[Hoff8]

I've been attempting some past exam questions before I go back to University next month and there's a couple that I am completely stuck on. I've been through all my Inorganic notes but I still can't come up with an answer for them.

Any help you could give me with them would be great.


Describe the type of bonding present in two of the following compounds between the metal and organic species.

BuMgBr      Ge(C₄H₉)₄       Ru(CO)₃(n⁴-C₄H₄)

Predict the stability to heat of two of the following compounds and explain the prediction.

Al(C₃H₇)₃       Mn₂(CO)₁₀        Ti(C₄H₉)₄

Thanks in advance

[cheese (MSW)]

Oliver: The answer you received on another forum is largely incorrect. For example, (OC)5Mn-Mn(CO)5 was the first cmpd shown by Dahl  to have a covalent metal-metal bond by X-ray crystallography back in the early 60s.  It is a reasonably stable red-brown crystalline solid that has a distinct metallic order.  The η-C4H4 is the aromatic cyclobutadienyl (C4H4^2-) unit trapped on a Ru atom; Petit made the first one (Fe cmplx) again in early 60s.
It is obvious from your question you're in your final year as an undergrad and hence you should be researching these cmpds by yourself (it's fun!).   The texts you need to consult are Comprehensive Organometallic Chemistry I, II, & III.  But you will find what you want in COMC I (Wilkinson, Stone & Abel eds) that covers the lit on organometallic chem up to 1980.  My set is green leather.  I hope you come across β-elimination and the aufbau reacktion (luv it!) in your travels.