Study of Molecular Dimer Morphology Based on Organic Spin Centers: Nitronyl Nitroxide Radicals
oleh: Dongdong Wei, Yongliang Qin, Zhipeng Xu, Hui Liu, Ranran Chen, Yang Yu, Di Wang
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2024-04-01 |
Deskripsi
In this work, in order to investigate the short-range interactions between molecules, the spin-magnetic unit nitronyl nitroxide (NN) was introduced to synthesize self-assembly single radical molecules with hydrogen bond donors and acceptors. The structures and magnetic properties were extensively investigated and characterized by UV-Vis absorption spectroscopy, electron paramagnetic resonance (EPR), and superconducting quantum interference devices (SQUIDs). Interestingly, it was observed that the single molecules can form two different dimers (ring-closed dimer and “L”-type dimer) in different solvents, due to hydrogen bonding, when using EPR to track the molecular spin interactions. Both dimers exhibit ferromagnetic properties (for ring-closed dimer, J/k<sub>B</sub> = 0.18 K and ΔE<sub>S−T</sub> = 0.0071 kcal/mol; for “L”-type dimer, the values were J/k<sub>B</sub> = 9.26 K and ΔE<sub>S−T</sub> = 0.037 kcal/mol). In addition, the morphologies of the fibers formed by the two dimers were characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM).