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Ionic Assembly, Anion–π, Magnetic, and Electronic Attributes of Ambient Stable Naphthalenediimide Radical Ions
Author(s) -
Kumar Sharvan,
Malik Vikas,
Shukla Jyoti,
Kumar Yogendra,
Bansal Deepak,
Chatterjee Ratnamala,
Mukhopadhyay Pritam
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201805978
Subject(s) - electron paramagnetic resonance , chemistry , ion , radical ion , photochemistry , supramolecular chemistry , ionic bonding , radical , crystallography , crystal structure , organic chemistry , nuclear magnetic resonance , physics
Organic spin‐based molecular materials are considered to be attractive for the generation of functional materials with emergent optoelectronic, magnetic, or magneto‐conductive properties. However, the major limitations to the utilization of organic spin‐based systems are their high reactivity, instability, and propensity for dimerization. Herein, we report the synthesis, characterization, and magnetic and electronic studies of three ambient stable radical ions ( 1 a .+ , 1 b .+ , and 1 c .+ ). The radical ions 1 b .+ and 1 c .+ with BPh 4 − and BF 4 − counter anions, respectively, were synthesized in excellent yields by means of anion metathesis of 1 a .+ with Br − as its counter anion. Notably, synthesis of 1 a .+ was achieved in an ecofriendly, solvent‐free protocol. The radical ions were characterized by means of single‐crystal X‐ray diffraction studies, which revealed the discrete nature of the radical ions and extensive hydrogen‐bonding interactions within the radical ions and with the counter anions. Thus, radical ions can be organized to form infinite supramolecular arrays using weak noncovalent interactions. In addition, the Br − , BF 4 − , and BPh 4 − anions formed diverse types of anion–π interactions with the naphthalene and imide rings of the radical ions. The radical ions were characterized by means of X‐band electron paramagnetic resonance (EPR) spectroscopy in solution and in the solid state. Magnetic studies revealed their paramagnetic nature in the range of 10 to 300 K. The radical ions exhibited high resistivity approaching the gigaohm (GΩ) scale. In addition, the radical ions exhibited panchromism.