Magnetic Study on a Two-Dimensional Coordination Polymer with Mixed Bridging Ligands

Abstract

A two-dimensional coordination polymer, [Co(mu(1,3)-SCN)(2)(mu(1,6)-dmpzdo)](n)() (where dmpzdo = 2,5-dimethylpyrazine-1,4-dioxide), has been synthesized and its crystal structure determined by X-ray crystallography. In the complex, the adjacent Co(II) ions are coordinated by mu(1,3)-SCN(-) bridging ligands which forms a one-dimensional chain along the a axis; the one-dimensional chains are further connected by mu(1,6)-dmpzdo bridging ligands which leads to the formation of a two-dimensional layer on the ac plane. The theoretical calculations reveal that a ferromagnetic coupling exists between the mu(1,3)-SCN(-) bridging Co(II) ions and an anti-ferromagnetic interaction between the mu(1,6)-dmpzdo bridging Co(II) ions, and the anti-ferromagnetic interaction is stronger than the ferromagnetic interaction. The fitting of the variable-temperature (34-300 K) magnetic susceptibilities reveals that there is an anti-ferromagnetic coupling between the bridging Co(II) ions with the magnetic coupling constant J = -3.52 cm(-1).

First-principle study on the electronic structure and the anti-ferromagnetic properties of the organic–inorganic hybrid compound [Co(μ1,3-SCN)2(μ1,6-dmpzdo)]n

“…In the AFM state, the total magnetic moment is 0.000 m B due to the interchain anti-ferromagnetic coupling and the spin population on Co 2+ is also about 2.358 m B (the other one is À2.358 m B ). So we can draw the conclusion that the Co 2+ ions of the compound are in the high-spin state in both FM and AFM states, which is in agreement with the experimental results [22]. Because of the 3d 7 4s 2 electronic configuration of Co, the Co 2+ has seven d electrons with five spin-up and two spin-down, and the Co atom has a local moment of 3 m B expected from electron-counting considerations [25].…”

“…The results reveal that the AFM state has the lowest energy among the three configurations and the difference is about 0.011 Ry between AFM and FM, while 0.153 Ry between AFM and NM. So the AFM phase is a stable ground state and the FM phase is a metastable state for [Co(m 1,3 -SCN) 2 (m 1,6 -dmpzdo)]n, which is in good agreement with the experimental results [22]. Table 1 also gives the total magnetic moments of the compound in FM and AFM states.…”

“…According to the experiment of X-ray diffraction, the optimized values of the compound, with space group P2(1)/c, adopted in the calculation are a ¼ 5.7128(14)Å, b ¼ 14.346(4)Å, c ¼ 6.9722(17)Å and a ¼ 90.001, b ¼ 97.468(3)1, g ¼ 90.001; and more details of the crystal data, including atomic positions, can be obtained from Ref. [22].…”

“…These materials may display two or more physical properties, such as conducting, magnetic and optical properties, coexisting in the same material, which might result in new physical phenomena and novel applications. In the meantime, numerous one-, two-and three-dimensional coordination polymers containing transition metal and light elements, typically C, N, O, S and H, exhibit a wide variety of cooperative phenomena, which attracts increasing interests among theoretical physicists and chemists [1][2][3][4][5][6][7][8], and there have been many theoretical studies on these systems devoted to understand the magnetic and the electronic properties at the microscopic level [9][10][11][12][13][14][15][16][17]. In the magneto-structure study areas, it is a new way to handle the magnetic couplings of two-dimensional bridge structural complexes by using the theoretical calculation and experimental fitting as mentioned above [18][19][20][21].…”

Syntheses, Structures, and Characterization of Two Novel Copper(II) and Cadmium(II) Compounds Based on Pyridyl Conjugated 1,2,3-Triazole

“…[1][2][3][4][5][6][7][8][9][10][11] More and more people have been focused on the rational design and controlled synthesis of coordination compounds using multidentate ligands such as polycarboxylate and N-heterocyclic ligands. [12][13][14][15] In recent years, there is a growing interest in the construction of coordination compounds based on triazole, tetrazole and imidazole derivates.…”