REACTIONS OF TRISULFONATED TRIPHENYLPHOSPHINE, TPPTS, WITH COBALT CARBONYLS IN WATER

The synthesis and characterization of a series of water-soluble cobalt carbonyl complexes is described: HCo(CO)(3)(TPPTS), HCo(CO)(2)(TPPTS)(2), and [Co(CO)(3)(TPPTS)](-), where TPPTS=P(m-C6H4SO3Na)(3). Investigation of the substitution of Co-2(CO)(8) by TPPTS shows that the reaction proceeds via the ionic intermediate [Co(CO)(3)(TPPTS)(2)] [Co(CO)(4)], which is relatively stable in water. The hydride complexes are stable in the presence of water at low pH. Under these conditions, it is likely that the sodium cations are replaced with protons. A variety of reaction pathways to these compounds are described. The dimer, Co-2(CO)(6)(TPPTS)(2), undergoes base-induced disproportionation above pH 10 to yield the substituted anion [Co(CO)(3)(TPPTS)](-) as the only carbonyl-containing product. In the course of this investigation, crystals of the sodium salt of Co-2(CO)(6)(TPPTS)(2) were obtained. Crystaldata: space group C2/c, a=31.723(16)Angstrom, b=11.244(14)Angstrom, c=41.267(14)Angstrom, beta=107.456(35)degrees, Z = 8. Data were collected at 193 K, and a total of 5898 reflections with I > 3 sigma(I) were collected. The sodium ions and solvent are partially disordered, and two of the sulfonate groups are disordered. This and two very long cell axes contribute to the final residuals, R=0.0858 and R(W)=0.0997. Qualitative aspects of the structure are discussed.