Cyclodiphosphazanes with Hemilabile Ponytails: Synthesis, Transition Metal Chemistry (Ru(II), Rh(I), Pd(II), Pt(II)), and Crystal and Molecular Structures of Mononuclear (Pd(II), Rh(I)) and Bi- and Tetranuclear Rhodium(I) Complexes

Cyclodiphosphazanes having hemilabile ponytails such as cis-[tBuNP(OC6H4OMe-o)]2 (2), cis-[tBuNP(OCH2CH2OMe)]2 (3), cis-[tBuNP(OCH2CH2SMe)]2 (4), and cis-[tBuNP(OCH2CH2NMe2)]2 (5) were synthesized by reacting
cis-[tBuNPCl]2 (1) with corresponding nucleophiles. The reaction of 2 with [M(COD)Cl2] afforded cis-[MCl2(2)2]
derivatives (M = Pd (6), Pt (7)), whereas, with [Pd(NCPh)2Cl2], trans-[MCl2(2)2] (8) was obtained. The reaction of
2 with [Pd(PEt3)Cl2]2, [{Ru(η6-p-cymene)Cl2]2, and [M(COD)Cl]2 (M = Rh, Ir) afforded mononuclear complexes of
Pd(II) (9), Ru(II) (11), Rh(I) (12), and Ir(I) (13) irrespective of the stoichiometry of the reactants and the reaction
condition. In the above complexes the cyclodiphosphazane acts as a monodentate ligand. The reaction of 2 with
[PdCl(η3-C3H5)]2 afforded binuclear complex [(PdCl(η3-C3H5))2{(tBuNP(OC6H4OMe-o))2-κP}] (10). The reaction of
ligand 3 with [Rh(CO)2Cl]2 in 1:1 ratio in CH3CN under reflux condition afforded tetranuclear rhodium(I)
metallamacrocycle (14), whereas the ligands 4 and 5 afforded bischelated binuclear complexes 15 and 16,
respectively. The crystal structures of 8, 9, 12, 14, and 16 are reported.