| The supramolecular assembly and chirality of nucleotide are basic and hot issues in chemistry, biology, and material science. One of the most effective means to research about the supramolecular assembly and chirality is the X-ray single crystal diffractions analysis. In this thesis, twenty nine nucleotide-metal complexes with novel structures have been synthesized successfully at room temperature based on the tunning effects of metal ions, p H, auxilary ligands, solvent and so on, and the controllable synthesis were explored. These compounds were characterized and analyzed by various physical and chemical means, such as FT-IR, UV-vis, Elemental Analysis, XPRD, TGA, X-ray single crystal diffractions and circular dichroism(CD) spectroscopy. The supramolecular assembly modes, chirality, and chiral delievry rules have been discussed and studied. The main research results are as follows.1. Two types of nucleotide-metal complexes(1-4 and 5-6) have been successfully synthesized by choosing uridine 5′-monophosphate(UMP) and cytidine 5′-monophosphate(CMP) as the main ligands, modifying through the auxilary ligand 4, 4′-bipy, and reacting with Co, Ni and Cu salts. {[Co(UMP)(4, 4′-bipy)(H2O)3]·H2O}n(1) {[Co2(CMP)2(4, 4′-bipy)2(H2O)6]·11H2O}n(2) {Ni(UMP)(4, 4′-bipy)(H2O)3]·H2O}n(3) {[Ni(CMP)2(4, 4′-bipy)2(H2O)6]·11H2O}n(4) {[Cu2(UMP)2(4, 4′-bipy)2(H2O)4]·7H2O}n(5) {[Cu2(CMP)2(4, 4′-bipy)2(H2O)2]·9H2O}n(6)X-ray single crystal diffractions analysis reveals that the pyrimidine nucleotide 5′-monophosphate ligands coordinated with the metal centers by their phosphate groups. 1D coordinated polymer linked by 4, 4′-bipy can be obtained when the metal centers are Co(II) or Ni(II) ions, while Cu(II) centers can give 2D coordinated complexes of nucleotide which are linked both by 4, 4′-bipy and phosphate group of the nucleotide ligand. The megnetic properties of 5 and 6 are studied, and the results show that compound 5 and 6 mainly displays ferromagnetic interactions between the Cu(II) ions linked by O-P-O bridge. There are great different between coordination interactions, supramolecular assembly modes, and chiral delivery modes in the 1D coordinated polymer when different nucleotide ligands with different functional groups were used. However, no obvious distinction in these aspects were observed in 2D polymers with Cu(II) centers.In addition to the function of chirality delivery and supramolecular assembly, the nucleotide ligands can also serve as a chiral inducer to generate new chiral sources. Axial chirality of the twisted 4, 4’-bipy have been captured and delivered into infinite 1D architecture by two effective strategies, and Extended Axial Chirality(EAC) is defined on the basis of it for the first time. The absolute configuration of EAC and the relationship between structure and CD signals were studied by X-ray single crystal diffractions analysis combining with liquid- and solid-state circular dichroism(CD) spectroscopy. Finally, the present study demonstrates a facile method for the research on the axial chirality in coordination compound and completes an integrated chirality system.2. Twelve nucleotide-metal complexes(7-18) have been successfully synthesized by choosing cytidine 5′-monophosphate(CMP), uridine 5′-monophosphate(UMP) and d CMP=2′-deoxy cytidine 5′-monophosphate(d CMP) as the main ligands, modifying through the auxilary ligands 1, 2-di-(pyridin-4-yl)ethene(bpe) reacting with Mn, Co, Zn, and Cu salts. The regulating effect of p H for the controllable synthesis of these complexes and their chirality were studied. {[Mn(bpe)(H2O)4]·(CMP)·3H2O}n(7) {[Mn(HCMP)2(bpe)(H2O)2]·3.5H2O}n(8) {[Mn(bpe)3(H2O)2]·(Cl O4)2·(bpe)2·5H2O}n(9) {[Co(bpe)(H2O)4]·(CMP)·3H2O}n(10) {[Co(HCMP)2(bpe)(H2O)2]·3.5H2O}n(11) {[Co1.5(bpe)3(H2O)6]·(bpe) ·5NO3·4H2O}n(12) {[Zn(HCMP)2(bpe)(H2O)2]·5H2O}n(13) {[Zn(bpe)3(H2O)2]·(Cl O4)2·(bpe)2·x H2O}n(14) {[Co2(bpe)(H2O)4] ·2(UMP)·4H2O}n(15) {[Cu2(UMP)2(bpe)2(H2O)2]·7H2O}n(16) {[Co(d CMP)2(bpe)(H2O)4] ·6H2O}n(17) {[Mn(d CMP)(bpe)(H2O)3]·H2O}n(18)Three different 1D coordination polymers 7-9 can be obtained based on p H control, and other experimental conditions are fixed, including the ratio between three components(1:1:1), solvent(water/ethonal=2:1), and temperature(ambient temperature). At p H 6.0, 1D supramolecular coordination complex 7 with the CMP: bpe: M ratio of 1: 1: 1 is obtained. At p H 5.0, a 1D coordination polymer 8 with the CMP: bpe: M ratio of 2: 1: 1 is obtained. While, 1D polymer of M-bpe binary complex 9 was obtained at p H 7.0. Auxiliary ligand bpe can serve as a small-molecule fluorescent probe to indicate the pre-organization modes of the three components under different solution acidity and provide important information about the suitable p H range for CMP coordination. Complexes 10 is isostructural to 7, and complexes 11 and 13 are isostructural to 8, respectively, with isomorphous substitution of Co(II) or Zn(II) for Mn(II), which can be confirmed by PXRD, IR, and TGA. What’s more, binary complexes of 12 and 14 were also obtained at p H 7 with Co(II) and Zn(II) as metal centers respectively. The reversible convert between 7(10) and 8(11) based on p H control in solution can be detected by UV-vis titration spectra, and the crystal-to-crystal transformation between 7 and 8 can also be achieved through sample re-dissolving and p H adjusting. When the ligands were changed into UMP or d CMP, we can generate only one kind of ternary complexes with specific metal centers, including 1D supramolecular complex with Co(II) 15, 1D coordination polymers 17 and 18 with Cu(II), Co(II) and Mn(II) as metal centers, and 2D coordination polymer 16 with Cu(II) center. In complex 18(d CMP-bpe-Mn), bpe ligands coordinated to Mn(II) by one of its terminal nitrogen atom rather than bridging mode, and the 1D chain was formed based on the O-P-O bridge. This kind of coordination mode is the first example in nucleotide-metal complex.It is worthy to note that perfect self-complementary sugar-base hydrogen bond can be only found in the supramolecular coordination complexes of 7, 10, and 15, which plays an important part in transmitting stereochemical information from one nucleotide to its neighbor. And the phosphate groups of nucleotide ligands in these complexes can also assembled into supramolecular helical chains in these complexes. This discovery would be of great significance for constructing of monochiral nucleotide-metal complex controllably based on the chiral inducement of nucleotide ligands.3. Seven new nucleotide-metal complexes(19-25) have been successfully synthesized by choosing guanosine 5′-monophosphate(GMP) as the main ligands, modifying through the auxilary ligands 4, 4′-bipy, 1, 2-di-(pyridin-4-yl)ethene(bpe), and 1, 4-bis(4-pyridyl)-2, 3-diaza-1, 3-butadiene(bpda), and reacting with Co, Mn, Zn, and Cu salts. {[Co2(GMP)2(4,4′-bipy)2(H2O)6]·10H2O}n(19) {[Co2(GMP)2(bpe)2(H2O)6]·18H2O}n(20) {[Co(bpda)(H2O)4] ·2GMP·6H2O}n(21) {[Mn(GMP)(bpe)(H2O)3]·10H2O}n(22) {[Zn(bpda)(H2O)4]·2GMP·6H2O}n(23) [Cu Na(GMP)(HGMP)(H2O)7] ·6(H2O)·CH3OH(24) {[Cu2(GMP)2(4, 4′-bipy)2(H2O)6]·7H2O}n(25)The regulating effect of auxiliary ligands mainly contains two aspects:(1) the size and basicity of the auxiliary ligands show important influence on the coordination mode of nucleotide ligands and the structure of the nucleotide-metal complexes. We can obtain three 1D coordination polymers 19, 20 and 22 with 4, 4’-bipy and bpe as auxiliary ligands, in which the nucleotide ligands coordinated with metal ions through phosphate group. However, 1D supramolecular coordination polymers 21 and 23 can be generated with the larger and stronger alkaline auxiliary ligands bpda. There is no coordinated bond formed by nucleotide ligands, and the nucleotide ligands interact with metal centers by hydrogen bonding formed between its phosphate group, solvent water molecule and coordinated water molecules. Interestingly, DNA-like supramolecular helical chains exist in these two supramolecular coordination complexes.(2) Mononuclear complex of GMP-Cu(24) can be obtained without auxiliary ligand and the GMP ligands coordinated to Cu(II) ions by N-7 site. While, 1D coordination polymer 25 was formed with the addition of 4, 4’-bipy as an auxiliary ligand. The chirality delivery and the supramolecular assembly of helical chirality depend only on hydrogen bonding in complex 24, while on both hydrogen bonding and π-π stacking interaction in 25.4. Four new nucleotide-metal complexes(26-29) have been successfully synthesized by choosing adenosine 5′-monophosphate(AMP) as the main ligand, modifying through the auxilary ligands 4, 4′-bipy reacting with Cu salts. {[Cu(AMP)(4,4′-bipy)(H2O)3]·9H2O}n(26) {[Cu2(HAMP)4(4,4′-bipy)2(H2O)3]·17H2O}n(27) {[Cu2(HAMP)2(4,4′-bipy)2(H2O)6] ·2NO3·9H2O}n(28) {[Cu4(AMP)4(bpe)4(H2O)4]·20H2O}n(29)Deprotonation of AMP ligand coordinated with Cu(II) with the ratio of 1:1 in complex 26, which was synthesized at p H 5. In complexes 27 and 28, AMP ligand are protonated at N-1 site under p H condition of 4, and the ratio between AMP ligand and Cu(II) center are 2:1 and 1:1, respectively. The difference between 27 and 28 relates to the solvent effect that solvent with weaker polarity is good for the coordination interaction of nucleotide ligand. There is spiral tubular supramolecular assembly based on hydrogen bonding in 28, but only inherent chirality of nucleotide ligand and EAC of 4, 4-bipy in complex 26 and 27. As a result, apparent differences can be found in their CD spectra. Complex 29 is a 2D coordination polymer with bpe as auxiliary ligand, and its structural difference to 26-28 mainly depends on the regulation function of auxiliary ligand.The coordination regularity of nucleotide ligands, controllable synthesis and chirality of nucleotide complex and supramolecular assembly are studied systematically in this work. Nucleotide complexes with different structure have been obtained baesd on the control of metal ions, auxiliary ligands, p H, solvent, and so on. Different chiral structures or chiral sources are generated based on chiral delivery, chirality assembly, as well as chiral inducement, which can be proved and explained through the methods of X-ray single crystal diffractions analysis conbained with solide- and liquid- CD spectrascopy. Furthermore, we defined the “Extended Axial Chirality(EAC)” for the first time, which completes an integrated chirality system in coordination chemistry. The present study promotes the development of the coordination chemistry and supramolecular chemistry of nucleotide complex, and plays important roal for the research about the origin of biochirality. |
PDF Full Text Request