Design, Synthesis And Properties Of Novel Intercalation Compounds Of Macrocyclic Polyamines

Considerable research activity has focused on the inorganic-organic hybrid materials due to their theoretical significance and applications in many fields. Intercalation of organic species into layered inorganic solids provides a useful approach to design and synthesize some functional materials including optical, electric and magnetic materials. The intercalation compounds with the transition metal phosphorus trisulfides as hosts have attracted scientists' great interests mainly due to their unique magnetic properties. Now some important challenges remain to be answered by material chemists. For example, how to synthesize new intercalates with higher magnetic transition temperature? Is that possible to synthesize multifunctional materials, especially conductive magnet by this approach? This thesis has attempted to respond to these challenges. Various cyclic polyamines and their complexes were chosen as the guests due to their strong ability to coordinate the transition metal ions and some other features. In this thesis, more than ten intercalation compounds with a variety of the guests and the hosts have been designed and synthesized, and their solid state electrical and magnetic properties studied. A new type of conductive magnet has been obtained through intercalation approach for the first time. The main contents and discoveries in the thesis are as the following:The thesis is divided into two parts. The first part (Chapters 2-5) focuses on the synthesis, structural characterization and electrical and magnetic properties of some new intercalation compounds of MnPS3 or Mn_xCu_yP_zS₃ with some cyclic polyamines and their transition metal complexes. The second part (Chapter 6) reports the study on the synthesis and properties of the intercalation compounds based on the host a-zirconium phosphate. In this thesis, nineteen new compounds have been synthesized including thirteen intercalation compounds of the lamellar MnPS3, three intercalation compounds of mixed transition metal phosphorus trisulfides Mn_xCu_yP_xS3 and three intercalates based on the host a-zirconium phosphate.Chapter 1 reviews the recent advances on the intercalation compounds including the major preparation methods, structures, properties and their potential applications, with the emphasis on the macrocycle-inorganic intercalation compounds and the MPS3 intercalates. Furthermore, the design strategies and the research contents of the thesis are presented in the end of this chapter.Chapter 2 describes the synthesis, structural characterization and some physical properties of four new intercalation compounds based on the host MnPS3; employing two macrocyclic tetraamines and their copper(II) complexes as the guests.Compared with the lattice spacing and the molecular size, it is proposed that the plane comprised of four nitrogen atoms and copper(II) cation of the guests is almost parallel to the layer of the host. The UV-vis adsorption spectra of the filtrates in preparation of the intercalates of macrocyclic polyamines into M11PS3 indicate that macrocyclic polyamines complex the Mn2+ which is removed from the intralamellar into the solution during the reaction. The room-temperature electrical conductivity of Mno.84PS3(Cu-dioxo[13]aneN4)o.i6 is 1.4x 10"9 S/cm, higher than that of the other three intercalates which are all lower than 10¹0 S/cm. Their magnetic properties are studied with SQUID. For the intercalates Mno.84PS3(dioxo[13]aneN4)o.32 and Mno.82PS3(cyclam)o.i8, bulk spontaneous magnetization below 40 K was observed. For Mno.89PS3(Cu-dioxo[13]aneN4)o.n, four magnetic transitional periods occur in the range between 40 K and 14 K. The first magnetic transition at 40 K indicates a ferromagnetic transition, but in the range of 32 K to 20 K, the antiferromagnetism plays the main role in it. The intercalate exhibits bulk spontaneous magnetism between 20 K and 14 K, and below 14 K the intercalate exhibits antiferromagnetism. The similar magnetic property was observed for the intercalate Mno.57PS3(Cucyclam)o.43- In Chapter 2, the intercalation process of dioxo[13]aneN4 into layered M11PS3 is also monitored in detail with X-ray powder diffraction. It is found that the absence or presence of acetate acid greatly influences the reaction process. The intercalation mechanism is proposed on the base of the experiments and the in-situ coordination of the inserted guest is observed.In Chapter 3, a mesocyclic diamine and a Schiff base kind of macrocyclic tetraamine and their transition metal complexes(M = Ni, Cu, Co) are selected as guests to react with MnPS3. The best reaction conditions are explored and the intercalates with better crystallinity are obtained. The intercalation compounds are characterized by elemental analysis, thermal analysis, X-ray powder diffraction and infrared spectroscopy. During the course of the intercalation of Schiff base kind of macrocyclic tetraamine into MnPS3, the guest hydrolyzed into dihydrobromate salt of ethylenediamine, so the really inserted guest is the cation form of ethylenediamine. The electrical conductivity is measured with two probe method. The room-temperature electrical conductivity of the two intercalates with copper(II) complexes as guests are little higher than the pristine host and the other intercalates do not increase electrical conductivity of M11PS3. The magnetic measurements with SQUID indicate that the intercalation compounds of mesocyclic diamine and ethylenediamine exhibit paramagnetism in the whole temperature range of the measurement, most probably because of the strong dilution effect of the cation vacancies. The four intercalates of Ni(II) and Cu(II) complexes exhibit similar magnetic properties, and they show bulk spontaneous magnetism around 40 K.Chapter 4 describes the synthesis, structural characterization and properties of a new intercalation compound, Mno.76PS3(NiPc)o.45. It is synthesized through the pre-intercalate Mno.83PS3(bipy)o.5j with NiPcIx. Comparing the molecular size and the interlayer expansion, the most possible arrangement of the guest is presumed. Guest NiPc is a nearly plannar compound and it adopts two forms of arrangements within the interlayer region. One is the molecular plane parallel to the layers with a monolayer and the other arrangement is the incline of the molecular plane to the layers with the angle of 26°. The room-temperature electrical conductivity of the intercalate is 3.7 X 10"9 S/cm, just a little higher than the pure MnPS3. The reason of the low conductivity is presumed. The magnetic property of the intercalate is studied with SQUID and the intercalate shows paramagnetism in the whole temperature range of the measurement.hi Chapter 5, a new type of molecular conductive magnet has been obtained through intercalation approach for the first time by reacting Cu(II)- dioxo[13]aneN4 complex with mixed transition metal phosphorus trisulfides MnxCuyPzS3. The intercalation process has been successfully repeated leading to the products with almost identical physical properties. The compositions of the hosts and intercalates are ascertained by elemental analysis. Through X-ray powder diffraction, the expansion of the lattice spacing are around 3.8 A, indicating the plane comprised of four nitrogen atoms and copper(II) cation of the guests is almost parallel to the layer of the host. The UV-vis adsorption spectra of the filtrates after the reaction indicate the existence of Mn2+ in the solution and it has also been proved by the infrared spectroscopy which shows the presence of intralamellar manganese vacancies. Their elemental valences are studied with X-ray photoelectron spectroscopy. The states of the Cu elements in the hosts are the mixed valences of +1 and +2. In the intercalation compounds, the copper exsits mainly in the form of univalence. The states of S and P in both the hosts and the intercalates are found to be probably mixed valences. The change of the valences is presumed to be caused by the electron transfer between the hosts and the guests. Their room-temperature electrical conductivity studied with four-probe method is much higher than the pristine MnPS3. We also perform the measurement of the electrical conductivity versus the temperature of the hosts and intercalates. The room-temperature electrical conductivities of the intercalates are as high as 4.4⁸.7 S/cm and the temperature dependence of the resistance of the intercalates I2 and I3 exhibits a metallic behavior over the entire temperature range we investigated (from 300 K down to 26 K). This kind of character is very special among transition metal phosphorus trisulfides and their intercalation compounds. This feature may be caused by the mixed valences in the compounds and possible interaction between the host and guest. Their magneticproperties are studied by a SQUID magnetometer. For the three intercalates, spontaneous magnetization at low temperatures were observed with the transition temperatures being 28 K, 8 K and 50 K, respectively. The spontaneous magnetization is further confirmed by the hysteric behavior in the magnetization curve at 1.85 K.In Chapter 6, a macrocyclic dioxotetraamine(Lj) and two chiral macrocyclic polyamines(L2, L3) have been successfully intercalated into a-zirconium phosphate(a-ZrP) and the intercalates are characterized by elemental analysis, X-ray powder diffraction, thermal analysis and infrared spectroscopy. The intercalation procedures of Li into a-ZrP at different temperatures are performed. It is found when the temperature increases, the interlayer distance decreases and leads to lower contents of the macrocycle. The adsorption ability of Li- ZrP intercalate toward transition metal ions has been investigated and it exhibits the strongest adsorption ability of Cu2+ cations. The chiral recognition abilities of L2- ZrP and L3- ZrP intercalates to the two enantiomers of chiral carboxylic acids are studied by NMR method and the research results are discussed.