New Metal Zwitterionic Thiolate Complexes:Preparation,Structures And Properties

Thiols,being a common family of sulfur-containing ligands,have been widely used in organic intermediates,pesticide preparation,antidotes,pharmaceutical synthesis and so on.The chemistry of metal thiolate complexes has attracted much interest due to their diverse chemical structures and potential applications in electronics,optics,catalysis,sensing,biological simulation,advanced materials and other fields.Among them,there have been few reports about the research on metal zwitterionic thiolate complexes despite of their good solubility.In this thesis,new metal zwitterionic thiolate complexes have been prepared through different synthetic approaches using metal ions and aromatic zwitterionic thiolate TabHPF6(TabH = 4-(trimethylammonio)benzenethiol)as a ligand.Their physical and/or chemical properties have been further studied in order to explore the potential applications in the areas of optics,electricity,photocatalysis and sensing,etc.The results are mainly described as follows:1.A controllable two-step room temperature solid-state reaction of Pb(OAc)2 with TabHPF6 gave rise to a one-dimensional coordination polymer {[Pb(Tab)2]2(PF6)4}n(1)as an intermediate,which reacted with N-containing ligands(4,4'-bipy,bpb)to form two-dimensional coordination polymers {[Pb(Tab)2(4,4'-bipy)](PF6)2)n(2)and{[Pb(Tab)2(bpb)](PF6)2}n(3)in quantitative yields,respectively.This method avoids heating and use of solvents,which is in line with the requirements of green chemistry.All these complexes exhibited excellent dielectric properties with their permittivity smaller than SiO2 in the high-frequency range.It is anticipated that such metal zwitterionic thiolate complex-based functional materials may have potential applications as low-k materials in the field of microelectronics.2.Ambient temperature solid-state reaction of compound 1 with 1,2-bis(4-pyridyl)ethylene(bpe)quantitatively produced a unique two-dimensional coordination polymer {[Pb(Tab)2(bpe)]2(PF6)4}n(4).A Ag(?)-doped coordination polymer{[Pb(Tab)2(bpe)]2(PF6)4·1.64AgNO3}n(4a)was readily prepared by immersing 4 into AgNO3 aqueous solution via silver-sulfur interactions.Compared with its two precursors 1 and 4,4a exhibited greatly enhanced photocatalytic activity towards the degradation of a family of 12 azo dyes within a short period of time under UV light irradiation and excellent adaptability on the low-cost elimination of azo dyes in water.Such a synthetic strategy can be applicable to other coordination polymer systems to prepare more catalysts with new structures and better catalytic performance.3.Reaction of AgBr with TabHPF6 readily yielded a one-dimensional coordination polymer[(TabH)(AgBr2)]n(5),consisting of anionic chains[AgBr2]n n-with hydrogen bonds to TabH+ cations.The proton of the sulfhydryl group of each TabH+ cation was retained,which could further react with NH3 and organic amines through deprotonation of the acidic-SH groups,forming the corresponding products 6-10.By examining its electrical resistance and stability upon exposure to NH3 and 7 organic amines in water under ambient conditions,compound 5 exhibited good stability and reproducibly high sensitivity toward these analytes at low concentrations.Especially,it could selectively detect NH3 in water with the detection limit of 0.05 ppm.This chemiresistive sensing system has the potential for highly efficient monitoring of low-concentration NH3 and amines responsible for water eutrophication and food contamination.4.Tab-protected Ag nanoclusters were tentatively prepared due to intermolecular or intramolecular Ag … Ag interactions.The silver salts and TabHPF6 or Ag/thiolate complexes as precursors were employed to construct zwitterionic thiolate-protected polynuclear silver clusters(11-16)with unique structures through appropriate synthetic routes,which have been preliminarily characterized by elemental analysis,IR,TGA,XPS and EDS.