4/29/2012 - Synthesis of Lithium Alkyls

As I swerve back into the history of Organometallics I want to start back to 1917 in Germany.  A chemist named Wilhelm Schlenk, at the University of Munich, determined how to synthesize organolithium compounds through a Transalkylation process coupled with organomercury compounds.  He came up with two different methods of synthesis, one where there is nothing attached to the Lithium in the beginning and then the other method where there is an organic group that is transferred to the Mercury with a shorter alkyl group.  Both reactions are seen here below.

2Li + R₂Hg → 2LiR + Hg
2EtLi + Me₂Hg → 2MeLi + Et₂Li

The synthesis of the dimethylmercury (Me₂Hg) can be found here.


Source: 

2/29/2012 - Synthesis of Diethylmagnesium

     Up to the point in 1866 there had been no way of synthesizing a magnesium organometallic compound without having attached a halide to the complex.  James Alfred Wanklyn (famous for methods of determining water quality) came up with a method of synthesis to exclude any presence of a halide anywhere in the synthesis.  This involved the use of Frankland's development of diethylmercury  and mixing it in dissolved magnesium yielding a mixture of diethylmagnesium and dissolved mercury.

(C₂H₅)₂Hg + Mg → (C₂H₅)₂Mg + Hg

2/18/2012 - Synthesis of Dimethylmercury

    In the following years Edward Frankland continued researching organometallic compounds as he realized how much new chemistry can be harnessed from these studies.  In 1852 he branched into Mercury chemistry and then following into Tin and Boron reactions.  With these reactions he focused on simple methyl additions onto the metal creating a linear dimethylmercury through the reaction 2CH₃X + 2Na + Hg → (CH₃)₂Hg + 2NaX.  This dimethylmercury compound is extremely toxic, to the degree that one drop on a latex glove will absorb through and  absorbs into the skin and months later the fatality takes over.  And as stated before he transcended these alkylhalide reactions into adding different R groups onto Hg, Sn, and B.

1/29/2012 - Pharaoh's Serpent

    This reaction doesn't involve the mixing of chemicals, but instead an exothermic reaction when the compound is in contact with a significant enough heat source.  The compound needed for this reaction is Mercury (II) thiocyanate or Hg(SCN)₂, which is an incredibly toxic compound, so I advise you not to try this reaction at home, due to the toxic gases and the toxicity of the compound.  The reaction was discovered by Wohler in 1821 right after his first synthesis when he observed the winding, worm-like projections.