• Titanium;
  • Alkoxides;
  • Phosphorus;
  • Hydrolysis;
  • Cluster compounds


The reaction of titanium isopropoxide, Ti(OiPr)4, with bis(trimethylsilyl) phosphonates has led to structures containingTi3O units [= Ti33-O)(μ2-OiPr)3(OiPr)3(O3PR)3] as the basic structural motif. This unit can be capped by a single Ti(OiPr)2L group (L = neutral ligand) through phosphonate bridges (for R = xylyl), or sandwich-like structures can be formed with two Ti3O units bonded to a central Ti atom (for R = CH2CH2CH2Cl or benzyl). For R = allyl or ethyl, dimeric clusters were formed in which two Ti4 cluster units are bridged by isopropyl phosphonate ligands. For comparison, Ti(OiPr)4 was also treated with allylphosphonic acid to yield a Ti4 cluster. The reaction of Ti(OiPr)4 with the bulky bis(trimethylsilyl) 2-naphthylmethyphosphonate did not yield an oxo cluster but instead the phosphonate-substituted titanium alkoxide Ti4(OiPr)8(O3PCH2naphthyl)4.