The Design, Synthesis, Structure And Porperties Of Complexes Based On Rac-β-amino Acids And Rac-schiff Base

Chirality is a widespread phenomenon in nature and plays an important role on life. At present, it is uncontrollable to get homochiral complexes by the spontaneous resolution of complexes with rac-ligands. It is important to summarize the laws of spontaneous resolution, chirality transfer and self-assembly in complexes with rac-ligands for controllable synthesis of homochiral complexes and functional materials. A few ligands, rac-β-amino acids and rac-schiff-base, were designed and synthesized. Thirty novel crystal compounds were obtained by the self-assemble of metal salts or inorganic acids with above ligands at room temperature and they are further characterized by single crystal X-ray diffractions, FT-IR, UV-vis, X-ray powder diffraction (PXRD), thermogravimetric analysis, elemental analysis and so on.The main experimental results are listed as follows:1. The study of crystsal structures of β-amino acids and their transition metal complexes.(1) Three β-amino acids:3-Amino-3-(4-fluoro)phenylpropionic acid (HL1), 3-Amino-3-(4-bromo)phenylpropionic acid (HL2) and 3-Amino-3-(4-methoxyl)phenylpropionic acid (HL3) were synthesized by literature and the 3-Amino-3-phenylpropionic acid (HL4) was purchased. The crystals of ligands and metal complexes of above ligands were obtained. HL1 (1) HL2 (2) HL3 (3) [Cu(L1)2(CH3OH)2]-2CH3OH(4) [Cu(L2)2(CH3OH)2]·2CH3OH (5){[Cd(L4)2]·H2O} n (6) Helical chains (P-helix and M-helix) constructed by H-bonding interactions were found in β-amino acids 1 and 2 while there was no helix in complexes 4 and 5. The hydrogen bonds between terminal NH3+and adjacent COO- in β-amino acids 1 and 2 are responsible for constructing supramolecular helixes. While, this kind of H-bonding interactions disappears in their Cu(II) coordination complexes 4 and 5 in which the coplanar coordinated bonds (N-Cu-O) between -NH2 and -COO- construct a central-symmetrical dimer. The weak halogen-hydrogen bonding interactions (C-Br…H-C) also make influence on the crystal packing of compound 2. The spontaneous resolution phenomenon was found in crystal 3 without any chiral inducer in which only homochiral right-handed helixes constructed by H-bonding interactions were found. The 1D coordination chains exist in complex 6.(2) In order to find the influenc of chiral carbon atoms on the structure packing, the achiral β-alanine (HL5) was studied as a comparison. Three crystals were obtained by the self-assemble of metal salts with achiral ligand (HL5) at room temperature. [Cu2 (HL5)4(H2O)2] (NO3)4·2CH3OH (7) [Cd(HL5)4](NO3)2 (8) [Zn(L5)2]n (9) Crystals 7 and 8 are binuclear and mononuclear complexes of Cu and Cd, respectively. The coordinated bonds (N-Zn-O) induce complex 9 to be a MOFs marerials. Complex 8 possesses H-bonding diamondoid framework whereas complex 9 possesses three-fold interpenetrated diamondoid metal organic frameworks. The asymmetrical H-bonding connections induce the polarity of complex 8 and the different molecular conformations of ligands in diamondoid framework induce the polarity of complex 9, which are the reasons for both complex 8 and complex 9 displaying SHG. The achiral β-alanine induces no new chirality into its complexes, but it is a good candidate for constructing polar materials.(3) H-bonding interactions make great influence on the structure packing of compounds. Four crystals were synthesized by the self-assemble of inorganic acids, H2SO4 and HClO4, with β-amino acids (HL1, HL2 and HL5) at room temperature.(H2L5)2SO4 (10) H2L5ClO4(11) (H2L1)2SO4 (12) (H2L2)2SO4 (13) Various kinds of H-bonding interactions exist in compounds 10-13. Helical chains were found in achiral β-alanine compounds 10 and 11, which are mainly induced by H-bonding interactions. Many halogen-hydrogen bonding interactions (C-H…X (X=F/Br)) and Br…Br interactions were found in compounds 12 and 13.2. The study of crystsal structures of rac-schiff-base ligands and their transition metal complexes.(1) Four new rac-schiff-base ligands, (N1E,N2E)-N1,N2-bis(benzene-2,4-diol-1-ylmethyl-ene)propane-1,2-diamine(H2L6), (N1E,N2E)-N1,N2-bis(benzene-1,4-diol-2-yl methyl ene)propane-1,2-diamine (H2L7) and L8 ((E)-N1-(pyridin-2-ylmethylene) propane-1,2-diamine (L81) and (N1E,N2E)-N1,N2-bis(pyridin-2-ylmethylene)propane-1,2-diamine(L82)), were designed and synthesized. The reaction ratio of 1,2-Diaminopropane and 2-Pyridinecarboxaldehyde (L81 with 1:1 and L82 with 1:2) can be controled by reaction time, which indicates that the L8 synthesis system is a candidate for unsymmetrical schiff-base synthesis. Nine novel complexes were synthesized by the self-assemble of metal salts with ligands, H2L6, H2L7 and L8, at room temperature. (CuL6)-2H2O (14) (NiL6)-2H2O (15) (NiL7)-H2O (16) [Fe2(Cl)2(L7)2]-2CH3OH (17) [Zn(L81)2]·(ClO4)2(18) [Ni(L81)2]·(ClO4)2(19) [Cd (H2O)]·(Cl)2·L82 (20) [Cd2(L82)3(H2O)2]2·(ClO4)8·2H2O (21) La(NO3)3(L82)(H2O) (22) Complexes 14-16 have the similar Salen-structure characters that they all have two exposed uncoordination site in the axial position, which induce complexes 14-16 to be candidates for chiral catalyst. Crystal 17 is a binuclear complex of Fe and its magnetic characterization is in progress. The differences of the coordinted structures among complex 17 and complexes 14-16 are induced by the coordinated metal center with different valence, while the differences of chiral self-assembly among complexes 14-17 are induced by the ligands with diffetrent functional groups positions. Complexes 18-20 are also three mononuclear complexes with Salen structures. Complex 21 is a binuclear complex of Cd in which the ligand L82 displays both torsional coordianting model and salen coordianting model. The differences of the coordinted structures between complex 20 and complex 21 are induced by the anions. Complex 22 is a mononuclear complex of rare-earth metal La.(2) The rigid or flexibile ligands will make great influence on the structure packing. Three new long rac-schiff-base ligands,2,2’-((lE,l’E)-((cyclohexane-1,3-diylbis (methylene))bis(azanylylidene))bis(methanylylidene))dipheno (H2L9),6,6’-((lE, l’E)-((cyclohexane-1,3-diylbis(methylene))bis(azanylylidene))bis(methanylylidene))bis(2-metho xyphenol) H2L10 and 4,4’-((lE,l’E)-((cyclohexane-1,3-diylbis(methylene))bis (azanylylidene))bis(methanylylidene))bis(benzene-1,3-diol) (H2L11), were designed and synthesized. Six novel metal complexes of ligands, H2L9, H2L10 and H2L11, were obtained at room temperature. Cu2(L9)2 (23) Mn2(CH3COO)2(L9)2 (24) (ZnL9)n (25) Cu2(L10)2 (26) Mn2(CH3COO)2(L10)2 (27) [Cu2(L11)2]-4CH3OH (28) Crystals 23 and 24 are binuclear complexes of Cu and Mn, respectively. The 1D coordinated chians exist in the Zn complex 25. Crystals 26-28 are binuclear complexes of Cu, Mn and Cu, respectively. In the synthetic process of both complexes 24 and 27, the Mn2+ in the start material Mn(OAC)2 was accordingly oxidized to higher valence Mn3+ by the oxygen in the air, which may be a common characteristic of such a system and make complexes 24 and 27 to be candidates of catalyst. The differences of the coordinted structures and chirality transfer among complexes 23-28 are induced by the solvent molecules, the ligands with diffetrent functional groups and functional groups positions and so on. Complexes 23-28 are mainly binuclear complexes rather than Salen ones, which are ascribed to the long and flexibile ligands.(3) To further search the influnec of flexibile ligands on the structure packing, four new more flexibile rac-schiff-base ligands,6,6’-((1E,1’E)-((methylenebis(cyclohexane-4,1-diyl))bis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol) (H2L12),2,2’-((1E, 1’E)-((methylenebis(cyclohexane-4,1-diyl))bis(azanylylidene))bis(methanylylidene))diph-enol (H2L13), (NE,N’E)-4,4’-methylenebis(N-(pyridin-2-ylmethylene) cyclohexanamine) (H2L14) and 3,3’-((1E,1’E)-((methylenebis(cyclohexane-4,1-diyl))bis(azanylylidene))bis (methanylylidene))bis(benzene-1,2-diol) (H2L15), were designed and synthesized. Two novel complexes were synthesized by the self-assemble of metal salts with ligand H2L14. [Fe10(NO3)7(O)8(MP)8]·6H2O (MP=Methyl Picolinate) (29) [Ni(L16)2]2·CH3OH-9H2O (L16=(E)-3-(1H-imidazol-4-yl)-2-((pyridin-2-ylmethylene) amino)propanoic acid)(30) Complex 29 is a ten-nuclear Fe cluster. The ten Fe ions in complex 29 contain both Fe2+ and Fe3+. Complex 29 may be an antiferromagnetic material according to its magnetic data. Crystal 30 is a mononuclear complex of Ni. The chirality of L-histidine induces complex 30 to pack with chiral space group.