The new water-soluble ligand dmPTA(OSO2CF3)2 (1) (dmPTA = N,N′-dimethyl-1,3,5-triaza-7-phosphaadamantane) has been synthesized by reaction of PTA with MeOSO2CF3 in acetone (PTA = 1,3,5-triaza-7-phosphatricycle-[3.3.1.13,7]decane). The reaction of 1 with KOH gave rise to the new water-soluble ligand dmoPTA (3) (dmoPTA = 3,7-dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) by elimination of the -CH2- group located between both NCH3 units. Compound dmPTA(BF4)2 (2) and complex [RuClCp(HdmoPTA)(PPh3)](OSO2CF3) (4) have also been synthesized, while compounds HdmoPTA(BF4) (3a) and [RuClCp(dmPTA)(PPh3)](OSO2CF3) (5) were characterized but not isolated. The new ligands and the complex have been fully characterized by NMR, lR, elemental analysis, and X-ray crystal structure determination (ligand 1 and complex 4). The synthetic processes for 3 and 4 were studied. [ABSTRACT FROM AUTHOR]