Synthesis and characterization of water-soluble 1,2-bis(bis(hydroxyalkyl)phosphino)ethane ligands and their nickel(II), ruthenium(III), and rhodium(I) complexes

The syntheses of the water-soluble, chelating phosphines 1,2-bis(bis(hydroxybutyl)phosphino)ethane (1, n = 3; DHBuPE) and 1,2-bis(bis(hydroxypentyl)phosphino)ethane (1, n = 4; DHPePE) are reported. These ligands (and, in general, other 1,2-bis(bis(hydroxyalkyl)phosphino)ethane ligands) can be used to impart water solubility to metal complexes. As examples of this, the [Ni(DHPrPE)(2)Cl]Cl (2), [Rh(DHPrPE)(2)][Cl] (3), and [Ru-(DHBuPE)(2)Cl-2][Cl] (4) complexes were synthesized; they are indeed soluble in water (>0.5 M). Crystals of DHPrPE (1, n = 2) are monoclinic, space group P2(1)/c, with a = 9.5935(8) Angstrom, b = 9.353(2) Angstrom, c = 10.655(2) Angstrom, alpha = 90 degrees, beta = 100.03(1)degrees, gamma = 90, V = 941.5(5) Angstrom(3), R = 0.051, and Z = 2. Crystals of [Ni(DHPrPE)(2)Cl]Cl (2) an monoclinic, space group I2, with a = 15.951(3) Angstrom, b = 11.454(2) Angstrom, c = 20.843(3) Angstrom, alpha = 90 degrees, beta = 91.24(2)degrees, gamma = 90 degrees, V = 3807(2) Angstrom(3), R = 0.062, and Z = 4. Crystals of [Rh(DHPrPE)(2)][Cl] (3) are triclinic, space group P (1) over bar, with a = 13.900(2) Angstrom, b = 15.378(2) Angstrom, c = 18.058(2) Angstrom, alpha = 87.71(1)degrees, beta = 75.03(1)degrees, gamma = 85.24(1), V = 3715(2) Angstrom(3), R = 0.044, and Z = 4. Crystals of [Ru(DHBuPE)(2)Cl-2][Cl] (4) are monoclinic, space group C2/c, with a = 14.310(2) Angstrom, b = 21.630(2) Angstrom, c = 15.459(3) Angstrom, alpha = 90 degrees, beta = 99.83(1)degrees, gamma = 90, V = 4715(1) Angstrom(3), R = 0.056, and Z = 4.