From Monomers to Solids:  Controlled Hydrolysis To Form Novel, Heteroleptic Hydroxide-Containing Complexes

Abstract

Four novel alkaline earth metal tetranuclear aryloxide/pyrazolate hydroxides of the general formula M4(ligand)6(OH)2(donor)n have been prepared by either adding stoichiometric quantities of water to preformed alkaline earth metal aryloxides or in a direct metalation regime combining metal, ligand (alcohol, pyrazole), and donor with stoichiometric amounts of water. The compounds are considered as potential intermediates in the sol-gel process. A nonhydrolyzable magnesium aryloxide has also been obtained using the same reaction scheme. Unexpectedly, a dimeric strontium complex with further association of a second dimer via hydrogen bonding from the solvent of crystallization, ethylenediamine, has been isolated by the treatment of strontium metal with a mixture of alcohol and water. All compounds were characterized using X-ray crystallography, 1H and 13C NMR, and IR spectroscopy.

Surface Organobarium and Organomagnesium Chemistry on Periodic Mesoporous Silica MCM‐41: Convergent and Sequential Approaches Traced by Molecular Models

“…[15] The structural motif of MA C H T U N G T R E N N U N G [m 3 -OH] 2 [OR] 6 (M = Mg, Ca; OR = siloxide, aryloxide) is well known from the literature, whereas the formation of hydroxyl groups has been explained by partial hydrolysis or generated by exposure to M(OH) 2 . [41] The formation of Mg-O-Mg or Mg-OH-Mg surface functionalities is certainly not the primary target of SOMgC, but can display likely reaction pathways when 1) non/incompletely dehydrated support materials are employed, 2) the grafting reaction is performed at elevated temperature, or 3) the hybrid materials are thermally post-treated. Particularly, the thermal degradation of metal alkoxide species to metal oxides is well established.…”

Well‐Defined Silica‐Supported Calcium Reagents: Control of Schlenk Equilibrium by Grafting

“…[20] This particular framework, which also has been observed in several other crystal structures of aryloxide calcium complexes, must be a highly favored structural type. [21] As suggested, the […”

“…[20] The cluster contains two terminal (tBuO) 3 SiO À ligands, while the other four bridge two Ca 2 + ions. All bridging ligands show additional coordination of a tBuO side arm to one of the Ca 2 + ions.…”

Hydrolysis of a (2‐Propanol)yttrium Triiodide Complex in the Presence of Glymes: Synthesis and X‐ray Structures of Hydroxo‐Bridged Dinuclear Yttrium Complexes and Their Applications in Materials Science

“…[3] Hydroxo complexes are also often proposed as intermediates in the degradation pathways of f-element organometallic and coordination compounds. [4] Polynuclear oxo and/or hydroxo complexes of lanthanides with [Ln 4 (µ 3 -OH) 4 ] 8+ , [5] [Ln 6 (µ 6 -O)(µ 3 -OH) 8 (H 2 O) 24 ] 8+ , [6] or [Ln 15 (µ 3 -OH) 20 (µ 5 -X)] 24+ [7] (X = halide) cores have been obtained by direct hydrolysis of lanthanide nitrates, perchlorates, or halides (chloride and iodide) in aqueous media. However, the high charge and polarizing power of lanthanides as well as the absence of any organic auxiliary ligands result in a high tendency to readily hydrolyze, thus making it difficult to control oligomerization of rare-earth centers.…”

“…These compounds are potentially good starting materials for the synthesis of larger yttrium oxo/hydroxo clusters. [24] In addition, their utility as sources of yttrium oxide for high T c superconductors has also been evaluated, and the preliminary results are presented in this paper.…”