Reverend Necroticus Rex - 13-9-2004 at 19:32
I have been wondering, what would be the effects of substituting the sulfur atoms on mustard agents, and nerve agents with either selenium or
tellurium, would this make for a more toxic agent, as usually seems to be the case with Se or Te substitutions im componds?
The tellurium analogues would likely have the amusing (if you arent the victim!) effect of ensuring that if you survive, you smell so bad nobody will
go near you for months
[Edited on 5-10-2004 by chemoleo]
JohnWW - 13-9-2004 at 20:04
Selenium as a health supplement is often supplied as thio-amino-acids, especially cysteine and methionine, in which the S has been replaced with Se.
It is the most powerful dietary antioxidant, and also makes vitamins A and E "go further". Roughly 100 to 1,000 micrograms/day is the
recommended dose, depending on previous dietary deficiencies of it. Gross excesses of Se, however, cause symptoms similar to loco-weed poisoning in
cattle, and cause brittleness and malformation in hair and nails (which have particularly high concentrations of thio-amino-acids, and which
concentrate Se).
I would think that poison war gases containing S(II), like mustard gases and H2S, would be even more toxic if the S is substituted with Se. Se(II), as
in H2Se, would bond even more strongly to the Fe in hemoglobin than the S(II) in, for example, H2S. Any that are mercaptans would have even stronger
and worse smells if they become selenomercaptans.
But, because of the higher atomic weight of Se, analogous poison gases made with Se instead of S would have higher molecular weights, and so have
higher boilng points and be more difficult to vaporize or disperse. They would also be substantially more expensive.
John W.
ziqquratu - 14-9-2004 at 01:41
I dont know much about these agents, but isnt the point of mustard gases that the chlorines beta to the sulfur atom are good leaving groups when they
undergo a cyclisation to form a three membered ring (with the sulfur taking a positive charge), which are then highly reactive (due to charge and
strain considerations) with water in the mucous membranes?
Therefore, you'd think that for them to act the same, you'd need to substitute the sulfur for an atom that could form an analogous cyclic
intermediate...
Of course, as I mentioned, I know little about these things, so I may be waaaay off the track!!
Reverend Necroticus Rex - 17-9-2004 at 15:56
The seleno or telluro-nerve agent analogues might have some interesting possibilities, maybe in the form of thio- or thiocyclo- agents but of course,
with Se or Te substituted for sulfur.
chemoleo - 5-10-2004 at 09:01
But maybe, jsut maybe, the reason why those derivatives are not used is because the physical properties change, i.e. from gas or low-temp boiling
liquid to one with a low vapour pressure, thus rendering it useless unless it is literally sprayed upon the poor victim?
Also... I should think the Se/Te derivatives are less reactive?