The isotopomeric complexes
trans-W(Cmesit
yl)[(C(H,D)
3)
2PCH
2CH
2P(C(H,D)
3)
2]
2(H,D)
1-4 wereprepared.
2 (W(C
mesityl)(dmpe)
2D) was used to stud
y the Deuterium Quadrupole Coupling Constant (DQCC)and the ionicit
y of the W-D bond (DQCC = 34.1 kHz; ionicit
y 85%).
1 (W(C
mesityl)(dmpe)
2H) shows severald
ynamic exchange processes in solution, such as H
W/H
W, H
W/
ortho-Me
mesityl, and H
W/H
2 exchanges observedb
y NMR in combination with deuterium labeling studies and double label crossover experiments. Exceptfor the H
W/H
2, these reactions comprise elementar
y steps, which also appear along the isomerizationpathwa
y of
1 into (2,3,5-trimeth
ylphen
ylcarb
yne)(dmpe)
2WH (
5) at 60
![](/images/entities/deg.gif)
C.
5 was characterized b
y an X-ra
ydiffraction stud
y. In the solid state onl
y an H
W/Me
p exchange process prevails appearing at highertemperatures, which was identified b
y NMR and b
y Quasielastic Neutron Scattering. The latter also providedan activation barrier of 5 kcal/mol and a "jump width" for the moving H nucleus in agreement with theH
W···Me
p distance of the X-ra
y diffraction stud
y of
1.