Synthesis and reactivity of Li and TaMe3 complexes supported by N,N′-bis(2,6-diisopropylphenyl)-o-phenylenediamido ligands

Redox-active diamido ligands sponsor heterodinuclear TaLi complexes and a TaMe₃ species which undergoes photoreduction to yield a Ta(iv) dimer.

Ortho-phenylene-bridged aryloxy phosphine ligands and their coordination chemistry with tantalum(V)

The lithium complexes RP(3,5-tBu2C6H2OLi)2(THF)4, where R = Ph or iPr, (R[OPO]Li2)2(THF)4, can be converted quantitatively into the protonated forms, R[OPO]H2, by reaction with Et3NHCl. Reaction of the protonated compounds with KH yields the potassium complexes (Ph[OPO]K2)2(THF)6 and (iPr[OPO]K2)3(THF)3. The reaction of R[OPO]H2 with TaCl5 yields the sparingly soluble tantalum trichloride complexes R[OPO]TaCl3 via elimination of HCl. Reaction of Ph[OPO]H2 with TaMe3Cl2 leads to the monomethyl complex Ph[OPO]TaMeCl2, or the dimethyl halide complex, Ph[OPO]TaMe2Cl, via protonolysis, and the potassium complex (Ph[OPO]K2)2(THF)6 yields the trimethyl complex, Ph[OPO]TaMe3 by a metathesis process.