Homo- and Heteropolynuclear Clusters of Phosphine Triphenolates

The
synthesis and structural characterization of a series of homo- and
heteropolynuclear
clusters constructed with a potentially tetradentate phosphine triphenolate
ligand are presented. Treatment of tris­(3,5-di-tert-butyl-2-hydroxyphenyl)­phosphine (H3[O3P])
with 3 equiv of nBuLi in diethyl ether at −35
°C affords hexanuclear Li6[O3P]2(OEt2)2 (1) as colorless crystals.
In situ lithiation of H3[O3P] with 3 equiv of nBuLi in THF at −35 °C followed by metathetical
reactions with MnCl2 or NiCl2(DME) gives crystals
of forest green pentanuclear MnLi4[O3P]2(THF)3 (2) or dark brown tetranuclear
Ni2Li2[O3P]2(THF)2 (3), respectively. Alkane elimination of ZnR2 (R = Me, Et) with H3[O3P] in THF at
25 °C generates high yields of colorless crystalline trinuclear
Zn3[O3P]2(THF)2 (4). The cluster structures of 1–4 were all determined by single crystal X-ray diffraction
studies. These molecules represent the first examples of metal complexes
supported by phosphine triphenolate derivatives. The cluster 2 contains a paramagnetic core of high spin Mn­(II) (S = 5/2) as indicated by solution and solid state magnetic
susceptibility measurements.