Rapid sample throughput is essential for multi-user scientific instruments located in central core facilities such as the Department of Chemistry's Instrumentation Facility (DCIF) at the Massachusetts Institute of Technology (MIT). Funds are requested from the NIH to assist in the purchase of a complete 400 MHz nuclear magnetic resonance (NMR) instrument to better serve 104 researchers from the groups of this proposal's seven Major Users. The requested instrument will replace a 13-year-old Varian XL-300 instrument (which has recently experienced considerable down time including a magnet quench) and will sere as the primary workhorse instrument for researchers working on a wide array of NIH-funded research programs. The inclusion of a modern 400 MHz NMR instrument in the DCIF at MIT is an integral part of a major initiative- -including the recent $540,000 renovation of the DCIF--to upgrade and modernize the instrument services provided to Departmental and other academic researchers. The increased efficiency, enhanced biologically- related research in the Department. Projects that will benefit from the acquisition of this instrument include the following: asymmetric catalysis, new reaction development, total synthesis, electron transfer studies, oligosaccharide synthesis, and investigations of peptide conformation. At present, all but one of the DCIF's NMR instruments is severely outdated. Even the DCIF's newest NMR instrument (a Unity 300 with a widebore magnet intended for solid-state work) is eight year old. All other NMR instruments are more than ten years old excepting a Bruker AC-250 which is nine years old. The lack of modern and efficient NMR instrumentation in the DCIF negatively impacts productivity. NIH-funded research on small and intermediate size molecules being carried out in the Department would be greatly facilitated by a 400 MHz NMR instrument with increased sensitivity, internet access for moving data, an automatic sample change, rapid autoshimming capability, and a four- nucleus probe.