Multiple Metal-Carbon Bonds, Metallacycles, and Catalytic Reactions Involving Olefins and Acetylenes

无机化学、生物无机化学和金属有机化学项目属于过渡金属有机金属化学领域。该项目的成果将加强对开发用于化学合成和碳氢化合物转化的新催化剂至关重要的领域的基础知识。研究的重点是Mo、W的单亚胺基亚烷基化学和Re的亚烷基、亚烷基和亚胺基配合物的化学。将对M(Chr‘)(NaR)(OR)2型钼和钨配合物的烯烃歧化反应进行机理研究，其中Ar=2，6-二异丙基苯基。这些实验的目标将是找出三角双锥金属环丁烷配合物与正方形金字塔金属环丁烷配合物的作用，以及通过改变OR基团的性质来控制烯烃歧化活性的精确程度。另一个目标是开发一条实用的钼催化剂合成路线，因为钼比钨对官能团的耐受性更强。第三个目标是将已学到的知识推广到Re，即制备Re乙炔和烯烃歧化催化剂，其活性可以通过选择醇盐配体来控制，部分原因是Re可能是这些金属中对官能团最宽容的。还将研究Re(CR‘)(NAR)(OR)2类型的单亚胺基烷基络合物作为乙炔歧化催化剂的行为，因为至少有一个相关的络合物已知是内部乙炔的活性催化剂。一般情况下，Re(Vii)的有机金属化学将随着这类化合物的路线的出现而发展。

This project in the Inorganic, Bioinorganic and Organometallic chemistry Program is in the area of transition metal organometallic chemistry. The results of the project will enhance fundamental knowledge in an area critical to the development of new catalysts for chemical synthesis and hydrocarbon conversion. The foci of the research are the monoimido alkylidene chemistry of Mo and W and the chemistry of alkylidyne, alkylidene and imido complexes of Re. Mechanistic studies will be carried out on olefin metathesis reactions involving Mo and W complexes of the type M(CHR')(NAr)(OR)2, where Ar=2,6-diisopropylphenyl. The goal of these experiments will be to sort out the role of trigonal bipyramidal metallacyclobutane complexes versus square pyramidal metallacyclobutane complexes, and how precisely olefin metathesis activity is controlled by varying the nature of the OR group. Another goal will be to develop a practical synthetic route to molybdenum catalysts, since molybdenum is more tolerant of functional groups than is tungsten. A third goal will be to extend what has been learned to rhenium, i.e.,to prepare rhenium acetylene and olefin metathesis catalysts whose activity can be controlled by the choice of alkoxide ligands, in part because rhenium is likely to be the most tolerant of these metals toward functional groups. The behavior of monoimido alkylidyne complexes of the type Re(CR')(NAr)(OR)2 as acetylene metathesis catalysts will be investigated also, since at least one related complex is known already to be an active catalyst for internal acetylenes. The organometallic chemistry of Re(VII) in general will be developed as routes to such compounds become available.