Thermodynamic Studies of Metal/Sulfur/Hydrogen Systems

该奖项将支持迈阿密大学化学系的卡尔·D·霍夫博士对有机金属反应热力学的研究。尽管霍夫将研究各种各样的反应，但特别有趣的是钼硫络合物的反应。这些络合物之所以被选为研究对象，是因为它们参与了加氢脱硫催化，影响了燃料中的硫的脱除和植物的固氮。将研究氢、硫化氢、硫醇和二硫化物与钼的氧化加成反应。还将测定各种含硫物种--硫醚、硫醇、硫化氢、噻吩硫、二硫化物、金属硫醇和二氧化硫--与钼的结合热。霍夫博士将研究钼-硫键的能级。这一结果将引起广泛的兴趣，因为目前关于金属-硫键热力学的基础数据很少。硫可以以多种成键方式(单键、多键、桥联)与金属结合，这些键的强度受金属的氧化状态和金属周围其他基团的存在的影响。了解这些因素对钼的影响有助于更好地理解和控制加氢脱硫和固氮的催化过程。

This award in the Inorganic, Bioinorganic, and Organometallic Program will support research on the thermodynamics of organometallic reactions by Dr. Carl D. Hoff of the Chemistry Department, University of Miami. Although Hoff will investigate a wide variety of reactions, of particular interest are reactions of molybdenum sulfur complexes. These complexes are chosen for study because of their involvement in hydrodesulfurization catalysis, which effects the removal of sulfur from fuels, and nitrogen fixation in plants. Oxidative addition of hydrogen, hydrogen sulfide, thiols, and disulfides to molybdenum will be studied. The enthalpies of binding of various sulfur-containing species--thioethers, thiols, hydrogen sulfide, thiophene, disulfides, metallothiolates, and sulfur dioxide--to molybdenum will also be determined. %%% Dr. Hoff will investigate the energetics of molybdenum-sulfur bonds. The results will be of wide interest because little fundamental data concerning the thermodynamics of metal-sulfur bonds is currently available. Sulfur can bond to metals in a variety of bonding modes (single, multiple, bridging) and the strength of these bonds is influenced by the oxidation state of the metal and the presence of other groups around the metal. Understanding the influence of these factors for the molybdenum case could contribute to a better understanding and control of the catalytic processes of hydrodesulfurization and nitrogen fixation.