Pillared Layered Compounds: Their Synthesis, Structure and Properties

设计多功能微孔或介孔材料是当前的热点。本项目的主要目标是有机-无机杂化材料的合成，主要研究方向是羧酸作为有机络合剂。这项工作还涉及到更复杂的膦酸。该策略是制备柱状层状材料，其中无机部分构成层，有机部分构成柱状材料。产品具有高表面积（~400m2/g），孔径小（~7-8直径）至中孔（~25直径）。该柱可以用磺酸、羧酸、氨基等基团进行官能团化。此外，柱子可以通过小的间隔物进一步分开，这些间隔物本身带有官能团。因此，它们可以制备为离子交换剂、特定络合剂、催化剂和发光材料。当金属为四价时，形成的粒子是纳米粒子，其布拉格反射不足以解析其晶体结构。这些孔隙在没有使用模板或间隔基团的情况下生长，通常大于层间距离，并产生I型气体吸附等温线，这一事实进一步加剧了它们结构的神秘性。这是前所未有的，因为孔隙的形成取决于所使用的溶剂。因此，我们使用了多种工具，如扩展x射线吸收精细结构和高分辨率电子显微镜以及原位方法来探测它们的结构，以及更常用的红外，可见光，核磁共振，中子散射和气体吸附方法来表征孔隙。该研究还针对通过使用由高水平间隔基团分隔的柔性烷基、聚醚和聚酰亚胺柱来呼吸的分子。因此，学生学习合成不寻常的材料，并使用尖端的光谱工具以及最新的晶体结构方法。化学方面的研究常常导致意想不到的结果。存在大量含有孔隙的类矿物化合物。这些孔隙的大小为4-13埃，其中1埃约为1亿分之一英寸。这些孔是小分子的大小。这些矿物状物质是石油炼制和许多其他有用反应中使用的主要催化剂。因此，它们引起了化学家和化学工程师的极大兴趣。该项目旨在将无机材料层与有机（碳基）支柱粘合在一起，从而生产多孔材料。想象一个停车场，地板和天花板由无机矿物制成，由碳基支柱连接。合成了孔径在7 ~ 25埃之间的样品。通过连接酸或碱基团，可以使柱具有高活性。它们可以用来传导用于燃料电池膜的质子，并进行各种有用的反应。其中一个反应将相对无用的化合物转化为对制药工业有用的化合物。它们还可以根据大小分离分子，最后合成出一种利用柔性支柱呼吸的生物。它们在吸收溶剂时膨胀，在排空时收缩。预计这些神奇的材料将有大量的用途。对这些材料的研究为学生提供了合成和处理纳米粒子技术的特殊技能，以及光谱x射线，中子和电子显微镜方法的科学状态。与历史上的非裔美国大学的合作增加了我们研究小组已经很高的多样性（西班牙裔，女性，波多黎各人）。

There is great current interest to design multifunctional micro- or mesoporous materials. A main goal of this project is the synthesis of organic-inorganic hybrid materials Most of the research is directed towards carboxylic acids as the organic complexing agent. The effort also involves the more complex phosphonic acids. The strategy is to prepare pillared layered materials in which the inorganic portion constitutes the layer and the organic the pillars. The products can have high surface areas (~400m2/g), with small pores (~7-8 diameter) up to mesopores (~25 diameter). The pillars can be functionalized with sulfonic acid, carboxylic acid, amino, etc. groups. Furthermore, the pillars can be further separated by small spacers which themselves carry functional groups. Thus, they can be prepared as ion exchangers, as specific complexants, catalysts and as luminescent materials. When the metal is four valent, the particles formed are nanoparticles in which insufficient Bragg reflections to solve their crystal structures are obtained. The mystery of their structure is further compounded by the fact that the pores grow without the use of templates or spacer groups and are often larger than the interlayer distances and yield type I gas sorption isotherms. This is unprecedented as the pore formation depends upon the solvent used. Therefore, we employ a variety of tools such as extended x-ray absorption fine structure and high resolution electron microscopy as well as in-situ methods to probe their structures along with the more usual infra-red, visible, nuclear magnetic resonance, and neutron scattering and gas sorption methods to characterize the pores. The research is also directed towards molecules that breathe by using flexible alkyl, polyether and polyimine pillars separated by high levels of spacer groups. Thus students learn to synthesize unusual materials and employ cutting edge spectroscopic tools as well as the latest crystal structure methodology. %%%Research in chemistry often leads to unexpected results. There exist a large number of mineral-like compounds that contain pores. These pores are of the order of 4-13 Angstroms, where one Angstrom is about a hundred-millionth of an inch. So these pores are the sizes of small molecules. These mineral-like materials are principal catalysis used in petroleum refining and many other useful reactions. Therefore, they are of great interest to chemists and chemical engineers. This project aims to produce porous materials from layers of inorganic material bonded together with organic (carbon based) pillars. Visualize a parking garage with the floor and ceiling made of inorganic minerals connected by the pillars that are carbon based. Samples with pores that range from 7 angstroms to 25 angstroms are synthesized. The pillars can be made highly reactive by attaching acid or basic groups. They can be made to conduct protons for use in fuel cell membranes and to carry out a variety of useful reactions. One such reaction converts relatively useless compounds to those useful to the pharmaceutical industry. They can also separate molecules by size and finally a variety that breathes by using flexible pillars I sbeing synthesized. They swell when taking up solvent and deflate when emptied. A large number of uses for these fascinating materials is predicted. Research on these materials provides students with special skills in synthesis and techniques of handling nano-sized particles and state of the science spectroscopic X-ray, neutron and electron microscopy methodology. A partnership with a historically African-American University augments the already high diversity (Hispanic, women, Puerto Rican) of our research group.