Synthesis Of Bis (Triarylamine) Diradicals And Study On Their Near-Infrared Absorption Properties

A diradical is a compound that contains two weakly interacting unpaired electrons.The diradicals with nitrogen atoms have significantly optical,electrical and magnetic properties,which make them be potential candidates in information storage materials,electronic devices,molecular magnets,lithium ion batteries,optoelectronic materials and so on.In this thesis,we designed and synthesized a series of dicationic diradicals with nitrogen atoms,which possess different bridging groups that bear weakly coordinating anions.The structures and properties of these compounds were studied in detail.This paper provides a new perspective for the construction of diradical compounds with novel structures and properties.1.A series of bis?triarylamine?compounds 1-5 with the bridging rings of naphthalenyl,and anthracenyl groups were synthesized.Dicationic diradicals 1²⁺"2[Al?ORF?₄]^--5²⁺,2[Al?ORF?₄]^-were successfully stabilized and isolated through two-electron oxidation with two molar equivalents of AgAl?ORF?4.The geometry and electronic structural properties were studied by various experimental methods and DFT calculations.The ground state of the diradical compounds 1²⁺?1,5-di?bisarylamine?naphthalene dication?and 2²⁺?2,6-di?bisarylamine?naphthalene dication?with Kekule configuration are closed-shell singlets.In contrast,3²⁺?2,7-di?bisarylamine?naphthalene dication?is ground-state triplet molecule.The naphthalenyl and anthracenyl bridged Kekule-type compounds 4²⁺?1,2-di?bisarylamine?naphthalene dication?and 5²⁺?1,2-di?bisarylamine?anthracene dication?with Kekule configuration exhibit large diradical property,4²⁺ is an open—shell singlet diradical.Our work further enriches the Kekule and non-Kekule type diradical systems with naphthalene and anthracene as ?-linker groups.2.We synthesized a series of organic dye molecules based on diradical concept that have a strong near-infrared?NIR?absorption peak beyond 1000 nm.In this part,a series of diradicals on the basis of BODIPY core(6²⁺-10²⁺)with different substituents were obtained.The UV-vis spectra show that each of them has a strong near-infrared absorption peak in CH2Cl2 solution.We can obtain NIR dyes with different absorption wavelengthes by tuning the electronegativity of the terminal 2,6-position substitutions.This work provides a new class of potential materials for the optical communication field of 1300 nm and provides guidance for the preparation of near-infrared absorption dyes using the concept of diradicals.