With this award from the Chemistry Research Instrumentation and Facilities: Multi-user (CRIF:MU) program, Professor Daniel Talham and colleagues Alexander Angerhofer, Lisa McElwee-White, Juan Nino and Adam Veige from the University of Florida will acquire a Fourier transform infrared (FTIR) spectrometer with far infrared capabilities as well as an electrochemical cell and a stop-flow system. The award will enhance research training and education at all levels, especially in areas of study such as (a) mechanism-based approaches for chemical vapor deposition (CVD) and atomic layer deposition (ALD) of copper barriers, (b) enzyme kinetics of wild-type and mutant oxalate decarboxylase, (c) design and evaluation of electrocatalysts for carbon dioxide reduction, (d) stopped-flow and electrochemical IR analysis of oxygen atom transfer from trianionic pincer chromium(V)-oxo species, (e) studies of FTIR in organic synthesis, and (f) studies of structure and electrical relationships in superconductors and dielectrics.
Fourier transform infrared (FTIR) spectroscopy is a technique used to obtain an infrared spectrum of absorption or emission of solids, liquids or gases. An FTIR spectrometer simultaneously collects spectral data in a wide spectral range and transforms the raw data using a mathematical algorithm to provide a spectrum. This type of modern instrumentation has opened up new applications of infrared spectroscopy using electromagnetic radiation with wavelengths longer than those of visible light. The stop-flow system allows rapid mixing for the study of chemical kinetics and the electrochemical cell allows use of direct current to oxidize or reduce compounds and simultaneously study the changes in the spectra. The instrumentation will be located in a spectroscopy facility and will be used by a large number of researchers and students.
,' allowed the Department of Chemistry at the University of Florida to procure a state-of-the-art FTIR spectrometer covering the mid-IR and far-IR frequency ranges. The spectrometer is equipped with a stopped-flow set-up that allows fast kinetic measurements useful in studying chemical reaction dynamics in solution. The instrument is also equipped with an electrochemistry cell that allows spectroelectrochemistry experiments. The instrument serves the needs of a diverse faculty with many different research interests. For example, the instrument has helped to make contributions in the following areas: Biological metal clusters catalyze multi-electron redox reactions, which are central to global element cycles. However, few synthetic systems that demonstrate comparable redox cooperativity and reactivity as observed in these biological clusters have been reported, despite the fact that they have far reaching implications from chemical synthesis (e.g., heteroatom transfer) to renewable energy research (e.g., water oxidation). Novel macro-bicyclic ligands were synthesized by the Murray group and characterized with the help of the FTIR spectrometer. These ligands are used to template the controlled assembly of trimetallic clusters. Far infrared spectra collected on a sulfide-bridged complex confirmed incorporation of a central sulfide donor - a structure which bears strong similarity to active site of nitrous oxide reductase - and mid-IR data contributed to the routine characterization of all other trinuclear compounds that have so far been made in this study. The Castellano lab recently reported that benzotrifuranone (BTF) is uniquely suited for multifunctionalization through sequential aminolysis reactions. The platform affords rapid access to mono-, di-, and tri-functionalized targets provided routine control of temperature and amine reagent stoichiometry, and lends itself to the one-pot synthesis of multi-functionalized derivatives from BTF in excellent yield (85%) and a single day. Initially an electronic/inductive argument was proposed to rationalize the kinetic deactivation observed upon successive aminolysis. With the new stopped-flow IR instrumentation provided by the CRIF-supported Bruker v80 FTIR instrument a more comprehensive understanding of the aminolysis behavior of BTF through comparative kinetics measurements could be achieved. Analysis of the kinetic data, as well as additional computational and X-ray crystallography data, now point more strongly to a "ring strain gradient" as the most significant selectivity driver for multi-functionalization of BTF. The Sumerlin group has used the Bruker v80 FTIR instrument to investigate the conjugation of a novel polymeric drug to magnetic nanoparticles (MNPs). These particles have been proposed as drug carriers with remote release actuation triggered by the heat generated upon exposure to an alternating magnetic field (AMF). The objective of this work to synthesize a novel polymeric drug-magnetic nanoparticle conjugate system, which will significantly improve the drug loading, water solubility and biocompatibility of the magnetic nanoparticles. It will reduce the possibility of deactivation during circulation as well. The polymeric drug is synthesized by RAFT (Reversible Addition Fragmentation chain Transfer) polymerization with a temperature-sensitive Diels-Alder linked fluorescein monomer. The drug release behavior could be controlled by localized hyperthermia induced by alternating magnetic field. The Bruker v80 FTIR instrument is an important tool to investigate the conjugation of the polymeric drug to the magnetic nanoparticles. The Talham group has used Far IR spectroscopy (600-250 cm-1) in an exploratory study to probe the Mo-C bonding in a new coordination polymer (K4Cu2.5Mo(CN)12.5·nH2O) and help elucidate the coordination environment around the Mo ion. The study is part of a project aimed at developing new examples of thin film and particle heterostructures based on cyanometallate coordination polymers to explore how coupling across the heterostructure interface can be used to influence magnetic and photo-induced magnetic behavior. So far 12 different research groups in the Department of Chemistry have utilized the FTIR instrument. 3 papers have already appeared in the peer-reviewed literature that used data acquired on the instrument. Several more papers are in preparation. In addition to the scientific impact the instrument has also helped to develop human resources. 35 students and postdocs were trained on the instrument during the reporting period. Of these 15 belonged to traditionally underrepresented groups. All of these researchers have learned valuable skills that will serve them in their future careers.
