Coordination Behavior of N,N'-Bis(diisopropylphosphinoacetyl)-o-phenylenediamide with NiII and CuI Ions.

The reaction of N,N'-bis(diisopropylphosphoniumacetyl)-o-phenylenediamide dibromide (H₄L⋅2Br) with Ni^II[ClO₄]⋅ 6H₂O in the presence of Et₃N resulted in the formation of N,N'-bis(diisopropylphosphinoacetyl)-o-phenylenediamidate nickel(II) ([Ni^II(L)]). The single-crystal X-ray diffraction analysis of [Ni^II(L)] revealed that each pair of N and P atoms in L^2- coordinates in a tetradentate fashion to afford a distorted squareplanar Ni^II amide complex. On the other hand, N,N'-bis(diisopropylphosphinoacetyl)-o-phenylenediamide copper(I) bromide ([Cu^I(H₂L)Br]) was isolated by the reaction of H⁴L⋅2Br with [Cu^I(MeCN)₄][PF₆] in the presence of Et₃N. The structural analysis revealed that the two P atoms in H₂L coordinate in a bidentate fashion to afford a trigonal-planar CuI complex, in which the amide moieties remain in free form. Complex [Ni^II(L)] showed reversible deprotonation processes on the amidate ligand (L^2-), whereas the protonated state of the N atoms of the amide ligand (H₂L) in [Cu^I(H₂L)Br] was maintained, even in the presence of excess Et₃N, suggesting substantial stability for the protonated state. [ABSTRACT FROM AUTHOR]