[Serenagreene]

I missed the class where the teacher went over how to calculate the oxidation state of the metal in an organometallic complex and how to tell if it's saturated or not.  Can someone take a look at this and tell me if I am doing this correctly?  I have attached the worksheet and my answers are:

a) Charge on Fe = -2 and it's unsaturated (I'm not sure if I am figurering this out correctly ( 8e'(Fe) + 2 (Na) * 2e' + 4 * 2e' = 20 but to be saturated I would need 28 e'?) 

b)  Charge on Pd = +2 and it's unsaturated (8e’ + 2e’ + 2e’ + 2(allyl)*2e’ = 16 (saturated would be 18 e’))

c) Charge on Pd = +2 and it's unsaturated (8e’ + 2e’*4 = 16 – (saturated would be 18 e’))

d) Charge on Fe = -1 and it's unsaturated (7e’ + 3*2e’ + 2*2e’ = 15 – (saturated would be 18e’))

e) Charge on Cr = -6 and it's saturated (2e’ + 5*2e’ + 2*2e’ = 18)

f) charge on Pd = +2 and it's unsaturated (16e' total)

g) Charge on Pd = +2 and it's unsaturated (16e' total)

[azmanam]

Excellent, excellent chart on page 4/5 to help you here.  I use this chart almost every time I count electrons:

http://bama.ua.edu/~kshaughn/ch609/notes/2-18-electron.pdf

[azmanam]

I went through these quickly, but

a) no (it's 18e - how many electrons will Na⁺ donate???)
b) yes
c) yes
d) no (watch the formal positive charge)
e) no Cr is not -6, but I do get 18e
f) yes
g) that's not what I get, but this one didn't make a lot of sense to me.  I got 15e total
h) ...

[Serenagreene]

Thanks, Okay I revised my answers.

a) Fe is -2, but as Na can only supply 1 electron - the total # of e' are 18 and it's saturated. 
d) Fe is +2, the Fe has 4 e', the 3 CO contribute 6e', the ring donate 6e' for a total 16e' so it is unsaturated.
e) Cr has a -1 charge
h) Pd has a +3 charge and it has 15e' and is unsaturated....

I'll have to print out the reference and read it a bit more in depth when I get home tonight.

Thanks for you help it is starting to make a little more sense (I think).

-Serena

[azmanam]

a) if Na^o were somehow a ligand, I'd buy that it donates 1 e^-.  But Na⁺ is not Na^o, it is not a ligand, and doesn't even have any e^- to donate.  Just a cation.

d) no.  Fe2+ does not have 4 e^-. ligand counts are correct, tho.

e) Cr is not -1.  These are not readily obvious.  Check the table in the pdf for how to deal with carbene ligands.  NOTE: there are two types of carbene ligands, make sure you're applying the correct one...

h) Nope.  And these ligand's aren't explicit in the book either.  What if the oxygen atoms were carbon atoms.  Treat it as an allyl ligand (I think - if anyone knows better, please correct me!)