Compounds of formula I are disclosed:

##STR00001##

wherein X.sup.1, X.sup.2, X.sup.3, X.sup.4 are independently H, F, Cl, Br, I, CN, NO.sub.2, OR.sup.1, SR.sup.1, NR.sup.1R.sup.2, COR.sup.1, COOR.sup.1, CONR.sup.1R.sup.2, PO.sub.3R.sup.1R.sup.2, SO.sub.2R.sup.1, SO.sub.3R.sup.1 or R.sup.3; R.sup.1 and R.sup.2 are, e.g., H, alkyl or aryl or optionally a ring; R.sup.3 is, e.g., alkyl, alkenyl, alkynyl, aryl or cycloalkyl; Y is OR.sup.1, NR.sup.1R.sup.2, or NR.sup.1R.sup.3; Q is O, S, SO.sub.2, NR, C(R.sup.3).sub.2, Si(R.sup.3).sub.2, Ge(R.sup.3).sub.2, P(O)R.sup.3 or P(O)OR.sup.3; Q and X.sup.1 can optionally form part of a ring; L and M are independently OR.sup.1, SR.sup.1, NR.sup.1R.sup.2 and R.sup.3; L and M can optionally form part of a ring; Z is O, S, NR.sup.1, CR.sup.1R.sup.3 or aryl; and Z and X.sup.4 can optionally form part of a ring.

The embodiments herein generally relates to compounds and methods for releasing H.sub.2S in a pH dependent manner. In particular, the invention provides compounds of various formulations which release H.sub.2S in a controlled, predictable and sustained manner upon contact with an aqueous environment, such as the circulatory system of an animal, and which are thus suitable for in vivo delivery of H.sub.2S.

The invention relates to the use of amino terminated phosphonamides and their oligomers, as flame retardant additives for a variety of polymers to impart flame retardancy while maintaining or improving processing characteristics and other important properties.

The embodiments herein generally relates to compounds and methods for releasing H.sub.2S in a pH dependent manner. In particular, the invention provides compounds of various formulations which release H.sub.2S in a controlled, predictable and sustained manner upon contact with an aqueous environment, such as the circulatory system of an animal, and which are thus suitable for in vivo delivery of H.sub.2S.