Titanium(IV) and zirconium(IV) sulfato complexes containing the Kläui tripodal ligand: Molecular models of sulfated metal oxide surfaces

Qian Feng Zhang, Tony C.H. Lam, Xiao Yi Yi, Eddie Y.Y. Chan, Wai Yeung Wong, Herman H.Y. Sung, Ian D. Williams, Wa Hung Leung

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22 Citations (Scopus)

Abstract

Treatment of titanyl sulfate in about 60 nM sulfuric acid with NaL, (LOEt= [(η5-C5H5)Co-{(P(O)(OEt)2}3]-) afforded the μ-sulfato complex [(LOEtOEtTi)2(μ-O)2(μ-SO4)] (2). In more concentrated sulfuric acid (> 1 M), the same reaction yielded the di-μ-sulfato complex [(LOEtTi)2(μ-O)(μ-SO4)2] (3). Reaction of 2 with HOTf (OTf = triflate, CF3SO3) gave the tris-(triflato) complex [LOEtTi(OTf)3] (4), whereas treatment of 2 with Ag(OTf) in CH2Cl2afforded the sulfato-capped trinuclear complex [{(LOEt)3Ti3(μ-O)3}(μ3-SO4){Ag(OTf)}][OTf] (5), in which the Ag(OTf) moiety binds to a μ-oxo group in the Ti3(μ-O)3core. Reaction of 2 in H2O with Ba(NO3)2afforded the tetranuclear complex (LOEt)4Ti4(μ-O)6(6). Treatment of 2 with [{Rh(cod)Cl}2] (cod = 1,5-cyclooctadiene), [Re(CO)5Cl], and [Ru(tBu2-bpy)(PPh3)2Cl2] (tBu2bpy = 4,4′-dl-tert-butyl-2,2′-dipyridyl) in the presence of Ag(OTf) afforded the heterometallic complexes [(LOEt)2Ti2(O)2(SO4){Rh- (cod)}2][OTf]2(7), [(LOEt)2Ti(O)2-(SO4){Re(CO)3}][OTf] (8), and [{(LOEt)2Ti2(μ-O)}(μ3-SO4)(μ-O)2{Ru-(PPh3)(tBu2bpy)}] [OTf]2(9), respectively. Complex 9 is paramagnetic with a measured magnetic moment of about 2.4 μB. Treatment of zirconyl nitrate with NaLOEtin 3.5 M sulfuric acid afforded [(LOEt)2Zr(NO3)][LOEtZr(SO4)-(NO3)] (10). Reaction of ZrCl4in 1.8 M sulfuric acid with NaLOEtin the presence Na2SO4gave the μ-sulfato-bridged complex [LOEtZr(SO4)(H2O)]2(μ-SO4) (11). Treatment of 11 with triflic acid afforded [(LOEt)2Zr][OTf]2(12), whereas reaction of 11 with Ag(OTf) afforded a mixture of 12 and trinuclear [{LOEtZr(SO4)(H2O)}3(μ3-SO4)][OTf] (13). The ZrIVtriflato complex [LOEtZr-(OTf)3] (14) was prepared by reaction of LOEtZrF3with Me3SiOTf. Complexes 4 and 14 can catalyze the Diels-Alder reaction of 1,3-cyclohexadiene with acrolein in good selectivity. Complexes 2-5, 9-11, and 13 have been characterized by X-ray crystallography.
Original languageEnglish
Pages (from-to)101-111
Number of pages11
JournalChemistry - A European Journal
Volume11
Issue number1
DOIs
Publication statusPublished - 18 Jan 2005
Externally publishedYes

Keywords

  • O ligands
  • P ligands
  • Sulfates
  • Titanium
  • Zirconium

ASJC Scopus subject areas

  • Chemistry(all)

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