[srya2000]

I have a IR spectrum of [(Cu6H5)₃P]₂CuBH₄ I have been able to identify everything above the wavelength 1000cm^-1 and having a really hard time figuring out the peaks at the lower wavelengths. Can anyone give me a run down on how to read inorganic ir spectra with metal complexes or point me in the right direction? How do i know which part of BH₄ bonds with the (C6H5)₃P?

[MasterMatt]

Have you considered unreacted reactant, side products, or unremoved solvent?

[MasterMatt]

And I believe BH4 is coordinated to the metal, so you'll only see B-H bonds from that part.

[srya2000]

Correction its [(C6H5)₃P₂]CuBH₄

Have you considered unreacted reactant, side products, or unremoved solvent?

I have not considered unreacted reactants or any of those things yet, but they would not make up for the entire 1000-400cm^-1 range where most of my activity is.

And I believe BH4 is coordinated to the metal, so you'll only see B-H bonds from that part.

And yes i have been able to figure out where the B-H bonds are and the atomic structure of BH₄ but that above 1000cm^-1

I just can not figure out where the P comes into play and who it is bonding with, the C or H.

[MasterMatt]

It won't be bonding to the H. Think about what the C6H5 ligand has to be.
EDIT:

And 400-1000 is usually called the "fingerprint" region. It's mostly due to carbon-carbon bonds and is really messy. IR is typically to prove you made the product/identifying unreacted reactant /solvent/side product. So you really want to see if there are new bonds formed in the product that aren't in the starting material. Forget the other stuff. But if you're doing something like FeCl2 + H2acac -> Fe(acac)2 + 2HCl an IR isn't going to prove s#*$, because the starting material and product IRs will be the same. That's pretty much the extent of my IR knowledge. Hope it helps.