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 (PASO(2)) was reacted with various transition metal precursors to give the complexes cis-[Mo(CO)(4)(PASO(2))(2)], [AuCl(PASO(2))] cis-[PtCl2(PASO(2))(2)], [Ru(eta(6)-p-cym)Cl-2(PASO(2))], [Rh(eta(5)-C5Me5)Cl-2(PASO(2))], and [Rh(eta(5)-C5Me5)Cl(PASO(2))(2)](+) as well as the cyclometalated palladium(II) complexes [PdCl{kappa C,N-C6H4C(Ph)NCH2CO2Et}(PASO(2))] and [PdCl(kappa C,N-1,8-C10H6NMe2)(PASO(2))]. The compounds were characterized by spectroscopic methods and several examples by single-crystal X-ray diffraction. The stereoelectronic properties of PASO(2) were determined by computational methods and were compared with those of other phosphines, in particular 1,3,5-triaza-7-phosphaadamantane.