NMR SPECTROSCOPIC CHARACTERIZATION OF METHYLCOBALT(III) COMPOUNDS WITH CLASSICAL LIGANDS - CRYSTAL-STRUCTURES OF [CO(NH3)(5)(CH3)]S2O6, TRANS-[CO(EN)(2)(NH3)(CH3)]S2O6 (EN EQUALS 1,2-ETHANEDIAMINE), AND O2)(3)(NH3)(2)(CH3)](2)-TRANS-[CO(NO2)(4)(NH3)(2)]

A series of methylcobalt(III) compounds with solely classical ligands such as NH3, H2O, NO2-, CN-, and 1,2-ethanediamine (en) has been prepa red by ligand substitution of the pentaamminemethylcobalt(III) cation. The new compounds have been characterized by H-1, C-13, and Co-59 nuc lear magnetic resonance spectroscopy and by absorption spectroscopy. S ingle-crystal X-ray structure determinations at 122.0(5) K were perfor med on [Co(NH3)(5)(CH3)]S2O6 (1), trans-[Co(en)(2)(NH3)(CH3)]S2O6 (2), and O2)(3)(NH3)(2)(CH3)](2)-trans-[Co(NO2)(4)(NH3)(2)] (3). Compound 1 is monoclinic, P2(1)/n, with cell dimensions a = 6.4856(9) Angstrom, b = 18.0720(11) Angstrom, c = 9.7854(14) Angstrom, and beta = 98.280( 13)degrees. Compound 2 is orthorhombic, P2(1)2(1)2, with cell dimensio ns a = 12.211(3) Angstrom, b = 10.107(3) Angstrom, and c = 11.514(3) A ngstrom. Compound 3 is monoclinic, P2(1)/n, with cell dimensions a = 8 .390(2) Angstrom, b = 8.970(3) Angstrom, c = 20.650(9) Angstrom, and b eta = 91.29(2)degrees. Virtually identical Co-C distances in the range 1.980-1.984 Angstrom are found in the three compounds. The methyl gro up exerts a strong trans influence. The largest relative elongation of the bond to the trans ligand is 0.170 Angstrom in the trans-[Co(en)(2 )(NH3)(CH3)](2+) cation. The structural trans influence appears to dec rease with the overall charge of the coordination compound. Estimates of the scalar one-bond cobalt-carbon coupling constants, (1)J(Co-C), i n the pentacyanomethylcobalt(III) anion was obtained by line shape ana lysis, yielding values of 127, 95, and 62 Hz for the cis cyano groups, the trans cyano group, and the methyl group, respectively.