On Wed, Dec 3, 2014 at 2:39 PM, Jason Gaudet <jason.r.gaudet@gmail.com> wrote:
Hi Pushkar,
Do you have a reliable source that tells you what Fe-O and Fe-S bond distances and coordination your iron triflate should have?
I'm not familiar with iron triflate but I was under the impression Fe was coordinated to the sulfonate through an oxygen? And if so, even if your sample didn't absorb water, you're trying to measure a S second-shell on the other side of an octahedral O shell? And apparently you're correctly fitting that O shell? Am I visualizing the structure correctly?
If your concentration of Fe was very low, or your setup was otherwise less than ideal (which, for catalyst studies, is pretty common), I would not be surprised if your data quality isn't sufficient to distinguish S scatterers on the other side of six O scatterers from your noise level.
But without knowing the structure, or your sample setup, or your spectra, all I can really do is imagine these things ...(And yes, it is hygroscopic.)
-JasonOn Tue, Dec 2, 2014 at 8:22 PM, pushkar shejwalkar <pshejwalkar2004@gmail.com> wrote:_______________________________________________Dear All,I am experiencing problem during my fit for Fe(OTf)2 anhydrous. The problem is as follows.I collected the data and used a model to fit. The fitting values and other technical information is as below. The basic problem is Fe(OTf)2 in anhydrous condition is probably not cyrstalline because of which there are no crystal data available. Although .cif file is available for hexahydrate and tetra acetonitrile. But obviously it is not directly useful as I am looking for Fe(OTf)2 only. I used hexahydrate for fitting, and the fit information is given. Is this fit acceptable?Now two questions1) Why do I not see any scattering or peak for Fe-S. I expected S to be a strong scatterer and would show a peak. Under given circumstances it looks like Fe is all surrounded by water and no triflate is present near Fe at all. Is this assumption even make sense (when the bottle said anhydrous) The bottle was not kept under inert condition (and its my fault), but does it mean Fe(OTf)2 is so hygroscopic and that it can actually form such hexahydrate to the full extent?OR there is some inherent problem with my fitting and collection itself. I used RBKG=1.02) Is anybody working on Fe(OTf)2 and had such or any other problem indicating that Fe(OTf)2 by itself is a bad choice of precursor because of its reactivity. Also any comments on purification method etc. does anybody know if crystal structure is available for Fe(OTf)2 anhydrous? I could not find it on the quick search or on CCDC. Any other site where I can get crystal data and .cif information?Thank you very much for all the help, I hope the question is asked appropriately and all the other information is provided, however, if anybody needs any other information please let me know.Thank you in an anticipationBestPushkarIndependent points : 16.1250000Number of variables : 4Chi-square : 7324.9401796Reduced chi-square : 604.1187777R-factor : 0.0195782Measurement uncertainty (k) : 0.0001264Measurement uncertainty (R) : 0.0004142Number of data sets : 1guess parameters:SO = 1.06525455 # +/- 0.05504541 [1.00000]delE = -2.32587026 # +/- 0.59606221 [-2.77870]delR = 0.00911122 # +/- 0.00503027 [-0.02322]ss = 0.00706809 # +/- 0.00071967 [0.00300]Correlations between variables:delr & dele --> 0.9154ss & so --> 0.9023All other correlations below 0.4name N S02 sigma^2 e0 delr Reff R=========================================================================O1.1 6.000 1.065 0.00707 -2.326 0.00911 2.09150 2.10061--Best Regards,
Pushkar Shejwalkar.
Post-doctoral -Researcher,JSPS FellowHokkaido University,Sapporo,Japan
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