I assume you are looking for a change in CO stretching frequency of a metal carbonyl complex? What metal, oxidation state, and ligands are you interested in?

 Aaron Its metal oxide using some acid precursor. - TiO2. 

Dear Michael, I want standard values if you have. I wrote it in the explaition.

Mr. Bakre,

The ranges are different for the different ligands. What kind are your ligands?

Ms Bojidarka

Its not Mr. Its Ms Bakre. I am using monocarboxylic acids.

Ms Bakre,

within 20 cm-1 for bvidentate coordination of nasCOO- mode

Hi Bojidarka

I dint get your answer. Please can you clear it?

Ms. Barke,

If I have understood your question properly, the topic is about a 'standard' value of shifting of IR-bands when COO- takes part in various coordination modes. If yes, then this value is 20 cm-1 as written before for nasCOO- band. This is the case when COO- participates in a bidentate coordination. Bidentate coordination involves a bridging fashion as well. So that you canon distinguish well between mononucler coplexes with bidentate coordination and dinuclear complex with bridging COO- ligand using only conventional IR-spectroscopy. This can be done using polarized IR-spectroscopy.

In a monodentate coordination, you have not characteristic frequencies about COO- group. Or, there are not nas COO- or nsCOO- modes in the spectrum of your complex. You have, in fact, nC=O, which is weakly affected and O-M bond. So, you need IR-spectra within far-IR region, where there are observed nM-O modes. In this context you cannot talk about 'shifting' of bands of COO-, comparing the IR-spectra of the ligands and the complex.

Thanks Bojidarka.

Actually I am working on metal oxides prepared from carboxylic acids. Thus I was looking for difference in absorption peaks  Δν values (of the adjacent peaks in the IR spectrum) of the product.

Pratibha

Ms. Bakre,

In such as cases you can use deconvolution, first in order to determin the number of those adjacent peaks, if they are with low Dn and "subtraction" procedure, as a second processing of the IR pattern,  "subtracting" both the IR-patterns of your starting system and final product.