Titanatranes Derailed:  Static and Dynamic Triethanolamine Slippage Induced by Polyphenoxide Chelation

Abstract

Aryloxytitanatranes [N(CH(2)CH(2)O)(3)]Ti[OC(6)H(2)-2,4-(t)()Bu(2)-6-CHPh(3)(-)(n)()(C(6)H(2)-3,5-(t)()Bu(2)-2-OH)(n)(-)(1)] (1, n = 1; 2, n = 2; 3, n = 3) containing aryloxides derived from substituted triphenylmethanes are formed in high yield in the reactions of the corresponding phenols with tert-butoxytitanatrane [N(CH(2)CH(2)O)(3)]Ti(O(t)()Bu). The aryloxytitanatranes adopt monomeric, trigonal bipyramidal structures, as confirmed by X-ray crystallography for 1 and 2. The compounds with pendant phenol groups display fluxional behavior due to interchange of the bound phenoxide with the free phenol groups, most likely via a mechanism involving displacement of one arm of the nitrilotriethoxide by the dangling phenol group. The amidotitanatrane [[N(CH(2)CH(2)O)(3)]Ti(NEt(2))](2) reacts with the bisphenol PhCH(C(6)H(2)-3,5-(t)()Bu(2)-2-OH)(2) to give a crystallographically characterized fully metalated cyclic octatitanium complex of the formula [PhCH(C(6)H(2)-3,5-(t)()Bu(2)-2-O)(2)Ti(2)[(OCH(2)CH(2))(3)N](2)](4) (4). The structure of 4 reveals a metallamacrocycle (minimum ring size = 28 members) consisting of four repeating unsymmetrical dititanium units. In each dititanium unit, there is an unprecedented slippage of the nitrilotriethoxide ligand such that both triethanolamine nitrogens coordinate to only one of the two titaniums, while the bisphenoxide is coordinated only to the other titanium. The propensity of the polyphenoxide ligands to chelate is attributed to favorable pi-bonding interactions attainable in the eight-membered chelate rings.

Crystal structure of the salt bis(triethanolamine-κ4N,O,O′,O′′)cadmium bis[2-(2-oxo-2,3-dihydro-1,3-benzothiazol-3-yl)acetate]

“…The interaction of metal ions with TEA results in the formation of complexes in which TEA demonstrates monodentate (Kumar et al, 2014), bidentate (Kapteijn et al, 1997;Long et al, 2004), tridentate (Gao et al, 2004;Ucar et al, 2004;Krabbes et al, 1999;Haukka et al, 2005;Yeşilel et al, 2004;Mirskova et al, 2013) or tetradentate binding modes (Zaitsev et al, 2014;Kazak et al, 2003;Yilmaz et al, 2004;Rickard et al, 1999;Maestri & Brown, 2004;Kovbasyuk et al, 2001;Tudor et al, 2001). In some complexes, TEA has bridging properties (Langley et al, 2011;Atria et al, 2015;Wittick et al, 2006;Sharma et al, 2014;Yang et al, 2014;Funes et al, 2014).…”

Crystal structure of the salt bis(triethanolamine-κ3N,O,O′)cobalt(II) bis[2-(2-oxo-2,3-dihydro-1,3-benzothiazol-3-yl)acetate]

“…Benzothiazole is a precursor for rubber accelerators, a component of cyanine dyes, a slimicide in the paper and pulp industry, and is used in the production of certain fungicides, herbicides, antifungal agents and pharmaceuticals (Bellavia et al, 2000;Seo et al, 2000). The interaction of metal ions with TEA results in the formation of complexes in which TEA demonstrates monodentate (Kumar et al, 2014), bidentate (Kapteijn et al, 1997), tridentate (Gao et al, 2004;Ucar et al, 2004;Topcu et al, 2001;Krabbes et al, 1999;Haukka et al, 2005;Yeşilel et al, 2004;Mirskova et al, 2013) and tetradentate binding (Zaitsev et al, 2014;Kazak et al, 2003;Yilmaz et al, 2004;Langley et al, 2011;Rickard et al, 1999;Maestri & Brown, 2004;Kovbasyuk et al, 2001;Tudor et al, 2001). In some complexes, TEA can show bridging properties (Atria et al, 2015;Wittick et al, 2006;Sharma et al, 2014;Yang et al, 2014;Funes et al, 2014).…”

Vanadium(v) tetra-phenolate complexes: synthesis, structural studies and ethylene homo-(co-)polymerization capability

“…Indeed, there was only one example of the previous use of the parent L 3 H 2, which was a report of its utilization in titanium chemistry. [17,19] Figure 9. Representation of the molecular structure of complex 8, indicating the atom numbering scheme.…”