The photochemical synthesis of [Cr(CO)5(H2)]in solution: i.r. evidence for co-ordinated molecular dihydrogen

[Cr(CO)5(H1)](1) is synthesized by u.v. photolysis of [Cr(CO)6] dissolved in liquid Xe doped with H2 at 200 K and the co-ordinated molecular dihydrogen has a νH–H i.r. band at 3030 cm–1; [Cr(CO)5(H2)] can also be generated photochemically in n-heptane at room temperature under high pressures (100 atm) of H2.