Bulky 2,6-disubstituted aryl esters of phosphoric acid, 2,6-dimethylphenyl phosphate (dmppH(2)), and 2,6-diisopropylphenyl phosphate (dippH(2)) react differently with Cp*TiCl3 (Cp* = C5Me5) under identical reaction conditions. While dippH(2) and Cp*TiCl3 react in THF at 25 degrees C to yield air-stable trinuclear titanophosphate cage [(Ti3Cp*Cl(mu(2)-O) (dipp)(2)(dippH)(4)(THF)].(toluene) (1), the similar reaction involving dmppH2 yields the tetranuclear titanophosphate [Ti4Cl2(mu(2)-O)(2)(dmpp)(2)(dmppH)(6)(THF)(2)].(toluene)(2) (2). Interestingly, the change of titanium source to Ti(OiPr)(4) in the reaction with dippH(2) produces a pentanuclear titanophosphate, [Ti-5(mu(3)-O)(OiPr)(6)((dipp)(6)(THF)] (3). Compounds 1-3 were the only products isolated as single crystals from the respective reaction mixtures in 59, 75, and 54% yield, respectively. The new clusters 1-3 have been characterized by elemental analysis, IR and NMR (H-1 and P-31) spectroscopy, and single crystal X-ray diffraction studies. The structural elucidation reveals that in the reactions leading to 1 and 2, extensive Cp*-Ti bond cleavage occurs, leaving only one residual Cp*-ligand in cluster 1 and none in 2. Closer analysis of the structures of 1-3 shows common structural features which in turn imply that the formation of all three products could have proceeded via a common Ti-O-Ti dimeric building block.