A SERIES OF MONOHAPTO PYRAZOLATES OF IRIDIUM(I) AND IRIDIUM(III)

Article abstract of DOI:10.1016/0022-328X(84)80280-6

The reaction of trans-IrCl(CO)L2 with pz^-* gives trans-Ir(pz-N)(CO)L2, where pzH is 3,5-dimethyl-, 3,5-dimethyl-4-nitro- or 3,5-bis(trifluoromethyl)-pyrazole, and L = PPh3.The nitrogen atom not involved in coordination can be protonated with HBF4 to give the corresponding ⁺ cation.The iridium(I) pyrazolates undergo oxidative addition, yielding Ir(H)2(pz-N)(CO)L2 species, while gaseous HCl cleaves the Ir-N bond, affording IrH(Cl)2(CO)L2.The iridium(I) derivatives can be obtained in several solid-state forms, each characterized by a slightly different CO stretching frequency.The presence of a monodentate pyrazolato ligand in trans-Ir(3,5-(CF3)2pz-N)(CO)L2, in the form with ν(CO) at 1975 cm^-1, is supported also by an X-ray crystal structure determination.The compound crystallizes in the monoclinic system, space group P2₁/n, with cell dimensions a = 21.106(6), b = 19.700(5), c = 9.437(2) Angstroem, and β = 94.34(2) deg and Z = 4.