Oxides rhenium oxide like structures

The corrosion of Re-containing alloys, such as CoNiMnReP, has not been reported, but in disk structures with an Si02 overcoat they perform well in corrosion tests [55]. Rhenium itself is very reactive and prone to corrode [136]. Small amounts of Re in magnetic alloys are most likely in an oxidized state and play a role similar to that of Mo in the protection of stainless steel. 

In both the case of epoxidations via j2-peroxides and that of diolate cycloreversion, chemists must exercise caution that the mechanistic lessons learned for rhenium may not translate to processes mediated by other metals, ligands, or oxidation states. This has always been a particular problem in mechanistic organometallic chemistry. However, it is likely that systems can be developed based on the observations described here that can discern the structural features that control competing mechanistic manifolds. 

Technetium oxide tetrafluoride like the pentafluoride is formed as a by-product of TcFf, in the lluorination of technetium metal [59,78,79]. TCOF4 forms two phases that may be separated from TcFs and from one another by vacuum sublimation. One phase of TcOF forms blue needles, has a chain structure, and is isostructural with its rhenium analogue. The other modification is a more volatile green compound of tri-meric structure [78,79]. 

T -Arene complexes containing late metals have been known for many years, but the scope and utility of these complexes have increased in recent years. Copper(I) and silver form labile arene complexes of various stoichiometries that are apparently T -arene complexes. A few of these complexes have been structurally characterized. More recently, a large number of V-arene and heteroarene complexes of osmium, rhenium, molybdenum, and tungsten have been prepared for the purpose of dearomatization of the arene or heteroarenes. Two examples are shown in Figure 2.33. This dearomatization creates a diene or vinyl unit that imdergoes the organic chemistry of ttiese isolated units, instead of the chemistry of an arene. n -Arene complexes of rhodium and platinum have been characterized structurally and studied in the context of their likely intermediacy in the oxidative addition of arene C-H bonds. ... 

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