A STUDY OF THE PALATIONSHIP BETWEEN STRGCTGRE AND CHEMCAL PROPERTIES OF FUNCTIONALIZED MACROCYCLIC POLYAMINES

TABLE OF CONTENTS [Abstracts] / p1 [CHAPTER I] NEW MACROCYCLIC TETRAAMINE METAL COMPLEXES APPENDED WITH AN INTRAMOLECULAR IMIDAZOLE. 　Introduction / p4 　Experimental Section / p6 　Results and Discussion / p10 　Conclusion / p28 　References / p29 　Supplementary Materials / p31 [CHAPTER II] SYNTHESIS OF NOVEL FLUORINATED MACROCYCLIC TETRAAMINES AND CHEMICAL PROPERTIES OF THEIR METAL COMPLEXES. 　Introduction / p39 　Experimental Section / p41 　Results and Discussion / p50 　Conclusion / p81 　References / p83広島大学(Hiroshima University)博士(薬学)Pharmacologydoctora

Supramolecular metal arrays on artificial metallo-DNAs and peptides.

abstract: A review covers the recent approaches to metal arrays on artificial DNAs and cyclic peptides. [on SciFinder(R)] Cited Reference: Citations: 1) Beaucage, S; Current Protocols in Nucleic Acid Chemistry 2001|2) Kool, E; Acc Chem Res 2002, 35, 936|3) Shionoya, M; Curr Opin Chem Bioi 2004, 8, 592|4) Tanaka, K; J Org Chem 1999, 64, 5002|5) Cao, H; Chem Pharm Bull 2000, 48, 1745|6) Tasaka, M; Supramol Chem 2001, 13, 671|7) Tanaka, K; J Am Chem Soc 2002, 124, 8802|8) Tanaka, K; J Am Chem Soc 2002, 124, 12494|9) Meggers, E; J Am Chem Soc 2000, 122, 10714|10) Atwell, S; J Am Chem Soc 2001, 123, 12364|11) Zimmermann, N; J Am Chem Soc 2002, 124, 13684|12) Weizman, H; Chem Commun 2001, 453|13) Weizman, H; J Am Chem Soc 2001, 123, 3375|14) Clever, G; Angew Chem Int Ed 2005, 44, 7204|15) Tanaka, K; Science 2003, 299, 1212|16) Ranganathan, D; J Am Chem Soc 1998, 120, 2695|17) Weiss, T; Adv Mater 1999, 11, 331|18) Yang, D; J Am Chem Soc 2002, 124, 12410|19) Strauss, J; Org Lett 2002, 4, 683|20) Ghadiri, M; Nature 1994, 306, 301|21) Ishida, H; J Org Chem 2001, 66, 2978|22) Kartha, G; Proc Natl Acad Sci USA 1982, 79, 4519|23) Xie, P; J Am Chem Soc 1995, 117, 429|24) Tanaka, K; Chem Commun 1999, 2475|25) Bong, D; Angew Chem Int Ed 2001, 40, 988|26) Lopez, S; Nature 2001, 412, 452|27) Nakanishi, T; Phys Rev B 2002, 66, 165417|28) Okada, T; Chem Commun 2005, 148

塩谷光彦先生の講演

塩谷光彦先生の講

The Effects of Magnesium Ions on the Enzymatic Synthesis of Ligand-Bearing Artificial DNA by Template-Independent Polymerase

A metal-mediated base pair, composed of two ligand-bearing nucleotides and a bridging metal ion, is one of the most promising components for developing DNA-based functional molecules. We have recently reported an enzymatic method to synthesize hydroxypyridone (H)-type ligand-bearing artificial DNA strands. Terminal deoxynucleotidyl transferase (TdT), a template-independent DNA polymerase, was found to oligomerize H nucleotides to afford ligand-bearing DNAs, which were subsequently hybridized through copper-mediated base pairing (H–CuII–H). In this study, we investigated the effects of a metal cofactor, MgII ion, on the TdT-catalyzed polymerization of H nucleotides. At a high MgII concentration (10 mM), the reaction was halted after several H nucleotides were appended. In contrast, at lower MgII concentrations, H nucleotides were further appended to the H-tailed product to afford longer ligand-bearing DNA strands. An electrophoresis mobility shift assay revealed that the binding affinity of TdT to the H-tailed DNAs depends on the MgII concentration. In the presence of excess MgII ions, TdT did not bind to the H-tailed strands; thus, further elongation was impeded. This is possibly because the interaction with MgII ions caused folding of the H-tailed strands into unfavorable secondary structures. This finding provides an insight into the enzymatic synthesis of longer ligand-bearing DNA strands

Concerted Ligand Exchange and the Roles of Counter Anions in the Reversible Structural Switching of Crystalline Peptide Metallo-Macrocycles

To understand reversible structural switching in crystalline materials, we studied the mechanism of reversible crystal-to-crystal transformation of a tetranuclear Ni^II macrocycle consisting of artificial β-dipeptides. On the basis of detailed structural analyses and thermodynamic measurements made in a comparison of pseudo-isostructural crystals (NO₃ and BF₄ salts), we herein discuss how ligand-exchange reactions take place in the crystal due to changes in water content and temperature. Observations of the structural transformation of NO₃ salt indicated that a pseudo crystalline phase transformation takes place through concerted ligand-exchange reactions at the four Ni^II centers of the macrocycle with hydrogen bond switching. A mechanism for this ligand exchange was supported by IR spectroscopy. Thermodynamic measurements suggested that the favorable compensation relationship of the enthalpy changes due to water uptake and structural changes are keys to the reversible structural transformation. On the basis of a comparison with the pseudo-isostructural crystals, it is apparent that the crystal packing structure and the types of counter anions are important factors for facilitating reversible ligand exchange with single crystallinity