The bonding of H2 in W(CO)5(H2), a reactive intermediate stabilized and identified in liquid xenon

Liquid Xenon (LXe) appears to be an ideal solvent for the study of reactive intermediates in photochemical reactions because of its complete inertness and transparency in both the IR and UV/Visible spectral regions. Photolysis of a H2-doped solution of W(CO)6 in LXe at 193 K leads to the formation of W(CO)5H2 having CO stretching modes at 2098.4 (A21), 1972.2 (E) and 1970.5 cm−1 (A11) and v(H-H) at 2707 cm−1. From a comparison of these CO stretching frequencies with those of other W(CO)5L complexes it is concluded that the W(dπ) H2(σ*u) interaction is stronger than expected theoretically.