Few organic solid-state systems are amenable to systematic and precise manipulation of crystal architecture and lattice metrics with predictable structural outcomes, which is crucial for the design and synthesis of molecular-based functional materials. Hydrogen-bonded frameworks based on the two-dimensional guanidinium-sulfonate (GS) sheet, however, have proven to be a benchmark in ?crystal engineering? owing to their structural robustness, which permits facile interchange of molecular constituents in selected framework architectures that often can be predicted and controlled through straightforward empirical principles. The versatility of the GS system will be exploited for (i) the synthesis of new class of GS hosts derived from a library of calixarene tetrasulfonates that form molecular baskets, suspended from the GS sheet, capable of including guest molecules within the calixarene rather than within the gallery regions between opposing GS sheets, (ii) examination of the hydrogen sorption characteristics of various guanidinium calixarenetetrasulfonates, (iii) the exploration of ferroelectric behavior associated with polar guests embedded within the suspended calixarenes, (iv) GS channel inclusion compounds with laser dyes as guests, aimed at regulating of the aggregation states of the dyes and their corresponding emission characteristics, (v) GS channel inclusion compounds with organic nitroxide guests, aimed at unraveling structure-property relationships in a new class of molecular magnets, (vi) enantioselective inclusion by chiral organomonosulfonate hosts, (vii) synthesis of discrete molecular capsules based on complementary hydrogen-bonding spacers between opposing calixarene units.
NON-TECHNICAL SUMMARY: This project aims to capitalize on molecules that can be used as ?tinkertoys? to construct designer materials with optical, electronic, magnetic and storage properties that can be tuned systematically through swapping of the molecular components, which is difficult to achieve through more conventional routes. As such, these materials have to potential to impact several U.S. technologies, including data storage, communications, energy, health, and specialty chemicals, including pharmaceutical materials. Additionally, the project will provide education and research training in STEM while cultivating the next generation of scientists and engineers through (i) summer research experiences for undergraduates and faculty from minority-serving and four-year institutions through connections to the NYU Materials Research Science and Engineering Center and a Research Experiences for Undergraduates site, (ii) research experiences for high school students from various NYC schools, including the Spence School, and all-girls K-12 institution in NYC, (iii) development of courses for high school teachers enrolled in the NYU Chemistry Masters of Science for High School Educators program, thus enhancing science education in the largest and most diverse school system in the U.S., (iv) offer professional development of student and postdocs through the creation of a Northeast Solid State Chemistry Symposium that will elevate their skills and confidence in scientific presentations, (vi) expose graduate students and postdocs to scientists from industrial laboratories and other academic institutions, U.S. and international through direct research collaborations.
for Crystalline Encapsulants Through Molecular Design (DMR-0906576) Intellectual Merit. This award supported the design and synthesis of new functional materials based on customized molecular frameworks constructed from simple building blocks consisting of guanidinium ions and mono-, di-, and polysulfonates. The core concept underlying the design of the these frameworks – versatility through interchangeability with retention of global structural features – was demonstrated through several key achievements. A new family of compounds based on "molecular baskets" tethered to hydrogen-bonded sheets was designed, and one of these was used to encapsulate the active male-produced monomeric form of the Mediterranean fruit fly pheromone providing an effective strategy for storing this otherwise unstable compound while allowing controlled release in agricultural applications (see accompanying POR-1). Other related compounds based on the hydrogen-bonded sheet permitted controlled alignment of photoactive and electrically conductive molecules, and directed organization of dye molecules in an effort to make tunable organic solid-state lasers. The project also led to the discovery of a new class of organic hydrogen-bonded zeolite-like frameworks based on the design of Archimedean polyhedra, which serve as the secondary building units for the zeolite-like frameworks (POR-2, figure courtesy of J. Lauher, Perspectives, Science, 2011, 333, 415). The supramolecular truncated octahedron cage was constructed from two kinds of hexagonal "molecular tiles." The interior volume of each cage is 2200 Å3, enabling encapsulation of a wide range of differently charged species, including organic molecules, transition metal complexes, and "ship-in-a-bottle" nanoclusters not observed otherwise. The elegant symmetry of these frameworks can be gleaned immediately from the shape of the crystals, which range in size from microns to millimeters (POR-3). Broad Impacts. In additional to the technical achievements described above, undergraduates, graduate students and postdocs in the PI laboratory are exposed to interfacial science and engineering, crystal nucleation and growth, crystal engineering, crystallography, and atomic force microscopy, providing an interdisciplinary experience that spans materials science, chemistry, and engineering. During the previous award period, the principal investigator supervised numerous graduate students, postdoctoral researchers, high school students and undergraduates, including students from the NYU Abu Dhabi campus, REU students supported by the NYU MRSEC, and two faculty-student research teams, one from a four-year college and the other from Xavier University of Louisiana, an HBCU partner through the Xavier-NYU Partnership for Research in Education and Materials. The principal investigator also assisted the Noyce Scholars program, which encourages students with B.S. degrees to pursue high school teaching careers. The principal investigator organized (and presented at) a weeklong workshop of lectures and lab modules with other NYU faculty during the Network Summer program hosted by the Faculty Resource Network at NYU and co-sponsored by the NYU MRSEC. The workshop was attended by faculty members from minority-serving institutions and four-year colleges in the FRN network, and the format comprised a presentation in the morning followed by a related lab exercise in the afternoon, with an emphasis on blending modern materials topics with classroom and laboratory curriculum. The PI principal investigator a partnership with the Chemists’ Club to establish its first University Chapter. The Chemists’ Club, which comprises a sizeable membership of industrial scientists and engineers is a 501(c)(3) organization dedicated to educational initiatives. Through workshops organized by students at NYU with industrial members of the Chemists’ Club, the NYU University Chapter provides a mechanism to increase the awareness of industrial career paths for undergraduates, graduate students and postdocs.
