Novel phosphinic acids and their sulfur derivatives and methods for their preparation

Compounds, methods for preparing a secondary phosphine and for preparing a formula, and use of a compound or a salt thereof. The present invention provides phosphinic acids and their sulfur derivatives according to the following formula (I): wherein R1 and R2 are different and each of R1 and R2 is independently selected from an organic radical which is a branching of alpha carbon And an organic radical which is a branching of the beta carbon, and each of x and y is independently o or s, said liquid compounds being at room temperature. Compounds of formula (I) are useful, for example, as metal extractors. There are also provided methods for manufacturing compounds of formula (I) and their phosphinic intermediates.