CAREER: Structure/Property Relationships for Dendritic Macromolecules Containing Stereogenic Centers

9702123 McGrath Research：该职业奖主要展示了包含内部手性基团的枝状材料的设计、合成和研究，以及这些材料中手性和构象顺序之间的基本关系。本研究的主要目的是了解手性对三维枝晶微观结构构象顺序的影响。本研究的最终目标是开发用于不对称催化和手性分离技术的新材料。本研究的初始阶段是系统地研究具有相同基本结构的大家族树状大分子的结构/性质关系，以阐明这类合成大分子中控制构象不对称和手性微环境的因素。所提出的树状大分子体系是基于对映体纯1,2-二醇键和苄基芳基或烷基芳基醚。这些具有不对称内腔和具有吸引相互作用（氢键）的官能团的材料应该能够选择性地包合一定形状和官能团排列的客体。因此，树状大分子和小分子之间的主客体相互作用将被研究。然后，这些材料将在高效液相色谱（HPLC）和胶束电动毛细管色谱（MECC）中进行手性鉴别测试。选择性封装和客体结合也将是这些材料作为不对称催化的多位点反应器发展的基础。反应速率的加速是由于(a)树状大分子内部的反应物的疏水结合或(b)树状大分子的1,2-二醇键上的过渡金属催化中心的反应。教学：从事物理科学职业的女性比男性少。很少有女性在研究生、本科生甚至高中阶段做出不进入科学领域的决定。研究表明，早期的社会和文化影响，而不是生理因素，引导女孩远离科学，在四年级到八年级之间，男孩和女孩对科学的态度存在巨大差异。为了解决这一问题，建议在当地小学（3年级和4年级）开展一项推广计划，以鼓励好奇心、实践科学经验和积极的男女榜样为基础，目的是将科学描绘成一项有吸引力的活动/职业机会，吸引女孩和年轻女性去追求。希望这种对科学兴趣的提高将有助于克服社会、文化和课程因素，这些因素目前导致女孩在初中阶段对科学的态度下降。这一研究项目将有助于理解手性对树突大分子构象的影响，并为设计手性树突大分子提供一个新的范例，它可以为被封装的客体分子提供不对称的环境。此外，还将制备可用于手性色谱分离和不对称催化的新一代材料。＊＊＊

9702123 McGrath Research: This CAREER award presents the design, synthesis, and study of dendrimeric materials containing interior chiral moieties and the study of the fundamental relationships between chirality and conformational order in these materials. The primary goal of this research is to develop an understanding of the effect that chirality has on the conformational order of three-dimensional dendritic microstructures. The ultimate goal of this research is the development of new materials for asymmetric catalysis and chiral separations technologies. The initial phases of this research are a systematic study of the structure/property relationships of a large family of dendrimers of the same basic structure in an effort to elucidate the factors governing conformational asymmetry and chiral microenvironments in this class of synthetic macromolecules. The dendrimer systems proposed for study are based on enantiomerically pure 1,2-diol linkages and benzyl aryl or alkyl aryl ethers. These materials with asymmetrlc interior cavities and functional groups capable of attractive interactions (hydrogen bonding) should be able to selectively clathrate guests of a certain shape and functional group arrangement. Hence, host-guest interactions between the dendrimers and small molecules will be studied. These materials will then be tested for chiral discrimination in high performance liquid chromatography (HPLC) and micellar electrokinetic capillary chromatography (MECC). Selective encapsulation and guest binding will also be the basis for the development of these materials as multi-site reactors for asymmetric catalysis. Reaction rate acceleration will result from either (a) hydrophobic binding of reactants in the dendrimer interior or (b) reaction at transition metal catalytic centers anchored on the 1,2-diol linkages of the dendrimer. Teaching: Fewer women than men embark on c areers in the physical sciences. A woman's decision not to enter the sciences is rarely made at the graduate, undergraduate, or even high school level. Research has shown that very early social and cultural influences, rather than biological factors, steer girls away from science, with a sharp disparity in attitude towards science between boys and girls occurring between grades 4 and 8. It is proposed to address this problem by developing an outreach program to local elementary schools (grade 3 and 4) based upon providing encouragement of curiosity, hands on scientific experiences, and positive male and female role models with the aim of portraying science as an attractive activity/career opportunity for girls and young women to pursue. It is hoped that this heightened interest in science will help overcome the social, cultural, and curriculum factors which currently contribute to girls' declining attitudes towards science through the junior high years. %%% This research program will result in an understanding of the effect of chirality on the onformation of dendritic macromolecules and a new paradi gm for the design of chiral dendrimers which can provide asymmetric envir onments to encapsulated guest molecules. In addition, a new generation of materials with applications in chiral chromatographic separations and asymmetric catalysis will be prepared. ***