[7] The same procedure, sans cyclopentene, also yields W(PMe3)4(η2-CH2PMe2)H. Alternatively, W(PMe3)4(η2-CH2PMe2)H can also be synthesized by condensing PMe3 into an ampule with Na(K) alloy and adding WCl6.

[10] Selective deuteration the alkylidene derivative (vide supra) leads to a statistical distribution of deuterium throughout the hydrogen sites of that phosphine as the alkyl ligand can change through the W(PMe3)4(PMe2CH2D) intermediate.

Upon crystallization, W(PMe3)4F2H2 becomes the dodecahedral complex [W(PMe3)4F(H2O)H2]F.[8][13] Inter-ligand hydrogen bonding exists between the fluoro and aqua ligands.

Furthermore, the contributing atoms to hydrogen binding (O-H – - – O) are not colinear, contrary to some prior misconceptions of metal-aqua complexes.

[13] W(PMe3)4(η2-CH2PMe2)H will ligate to buta-1,3-diene when the latter is in vast excess and in the presence of light petroleum at 50 °C to make the same product as ethylene.

[9] In the reaction with quinoxaline (QoxH,HH) and its derivatives 6-methylquinoxaline (QoxMe,HH) and 6,7-dimethylquinoxaline (QoxMe,MeH), W(PMe3)4(η2-CH2PMe2)H forms [κ2-C2-C6RR'H2(NC)2]W(PMe3)4, (η4-C2N2-QoxR,R'H)W(PMe3)3H2 (vide infra), and W(PMe3)4H2 (R,R'=H, Me), wherein the first listed product is generated from C-C bond cleavage to form two W=C=B bond motifs.

[20]The reaction of W(PMe3)4(η2-CH2PMe2)H with SiH4 with light petroleum leads to the dissociation of one PMe3 ligand and activation of two Si–H bonds of separate SiH4 molecules to yield W(PMe3)4(SiH3)2H2.

This brown, air-sensitive complex can also be directly generated from W(PMe3)4(η2-CH2PMe2)H by heating with toluene and Ge(C6H3-2,6-Trip2)Cl at 50 °C.

trans-[Cl(PMe3)4W≡Ge-C6H3-2,6-Trip2] is, in turn, also a retron for further chemistry by substitution of the labile chloride ligand.

With lithium dimethylamine in THF, the chloride is substituted for a hydride, generating red-brown, air-sensitive trans-[H(PMe3)4W≡Ge-C6H3-2,6-Trip2].

[22][23] This η2 ligand (which Rabinovich and Parkin argue to be a WVI metallaoxirane in some instances but calls a WIV aldehyde in others) is also weakly bound.

[22][23] Two equivalents of H2S's hydrogens are eliminated upon reaction with W(PMe3)4(η2-CH2PMe2)H in pentane to give yield the yellow thiol-ligated complex W(PMe3)4(SH2)H2.

The complex then undergoes reduction elimination in the presence of a hydrogen trap, producing two equivalents of H2 (in the form of W(PMe3)4H3(OC6H5)) (vide supra) and purple trans-W(PMe3)4S2.

Two equivalents of PMe3 are reversibly lost upon reaction with RCHO (R=H, CH3, C6H5, para-C6H4CH3, para-C6H4OCH3) to yield red-purple, 16 electron, cisoid W(PMe3)2S2(η2-OCHR).

[23][24] Unlike with sulfur, the formation of W=Te bonds with W(PMe3)4(η2-CH2PMe2)H requires the use of elemental tellurium, wherein it is hypothesized the PMe3 acts as a catalyst to form PMe3Te and deliver Te to W(PMe3)4(η2-CH2PMe2)H. The resultant compound is red-brown trans-W(PMe3)4Te2, the first of its kind with a terminal telluride ligand.

Benzothiophene similarly experiences one C-S bond cleavage, leading to two PMe3 ligand dissociations to generate both (κ1,η2-CH2CHC6H4S)W(PMe3)3(η2-CH2PMe2) and (κ1,η2-CH2CC6H4S)W(PMe3)4.

Complexes of this type include W(PMe3)4(κ2-OC6H2(CH2)RR')H2 (R, R'=H, CH3) If there is no methyl group in either ortho-site, W(PMe3)4(η2-CH2PMe2)H will activate the ortho sp2 site, forming a four-membered oxometallacycle.

These equilibria lead to the statistical distribution of deuterium throughout the hydride sites and sp2 ortho-sites at room temperature and ortho-methyl substituents upon heating at 55 °C for 24 hours.

[30] To imitate oxygen-rich surfaces (e.g., silica) for catalysis, W(PMe3)4(η2-CH2PMe2)H was reacted with a calixarene, para-tert-butyl-calix[4]arene.

[31] Upon the addition of bromobenzene, iodobenzene, or para-bromotoluene, W(PMe3)4(η2-CH2PMe2)H undergoes hydride abstraction to form the cation [W(PMe3)4(η2-CHPMe2)H]+ with the corresponding halide anion.

LiAlH4 can be used to do the reverse reaction from [W(PMe3)4(η2-CHPMe2)H]+ to W(PMe3)4(η2-CH2PMe2)H.[12] The novel activation of the aromatic C-C bond in QoxH by W(PMe3)4(η2-CH2PMe2)H under relatively mundane conditions inspired mechanistic theorizations.

In their original publication, Sattler and Parkin suggested a mechanism in QoxH first acts as an L-type ligand from the N lone pair.

The first pathway suggests that the hydride moves towards the tucked-in alkyl ligand to form W(PMe3)5 before QoxH binds.

Then, the agostic interaction is transformed into a standard PMe3 L-type ligand to join the first pathway in following the original proposed mechanism.

[33] Miscione and coworker's results substantiate Sattler and Parkin's hypothesis that the ring strain in the η2-C2 complex facilitates the C-C bond cleavage.

The latter carbon's C-H bond forms an agostic interaction with tungsten to account for the lost electron density.

The second pathway sees the two hydride ligands move such that they are cis to the W=C bonds before undergoing reductive elimination.

[34] Li and Yoshizawa – using the B3LYP* functional with the LANL2TZ(f) and 6-31G(d,f) basis sets – also proposed two mechanisms which start with ligand dissociations.

Overall, Li and Yoshizawa's work suggest that the C-C bond mechanism is exergonic overall, with the product being 18.5 kcal/mol lower in energy relative to W(PMe3)4(η2-CH2PMe2)H.[35] The η4-C2N2-QoxH ligand is a novel binding behavior discovered from the reaction of W(PMe3)4(η2-CH2PMe2)H with QoxH.

The former group suggests that upon formation of W(PMe3)5 (vide infra), the tungsten undergoes the oxidative addition of H2, forming hydride bonds.