An Easy and Practical Synthetic Route to Electron Rich Water Soluble Ligands: α-Aminomethylation of Trishydroxymethylphosphine

Hydrophilic aminomethylphosphines 6a–e were prepared in excellent yield by the condensation of P(CH2OH)3 (THP) with a variety of easily accessible water soluble secondary amines, such as sarcosine (5a), N-methyltaurine (5b), N-methylethanolamine (5c), diethanolamine (5d) and 3-(N-butylamino)propanesulfonic acid sodium salt (5e). All products 6 are highly water soluble and are stable in air as well as under a wide pH range. The basic character of 6a–e has been proven by titration and by infrared analysis of the ν(CO) A1 frequencies of their corresponding nickel complexes 7a–e of the type Ni(CO)3L.