Tetravalent Titanium, Zirconium, and Cerium Oxo and Peroxo Complexes Containing an Imidodiphosphinate Ligand

Dinuclear Ti­(IV), Zr­(IV), and Ce­(IV) oxo and peroxo complexes
containing the imidodiphosphinate ligand [N­(i-Pr2PO)2]− have been synthesized
and structurally characterized. Treatment of Ti­(O-i-Pr)2Cl2 with KN­(i-Pr2PO)2 afforded the Ti­(IV) di-μ-oxo complex
[Ti­{N­(i-Pr2PO)2}2]2(μ-O)2 (1) that reacted
with 35% H2O2 to give the peroxo complex Ti­[N­(i-Pr2PO)2]2(η2-O2) (2). Treatment of HN­(i-Pr2PO)2 with Zr­(O-t-Bu)4 and Ce2(O-i-Pr)8(i-PrOH)2 afforded the di-μ-peroxo-bridged
dimers [M­{N­(i-Pr2PO)2}2]2(μ-O2)2 [M = Zr (3), Ce (4)]. 4 was also obtained
from the reaction of Ce­[N­(i-Pr2PO)2]3 with 35% H2O2. Treatment
of (Et4N)2[CeCl6] with 3 equiv of
KN­(i-Pr2PO)2 afforded Ce­[N­(i-Pr2PO)2]3Cl (5). Reaction of (Et4N)2[CeCl6] with
2 equiv of KN­(i-Pr2PO)2 in
acetonitrile, followed by treatment with Ag2O, afforded
the μ-oxo-bridged complex [Ce­{N­(i-Pr2PO)2}­Cl]2[μ-N­(i-Pr2PO)2]2(μ-O) (6). 6 undergoes ligand redistribution in CH2Cl2 in air to give 5. The solid-state structures
of [K2{N­(i-Pr2PO)2}2(H2O)8]n and complexes 1–6 have been
determined.