Synthesis, Structures, Properties Of Complexes Of Thiapyrazinophane With Transition Metals

Since the fifties of last century, the chemists began to pay attention to the phane compounds, and researched them widely. Cyclophane is important one of the phane compounds. Especially in the coordination chemistry and supramolecular chemistry, it was used widely.The bridging of cyclophane containing sulfur atoms is easy to corrdinate,Because of the sulfur atoms of alone electronic,make its isolated with the combination of transition metal ability will increase, The coordination compounds formed will be more stable. In recent years,our laboratory starts to study the bridging of pyrazinophane containing sulfur in-depth. In this paper, we use 2,6-dimethylpyrazine as the starting material, synthesize 2,11-dithia[3.3](2,6)pyr azinophane, and contain 2,11,20-trithia[3.3.3](2,6)pyrazionphane and 2,11,20,29-tet rthia[3.3.3.3](2,6)pyrazinephane. We used 2,11-dithia[3.3](2,6)pyrazinophane as the ligand to synthesize four coordination compounds with Cu(Ⅰ),Cu(Ⅱ) and Fe(Ⅱ). we analyze them by X-ray structure analysis.When we use 2,11-dithia[3.3](2,6)pyrazinophane to coordinate with copper nitrate, We find that part of the ligand is oxidated by Cu (Ⅱ), and Cu (Ⅱ) is reducted into Cu (I), we get two corrdination compounds 25 and 26. The conformation of two coordination compounds is the syn (boat-boat), different from conformation of the ligand syn (boat-chair). The complex dihedral angle formed by the two pyrazine molecules is to 34.99°. Cu(Ⅰ) ion coordinates with five atoms, which is two sulfur atoms, two nitrogen atoms in between of bridging and one nitrogen atom of the other thiapyrazinophane. The 2,11-dithia[3.3](2,6)pyrazinophane is formed one-dimensio nal chains structure through Cu(Ⅰ). The adjacent pyrazine molecules rotate 90°along the chain formed through Cu(Ⅰ). Between of chains reserve arrangement,and haveπ···πstacking, form hydrogen bonds through nitrate ions. The coordination compound 25 forms the three-dimensional structure through hydrogen bonds andπ···πstacking. That the complexs dihedral angle formed by the two pyrazine molecules is to 68.35°in the coordination compound 26, Cu(Ⅱ) ion coordinates six atoms, which is with two sulfur atoms, two of the nitrate oxygen atoms and two nitrogen atoms in between of bridging, and forms contorted octagonal configuration. The coordination compound 26 forms the three-dimensional structure through hydrogen bonds andπ···πstacking.When we use 2,11-dithia[3.3](2,6)pyrazinophane to coordinate with ferric trichloride, it happens redox reaction. we get the coordination compound with Fe(Ⅱ) 28. when we use 2,11-dithia[3.3](2,6)pyrazinophane to coordinate with copper chloride, we get the coordination compound with Cu(Ⅱ) 27. The two coordination compounds 27 and 28 have the same structure. The conformation of two coordination compounds 27 and 28 are the syn (boat-boat), and different from the conformation of the ligand syn (boat-chair). The metal ions of the two complexs are in coordination with six atoms, the metal ion coordinate with two sulfur atoms, two the nitrogen atoms in between of bridging and two chloride ions , and form contorted octagonal configuration. The corrdination compounds 27 and 28 form the three-dimensional structure through hydrogen bonds.We research the electrochemical properties of the complexs 25,27,28. From the cyclic voltammograms of the pictures,we can conclude that the stability of the complexs increases, and the complexs is not easy to happen redox reaction. We research the optical properties of complexes 25,27 and 28. In the ultraviolet spectrum of the complexes 27 and 28, we find that the maximum absorption peaks of the two complexs unchange compared with the ligand position. The complex 25 has a blue shift, and they all show electronic warp of the ligand. In fluorescence spectrum, we find that the fluorescent intensity of the complexes 25,27,28 was weak in comparison with the ligands fluorescence. The magnetic property of 27 is antiferromagnetic.