The crystal and molecular structures of two derivatives of Werner's hexol cluster cation: [Co{(OH)(2)Co(NH3)(4)}(3)](NO3)(5)(OH) center dot 4H(2)O(I)and [Co{(OH)(2)Co(NH3)(4)}(3)](NO3)(6) center dot 2H(2)O(II)

Crystals of compound (I) and (II) are black in redected light and brown-bla ck in transmitted light. The H-1-nmr of the cations of (I), recorded in D-6 -DMSO, show peaks, relative to the H-1 of D-6-DMSO, at + 0.46 ppm(rel. int. = 3); + 0.85 ppm(rel. int. = 1.2); + 1.80 ppm (rel. int. = 3); and -4.18 p pm(rel. int.=1). The magnetic susceptibility of (I) is C ' (m) (293.18 K) = 588.45 x 10(-6) c.g.s. units, which corresponds to a m(eff)=0.295 B.M. per Co ion; however, the small shifts and sharp H-1-nmr lines in the DMSO spec trum preclude the presence of paramagnetic clusters. Cyclic voltametry of t he cation present in (I) shows highly distorted, irreversible, oxidation an d reduction waves which indicate the lack of stability of any oxidized or r educed form - a fact which accords with the sharp lines of the NMR spectra; e.g., no stable paramagnetic species are present in (I). Compound (I), M.W . = 941.24, crystallizes in P2(1)/n (No. 14), with cell constants a = 11.78 9(2)degrees; b = 13.655(2), c = 21.534(3)Angstrom, beta =91.94(1)degrees; V =3515.44 Angstrom (3), d (meas; z = 4) = 1.778gm-cm(-3). A total of 4705 da ta were collected in the range 4 degrees less than or equal to 2 theta less than or equal to 50 degrees. They were 1.778 gm-cm corrected for absorptio n (mu = 19.562cm (-1); rel, trans. coeff. range = 0.8642 to 0.9997); of the se, 2623 were unique and had l greater than or equal to 3 sigma (l). The st ructure was solved by direct methods, none of the hydrogens of the amine li gands were found experimentally at sensible positions; thus, they were left out. Refinement of the heavy atoms (anisotropic) led to final residuals of R(F)= 0.0637 and 0.0771. Compound (II), M.W.=950.20, crystallizes in space group pi (bar; No. 2), with cell constants a = 12.858(3), b = 12.475(2), c =12.114(2) Angstrom, alpha = 96.63(1), beta =91.94(1) and gamma= 61.71(2)d egrees; V= 1615.68 Angstrom (3), d(meas; z = 2)= 1.953 gm-cm(-3). A total o f 5657 data were collected in the range 4 degrees less than or equal to 2 t heta less than or equal to 50 degrees. They were corrected for absorption ( mu = 21.301cm(-1); rel. trans. coeff. range = 0.7372 to 0.9998); of these, 4456 were unique and had l greater than or equal to 3 sigma (l). The struct ure was solved by direct methods, the majority of the hydrogens of the amin e ligands were found experimentally at sensible positions, the rest were ca lculated at idealized positions (N-H = 0.95 A). The hydrogens of the OH lig ands were located experimentally in a final difference Fourier map. Refinem ent of the heavy atoms (anisotropic) with fixed hydrogens (B = 5.00 Angstro m (2)) led to final residuals of R(F)= 0.0348 and 0.0440. Precisely as visu alized by Werner, the hexol cations consist of a central Co(III) cation sur rounded by three [Co(NH3)(4)(OH)(2)] (1+) ligands. In (I), the O -Co1-O ang les are acute (av. value = 82.97 inverted perpendicular), as expected from the electrostatic repulsion of the Co(III) central cation and the monoposit ive ligands surrounding it. Consequently, the Co....Co distances are long ( 2.896, 2.888 and 2.889 Angstrom; on average, 2.891 Angstrom) and the the av . Co-O-Co angles are 97.43 degrees. The remaining portions of the cation an d anions are as expected from standard values; i.e., Co-O= 1.90-1.95 and Co -N=1.95-2.00 Angstrom. In (II), the Co1-O-Co angles are also obtuse (av, va lue = 97.87 degrees), as expected from the electrostatic repulsion of the C o(III) central cation, and the Co...Co distances are equally long (2.881, 2 .876 and 2. 874 Angstrom; on average, 2.877 Angstrom).