Study On Coordination, Structure And Properties Of N, O Organic Ligands And Transition Metals

Transition metal ions are ubiquitous in nature. The human body and the environment has been a certain degree of hazard by the over use of transition metal ions. How to apply the proper organic ligand to make these transition metal ions into environmental friendly and widely used materials, which are of considerable potential values with their special properties of magnetism, bioactivity, SOD activity and catalysis etc, has become a research hotspot subjects in many fields such as chemistry, physics, biology, medicine, environmental science, materials science, etc. These environmental friendly and widely used materials are called metal organic functional complex which are also called Metal-Organic Frameworks(MOFs). Study on MOFs not only broadens the research subjects, but also provides a new research idea. On one hand, advanced treatment about overuse of transition metal ions should be carried out. On the other hand, it is also an effective treatment to make these transition metal ions become considerable potential materials. In conclusion, it is a real study of comprehensive treatment and utilization of transition metal ions.Transition metal complexes have drawn great attention and become one of the most popular research toptics due to their unique structures, large surface areas, designable pore texture, hight porosity and special physical and chemical properties. These complexes have also been proved to be very promising in environmental science fields, such as gas adsorption, separation, purification, capture of greenhouse gas CO2and so on. Recently, some of these special transition metal complexes are utilized not only a noval adsorbent but also a new photocatalyst to decompose organic pollutants. But at present, reseach on this aspect is very weak and lacks the corresponding experimental data and theorectical analysis.In order to design and synthesize MOFs, this thesis is firstly focus on using organic ligands containing N-or O-donors as major ligands, and using small molecule of organic carboxylate and SCN" etc as coligands to coordination to transition metal ions such as Cu2+、Co2+、Ni2+、Mn2+by means of solvent evaporation method and hydrothermal synthesis. Secondly, these MOFs have been characterized by IR, elemental analyses and TGA analyses, and X-ray diffraction technique. Their interesting structures have been analysed deeply by the softwares such as Topos, Diamond and Olex2. Thirdly, these MOFs were valued for their antimicrobial activity, magnetic properties, SOD activity and photocatalytic properties of degradation of methylene blue(MB). This thesis reveals not only the stacking, sorting characteristics, interaction between coordination units in the complexes, but also the relationship between the structures and properties. The work could provide more information for the research and development of new transition metal functional materials. All of this can offer abundant theoretical models and provide a stable academic foundation for the purpose of actual application of MOFs. Specific contents are summarized as follows:(1) Three MOFs namely {[Cu(phen)(H2O)]·SO4}n(1),{[Co(phen)(H2O)3·SO4]}n(2) and {[Cu2(phen)2(tar)(H2O)]·8H2O}n(3) have been obtained using1,10-phenanthroline and tartaric acid as ligands. In complex1and2, because synthetic materials are sulphates and the coordination ability of sulfate is more power than tartrate’s, tartaric acid are not coordinated to the metal ions. In complex1, interestingly, by means of hydrogen bonds, the two parts of [Cu(phen)(H2O)]2+molecular fragments and sulfate groups in the same structure unit are connected with other adjacent sulfate groups and [Cu(phen)(H20)]2+molecular fragments, respectively. In addition, π...π interactions of complex1have been observed and centroid-centroid distance is3.535A. Due to these driving forces,3D network structure of the supramolecular is consolidated. In complex2, rare Co...H hydrogen bond with the distance of1.995A is observed. π...π interactions are observed with centroid-centroid distance of3.728A and3.832A. Each of the two coordination units connected by means of π...π interactions has the same arrangement in the odd layer. In the even layer, the situation is the same.π...π interactions has the feature of chiral.{[Cu2(phen)2(tar)(H2O)]·8H20}n(3) is dinuclear complex, and diverse hydrogen bonds and π-π interactions have been observed in it. Centroid-centroid distances span the range3.610-3.864A. It is worth mentioning that six of the eight uncoordinated water molecules are connected via hydrogen bonding interations forming a pecular1D wavy layer. Similarity,2D structure by these significant hydrogen bond interactions have been constructed. Magnetic susceptibility measurements of complex3shows weak antiferromagnetic exchange between the copper(II) ions (J=-5.92cm-’).(2)A new supromolecular, namely{[Co(C5H8N2)2(NCS)2]·H2O}n(4) has been synthesis based on3,5-dimethylpyrazol, and it forms1D network by extended hydrogen bonding.(3)Two novel coordination polymers based on Schiff-base ligands, namely {[Co3(bpd)5.5(NCS)6(NH3)]2}n·2H2O(5) and{[Co(C13H1oN2O2)2(Cl)2]·2H20}n (6) have been synthesized. In complex5, one trinuclear cluster is further connected with another to form a hexanuclear chain by a bpd ligand. Compound5presents2D[3,4,4]-connected3-nodal net with the point symbol (42·6·82·10)(44·62)(82·10). In addition, four identical2D single nets is interlocked with each other in parallel, thus directly leading to the formation of a polycatenated layer(2D→2D). Magnetic susceptibility measurements of complex5shows weak antiferromagnetic exchange between the copper(II) ions (θ=-21.3K). Fairly rich intermolecular hydrogen bonds have been obtained in complex6. A structural unit is divided into two parts, namely [Co(C13H10N2O2)2(Cl)2] and two uncoordinated water molecules, but there is no hydrogen bonding between them and they are connected with other adjacent [Co(C13H10N2O2)2(Cl)2] or uncoordinated water molecules. Most notably, the arrangement of [Co(C13H10N2O2)2(Cl)2] bridged by hydrogen bonds has the characteristic of chirality. In oven layer, the arrangement of [Co(C13H10N2O2)2(Cl)2] is the same, while in odd layer, the arrangement is the same, too. In the same oven layer or odd layer, one [Co(C13H10N2O2)2(Cl)2] molecular fragment is connected with another bridged by hydrogen bonds forming along the horizontal direction. In addition, two adjacent [Co(C13H10N2O2)2(Cl)2] in the oven layer and odd layer respectively, is also connected by means of hydrogen bonds along the vertical direction. Thus, a chiral supramolecular with2D networks is formed. Magnetic susceptibility measurements of complex6shows very weak antiferromagnetic(θ=-1.21K).(4) Two novel coordination compounds, namely{[Co(nic)2(H2O)4]}n(7) and {[MnNa2(imdz)2(NCS)2]·H2O}n(8) have been synthesized based on heterocyclic carboxylic acid. In complex7, on one hand, the four O-atoms of the coordinated water in each chain are engaged in sixteen hydrogen bondings with the non-coordinating carboxylate groups of nicotinic acid ligands of the six adjacent units,on the other hand, in each unit, the four O-atoms of the two nicotinic acid ligands are also engaged in eight hydrogen bondings with six O-atoms of the coordinated water in the adjacent units.It is worthwhile to note that a3D hydrogen bonding network were formed in complex7if the hydrogen bonding interactions between oxygen atoms of carboxylate groups and H atoms of the pyridyl group with carbon atoms are all taken into account. Moreover, π...π interactions are observed with centroid-centroid distance of3.744A, which contributes to the additional stability of the structure. Complex7was found to be active against the three test bacterial organisms, namely, Staphylococcus aureus, Bacillus subtilis and Escherichia col. With the increase of concentration, the complex of bacteriostatic effect also increase. Compound8is a polynuclear hetermetallic polymeric compound. The organic ligand,2,4-Imidazole dicarboxylic acid coordinated with metal ions in the form of protons. Along the horizontal direction, the organic ligand coordinated with manganese ion to form2D plane, while along the vertical direction, SCN-is bridged with sodium ion through sulfur atoms and bridged with cobalt ions through nitrogen atoms. Along the same direction, organic ligand is also connected with sodium ion. Compound8presents3D[20,21]-connected2-nodal net with the point symbol (386·495·59)2(392·4113·55). Magnetic susceptibility measurements of complex6shows weak antiferromagnetic(θ=-3.16K).(5) A novel coordination compound, namely {[Ni(BPA-)(SCN-)]·1.5H2O}n has been synthesized based on N2-(2-pyridylmethyl)-2-pyridinecarboxamide, which was obtained by the reaction of picolinic acid and2-(aminomethyi)pyridine. Intermolecular C-H...O, O-H...S and O-H...O hydrogen bonds and π...π interactions were found in this complex, which urge the complex to form3D supramolecular networks. Interestingly, the non-coordinated water molecules connect through hydrogen bonds to form "V-like" intermolecular hydrogen bonding interactions with donor-acceptor (O...O) separations of1.91A. Magnetic susceptibility measurements of complex6shows weak ferromagnetic(θ=3.1K).(6)The SOD-like activity of the nine single crystals of complexes have been determined. The results indicate that these complexes,{[Cu2(phen)2(tar)(H2O)]·8H2O}n(3)and {[Ni(BPA")(SCN-)]·1.5H2O}n(9) possess excellent SOD-like activities with IC50values of40.52)μM and27.02μM, respectively. (7) Moreover, these nine single crystals of complexes have been applied to catalyze the reaction of photocatalytic degradation of methylene blue(MB)(10mg/L) under high-pressure mercury lamp irradiation. Excitingly, these complexes,{[Co3(bpd)5.5(NCS)6(NH3)]2}n·2H2O (5) and {[MnNa2(imdz)2(NCS)2]·H2O}n(8) present extremely good photocatalytic properties with their photocatalytic activities increasing from18%(without any catalyst) to87.41%for5and61.63%for8after300minutes of irradiation. Complexes5and8show distinct catalytic activity due to the directionality of metal ions-ligand coordination and the specific configurations defined by the multipodal linkers, which could generate cavities/channels that might be accessed from the exterior allowing mass transfer and the incorporation of substrates inside the crystal.