Reactivity of Triosmium Carbonyl Clusters with 1,8-Diaminonaphthalene - Synthesis and Structural Characterization of Amido, Diamido, and C-Metalated Trinuclear Derivatives

摘要

The compounds [OS_3(CO)_(12)] and [OS_3(μ-H)_2(CO)_(10)] do not react with 1,8-diaminonaphthalene (H_2dan) under thermal conditions (110 ℃, 30 min). However, [OS_3(CO)_(10)(MeCN)_2] reacts with H_2dan (THF, reflux temperature) to give two isomers of [Os_3(μ-H)(μ-Hdan)(CO)_9] (1 and 2). In toluene at reflux temperature, these reagents afford [Os_3(μ-dan)(CO)_(10)] (3). Compound 2 can be converted into 3 under thermal conditions, but no interconversion between 1 and 2 has been observed. The three compounds have been characterized by X-ray diffraction methods. Compound 1 arises from the C-metalation of H_2dan in a position adjacent to an NH_2 group; this generates a hydride and a ligand that interacts with the three metal atoms through one of the NH_2 groups, through the metalated carbon atom (which spans an Os-Os edge), and through one of the C=C bonds of the metalated ring. In compound 2, the hydride arises from the oxidative addition of an N-H bond of H_2dan; the resulting ligand interacts with two of the three metal atoms through the amido NH fragment (bridging position) and through the remaining NH_2 group. Compound 3 is derived from the transformation of both NH_2 groups of H_2dan into amido NH groups and consists of a 50-electron trinuclear cluster with the longest edge doubly-bridged by both amido groups.