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Yu Xie Hao-Han Wu Yong Cui Long Pan Rong Fan Yang-Chao Tian Liu-Si Sheng 《Inorganica chimica acta》2007,360(5):1669-1677
Three homochiral metal-organic coordination networks [Co2(l-Trp)2(Py)6] · Py · (ClO4)2 (1), [Ni(l-Trp)(Py)3] · H2O · ClO4 (2) and [Co2(l-Trp)(INT)2(H2O)2(ClO4)] (3), all containing natural amino acid l-HTrp (l-typtophan), were hydrothermally synthesized and structurally characterized. The compounds 1 and 2 crystallize in the orthorhombic space group C2221, with a = 10.731(2) Å, b = 19.709(4) Å, c = 27.365(6) Å and Z = 4 for 1 and a = 10.710(10) Å, b = 20.088(18) Å, c = 27.63(3) Å and Z = 8 for 2, respectively. The compound 3 has the monoclinic space group P21, with a = 8.1934(14) Å, b = 13.209(2) Å, c = 12.464(2) Å, β = 104.107(3)° and Z = 2. Both 1 and 2 consist of 1D helical chains. Compound 3 is composed of 2D networks, which further assemble into a 3D supramolecular structure via weak interlayer interactions. The optically pure amino acid l-HTrp plays an important role leading to homochiral structures reported here. 相似文献
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A series of coordination polymers have been prepared by the combination of flexible ligand 1,1′-biphenyl-2,2′-dicarboxylic acid (H2dpa) and different types of nitrogen-containing ligands, with various metal ions such as Co(II), Zn(II) and Cd(II). The single-crystal structure analyses reveal that the above complexes possess different structure features with the introduction of different nitrogen-containing ligands. When auxiliary linear ligand 4,4′-bipyridine (4,4′-bpy) is introduced, two-dimensional layered complex, [Co2(dpa)2(4,4′-bpy)2(H2O)]n (1) is formed. Whereas if chelating ligand, 1,10-phenanthroline (1,10′-phen) and 2,2′-bipyridine (2,2′-bpy) are introduced, one-dimensional complex [Zn(dpa)(1,10′-phen)]n (2) and discrete complexes [Co2(dpa)2(2,2′-bpy)2(H2O)2] (3), [Co3(dpa)3(1,10′-phen)6(H2O)2] (4), [Cd(dpa)(1,10′-phen)2][(H2dpa)2(H2O)2] (5) are synthesized. To our interest, 1 and 2 crystallize in homochiral spacegroup. Furthermore, the magnetic property of complex 1 and the fluorescent properties of complexes 2 and 5 are studied. 相似文献
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Hidehito Urata Hana Shimizu Masao Akagi 《Nucleosides, nucleotides & nucleic acids》2013,32(4-6):359-367
Using DNA and RNA heptanucleotides containing an unnatural L-nucleotides as well as the complementary strands, effects of the introduction of an L-nucleotide on the structure of DNA/DNA, RNA/RNA, and DNA/RNA duplexes were investigated by circular dichroism experiments and RNase H-mediated RNA strand cleavage reaction. The results suggested that the substitution of the central D-nucleotide with an L-nucleotide in the duplexes causes the significant structural alterations as the duplex structures change to conformations with more B-form similarities. 相似文献
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Paola Pedrini Pier Paolo Giovannini Matteo Mantovani Elisa Andreotti Chiara Colalongo 《Journal of Molecular Catalysis .B, Enzymatic》2009,60(3-4):145-150
Twelve strains of endophytic fungi, isolated from various plants (i.e. Eugenia hallii, Schinus molle, Crataegus monogyna, Juniperus communis and Sambucus nigra) sampled in Amazonian forest and in Italy, were screened for their reduction activity with a cocktail of ketones 1–4. The four most active strains [i.e. Phomopsis (FE86 and FE290), Pestalotia and Epicoccum] were chosen for the reduction of 5-hexen-2-one 1, acetophenone 2, cis-bicyclo[3.2.0]hept-2-en-6-one 3, 2-methylcyclohexanone 4, 6-methyl-5-hepten-2-one 5, 2-furyl methyl ketone 6, 1-indanone 7, and 2,4,4-trimethyl-2-cyclohexen-1-one 8 and in all cases the S-alcohols were obtained with variable yields and enantiomeric excesses depending on the strains. 相似文献
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Meir Lahav 《Origins of life and evolution of the biosphere》2007,37(4-5):371-377
Some experimental aspects concerning either the enantio-enrichment of α-amino acids starting from non-racemic mixtures or
the formation of homochiral oligopeptides and oligonucleotides starting from racemic precursors are described. In principle,
it is possible that more than one of these processes had played a role in chirobiogenesis.
Presented at the International School of Complexity – 4th Course: Basic Questions on the Origins of Life; “Ettore Majorana”
Foundation and Centre for Scientific Culture, Erice, Italy, 1–6 October 2006. 相似文献
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Structural and spectroscopic studies on some metal complexes of an 8-hydroxyquinoline derivative 总被引:1,自引:0,他引:1
Mononuclear metal complexes of 2-[(2-hydroxyethylimino)methyl]quinolin-8-ol (H2L) were obtained by reaction of 8-hydroxyquinoline-2-carboxaldehyde, 2-aminoethanol and the corresponding metal(II) acetate (M = Co, Ni, Cu, Zn or Cd) in 2:2:1 molar ratios. The Schiff base ligand is acting as a monodeprotonated O,N,N-donor in the helical complex Ni(HL)2, which could be crystallographically characterised. This crystal structure contains homochiral chains of Ni(HL)2 connected through double O-H?O connections, which relate both non-coordinated hydroxy groups of the ethanolic arms with both phenolic O atoms of a neighbouring complex, in a “head-to-tail” disposition. A study of the luminescence properties in methanol solution showed that the quantum yields of Zn(HL)2·H2O (ΦF = 0.02) and Cd(HL)2·H2O (ΦF = 0.04) are lower than that of 8-hydroxyquinoline-2-carboxaldehyde (ΦF = 0.06). 相似文献
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