In the metal complexes, differentiate between coordinated and no-coordinated water molecules using a thermogravimetric analysis. In this analysis, 50 to 100 'C is the non coordinated water and 100 to 150 'C is the coordinated water molecules.
The best way to differentiate between coordinated and non coordinated water molecule is thermogravimetric analysis. The non coordinated molecules gives and endothermic peaks at temprature ranging between 50-70' C and coordinated molecules appear as endothermic peaks at around 100-120'C. TG in combination with DTA.
It is also possible to differentiate the same by spectroscopic methods such as IR and UV visible
It depend on valences of metal and strength of nucleophilicity of other ligands. You can found this without any analysis.
If you the complex as a solid, the best way is thermogarvimetry. the loss of both kind of water molecules should occur at different temperature. Spectroscopy can also help
IF you have both type of water within the same compound, vibrational spectroscopy can give some possibility to distinguish them. The deformation bands and libration bands might be different, but it depends on the strength of coordination, number of waters, position, etc.
A broad peak in the IR spectrum of complex in 3500- 3200 cm-1 region may suggest the presence of water molecules in the complex . The coordinated water molecules generally show characteristic peaks around 750 cm-1 due to ρr(H2O) and 650 cm-1 ρw(H2O). However, the presence of type of water molecules may be confirmed further by TG-DTG analysis.
I think that there are two important peaks in the ft-Ir spectra first one is at the region with high energy at 3500 to 3200 cm -1 the second peaks is at the region 700 - 890 cm -1 is observed as new bands comparison with ligand spectra the second band is important evidence for H2O coordinated molecular , another evidence is shown clearly form TGA studies .
I think the non ligand band occurring blw 800 - 900 cm-1 on the FT-IR spectra indicates water of coordination.
How can one determine the number of non coordinated water from Tga
Values of the hydrolytic constant of the bound water may give some hint. Thermogravimetry , DSC are OK
(TGA) Thermal GravimetricI analysis techniques In this analysis, (50-100) °C is the stage for (Crystalline) noncoordinated water, and (100-150) °C is the coordinated water molecules inside the coordination sphere.
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