77 research outputs found
Molecular tectonics: On the formation of 1-D silver coordination networks by thiacalixarenes bearing nitrile groups
Two new p-tert-butylthiacalix[4]arene derivatives 2 and 3 decorated at the lower rim with four nitrile groups have been prepared and structurally characterised in the crystalline phase. The two ligands, differing by the length of the spacer between the calix moiety and the nitrile group, adopt the 1,3-alternate conformation in the solid state. The ligand 3 bearing four (CH2)3CN fragments behaves as a tecton in the presence of silver salts (AgX, X = BF4, PF6 or SbF6) and leads to the formation of analogous 1-D linear coordination networks. The tecton 3 acts as a bischelate unit and bridges consecutive silver cations adopting a tetrahedral coordination geometry. Anions and solvent molecules occupy the free space between networks and exhibit no specific interactions with the cationic architecture. © The Royal Society of Chemistry
Molecular tectonics: 3-D organisation of decanuclear silver nanoclusters
The combination of silver nitrate with a thiacalix[4]arene derivative bearing at the lower rim four benzonitrile groups leads in the crystalline phase to the formation of a 3-D coordination network in which the organic tectons are connected by decanuclear silver nanoclusters. © The Royal Society of Chemistry 2009
Molecular tectonics: Grid and porous coordination networks based on combinations of iron thiocyanate and pyridyl appended derivatives of tetrathiacalix[4]arene and tetramercaptotetrathiacalix[4]arene
© ISUCT Publishing. The combination of three pyridyl appended tetrathiacalix[4]arene (TCA) and tetramercaptotetrathiacalix[4]arene (TMTCA) derivatives in 1,3-alternate imposed conformation behaving as neutral tectons with octahedral FeII(NCS)2 complex as a metallatecton, leads to the formation of new coordination networks. Whereas the tecton 4, a tetrasubstituted TCA derivative (pyridyl in ortho position), leads to a 2D grid-like network, for the other two tectons 5 and 6, the formation of 3D diamond-like architectures is observed
Ethnography on Philippine Migration Labour : Case Studies on Ifugao Female Workers Overseas and Filipina Brides in Australia
この論文は、海外移住労働について民族誌的かつ記述的な研究を目差したものである。3セクションからなり、先ず、文献研究のセクションと、少数民族のイフガオ女性の労働状況についての記述、最後にオーストラリアのフィリピン花嫁の労働状況を記述したセクションである。第1セクションでは、統計資料からフィリピンの海外移住労働の現況を概括し、先行研究からフィリピン移民と海外移住労働の歴史や政策についてまとめた。次の節で、パレニャスによるローマとロスアンジェルスにおけるフィリピン移住労働者の比較研究を簡単に紹介し、その問題点を扱う。最後の節では、香港におけるフィリピン女性家事労働者についても、コンステーブルによる研究を要約し、問題点を取りあげた。第2セクションは、主に北部ルソン島におけるイフガオ女性の海外移住労働者とその家族についての事例と、香港とシンガポールでの労働状況について事例を記述した。同時に女性の海外移住労働が深刻な社会変化と文化変容を生じさせている現状を表した。第3セクションは、オーストラリアにおけるフィリピン花嫁の労働実態を中心に記述したが、その背後には家族呼びよせと不法就労者の実態が浮かび上がる。異なった視座から女性の移住労働者を捉えることで、各章と事例を総括することで結論とした。This paper aims to describe overseas Philippine migration labour. It consists of three sections. The first deals with statistical data and historical backgrounds on migration from the Philippines included national policies. There are two other parts in this section, which summarize Filipina workers in Rome and Los Angeles by Parenas and Filipina domestic helpers in Hong Kong by Constable, and point out some theoretical difficulties for better comprehension of Philippine society and culture. The second section treats ethnographic case studies on Ifugao female workers in Hong Kong and Singapore, and Ifugao families at home. The third section describes the working conditions and lives among Filipina brides and immigrant families in Australia
Molecular tectonics: Anion control of dimensionality and connectivity in meta-pyridyl appended tetramercaptotetrathiacalix[4]arene based silver coordination networks
The combination of the same organic tecton 1, a meta-pyridyl appended tetramercaptotetrathiacalix[4]arene in 1,3-alternate conformation offering four pyridyl units and eight thioether groups, with three silver salts AgX (X = BF4 -, NO3 - and SbF6 -) leads, under identical conditions (concentration, temperature and solvent system), to the formation of different silver coordination networks. Both the connectivity and the dimensionality of the three silver coordination networks depend on the nature of the anion used as a counter ion. Whereas the weakly coordinating BF4 - anion does not participate in the formation of the non-tubular 1D coordination network, the coordinating NO 3 - anion is bound to the metal cation and this leads to the formation of a tubular 1D silver coordination network. In both cases, the eight S atoms of the tecton 1 do not take part in the binding of the cation. In marked contrast, when the SbF6 - anion is used as a counter ion, the organic tecton 1 behaves as a tetrakismonodentate through its four meta-pyridyl moieties and as a bischelating unit of the SCCS type leading thus to the formation of a porous 3D diamondoid-type network. © 2014 The Royal Society of Chemistry
Molecular tectonics: P-H-thiacalix[4]arene pyridyl appended positional isomers as tectons for the formation of 1D and 2D mercury coordination networks
Three p-H-thiacalix[4]arene pyridyl appended coordinating tectons (2-4) in a 1,3-alternate conformation have been prepared and structurally characterised in the solid state. These compounds are positional isomers differing only by the position of the nitrogen atom on the pyridyl ring. Their combinations with HgCl2 lead to the formation of 1- and 2-D neutral mercury coordination networks. Whereas for tecton 2 (ortho isomer) a 2D architecture resulting from the bridging of consecutive tectons by the mononuclear HgCl 2 unit is obtained, for tecton 3 (meta isomer) again a 2D network is formed. However, in that case, the interconnection of consecutive organic tectons 3 takes place through a binuclear Hg2Cl4 species. Finally, in the case of tecton 4 (para position), a 1D ribbon type double chain arrangement resulting from the bridging of consecutive tectons by trinuclear Hg3Cl6 units followed by the interconnection of two chains through the fusion of the trinuclear centres into a hexanuclear node is observed. © The Royal Society of Chemistry 2013
Molecular tectonics: Control of the dimensionality in tetramercaptothiacalixarenes based coordination networks
Combinations of tetramercaptotetrathiacalix[4]arene pyridyl-appended positional isomers with HgCl2 lead to the formation of neutral coordination networks with their dimensionality imposed by the position of the N atom on the pyridyl group. © 2013 American Chemical Society
Molecular tectonics: Manganese(II), copper(II) and zinc(II) 1D coordination polymers based on tetramercaptothiacalix[4]arene bearing benzoate coordinating groups
© ISUCT Publishing. The combination under mild conditions of the carboxylic appended tetramercaptotetrathiacalix[4]arene (TMTCA) derivative 2 blocked in 1,3-A conformation with acetate salts of octahedral copper(II), manganese(II) and zinc(II), and pyridine, leads to the formation of new 1D coordination polymers in the crystalline state. Whereas for copper(II) and manganese(II) 1D linear coordination polymers are observed, for zinc(II) a zigzag chain has been evidenced
Titanium oxo-clusters derivatized from the Ti10O12(cat)8(py)8 complex: structural investigation and spectroscopic studies of light absorption
A series of deep-red colored nano-sized titanium oxo-clusters bearing catecholato ligands is reported. These architectures are produced via post-synthetic modification of the Ti10O12(cat)8(py)8 (cat = catecholato, py = pyridine) complex through quantitative substitution of labile pyridine ligands by three substituted pyridines (pico, 4-Phpy and pyrald). The crystal structure analysis reveals a common Ti10O12(cat)8 backbone for the three isolated molecular architectures. Partial charge analysis indicates two types of titanium atoms within these complexes with one resembling titanium(IV) found in TiO2. These complexes strongly absorb visible light in solution (λmax = 411 nm, ε = 10 800 for Ti10O12(cat)8(py)8 in CHCl3) and in the solid-state. The band gaps estimated from the reflectance spectra are between 1.85 eV and 1.97 eV. The present work also details the HOMO and LUMO representations obtained via DFT calculation for Ti10O12(cat)8(py)8 and a virtual Ti10O12(cat)8 complex as well as the DOS (density of states) plots calculated for those structures. This computational study highlights an impact of the pyridine ligand on the DOS plots
Molecular tectonics: Pyridyl containing thiacalix[4]arene based tectons for the generation of 2- and 3-D silver coordination networks
Three new organic tectons (2-4) based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1,3-alternate conformation, bearing four pyridyl coordinating moieties, have been synthesised and characterised in the solid state. The ligands are positional isomers and differ by the position of the N atom on the pyridyl unit (ortho for 2, meta for 3 and para for 4). Their combination with the Ag+ cation leads, reproducibly, to the formation of 2- and 3-D infinite silver coordination networks. Independent of the nature of the anion, the combination of 2 offering four (N,S) type chelates with the Ag+ cation affords an unprecedented diamond type 3D network. Both 3 and 4, behaving as tetrakis monodentate ligands, lead to the formation of 2-D architectures. © The Royal Society of Chemistry 2013
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