Syntheses and Structures of Acetyl‐Acetonato‐Alumo‐Diphenylsilanolates with Magnesium(II), Iron(II), Iron(III), Cobalt(II), and Nickel(II)

Bis(acetylacetonate)alumo‐oxo‐tetraphenyldisiloxane‐metal(II) dihydrates (acac)₂Al(O–SiPh₂–O–SiPh₂–O)]₂M(H₂O)₂ (M = Mg, Fe, Co, Ni) were obtained from the corresponding acetyl‐acetonate‐dihydrates (acac)₂M(H₂O)₂ by reaction with the alumosiloxane O–Ph₂Si–O–SiPh₂–O]₄Al₄(OH)₄. These new compounds display two acac ligands at the aluminum atoms as well as disilatrioxy chains linking the two aluminum atoms forming a (Al–O–Si–O–Si–O)₂ cycle (X‐ray structure analyses). Within this cycle the divalent metal ions M²⁺, to which two water molecules in trans positions are linked, are installed in almost planar MO₄ coordination spheres. Using water free (acac)₂Ni a different product forms: both reactants combine in a 2:1 ratio to yield O–Ph₂Si–O–SiPh₂–O]₄Al₄(OH)₂O(OH₂)Ni₂(acac)₄. Here, three of the acac ligands were transposed to the aluminum atoms. The nickel atoms are in a distorted octahedral coordination mode from oxygen atoms of the ligands. When iron(III)tris(acetylacetonate) reacts with the alumosiloxane O–Ph₂Si–O–SiPh₂–O]₃Al₂O(OH)Fe₂(acac)₃ was isolated, in which the two iron atoms still display one of the acac ligands. One of the aluminum atoms is in a tetrahedral oxygen environment, whereas the other is in the center of a trigonal bi‐pyramid formed of oxygen atoms either of the siloxane or of acac. The iron atoms have five‐ or sixfold coordination from oxygen atoms of siloxane, acac, hydroxide or oxide.