Alkene cleavage alkyne systems

Alkene and Alkyne Cleavage Systems Not Covered Here but Included in Chapter 1... 

There have been far fewer studies on the reactions between tetranuclear clusters and alkynes or alkenes than have been reported for trinuclear systems. The reactions that have been investigated have largely been with alkenes. Both R H CO) 2 and Os4H4(CO)12 react with mono- and polyalkenes, and substitution of hydrides and carbon monoxide ligands is observed in most cases (180-187), as shown by Eq. (10). There are a few examples, however, where metal-metal bond cleavage does occur and trinuclear clusters are isolated (181-183,188). In contrast, when Rh4(CO)12 and Ir4(CO)12 are treated with dienes, cluster growth occurs (189-193). 

---