Reactions of (Ph)tBuP-P(SiMe3)Li•3THF with [(PNP) TiCl2] and [MeNacNacTiCl2•THF]: synthesis of first PNP titanium(IV) complex with the phosphanyl-phosphinidene ligand [(PNP)Ti(Cl){η2-P-P(Ph)tBu}]

Herein, the lithium derivative of diphosphane, (Ph) tBuP-P(SiMe3)Li (1), is isolated for the first time and investigated in reactions with beta-diketiminate ((Me)Nacnac(-) = [Ar]NC(Me)CHC(Me)N[Ar]; Ar = 2,6-iPr(2)C(6)H(3)) and PNP-pincer (PNP = N[2-PiPr(2)-4-methylphenyl](2)) Ti(III) complexes. The beta-diketiminate titanium(III) complex containing the phosphanylphosphido ligand [(Me)NacNacTi(Cl){eta(2)-P(SiMe3)-P(Ph)tBu}] (2) is prepared via the reaction of [(Me)NacNacTiCl(2)center dot THF] with (Ph)tBuP-P(SiMe3)Li in toluene solution with good yield and purity. The corresponding titanium(IV) complex involving the phosphanylphosphinidene ligand [(Me)NacNacTi(Cl){eta(2)-P-P(Ph)tBu}] (3) is synthesized via the oxidation of complex (2) with [iBu(3)PAgCl](4). Interestingly, an analogous PNP titanium(IV) complex, [(PNP) Ti(Cl){eta(2)-P-P(Ph) tBu}] (4), is obtained in the reaction of [(PNP)TiCl2] with (Ph)tBuP-P(SiMe3) Li in toluene solution and a 1 : 1 molar ratio instead of the expected titanium(III) complex with the phosphanylphosphido ligand. The solid-state structures of (Ph)tBuP-P(SiMe3)Li center dot 3THF (1), [(Me)NacNacTi(Cl){eta(2)-P(SiMe3)-P(Ph)tBu}] (2), [(Me)NacNacTi(Cl){eta(2)-P-P(Ph)tBu}] (3) and [(PNP)Ti(Cl){eta(2)-P-P(Ph)tBu}] (4) are determined by single-crystal X-ray diffraction, which reveals that in all obtained complexes, both the phosphanylphosphinidene (Ph)tBuP-P and phosphanylphosphido (Ph)tBuP-P(SiMe3) ligands are bidentate-coordinated to the metal center.