輪状のポリオキシトングステート [Cu20Cl (((OH)) 24 (((H2O)) 12 (((P8W48O184) ]25-マクロアニオンは,水溶液中の超分子"ブラックベリー"構造を形成する
Guang Liu1, Tianbo Liu, Sib Sankar Mal
1Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
Journal of the American Chemical Society
|August 3, 2006
まとめ
研究者らは,水性ポリオキシトングステートが空洞で球状の"ブラックベリー"型構造に自己組み立てることを発見しました. この発見は,マクロイオンの一般的な現象を示唆し,ポリオキソモリブダテスに特異的ではない.
科学分野:
- 無機化学 無機化学とは
- 超分子化学 超分子化学
- マテリアルサイエンス 材料科学
背景:
- ポリオキソメタラート (POM) は,多様な構造と特性を有する多用途の無機クラスターです.
- マクロイオンの自己組み立てが複雑な構造を形成することは,超分子化学の重要な分野である.
- ブラックベリー形成に関する以前の研究は,ポリオキソモリブデットに限定されていました.
研究 の 目的:
- [Cu20Cl(OH) 24(H2O) 12(P8W48O184) ]25- ({Cu20P8W48}) の新型水性ポリオキソートングステートの自己組み立て行動を調査する.
- この非モリブデンを含むポリオキソメタラートでブラックベリー型構造の形成を調査する.
- これらの自己組み立てのマクロイオン構造の電泳的性質を研究する.
主な方法:
- ダイナミックライト分散 (DLS)
- 静的光散乱 (SLS) とは
- ゼータ・ポテンシャル分析
- スキャニング電子顕微鏡 (SEM)
主要な成果:
- {Cu20P8W48}ポリオキシトングステートは,水溶液で単層の,空洞の,球形のブラックベリー構造に自己組み立てられます.
- これは,モリブデンを含まないポリオキシメタラートによるブラックベリー形成に関する最初の報告です.
- ブラックベリーの形成はマクロイオン濃度と温度とは無関係でした.
- {Cu20P8W48} マクロイオンは,この自己組み立て行動 (等価半径<2 nm) を表す観測された最小のものである.
- エレクトロフォレティック研究により,ブラックベリー構造内の電荷密度が自由なマクロイオンよりも低いことが明らかになり,対対離子結合が示唆されています.
結論:
- ブラックベリー型構造の形成は,極性溶媒中の水性マクロイオンの一般的な現象である可能性が高い.
- {Cu20P8W48}システムは,希釈された溶液中の単純なイオンからマクロイオンへの移行の洞察を提供します.
- モノヴァレンントのカウンターイオンは,マクロイオンの自己組織化において重要な役割を果たし,ブラックベリーの形成のための魅力的な力を媒介する可能性がある.
関連する概念動画
02:48Ionic Bonding and Electron Transfer
Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. Compounds composed of ions are called ionic compounds (or salts), and their constituent ions are held together by ionic bonds: electrostatic forces of attraction between oppositely charged cations and anions.
02:54Lewis Structures of Molecular Compounds and Polyatomic Ions
To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
02:37Metallic Solids
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.