カプセル形成,カルボキシラート交換,およびカドミウムクラスター金属ロカビタンズのDFT探査:高度にダイナミックな超分子
Peter D Frischmann1, Glenn A Facey, Phuong Y Ghi
1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
Journal of the American Chemical Society
|March 4, 2010
まとめ
研究者らは,シフ基のマクロサイクル内に新しいカドミウムカルボキシラートクラスターを開発した. これらの金属ロカビタンドは,ユニークな宿主-ゲストの性質を持つカプセルを形成し,新しい超分子材料の設計に役立ちます.
科学分野:
- 超分子化学 超分子化学
- 協調化化学について
- マテリアルサイエンス 材料科学
背景:
- シーフ基底マクロサイクルは,金属クラスター形成のテンプレートとして機能します.
- メタロカビタンスは,ユニークな宿主-ゲストの性質と超分子組立能力を提供します.
研究 の 目的:
- シフ基底マクロサイクルによってテンプレートされたヘプタカドミウムカルボキシラートクラスタの新しいファミリーを合成し,特徴づけること.
- ホスト-ゲストの相互作用,超分子行動,およびこれらの金属ロカビタン複合体の動的性質を調査する.
主な方法:
- 変数温度溶液と固体NMRスペクトロスコーピー
- 単結晶X線 difraktion (SCXRD) とは,単結晶X線 difraktion (SCXRD) と呼ばれている.
- 密度関数理論 (DFT) の計算
- 熱力学と運動学の研究
- 固体 (2) H NMRスペクトロスコピー
主要な成果:
- [3 + 3] シフ基のマクロサイクルの内部にテンプレートされた孤立したヘプタカドミウムカルボキシラートクラスター.
- メタロカビタンドは,ボウル状の構造を採用し,客のためにアクセス可能な場所を持つ二分化によってカプセルを形成します.
- 濃縮されたN,N-ジメチルフォーマミド (DMF) の高包装系数 (0.80) は,強い宿主-ゲストの相互作用によるものです.
- ディメリゼーションはエントロピー駆動のプロセスで,リガンド交換とディメリゼーションの共通の速度決定ステップがあります.
- 固体状態 (2) H NMRスペクトロスコーピーを用いて封装されたDMF分子の3倍回転を観測した.
結論:
- この研究は,新しい種類の金属ロカビタンドの宿主-ゲストおよび動的性質の包括的な理解を提供します.
- これらの発見は,新しい超分子触媒と機能材料の設計を導くかもしれない.
さらに関連する動画
06:35Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
09:45Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
関連する概念動画
02:58Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
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...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
01:19Complexation Equilibria: The Chelate Effect
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
00:43Complexometric Titration: Ligands
Different monodentate and polydentate ligands are used as complexing agents in complexometric titration reactions. The formation of complexes by mono- and bidentate ligands involves two or more intermediate steps, limiting their use as complexing agents. In comparison, polydentate ligands can form complexes with metal ions in a single-step process, facilitating sharper end points. This means polydentate ligands, such as amino carboxylic acid derivatives, are most commonly employed in...
01:22EDTA: Chemistry and Properties
Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...