2-Thia-1,3,5-triaza-7-phosphaadamantane-2,2-dioxide Revisited: Computational and Experimental Studies of a Neglected Phosphine

The cage-phosphine 2-thia-1,3,5-triaza-7-phosphaadamantane-2,2-dioxide (PASO2) was reacted with various transition metal precursors to give the complexes cis-[Mo(CO)4(PASO2)2], [AuCl(PASO2)], cis-[PtCl2(PASO2)2], [Ru(η6-p-cym)Cl2(PASO2)], [Rh(η5-C5Me5)Cl2(PASO2)], and [Rh(η5-C5Me5)Cl(PASO2)2]+ as well as the cyclometalated palladium(II) complexes [PdCl{κC,N-C6H4C(Ph)NCH2CO2Et}(PASO2)] and [PdCl(κC,N-1,8-C10H6NMe2)(PASO2)]. The compounds were characterized by spectroscopic methods and several examples by single-crystal X-ray diffraction. The stereoelectronic properties of PASO2 were determined by computational methods and were compared with those of other phosphines, in particular 1,3,5-triaza-7-phosphaadamantane.