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University of Houston • University of Houston-Clear Lake • ISSO Annual Report Y2003 • 102-103
Coordination Polymers For Nanofibers
Jack Y. Lu [UHCL]
Abstract
Microporous metal-organic polymers have found a wide range of technological applications,
such as molecular separation and pollution prevention in air, liquid, and water systems,
where they can be used as ion exchangers and molecular sieves. These novel zeolite-like
materials may be fabricated into nanomaterials. One of the key factors for the success of
fabricating metal-organic nanomaterials is the synthesis of desirable metal-organic
polymers that can be suitable for nanomaterials fabrication. Exploration in this project
has produced several novel microporous metal-organic polymers.
SYNTHESIS AND FABRICATION OF FUNCTIONAL MATERIALS represent one of the great challenges in current research. The microporous metal-organic polymers have found a wide range of technological applications such as molecular separation and pollution prevention in air, liquid and water system, where they can be used as ion exchangers and molecular sieves. These novel zeolite-like materials may be fabricated into nanofibers. This project is designed to produce novel microporous metal-organic polymers desirable for generation of metal-organic nanofibers.
Experimental Activity, Results and Discussion
Among the new metal-organic polymers synthesized in our laboratory, {[Cu2(IN)3]·I5-·5/6I2·H2O}8 (IN: isonicotinato)1
is an unusual polyiodide inclusion metal-organic polymer with a novel 3-D nano
hollow-channel open-framework synthesized via an oxidation reaction route under
hydrothermal conditions. The diameter of the channel is about 1.15 nm, slightly smaller
than that of carbon nanotubes (~1.4 nm).
[Cd(NA)2]2 (NA= nicotinato), a new three-dimensional (3-D) neutral coordination polymer, has been synthesized under hydrothermal reaction conditions. The structure consists of distorted square pyramidal cadmium centers coordinated by two independent nicotinato ligands. One nicotinato ligand is tridentate; the other one is bidentate to cadmium metal centers. Every two cadmium atoms are bridged by two carboxylato groups of the tridentate nicotinato ligands through O(2) and O(4) atoms to form a binuclear cadmium unit: Cd2(NA)4. The O(4) atom is at the apical site while the two pyridyl groups and the other two oxygen atoms are at the equatorial positions. The formation of the binuclear units created eight-member rings, which are then linked by nicotinato ligands to result in large 24-member rings. There are four eight-member rings on each 24-member ring: two eight-member rings at trans-position to each other are perpendicular to the other two eight-member rings. Four 24-member rings connect to each eight-member ring, via covalent bonding to the binuclear cadmium centers: two 24-member rings are perpendicular to the other two 24-member rings. The propagation of the 24-member rings and eight-member rings extends into three directions to result in a 3-D open framework structure.
Acknowledgments
We thank the financial support from the ISSO. This work made
use of MRSEC/TCSUH Shared Experimental Facilities supported by the National Science Foundation and the Texas Center for Superconductivity at the
University of Houston.
References
1J. Y. Lu and V. Schauss. "A Novel Nanostructured
Open-Channel Coordination Polymer with an Included Fused-Polyiodide Ring," Eur. J.
Inorg. Chem. (2002): 1945-47.
2J. Y. Lu and E. E. Kohler.
"A Non-Interpenetrating 3-D Coordination Polymer Built from Binuclear Cd Units Elaborated with Square Pyramidal
Geometry of Cadmium," Inorg. Chem. Commun. 5 (2002):
196-98.
Institute for Space Systems Operations - Y2003
Annual Report
Copyright © 2004
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