A carboxylate-driven assembly strategy has first been developed to build calix[n]arene-based polyoxotitanate clusters with tuneable nuclearity and structures. Photocatalytic studies revealed that those clusters exhibit structural-dependent H2 evolution ability with...

With use of a macrocyclic polyphenol, tert-butylcalix[8]arene (TBC[8]), as ligands, a series of TBC[8]-stabilized {Ti 4 O 2 }clusters, containing penta-and hexacoordinated Ti centers, were synthesized. Such complexes are "core−shell" shaped containing a {Ti 4 O 2 } core arranged in a zigzag fashion. While outer walls of the clusters are decorated by deprotonated TBC[8], their upper and lower surfaces can be modified by various O-or N-donor ligands, and the ratio of the penta-and hexacoordinated Ti(IV) centers in the {Ti 4 O 2 } core can be precisely regulated from 4:0, to 3:1, to 2:2, to 1:3, and finally to 0:4. The combined coordination of different ligands in the axial direction shows significant influence on the adsorption of the TBC[8]-Ti 4 system in the visible-light region, and their absorption edge can be precisely regulated from 600 to 700 nm. The above structural functionalization in the TBC[8]-Ti 4 system also tunes their photocatalytic H 2 production activities and oxidative desulfurization ability. Thus, for the first time, by confining the polyoxotitanium cluster in macrocyclic molecules, we provide an example of understanding the structure−property relationship of titanium−oxygen materials by ligand modification.

Four polyoxouranium-based uranyl carboxylates have been synthesized based on silicon-centered carboxylate linkers. Oligomerization of the uranyl units from tetrameric unit, to octameric motif and ultimately infinite polyoxouranium chain was observed.