Main Group-Transition Element Clusters. Synthesis, Structure and Reactivity

无机、生物无机和有机金属化学项目的主要任务是合成含有硼的新型簇状化合物，这些化合物与钴和铁等过渡金属相连。除了提供有趣的新化合物和有助于理解将大簇化合物聚集在一起的力之外，该项目有望为制备由硼过渡金属簇芯组成的薄膜提供新的途径。在分离和表征离散过渡金属硼化物之后，第一个目标是定义六金属硼化物的化学性质，并合成相关但目前未知的系统。金属循环将被用作含有硼或铝原子的金属碳笼的便捷前体。将研究用其他碎片（如BF）代替铝碎片作为新笼的途径。过渡金属碳酸盐团簇，已被证明是一个非常庞大的，强烈提供π的配体硼，将被研究作为一种稳定富轨道（“缺电子”）主基团原子不寻常的键合模式的手段。由于团簇可以以各种方式耦合或凝聚以形成更大的组合，因此最终目标是证明B-O-B键作为共价团簇链接的有用性；双极性簇配体在组装簇前体或簇本身中的作用；主要基团过渡元素团簇作为由团簇核组成的固体薄膜的前驱体。

The main thrust of this project in the Inorganic, Bioinorganic and Organometallic Chemistry Program is the synthesis of new cluster compounds containing boron linked to such transition metals as cobalt and iron. In addition to providing interesting new compounds and contributing to an understanding of the forces which hold large cluster compounds together, the project is expected to provide new routes for the preparation of thin films made up of the cores of the boron-transition metal clusters. Following on the isolation and characterization of a discrete transition metal boride, the first objective is to define the chemistry of six-metal borides and to synthesize related, but presently unknown, systems. Metallacycles will be used as convenient precursors for metal-carbon cages containing boron or aluminum atoms. The facile replacement of the aluminum fragment by other fragments, such as BF, will be investigated as a route to new cages. A transition metal carbido cluster, which has been shown to serve as an exceedingly bulky, strongly pi-donating ligand to boron, will be investigated as a means of stabilizing unusual bonding modes of orbitally-rich ("electron deficient") main group atoms. Since clusters can be coupled or condnsed in a variety of ways to form larger assemblies, the final objective is to demonstrate the usefulness of B-O-B bonds as covalent cluster links; of bipolar cluster ligands in assembling cluster precursors or clusters themselves; and of main group-transition element clusters as precursors to solid thin films made up of the cluster cores.