Metallacrowns: A New Class of Metallamacrocycles

无机化学、生物无机化学和金属有机化学项目的这一奖项支持了密歇根大学的Vencent L.Pecoraro教授在以下方面扩大金属冠合物的广度的工作：1)制备外围修饰的手性金属冠醚。2)分子腔中客体的选择性识别；3)手性固体的模块化合成；4)新型单分子磁体的开发。重点是12元和15元金属大环的合成，这些金属大环已经形成了新的手性固体。这些建议的12-MC-4和15-MC-5分子可以用多种金属制备，这将允许调节化合物的物理性质。手性12-MC-4结构将用β-氨基异羟肟酸制备，而15-MC-5结构将用α-氨基异羟肟酸制备。通过修饰这些氨基异羟肟酸的侧链，可以极大地改变这些金属冠醚的结构和性质。侧链如苄基(苯丙氨酸)或对羟基苄基(酪氨酸)可以在固体中形成金属大环二聚体，可以区别识别单羧酸和二元酸以及手性氨基酸。实验的目的是用功能来装饰这些空腔，以帮助选择性识别其他分子，包括手性羧酸盐和醇。通过改变异羟肟酸的杂原子给体，提出了金属冠醚配合物的金属组成修饰是可能的。提出了一种制备层状手性固体的模块化合成方法。金属大环分子可以作为磁体(单分子磁性或SMM)的观察有望在磁存储设备中使用。金属冠手性识别可能为使用选择性结晶或层析方法分离手性分子提供新的方法基础。氨基酸、氨基醇或羟基酸是许多有机和药物合成的重要起始原料，分离它们是可能的。多孔性固体合成的模块化方法可能为制造新的催化剂或存储材料提供一种方法。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports work by Professor Vencent L. Pecoraro at the University of Michigan to expand the breadth of metallacrown complexes with regard to the: 1) Preparation of peripherally adorned chiral metallacrowns. 2) Selective recognition of guests in molecular compartments 3) Modular synthesis of chiral solids, and 4) Development of new classes of single molecule magnets. The focus is on the synthesis of 12 and 15 membered metallamacrocycles that have made new chiral solids. These proposed 12-MC-4 and 15-MC-5 molecules may be prepared with a variety of metals, which will allow moderation of the physical properties of the compounds. Chiral 12-MC-4 structures will be prepared using beta-aminohydroxamic acids whereas 15-MC-5 structures will be produced when alpha-aminohydroxamic acids are used. The structure and properties of these metallacrowns can be drastically altered by modifying the sidechains of these aminohydroxamic acids. Sidechains such as benzyl (phenylalanine) or p-hydroxybenzyl (tyrosine) allow formation of metallamacrocyclic dimers in the solid state that can differentially recognize mono and dicarboxylic acids and chiral amino acids. Experiments aim to decorate these cavities with functionalities that will aid selective recognition of other molecules, including chiral carboxylates and alcohols. By changing heteroatom donors of the hydroxamic acids, it is proposed that modification of the metal composition of the metallacrown complexes will be possible. A modular synthetic approach for preparing layered, chiral solids is presented. The observation that metallamacrocycles molecules may act as magnets (single molecule magnetism or SMM) promises use in magnetic storage devices. Chiral recognition by metallacrowns may provide the basis of new methods for separations of chiral molecules using either selective crystallization or chromatographic methods. It may be possible to perform separations of amino acids, amino alcohols or hydroxy acids that are important starting materials for many organic and pharmaceutical syntheses. The modular approach for porous solid synthesis may provide a way to make new catalysts or storage materials.