Tunable Reduction of 2,4,6‐Tri(4‐pyridyl)‐1,3,5‐Triazine: From Radical Anion to Diradical Dianion to Radical Metal–Organic Framework

Abstract

The reduction of 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT) with alkali metals resulted in four radical anion salts (1, 2, 4 and 5)and one diradical dianion salt (3). Single-crystal Xray diffraction and electron paramagnetic resonance (EPR) spectroscopyr eveal that 1 contains the monoradical anion TPTC À stackedi no ne-dimensional (1D) with K + (18c6) and 2 can be viewed as a1Dmagnetic chain of TPTC À ,while 4 and 5 form radical metal-organic frameworks (RMOFs). 1D pore passages,w ith ad iameter of 6.0 ,c ontaining solvent molecules were observed in 5.V ariable-temperature EPR measurements showt hat 3 has an open-shell singlet ground state that can be excited to at riplet state,c onsistent with theoretical calculation. The work suggests that the direct reduction approach could lead to the formation of RMOFs.

Preliminary chemical reduction for synthesizing a stable porous molecular conductor with neutral metal nodes

“…To the best of our knowledge, a similar method was used to the synthesis of radical MOFs only once, whereas their conducting properties were not reported. 26 To prove the validity of the method, [Co(acac) 2 ] (acac = acetylacetonate) was chosen to act as the neutral metal node because it can form stable linear coordination polymers with pyridyl-based bridging ligands. 27,28 As expected, upon mixing DMA solutions of [Co(acac) 2 (MeOH) 2 ] and NDI-py, the linear coordination polymer [Co(acac) 2 (NDIpy)]Á2DMA (2 0 ) rapidly precipitated (Fig.…”

Radical Stabilization of a Tripyridinium–Triazine Molecule Enables Reversible Storage of Multiple Electrons

“…In this way, the negative charge is delocalized on the two conjugated rings, which is acknowledged to favor the stabilization of the monoradical [16] . Figure 2 b reveals that the state 2 possesses a singlet open‐shell ground state, which is similar to the 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine molecule [17] . The spin density of the state 2 is distributed over two pyridinium rings and the central triazine ring, displaying biradical characteristics.…”

“…Its intensity decreases from state 0 to state 3, indicating the triazine structure gradually evolves as the reduction reaction proceeds. Two more absorption waves centered at 350 and 900 nm are seen for both state 1 and state 2, which can be attributed to the radical's transition [17, 18] . And the state 2 shows stronger absorbance than does the state 1, indicating that the state 2 is biradical.…”

Visible colorimetric dosimetry of UV and ionizing radiations by a dual-module photochromic nanocluster

“…The incorporation of a metal center with a high atomic number (Z) endows the material with increased radiation attenuation efficiency 18 , 19 . Furthermore, coordinating linkers decorated with a photoactive ligand, such as pyridine, viologen, and azobenzene, allows for charge transfer and formation of radical species upon irradiation, inducing visualizable color transitions 20 – 24 . Metal-organic complexes featuring ionizing radiation induced photochromism remain to be a small group among the numerous numbers of photochromic materials; systems showing photochromically modulated luminescence are even less common 25 – 27 .…”