PNP pincer osmium polyhydrides for catalytic dehydrogenation of primary alcohols.

This paper reports the synthesis, structure, and properties of a series of PNP pincer complexes of osmium OsH(3)Cl[HN(C(2)H(4)P(i)Pr(2))(2)] (1), OsH(3)[N(C(2)H(4)P(i)Pr(2))(2)] (2), OsH(4)[HN(C(2)H(4)P(i)Pr(2))(2)] (3), and OsH(2)(PMe(3))[HN(C(2)H(4)P(i)Pr(2))(2)] (4). The tetrahydride 3 operates as an efficient catalyst at 0.1 mol% loading for the reactions of amination and dehydrogenative coupling of primary alcohols, producing secondary amines and symmetrical esters, respectively. The catalyst 3 is distinguished by outstanding stability, and it can be used in an aqueous environment at temperatures as high as 200 °C.