Dear all,
Recently while performing a synthesis I've recorded a UV-Vis spectrum of a mixture of hexadecyl-amine (HDA) and sulfur, after heating treatment (please find it in the attachments, bright purple line).
The spectrum recorded shows 4 features, a couple of sharp ones at 263 and 270 nm plus a couple of big humps at 295 and 344 nm.
The first 3 (263, 270, 295) in my experience should belong to sulfur, but the 4th one i just can't find what it is! Other studies and measurements carried by myself point out a likely presence of thioamides or thio-imidamide. In the literature i've been looking at, some other organo-sulfur compounds (ex. mercaptanes) have a red shifted absorption edge, but nothing that goes over 300 nm.
Is anybody there who have some ideas about this feature?
HDA/S system is supposed to be fairly common in nanoparticles synthesis
Dear Steingrimur Stefansson,
Thanks for the interest.
In strict theory yes. both samples have been treated in oxygen-free Schlenk lines.
In the “prec2” the whole mixture is stored under nitrogen overpressure for several minutes before 20 min reaction, after which this spectrum is recorded.
In “T 280” refers to the sample of an hot injection synthesis, straight after injection. as good as one can be the transfer can’t be 100% oxygen free, but i purged the needle prior to the injection, so oxygen contamination should be minimal. And at my current knowledge i would also exclude CO2.
Thanks again
i might have forgotten to mention that there is a Ph3SiCl in the "T280" and we just found out that there might be a nickel leakage coming from a component of the reaction vessel.
Dear Bruno,
you posted an interesting but TOO VAGUE formulated question. Why??
I insert my answer in your sentence :
......The spectrum recorded shows 4 features, a couple of sharp ones at 263 and 270 nm plus a couple of big humps at 295 and 344 nm....
Please give the kind of spectrometer (e.g. single beam or dual beam or diodes array)and the kind of cuvettes (quartz ..cutoff around 160 nm and wavelength range below 380 nm)
Please give the kind of solvent used for the UV-Vis elucidation (you don't mention it).
According to the solvent , please note that you have a CUTOFF . P.e. sulfur in EtOH (cutoff 205 nm) (see picture 2 UV-Vis S).
Please give details about your synthesis pathways (like in picture 1 for details ) and the purity of S and HDA.
Thanks in advance
JRG
dear Jean Rene Grezes,
Thanks for the feed back and the literature reference.
About the literature i already knew this paper, and was the biggest help in finding the first 3 feature assignment, but the fourth one (344nm) is not given in this paper, that's the reason why my curiosity sparked.
The spectrometer is a double beam device.
The solvent is chloroform (cutoff not really observed cause probably lies at lover w.l. than the spectrometer range 250nm), but i'm more interested in the onset than the cutoff.
About the details, being an ongoing study, i cannot release too many details (not that i'm actually concerned, but this are the facility policies).
But, the "prec 2" consist in simply HDA (8 gr) and sulfur( 0.02 gr) heated up to 180° for 20 min, in the "T280" the "prec 2 " is injected in a vessel with 10 gr of HDA and Ph3SiCl at high temperture.
I hope this helps
Thanks
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