Domain: Organometallic chemistry

The organometallic precursor CpWMe_4 (Cp* = eta^5-C_5Me_5) is treated with RSi(OH)_3 (R = 2,6-iPr_2C_6H_3N(SiMe_3)) at 100–120 °C. During the course of the reaction, the silanetriol undergoes self-condensation to yield [RSi(OH)_2]_2O and water. The organometallic tungsten fragment subsequently reacts under these conditions to afford a unique W(V) oxo–methylidene complex as the final product. What is the structure of this final product?

Grading rubric:
criterion: Correctly identifies the role of the silanetriol as a controlled in situ water source via self-condensation, preventing uncontrolled hydrolysis of the precursor.
weight: 10
criterion: Correctly identifies the initial organometallic transformation as the protonolysis of Tungsten-Methyl bonds to generate a Tungsten-Oxo species.
weight: 10
criterion: Correctly identifies alpha-hydrogen abstraction (or alpha-elimination) as the mechanistic pathway for the conversion of a tungsten-methyl ligand to a tungsten-methylidene moiety.
weight: 10
criterion: Correctly formulates the transient monomeric intermediate as the high-valent oxo-methylidene complex Cp*W(O)(=CH_2). 
weight: 20
criterion: Correctly deduces that the high electrophilicity of the W(V) center drives the dimerization of the methylidene intermediates.
weight: 10
criterion: Correctly determines the oxidation state of the tungsten centers as +5 (d1) in the final product, consistent with the retention of the d1 configuration from the precursor.
weight: 10
criterion: Correctly identifies the geometry of the final complex as a centrosymmetric dimer with two bridging methylene (mu-CH_2) ligands.
weight: 10
criterion: Correctly validates the stability of the W_2O_2(mu-CH_2)_2 core based on the formation of a tungsten-tungsten single bond (pairing of the d1 electrons).
weight: 10
criterion: Correctly provides the structural formula of the final product as [Cp*W(O)(mu-CH_2)]_2..
weight: 10

Answer:
[Cp*W(O)(μ-CH2)]2