Syntheses of both the dimer (3) and the trimer (4) of all-para-brominated poly(N-phenyl-m-aniline)s (2c) were achieved in a one-pot procedure from the parent nonbrominated oligomers and benzyltrimethylammonium tribromide [(BTMA)Br(3)]. An X-ray crystallographic analysis revealed that 4 has a U-shaped structure, suggesting that 2c easily adopts helical structures. Furthermore, the redox properties were investigated by the UV-vis and EPR measurements. It was confirmed that the both 3 and 4 can be oxidized into the dications 3(2+) and 4(2+) with triplet spin-multiplicity.
A new dendritic oligoarylamine, N,N,N',N',N",N"-hexakis[4-(di-4-anisylamino)phenyl]- 1,3,5-benzenetriamine (BTA) 2, which contains a 1,3,5-benzenetriamine molecular unit as an potential precursor of a high-spin molecule and three oligoarylamine moieties as spin-carrying units surrounding the core BTA, has been prepared by the sequential palladium-catalyzed amination reactions. The redox property has been investigated by cyclic voltammetry, and the highly charged states up to the hexacation are accessible to 2. The polycationic high-spin species have been generated by stepwise chemical oxidation, and the electronic structures have been examined in detail by the continuous wave (CW) and pulsed ESR spectroscopy in comparison with the previously studied 1. The pulsed ESR technique enabled us to determine the definite spin multiplicity of the generated polycationic species of 2. It was confirmed that the dominant oxidized species observed by the two- and three-electron oxidations were assigned to the spin triplet 2(2+) and the spin quartet 2(3+), respectively. Moreover, these high-spin polycationic species turned out to be far more stable as compared to 1, and the isolation of 2(3+) as the SbCl(6)(-) salt has been accomplished. The temperature dependence of the magnetic susceptibility for the 2(3+)(SbCl(6)(-))(3) salt revealed that the intramolecular ferromagnetic interaction exists in 2(3+), and moreover, the trication 2(3+) was found to be deformed in the solid state.
Polycations of two oligoanilines based on Wurster's blue,N,N′,N″‐tris[4‐(dimethylamino)phenyl]‐N,N′,N″‐trimethyl‐1,3,5‐benzenetriamine (2) and N,N′‐bis(3‐{N‐[4‐(dimethylamino)phenyl]‐N‐methylamino}phenyl)‐N,N′‐dimethyl‐p‐phenylenediamine (3), have been generated efficiently by a stepwise oxidation procedure. Their redox behavior was characterized in terms of the embedded p‐phenylenediamine (PD) units and their intramolecular connectivity. EPR analysis of the oxidized 2 and 3 species revealed the existence of high‐spin species in solution. It was found that spin multiplicities of the dominant polycationic species of 2 and 3 formed by 3 equiv. of oxidant can be assigned to quartet and doublet states, respectively on the basis of pulsed EPR spectroscopy. These results demonstrate that the intramolecular connectivity between the spin‐containing units decisively influences the spin preference of the multispin systems based on oligoanilines.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.