Our research in the area of inorganic materials encompasses functional aspects of inorganic chemistry, hybrids and applications. Several projects include new catalytic materials based on metallacrown ethers, hybrid inorganic-organic polymers, metal-organic, and mixed valence third order nonlinear optical materials and semiconductor nanoclusters. The specific projects include new synthetic methodologies and characterization techniques.

Synthesis of novel inorganic materials

Metallacrown ethers
These are extremely interesting materials for use as catalyst in industrially important reactions such as alkene hydroformylation that use carbon monoxide as a reactant. The metallacrown ethers contain a number of different groups that are capable of interacting with the carbon monoxide and increasing both the activity and selectivity of its reactions. This research involves 1) the synthesis and characterization of a variety of metallacrown ethers, 2) studies of the properties of these materials that could affect their ability to function as catalysts and 3) evaluation of the metallacrown ethers as catalysts.

Poly(alkylene phosphonate)s
This project involves the synthesis, characterization and functionalization of poly(alkylene phosphonate)s, a class of polymers similar to DNA and RNA with phosphorus esters in the polymer chain. These polymers are of interest because they are readily prepared from inexpensive starting materials and they should be readily hydrolyzed to biocompatible products in vivo. This could make them extremely interesting materials for the controlled release of bioactive materials both because it should be possible to attach a variety of these materials to the phosphorus and because it should be possible to vary the hydrolysis rates of these polymers, and thus the release rates of the bioactive materials, by changing the alkylene group.

Materials with NonLinear Optical Properties and Applications

Third-order nonlinear optical materials are of interest for use in power limiters for protecting biological systems and sensitive detectors for exposure to high intensity laser light. These materials also have potential applications in all-optical computers. Collaborative research has demonstrated that transition metal complexes can exhibit third-order optical nonlinearities that are nearly as large as those of conjugated polymers (currently the best third-order nonlinear optical materials). Mixed valence complexes are molecules containing at least two metal ions in different oxidation states, which are significantly coupled to each other. As a consequence of the electronic coupling between the metal ions, electrons can be delocalized between them to varying degrees. Mixed valence complexes are therefore ideal candidates for the preparation of new nonlinear optical materials because they are intrinsically highly polarizable molecules. In addition, their properties can be easily tuned by substituting metal ions, varying their oxidation state, and adjusting the electronic coupling between them. We are currently preparing various mixed valence complexes and studying their nonlinear optical properties. Our goal is to both discover new and efficient nonlinear optical materials and determine correlations between their properties and structure.

A number of facilities in the Chemistry and Physics Departments are available for our research effort in inorganic materials. These include:

  • multinuclear NMR facility- 300MHz multinuclear NMR spectrometer (Bruker)
  • 400 MHz multinuclear NMR spectrometer (Bruker)
  • X-ray Crystallography Facility equipped with an Enraf-Nonius CAD4 single crystal X-ray diffractometer
  • a PC with SHELXTL-PC software for crystal structure solutions
  • microscopes for selecting and mounting crystals

This facility allows the solid-state structures of materials that crystallize in single crystals to be determined. Catalysis Evaluation Facility is equipped with a computer controlled, 500 ml Parr High Pressure reactor This facility allows the effects of reaction temperature, pressure and the pressures of gaseous reactants on the rates of catalytic reactions to be evaluated.

Nonlinear Optics Laboratory is housed in the UAB Department of Physics. UAB's Nonlinear Optics and Laser Laboratory houses state-of-the art spectroscopic analysis systems including:
  • Acton Research Corporation spectrometer system
  • Shimadzu spectrophotometer system
  • imaging polychromator-lens-coupled intensified CCD camera combination
  • 80 ps resolution Tektronics digitizer
  • Stanford Research boxcar integrator
  • Janis crystrostat
  • Spiricon beam profiling system
  • a wide variety of optical components and mounts
  • a low power Nd:YAG laser
  • Spectra-Physics GCR-250 high power Nd:YAG laser with injection seeder for single longitudinal mode
  • a Light Age alexandrite laser can be tuned in wavelength from 720 nm to 800 nm, extended to 300-1500 nm with our Raman cell module and frequency doublers and triplers. The temporal pulse width of the laser can be varied from 100 ps to 200 ms.

More recently, a picosecond mode-locked Nd:YAG laser has been purchased to provide an additional ps pulsed laser source for optical measurements. This facility allows the linear and nonlinear optical properties of both solutions and thin films to be fully characterized.