Multidentate aminophenol ligands prepared with Mannich condensations

Reaction of Al(OiPr)3 with the tris-phenol amine ligand L1H3 in toluene at ambient temperature results in the formation of the iso-propanol adduct [HOiPr.Al(L1)]. Single crystal X-ray diffraction analysis reveals the structure to be a hydrogen bonded dimer. Reaction of Al(OiPr)3 (or AlMe3) with L1H3 in THF affords the related, and structurally characterised THF adduct, [THF.Al(L1)]. Similar reaction of Al(OiPr)3 (or AlMe3) with the bis-phenol amine and tetra-phenol diamine ligands, L2H3 and L3H4, results in the formation and isolation of the complexes [Al(L2)]2 and [Al(L3)H] respectively, both of which have been structurally characterised via single crystal X-ray diffraction studies. Reaction of the alkoxide bridged dimer [Al(L2)]2 with the strong Lewis base HMPA results in the formation of the monomeric HMPA adduct [HMPA.Al(L2)] which was also structurally characterised. The adduct [HOiPr.Al(L1)] and the dimer [Al(L2)]2 were tested for their activity in the ring-opening polymerisation (ROP) of rac-lactide under solvent-free conditions (130 degrees C). Under the conditions employed [Al(L2)]2 failed to produce polymer after 48 h, in stark contrast to [HOiPr.Al(L1)] which after 24 h and 48 h produced narrow molecular weight polymer (24 h: yield=25%, Mn=14500 and PDI=1.05; 48 h: yield=65%, Mn=47700 and PDI=1.06).

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“…[39][40][41] In all cases synthesis of the aluminium complexes was achieved using inert atmosphere techniques.…”

Section: Synthesis Of Ligands and Complexesmentioning

confidence: 99%

Synthesis and structure of aluminium amine-phenolate complexes

et al. 2009

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“…The crystal structure of a V IV complex has also been reported [4]. Other metal complexes of this ligand type have included Zn II [5], Fe III [6], and Ga III [7]. Tetraphenols of this type have been shown to extract gallium from strongly basic solutions containing aluminates [8], giving high selectivity for recovery of Ga III over Al III .…”

mentioning

confidence: 99%

Zirconium complexes of amino(polyphenolic) ligands and their hydrolytic stability

Chartres

Dahir

Tasker

et al. 2007

Inorganic Chemistry Communications

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“…The assembly of complex ligands from multi-component reactions is less common, although in some cases, organic methodology is available. 1,2 Tris(2-aminoethyl)amine (tren) is a commercially available tripodal amine, which has found wide application as a ligand in the preparation of metal complexes. [3][4][5] Due to the tripodal arrangement of donor atoms, tren and a variety of N-functionalised derivatives have been commonly employed in the preparation of trigonal bipyramidal metal complexes.…”

Section: Introductionmentioning

confidence: 99%

“…Using the signals due to DABCO as an internal standard it was possible to plot conversion versus time, Figure 1b, showing the limitation of conversion to product. In all cases, the time at which the integrated area of these diagnostic benzyl CH 2 tion time for larger scale syntheses. Close examination of the 1 H NMR spectra of reaction mixtures of 1a allowed detection of a signal at 4.08 ppm corresponding to 2-(4-nitrobenzyl)phenol, 29 a by-product formed by an aldol condensation between para-nitrobenzaldehyde and cyclohexenone followed by iso-aromatisation.…”

Section: Introductionmentioning

confidence: 99%