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New Xtacy perfume rolled out

26 May 2019 - The illigal drug trade

xtacy the parfume.JPGQuick dispatch from the illegal drug laboratory battle front (earlier episode here). Parts of The Netherlands are littered with them but how to make members of the public aware of a hidden drug lab where they live or work? After all, the smell of cannabis from an illegal plantation may be familiar to a lot of people but what does an ecstasy lab smell like? In order to fill this obvious knowledge gap The Dutch Justice Department has come up with an xtc perfume, called Xtacy that should smell exactly like one. (AD newspaper) This perfume will become available in police stations to aid investigations. People who have tried the perfume mention mint, candy shop smell and most of all anise. Anise's key component is anethole which does not look like MDMA but smell perception does not work that way. After some careful treading in some 'specialist sites' we find that: MDMA itself does not have smell, that safrole a common precursor to MDMA does have a smell and that it has a chemical similarity to anethole. In fact my source informs me only sloppy chemists sell smelly xtc, Walter White would have carefully washed his xtc batches.

Penta aqua nitrosyl iron sulphate

24 May 2019 - Chemical Zoo

In the nitrate test iron(II) sulfate is added to a solution suspected of containing nitrates followed by slowly adding sulfuric acid so that it forms a layer below the aqueous layer. If nitrates are out there they reveal themselves by a visible brown ring between the two layers. The chemical reactions taking place are oxidation of Fe(II) to Fe(III) and formation of gaseous nitric oxide (NO) , nitric oxide is then reduced further to the NO- ion in (Fe(H2O)5(NO))SO4. This ancient chemical test is back in the news (briefly) thanks to Georg Monsch and Peter Klüfers who in Angewandte have been re-investigating what the brown stuff actually is. They are not the first in this investigation but others before them failed because NO gas escapes very easily and X-ray grade crystals have been impossible to grow. In their 2019 effort Monsch and Klüfers have been more successful because they swapped the sulphate counter ion for a much larger gallium pinacolato one. To do this they mixed iron triflate, gallium triflate, perfluoropinacol , sodium hydroxide and nitric oxide.

Crystallography for this metal nitrosyl complex has iron sitting in a octahedral_molecular_geometry with 5 water units and the NO ligand not linear (Fe-N-O making an angle). In a bent M-NO unit the bond order in NO is 2 rather than 3 and pi backbonding is considered less relevant. The compound is described as FeNO7 in Enemark-Feltham notation having 6 (iron d-electrons) + 1 = 7 electrons of pi symmetry and again in any metal nitrosyl complex above a value of 6 a bent bond is expected.

And what about the oxidation state? Earlier researchers have described the compound as either Fe+(NO+), Fe2+NO0 or Fe3+(NO)-, that is, nobody really knows. NO+ is isoelectronic with carbon monoxide as in a metal carbonyl. NO- is associated with bent bonds. Basically Monsch and Klüfers throw their hands up in the air. Computations seem to favor a neutral nitrosyl oxide. Mössbauer spectroscopy is ordinarily very good at detecting oxidation state differences but arguments are presented that it is of no use for this particular compound. The definition of an oxidation state is also fuzzy. The key quote: "an instructor may decide to abstain from teaching oxidation states just on the basis of this compound, or, likewise, to demonstrate either the limits of a formal concept or to discuss sensible future extensions of the oxidation state idea - the latter with the aim to include the current computational progress"

Ozonolysis latest

19 May 2019 - Organic chemistry

smaligo 2019 alkene fragmentation3 As pointed out by Smaligo et al. in a recent article in Science,(DOI) in organic synthesis it is not always about combining small molecules to create larger ones but occasionally it can be about cutting existing bonds. Ozonolysis is a classic reaction involving the cleavage of an alkenes, for example that of cyclohexene to methyl-6-oxo-hexanoate. (DOI) In cyclohexene both carbon atoms on the chopping board have sp2 hybridisation but as an expansion of the available toolbox the Smaligo team has have come up with hydrodealkylenylation with an sp3 - sp2 carbon bond. The name is a play on hydrodealkylation with for example the conversion of toluene to benzene.

That iron could be a useful catalyst in a hydrodealkylenylation came about after digging up an old article from F.F. Rust - what is in a name - (DOI) about the conversion of hydroperoxides (an intermediate in ozonolysis) to oxyradicals in the presence of Fe(II). The final result in the new ozonolysis modification is a reagent combination of iron(II) sulfate and benzenethiol (as proton donor). In the unauthorized reaction mechanism depicted, the first stage is the molozonide, then formaldehyde is ejected, followed by reduction of OOH to the oxo radical, followed by the actual C-C cleavage reaction and with finally phenylthiol jumping in to arrest the radical. Complaints are welcome at Twitter.

Rik