines

“…5 shows the voltammogram of MPA and the variation of n with E obtained by chronoamperometry. The maximum value of n is 2, and there is an intervalence state for n = 1 in 0.27 < E < 0.73 V. The oxidation mechanism of MPA has been reported to be [12,36,37] …”

“…1A, was synthesized from N,N 0 -diphenyl-1,4-phenylenediamine and 4-iodoanisole via the Ullmann reaction [12,15]. The purification was carried out by silica gel column chromatography and recrystallization (yield: 70%).…”

“…The intervalence complexes have been extended also to organic compounds such as phenylenediamine derivatives [11][12][13], hexamine derivatives [14], triaminobenzene derivatives [15], tetrathiafulvalene derivatives [16], arylenevinylenes [17], oligothiophenes [18,19], and topologically complicated p-conjugated oligoarylamines [15,[20][21][22][23] mainly based on the spectroscopic analysis. Since intervalence states vary with multi-redox states or various kinds of mixed-valence species, electrochemical study has played a vital role in controlling accurately intervalence states by electrode potential [24][25][26].…”

“…Since intervalence states vary with multi-redox states or various kinds of mixed-valence species, electrochemical study has played a vital role in controlling accurately intervalence states by electrode potential [24][25][26]. Geometrically symmetric redox sites have exhibited asymmetric voltammetric behavior in a complicated manner [15].…”