Home About us Contact
|
Home About us Contact | ||
|
|
||
Self-assembly Reaction (self-assembly + reaction)
Selected AbstractsTitanium-Based Molecular Squares and Rectangles: Syntheses by Self-Assembly Reactions of Titanocene Fragments and Aromatic N-HeterocyclesCHEMISTRY - A EUROPEAN JOURNAL, Issue 3 2005Susanne Kraft Dr. Abstract This paper reports on the potential of titanium compounds as building blocks for supramolecular polygons. Self-assembly reactions of low-valent titanocene units and N-heterocyclic bridging ligands lead to novel titanium-based supramolecular squares. Pyrazine (3), 4,4,-bipyridine (4), and tetrazine (5) were used as bridging ligands, and the acetylene complexes [Cp2Ti{,2 -C2(SiMe3)2}] (1) and [(tBuCp)2Ti{,2 -C2(SiMe3)2}] (2) as sources of titanocene fragments. Molecular rectangles can be synthesized by stepwise reduction of the titanocene dichlorides [Cp2TiCl2] and [(tBuCp)2TiCl2] and consecutive coordination of two different bridging ligands. The resulting complexes are the first examples of molecular rectangles containing bent metallocene corner units. Single-crystal X-ray analyses of the tetranuclear compounds revealed the geometric properties of the molecular polygons in the solid state. Comparison of bond lengths and angles in coordinated and free ligands reveals the reduced state of the bridging ligand in the low-valent titanium compounds. The syntheses and properties of these novel, highly air- and moisture-sensitive compounds are discussed. [source] Self-Assembly of 1D to 3D Cadmium Complexes: Structural Characterization and PropertiesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 15 2005Xing Li Abstract Self-assembly reactions of 5-sulfoisophthalic monosodium salt (NaH2sipa), Cd(NO3)2·4H2O and 2,2'-bipyridine (or 4,4'-bipyridine) under hydrothermal condition give rise to four polymeric complexes, namely {[Cd3(sipa)2(2,2'-bpy)4(H2O)2]·6H2O}n (1), {[Cd(sipa)(H-4,4'-bpy)(H2O)]·2H2O}n (2); {[Cd2(sipa)(4,4'-bpy)3(H2O)3]·[Cd(sipa)(4,4'-bpy)(H2O)]·8H2O}n (3),and {[Cd3(sipa)2(4,4'-bpy)4(H2O)2]·3H2O}n (4), respectively. X-ray diffraction analyses reveal that complex 1 possesses a 1D rail-like chain structure, 2 is a 1D double chain, 3 has a 2D network consisting of an independent [Cd2(sipa)(4,4'-bpy)3(H2O)3]nn+ cationic layer and a [Cd(sipa)(4,4'-bpy)(H2O)]nn, anionic layer, and 4 is a novel 3D self-penetrating network constructed from two mixed bridging ligands. Thermogravimetric analyses (TGA) and fluorescent measurements of complexes 1,4 have also been performed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Titanium-Based Molecular Squares and Rectangles: Syntheses by Self-Assembly Reactions of Titanocene Fragments and Aromatic N-HeterocyclesCHEMISTRY - A EUROPEAN JOURNAL, Issue 3 2005Susanne Kraft Dr. Abstract This paper reports on the potential of titanium compounds as building blocks for supramolecular polygons. Self-assembly reactions of low-valent titanocene units and N-heterocyclic bridging ligands lead to novel titanium-based supramolecular squares. Pyrazine (3), 4,4,-bipyridine (4), and tetrazine (5) were used as bridging ligands, and the acetylene complexes [Cp2Ti{,2 -C2(SiMe3)2}] (1) and [(tBuCp)2Ti{,2 -C2(SiMe3)2}] (2) as sources of titanocene fragments. Molecular rectangles can be synthesized by stepwise reduction of the titanocene dichlorides [Cp2TiCl2] and [(tBuCp)2TiCl2] and consecutive coordination of two different bridging ligands. The resulting complexes are the first examples of molecular rectangles containing bent metallocene corner units. Single-crystal X-ray analyses of the tetranuclear compounds revealed the geometric properties of the molecular polygons in the solid state. Comparison of bond lengths and angles in coordinated and free ligands reveals the reduced state of the bridging ligand in the low-valent titanium compounds. The syntheses and properties of these novel, highly air- and moisture-sensitive compounds are discussed. [source] Construction of 1D and 2D Copper(I) Coordination Polymers Assembled by PhS(CH2)nSPh (n = 1, 2) Dithioether Ligands: Surprising Effect of the Spacer Length on the Dimensionality, Cluster Nuclearity and the Fluorescence Properties of the Metal,Organic Framework,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2007Harmel N. Peindy Abstract Treatment of CuI with PhSCH2SPh in MeCN solution affords, by a self-assembly reaction, the monodimensional metal,organic coordination polymer [Cu4I4{,-PhS2CH2SPh}2]n (1), in which Cu4(,3 -I)4 cluster units are linked by the dithioether ligand in a 1D necklace structure. In contrast, the reaction of PhSCH2CH2SPh with CuI results in the formation of the metallopolymer [(CuI)2{,-PhS(CH2)2SPh}2]n (2). The 2D network of 2 is built from dimeric Cu2I2 units which are connected by 1,2-bis(phenylthio)ethane bridging ligands. The solid-state luminescence spectrum of 1 exhibits a strong emission around 532 nm, whereas a weak emission centred at 413 nm is observed in the case of 2. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Theoretical aspects of virus capsid assemblyJOURNAL OF MOLECULAR RECOGNITION, Issue 6 2005Adam Zlotnick Abstract A virus capsid is constructed from many copies of the same protein(s). Molecular recognition is central to capsid assembly. The capsid protein must polymerize in order to create a three-dimensional protein polymer. More than structure is required to understand this self-assembly reaction: one must understand how the pieces come together in solution. Copyright © 2005 John Wiley & Sons, Ltd. [source] A novel three-dimensional framework constructed by 2-[(1H -imidazol-1-yl)methyl]-1H -benzimidazole and infinite chains of hydrogen-bonded water moleculesACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2009De-Qiang Qi A novel three-dimensional framework of 2-[(1H -imidazol-1-yl)methyl]-1H -benzimidazole dihydrate, C11H10N4·2H2O or L·2H2O, (I), in which L acts as both hydrogen-bond acceptor and donor in the supramolecular construction with water, has been obtained by self-assembly reaction of L with H2O. The two independent water molecules are hydrogen bonded alternately with each other to form a one-dimensional infinite zigzag water chain. These water chains are linked by the benzimidazole molecules into a three-dimensional framework, in which each organic molecule is hydrogen bonded by three water molecules. This study shows that the diversity of hydrogen-bonded patterns plays a crucial role in the formation of the three-dimensional framework. More significantly, as water molecules are important in contributing to the conformation, stability, function and dynamics of biomacromolecules, the infinite chains of hydrogen-bonded water molecules seen in (I) may be a useful model for water in other chemical and biological processes. [source] | ||||||||||