WATER-SOLUBLE PHOSPHANES .5. COMPLEXES OF AMPHIPHILIC TERTIARY ALKYLPHOSPHANES WITH AMMONIUM GROUPS IN THE SIDE-CHAINS

Monocationic amphiphilic tertiary phosphines [RMe(2)N-(CH2)(n)-PR'(2)] (+) X(-) (1-3) obtained by P-alkylation of the corresponding primary p hosphines (R' = H) form stable tungstencarbonyl-, Rh(I)-olefin- and sq uare planar Pd(II)-complexes (4-8a). Stepwise protonation of [Me(2)N-( CH2)(2)]P-3 (9) by Ph(3)P . HBr or aqueous HCl affords tricationic ter tiary phosphine ligands, e.g. {[HMe(2)N-(CH2)(2)]P-3}(3+) 3X(-) (13, 1 3b) and the phosphonium salt {[HMe(2)N-(CH2)(2)]P-3-H}(4+) 4Cl(-) (13a ). The pK(a)-values 9.67, 8.86, 7.92 and 1.9 have been obtained by tit ration of 13a with NaOH in aqueous solution. Highly charged Pd(II)-com plexes (16a, 16b) with extreme water solubilities were obtained from 1 3 and PdBr2 or by N-protonation of cis-PdCl2(9)(2) with HCl. The cryst al structures of 13 . 0.5H(2)O and {trans-{[HMe(2)N-(CH2)(2)]P-3}2PdCl 2}(6+) 6Cl(-). 2MeOH (16b) (space group C2/c) have been determined. Wh ile the P(... N)(3) skeleton of the trication in 13 is almost flat, it is folded back on coordination to palladium(II) in 16b.