Synthesis, Structures And Properties Of Novel CuSCN-CuCN Anionic Coordination Networks Templated By Polypyridine Cationic Complexes

This thesis mainly focuses on the solvothermal syntheses and characterization of newcopper(â… ) pseudohalides(CuCN/CuSCN) frameworks templated by complexes containingbipyridine-like ligands. In situ reactions sulfur transformations were involved during thesyntheses. Based on the template function of polypyridine coordination cations, the syntheses ofsome interesting anionic copper(â… ) pseudohailides infinite networks are explored.The thesis is divided into three chapters.In Chapter 1, the research background is concisely introduced with the emphasis on thecurrent survey of coordination polymers and in situ syntheses of metal complexes underhydro(solvo)thermal condtions and the copper(â… ) pseudohalides coordination polymers ofN-Containing heterocyclic ligands. The significancy and the progress of the field have also beenoutlined.In Chapter 2, the reactions of 2, 2'-bipyridine (bipy) with CuSCN under solvothermalconditions have been carried out and examined. Two Cu complexes{[Cu₃(CN)₄]·[Cu₂(CN)(bipy)₂]·2CH₃CN}_n(1) and [Cu₂(bipy)₂CO₃]·2SCN·3.33H₂O(2)wereyielded. Complex 1 contains 2-dimension (2D) CuCN anion networks supported by the metalcomplex cation generated in situ, while complex 2 contains two Cu(â…¡)atoms chelated by twobipy group and bridged with carbonate anion which generated by uptaking the carbon dioxide inair.In Chapter 3, the assembly of polypyridine metal complex cations as templates to direct thefabrication of anionic copper(â… ) pseudohalides networks has been carried out and examined. Thesolvothermal reaction of CuCN with dmbipy (4,4'-dimethyl-2, 2'-bipyridine)and NiSO₄·6H₂Oyielded a coordination polymer [Cu₄(CN)₄Ni(SO₄)(dmbipy)₂]_n(3), which was characterized tobe a Cu^â… -Ni^â…¡heterometallic compound of 2D network. Interlamellar interpenetration occurs viametal complex cations in the complex. In the reactions of dmbipy ligand, NiSO₄·6H₂O, CuSCN,and PPh₃ under solvothermal conditions, two novel CuSCN/CuCN coordination polymers wereobtained: [Cu₅(SCN)₂(CN)₇Ni₂(dmbipy)₄]_n (4) with a 3-D(3, 4) CuSCN-CuCN network,[Cu₇(CN)₇(CN)₂Ni(dmbipy)₃·0.63H₂O]_n(5) with a unusual 3-D CuCN anion network andencapsulating [Ni(dmbipy)₃]²⁺metal complex cations, which played as template to direct the formation of the final anionic network. The difference in syntheses for the preparation ofcomplex 5 and 4 is the reacttion molar ratio of PPh₃. Increasing the amount of PPh₃ resulted incomplex 5. The complex 6 was synthesized under solvothermal conditions similar to thesynthesis of complex 5, just using FeSO₄·7H₂O to replace NiSO₄·6H₂O. The structure ofcomplex 6 is similar to complex 5. During the synthesis of complex 4, 5 and 6, we can find thatthe PPh₃ may be a good sulfur capturer which generated by decomposing CuSCN undersolvothermal condition. To examine the influence of the template sizes on copper(â… )pseudohalide networks, a tridentate ligand 2,2':6',2"-terpyridine (tpy) was chosen. Under thesame solvothermal conditions, by simply increasing the molar ratio of PPh₃, the reactions ofligand tpy, NiSO₄·6H₂O,CuSCN, and PPh₃ yield two coordination polymers at the same time:[Cu₆(CN)₇(SCN)·Ni(tpy)₂]_n(7) and [Cu(tpy)Cu₂(CN)₃]_n(8). Complex 7 is a 3-D anionicCuSCN-CuCN network with unusual charge cages encapsulating bis-tpy metal complex cations,which play a crucial role in the structure-direction of final anionic networks. Comparing withthe reported compounds: [Cu₆(CN)₆(SCN)₂·Ni(tpy)₂]_n, in the anion network, the ratio of CN^-ligand is increasing, and SCN^- become less. Complex 8 is a coordination polymer justcontaining CuCN and tpy. The resulting complexes indicate that the employment ofpolypyridine metal complex cations as template to construct novel CuSCN-CuCN anionicnetwork is feasible, and the PPh₃ is good agent for capturing sulfur of CuSCN. The way ofsynthesis CuCN complexes by decomposing CuSCN, which may be difficult to obtain by directuse of CuCN, provides a new strategy for synthesizing new CuCN complexes.