Structurally characterized aluminum alkoxide derivatives for aerosol spray materials production

A family of aluminum alkyl, alkoxides were synthesized via the reaction of trimethyl aluminum with a variety of ortho-substituted phenols and neopentoxides (homoleptic 7 shown). Single Particle Aerosol Mass Spectrometry (SPAMS) analyses indicated that Al0 particles had been produced by spray pyrolysis instead of the oxide. [Display omitted] •Family of aluminum alkoxides synthesized via the reaction of trimethyl aluminum using a series of sterically varied ortho-substituted phenols.•Homoleptic formed for least sterically hindering; heteroleptic for larger.•Neopentanol (H-ONep) led to the homo- and hetero-leptic species.•Aerosol spray pyrolysis produced amorphous mesoparticles.•Single Particle Aerosol Mass Spectrometry (SPAMS) indicated that Al0 particles produced. The synthesis of a family of aluminum alkoxides was undertaken via the reaction of trimethyl aluminum (Al(CH3)3) using a series of sterically varied ortho-substituted phenols (H-OAr), including: 2-methyl phenol (H-oMP), 2-isopropyl phenol (H-oPP), 2-phenyl phenol (H-oPhP), 2,6-di-methyl phenol (H-DMP), 2,6-di-isopropyl phenol (H-DIP), and 2,6-di-phenyl phenol (H-DPhP). The products isolated using the least sterically encumbered phenoxides proved to generate the homoleptic compounds: [(oMP)Al((μ-oMP)2Al(oMP)2)2] (1), and [Al(μ-oPP)(oPP)2]2 (2), [Al(μ-oPP)(oPP)2(THF)]2 (2-THF), and [Al(μ-oPhP)(oPhP)2]2 (3). As the steric bulk was increased only partial substitution was achieved forming the alkyl, alkoxide compounds: [Al(μ-OAr)(CH3)(OAr)]2 (OAr = trans-DMP (4a), cis-DIP (5a), trans-DPhP (6a)). Sub-stoichiometric metathesis reactions for the smaller OAr ligands were undertaken to produce a series of [Al(CH3)3-x(OAr)x]2 where × = 2: OAr = trans-oMP (1a); x = 1, OAr = oMP (1b), and DMP (4b). Alternatively, the use of neo-pentanol (H-ONep) led to the homoleptic species [(ONep)Al((μ-ONep)2Al(ONep)2)2] (7) and heteroleptic [Al(μ-ONep)(CH3)2]2 (7b). Efforts to generate 7 from [Al(OPri)3]4 resulted in the production of the mixed ligated species [Al4(μ-OPri)6(ONep)6] (8). The compounds were fully characterized using a variety of analytical tools as well as multinuclear NMR (1H, 13C, 27Al) spectroscopy. Select species were used for aerosol spray pyrolysis for the anticipated production of alumina (Al2O3) materials. The final products from 1, 1b, 7, and 7b proved to generate amorphous mesoparticles of size 2.1(0.1), 2.6(0.2), 2.7(0.2), and 2.5(0.2) μm, respectively as determined by SEM and pXRD analyses. Data