SYNTHESES AND SPECTRA OF [ETA-5-(C5H4COOCH3)]CR(NO)2L(L = CL, I, CH3) AND CRYSTAL-STRUCTURES OF [ETA-5-(C5H4COOCH3)]CR(NO)2L(L = CL, I)

Chlorination/nitrosylation of [eta-5-(carbomethoxy)cyclopentadienyl]dicarbonylnitroslychromium 5 with hydrogen chloride/isoamyl nitrite gives chloro[eta-5-(carbomethoxy)cyclopentadienyl]dinitrosylchromium 6 in 78% yield. Compound 6 was converted to [eta-5-(carbomethoxy)cyclopentadienyl iododinitrosylchromium 7 with potassium iodide in 85% yield. Compound 7 in turn was methylated with Grignard reagent to give 8 in 45% yield. The structures of 6 and 7 have been solved by X-ray diffraction studies. Both 6 and 7 crystallize in the monoclinic space group P2(1)/n. Lattice constants of 6 are a 6.932(2), b 18.239(5), c 8.117(2) angstrom, beta 93.48(2)-degrees and Z = 4. Lattice constants of 7 are a 7.229(2), b 8.177(3), c 19.201(7) angstrom, beta 99.38(3)-degrees and Z = 4. The organic carbonyl plane (C(1), C(11), O(3), O(4)) deviates from the coplanarity of the corresponding ring plane Cp(Cr) by 1.4 and 0.3-degrees in compounds 6 and 7, respectively. In 6 the chlorine atom is located at the site twoard the exocyclic carbon of the Cp(Cr) ring with a twist angle of 72.2-degrees, while in 7, the iodine atom has a twist angle of 68.9-degrees.