PHOTOCHEMISTRY OF CR(CO)5PCL3, CR(CO)5PYRIDINE AND CR(CO)5PYRAZINE IN AR MATRICES AT 10K - EVIDENCE FOR THE FORMATION OF CR(CO)5 AND 2 NOVEL COMPLEXES CIS-CR(CO)4-PYRIDINE AND CIS-CR(CO)4PYRAZINE

Photolysis of Cr(CO)5PCl3 in an Ar matrix at 10 K with different wavelengths (λ = 229, 254, 280, 313 and 366 nm) resulted in the formation of Cr(CO)5. The reaction is reversed by irradiation with λ = 546 nm. Photolysis of Cr(CO)5 pyridine and Cr(CO)5pyrazine in an Ar matrix at 10 K generated CO or the unique ligand, depending on the irradiated wavelength. New five coordinated species were detected: cis-Cr(CO)4pyridine and cis-Cr(CO)4pyrazine. Regeneration of the parent compound was only partly accomplished due to formation of trans-Cr(CO)4pyridine and -Cr(CO)4pyrazine. The difference in photochemical behaviour between PCl3 and nitrogen donor ligand complexes is discussed with the use of a m.o. scheme. Infrared and UV-visible data are reported in various media and assigned. © 1979.